// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * Copyright (c) 2013 Red Hat, Inc.
 * All Rights Reserved.
 */
#include "xfs_platform.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_attr_sf.h"
#include "xfs_attr.h"
#include "xfs_attr_remote.h"
#include "xfs_attr_leaf.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_buf_item.h"
#include "xfs_dir2.h"
#include "xfs_log.h"
#include "xfs_ag.h"
#include "xfs_errortag.h"
#include "xfs_health.h"


/*
 * xfs_attr_leaf.c
 *
 * Routines to implement leaf blocks of attributes as Btrees of hashed names.
 */

/*========================================================================
 * Function prototypes for the kernel.
 *========================================================================*/

/*
 * Routines used for growing the Btree.
 */
STATIC int xfs_attr3_leaf_create(struct xfs_da_args *args,
                                 xfs_dablk_t which_block, struct xfs_buf **bpp);
STATIC void xfs_attr3_leaf_add_work(struct xfs_buf *leaf_buffer,
                                   struct xfs_attr3_icleaf_hdr *ichdr,
                                   struct xfs_da_args *args, int freemap_index);
STATIC void xfs_attr3_leaf_compact(struct xfs_da_args *args,
                                   struct xfs_attr3_icleaf_hdr *ichdr,
                                   struct xfs_buf *leaf_buffer);
STATIC void xfs_attr3_leaf_rebalance(xfs_da_state_t *state,
                                                   xfs_da_state_blk_t *blk1,
                                                   xfs_da_state_blk_t *blk2);
STATIC int xfs_attr3_leaf_figure_balance(xfs_da_state_t *state,
                        xfs_da_state_blk_t *leaf_blk_1,
                        struct xfs_attr3_icleaf_hdr *ichdr1,
                        xfs_da_state_blk_t *leaf_blk_2,
                        struct xfs_attr3_icleaf_hdr *ichdr2,
                        int *number_entries_in_blk1,
                        int *number_usedbytes_in_blk1);

/*
 * Utility routines.
 */
STATIC void xfs_attr3_leaf_moveents(struct xfs_da_args *args,
                        struct xfs_attr_leafblock *src_leaf,
                        struct xfs_attr3_icleaf_hdr *src_ichdr, int src_start,
                        struct xfs_attr_leafblock *dst_leaf,
                        struct xfs_attr3_icleaf_hdr *dst_ichdr, int dst_start,
                        int move_count);
STATIC int xfs_attr_leaf_entsize(xfs_attr_leafblock_t *leaf, int index);

/* Compute the byte offset of the end of the leaf entry array. */
static inline int
xfs_attr_leaf_entries_end(
        unsigned int                    hdrcount,
        const struct xfs_attr_leafblock *leaf)
{
        return hdrcount * sizeof(struct xfs_attr_leaf_entry) +
                        xfs_attr3_leaf_hdr_size(leaf);
}

static inline bool
ichdr_freemaps_overlap(
        const struct xfs_attr3_icleaf_hdr       *ichdr,
        unsigned int                            x,
        unsigned int                            y)
{
        const unsigned int                      xend =
                ichdr->freemap[x].base + ichdr->freemap[x].size;
        const unsigned int                      yend =
                ichdr->freemap[y].base + ichdr->freemap[y].size;

        /* empty slots do not overlap */
        if (!ichdr->freemap[x].size || !ichdr->freemap[y].size)
                return false;

        return ichdr->freemap[x].base < yend && xend > ichdr->freemap[y].base;
}

static inline xfs_failaddr_t
xfs_attr_leaf_ichdr_freemaps_verify(
        const struct xfs_attr3_icleaf_hdr       *ichdr,
        const struct xfs_attr_leafblock         *leaf)
{
        unsigned int                            entries_end =
                xfs_attr_leaf_entries_end(ichdr->count, leaf);
        int                                     i;

        if (ichdr_freemaps_overlap(ichdr, 0, 1))
                return __this_address;
        if (ichdr_freemaps_overlap(ichdr, 0, 2))
                return __this_address;
        if (ichdr_freemaps_overlap(ichdr, 1, 2))
                return __this_address;

        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                if (ichdr->freemap[i].size > 0 &&
                    ichdr->freemap[i].base < entries_end)
                        return __this_address;
        }

        return NULL;
}

/*
 * attr3 block 'firstused' conversion helpers.
 *
 * firstused refers to the offset of the first used byte of the nameval region
 * of an attr leaf block. The region starts at the tail of the block and expands
 * backwards towards the middle. As such, firstused is initialized to the block
 * size for an empty leaf block and is reduced from there.
 *
 * The attr3 block size is pegged to the fsb size and the maximum fsb is 64k.
 * The in-core firstused field is 32-bit and thus supports the maximum fsb size.
 * The on-disk field is only 16-bit, however, and overflows at 64k. Since this
 * only occurs at exactly 64k, we use zero as a magic on-disk value to represent
 * the attr block size. The following helpers manage the conversion between the
 * in-core and on-disk formats.
 */

static void
xfs_attr3_leaf_firstused_from_disk(
        struct xfs_da_geometry          *geo,
        struct xfs_attr3_icleaf_hdr     *to,
        struct xfs_attr_leafblock       *from)
{
        struct xfs_attr3_leaf_hdr       *hdr3;

        if (from->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) {
                hdr3 = (struct xfs_attr3_leaf_hdr *) from;
                to->firstused = be16_to_cpu(hdr3->firstused);
        } else {
                to->firstused = be16_to_cpu(from->hdr.firstused);
        }

        /*
         * Convert from the magic fsb size value to actual blocksize. This
         * should only occur for empty blocks when the block size overflows
         * 16-bits.
         */
        if (to->firstused == XFS_ATTR3_LEAF_NULLOFF) {
                ASSERT(!to->count && !to->usedbytes);
                ASSERT(geo->blksize > USHRT_MAX);
                to->firstused = geo->blksize;
        }
}

static void
xfs_attr3_leaf_firstused_to_disk(
        struct xfs_da_geometry          *geo,
        struct xfs_attr_leafblock       *to,
        struct xfs_attr3_icleaf_hdr     *from)
{
        struct xfs_attr3_leaf_hdr       *hdr3;
        uint32_t                        firstused;

        /* magic value should only be seen on disk */
        ASSERT(from->firstused != XFS_ATTR3_LEAF_NULLOFF);

        /*
         * Scale down the 32-bit in-core firstused value to the 16-bit on-disk
         * value. This only overflows at the max supported value of 64k. Use the
         * magic on-disk value to represent block size in this case.
         */
        firstused = from->firstused;
        if (firstused > USHRT_MAX) {
                ASSERT(from->firstused == geo->blksize);
                firstused = XFS_ATTR3_LEAF_NULLOFF;
        }

        if (from->magic == XFS_ATTR3_LEAF_MAGIC) {
                hdr3 = (struct xfs_attr3_leaf_hdr *) to;
                hdr3->firstused = cpu_to_be16(firstused);
        } else {
                to->hdr.firstused = cpu_to_be16(firstused);
        }
}

void
xfs_attr3_leaf_hdr_from_disk(
        struct xfs_da_geometry          *geo,
        struct xfs_attr3_icleaf_hdr     *to,
        struct xfs_attr_leafblock       *from)
{
        int     i;

        ASSERT(from->hdr.info.magic == cpu_to_be16(XFS_ATTR_LEAF_MAGIC) ||
               from->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC));

        if (from->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) {
                struct xfs_attr3_leaf_hdr *hdr3 = (struct xfs_attr3_leaf_hdr *)from;

                to->forw = be32_to_cpu(hdr3->info.hdr.forw);
                to->back = be32_to_cpu(hdr3->info.hdr.back);
                to->magic = be16_to_cpu(hdr3->info.hdr.magic);
                to->count = be16_to_cpu(hdr3->count);
                to->usedbytes = be16_to_cpu(hdr3->usedbytes);
                xfs_attr3_leaf_firstused_from_disk(geo, to, from);
                to->holes = hdr3->holes;

                for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                        to->freemap[i].base = be16_to_cpu(hdr3->freemap[i].base);
                        to->freemap[i].size = be16_to_cpu(hdr3->freemap[i].size);
                }
                return;
        }
        to->forw = be32_to_cpu(from->hdr.info.forw);
        to->back = be32_to_cpu(from->hdr.info.back);
        to->magic = be16_to_cpu(from->hdr.info.magic);
        to->count = be16_to_cpu(from->hdr.count);
        to->usedbytes = be16_to_cpu(from->hdr.usedbytes);
        xfs_attr3_leaf_firstused_from_disk(geo, to, from);
        to->holes = from->hdr.holes;

        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                to->freemap[i].base = be16_to_cpu(from->hdr.freemap[i].base);
                to->freemap[i].size = be16_to_cpu(from->hdr.freemap[i].size);
        }
}

void
xfs_attr3_leaf_hdr_to_disk(
        struct xfs_da_geometry          *geo,
        struct xfs_attr_leafblock       *to,
        struct xfs_attr3_icleaf_hdr     *from)
{
        int                             i;

        ASSERT(from->magic == XFS_ATTR_LEAF_MAGIC ||
               from->magic == XFS_ATTR3_LEAF_MAGIC);

        if (from->magic == XFS_ATTR3_LEAF_MAGIC) {
                struct xfs_attr3_leaf_hdr *hdr3 = (struct xfs_attr3_leaf_hdr *)to;

                hdr3->info.hdr.forw = cpu_to_be32(from->forw);
                hdr3->info.hdr.back = cpu_to_be32(from->back);
                hdr3->info.hdr.magic = cpu_to_be16(from->magic);
                hdr3->count = cpu_to_be16(from->count);
                hdr3->usedbytes = cpu_to_be16(from->usedbytes);
                xfs_attr3_leaf_firstused_to_disk(geo, to, from);
                hdr3->holes = from->holes;
                hdr3->pad1 = 0;

                for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                        hdr3->freemap[i].base = cpu_to_be16(from->freemap[i].base);
                        hdr3->freemap[i].size = cpu_to_be16(from->freemap[i].size);
                }

                ASSERT(xfs_attr_leaf_ichdr_freemaps_verify(from, to) == NULL);
                return;
        }
        to->hdr.info.forw = cpu_to_be32(from->forw);
        to->hdr.info.back = cpu_to_be32(from->back);
        to->hdr.info.magic = cpu_to_be16(from->magic);
        to->hdr.count = cpu_to_be16(from->count);
        to->hdr.usedbytes = cpu_to_be16(from->usedbytes);
        xfs_attr3_leaf_firstused_to_disk(geo, to, from);
        to->hdr.holes = from->holes;
        to->hdr.pad1 = 0;

        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                to->hdr.freemap[i].base = cpu_to_be16(from->freemap[i].base);
                to->hdr.freemap[i].size = cpu_to_be16(from->freemap[i].size);
        }

        ASSERT(xfs_attr_leaf_ichdr_freemaps_verify(from, to) == NULL);
}

static xfs_failaddr_t
xfs_attr3_leaf_verify_entry(
        struct xfs_mount                        *mp,
        char                                    *buf_end,
        struct xfs_attr_leafblock               *leaf,
        struct xfs_attr3_icleaf_hdr             *leafhdr,
        struct xfs_attr_leaf_entry              *ent,
        int                                     idx,
        __u32                                   *last_hashval)
{
        struct xfs_attr_leaf_name_local         *lentry;
        struct xfs_attr_leaf_name_remote        *rentry;
        char                                    *name_end;
        unsigned int                            nameidx;
        unsigned int                            namesize;
        __u32                                   hashval;

        /* hash order check */
        hashval = be32_to_cpu(ent->hashval);
        if (hashval < *last_hashval)
                return __this_address;
        *last_hashval = hashval;

        nameidx = be16_to_cpu(ent->nameidx);
        if (nameidx < leafhdr->firstused || nameidx >= mp->m_attr_geo->blksize)
                return __this_address;

        /*
         * Check the name information.  The namelen fields are u8 so we can't
         * possibly exceed the maximum name length of 255 bytes.
         */
        if (ent->flags & XFS_ATTR_LOCAL) {
                lentry = xfs_attr3_leaf_name_local(leaf, idx);
                namesize = xfs_attr_leaf_entsize_local(lentry->namelen,
                                be16_to_cpu(lentry->valuelen));
                name_end = (char *)lentry + namesize;
                if (lentry->namelen == 0)
                        return __this_address;
        } else {
                rentry = xfs_attr3_leaf_name_remote(leaf, idx);
                namesize = xfs_attr_leaf_entsize_remote(rentry->namelen);
                name_end = (char *)rentry + namesize;
                if (rentry->namelen == 0)
                        return __this_address;
                if (!(ent->flags & XFS_ATTR_INCOMPLETE) &&
                    rentry->valueblk == 0)
                        return __this_address;
        }

        if (name_end > buf_end)
                return __this_address;

        return NULL;
}

/*
 * Validate an attribute leaf block.
 *
 * Empty leaf blocks can occur under the following circumstances:
 *
 * 1. setxattr adds a new extended attribute to a file;
 * 2. The file has zero existing attributes;
 * 3. The attribute is too large to fit in the attribute fork;
 * 4. The attribute is small enough to fit in a leaf block;
 * 5. A log flush occurs after committing the transaction that creates
 *    the (empty) leaf block; and
 * 6. The filesystem goes down after the log flush but before the new
 *    attribute can be committed to the leaf block.
 *
 * Hence we need to ensure that we don't fail the validation purely
 * because the leaf is empty.
 */
static xfs_failaddr_t
xfs_attr3_leaf_verify(
        struct xfs_buf                  *bp)
{
        struct xfs_attr3_icleaf_hdr     ichdr;
        struct xfs_mount                *mp = bp->b_mount;
        struct xfs_attr_leafblock       *leaf = bp->b_addr;
        struct xfs_attr_leaf_entry      *entries;
        struct xfs_attr_leaf_entry      *ent;
        char                            *buf_end;
        uint32_t                        end;    /* must be 32bit - see below */
        __u32                           last_hashval = 0;
        int                             i;
        xfs_failaddr_t                  fa;

        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);

        fa = xfs_da3_blkinfo_verify(bp, bp->b_addr);
        if (fa)
                return fa;

        /*
         * firstused is the block offset of the first name info structure.
         * Make sure it doesn't go off the block or crash into the header.
         */
        if (ichdr.firstused > mp->m_attr_geo->blksize)
                return __this_address;
        if (ichdr.firstused < xfs_attr3_leaf_hdr_size(leaf))
                return __this_address;

        /* Make sure the entries array doesn't crash into the name info. */
        entries = xfs_attr3_leaf_entryp(bp->b_addr);
        if ((char *)&entries[ichdr.count] >
            (char *)bp->b_addr + ichdr.firstused)
                return __this_address;

        /*
         * NOTE: This verifier historically failed empty leaf buffers because
         * we expect the fork to be in another format. Empty attr fork format
         * conversions are possible during xattr set, however, and format
         * conversion is not atomic with the xattr set that triggers it. We
         * cannot assume leaf blocks are non-empty until that is addressed.
        */
        buf_end = (char *)bp->b_addr + mp->m_attr_geo->blksize;
        for (i = 0, ent = entries; i < ichdr.count; ent++, i++) {
                fa = xfs_attr3_leaf_verify_entry(mp, buf_end, leaf, &ichdr,
                                ent, i, &last_hashval);
                if (fa)
                        return fa;
        }

        /*
         * Quickly check the freemap information.  Attribute data has to be
         * aligned to 4-byte boundaries, and likewise for the free space.
         *
         * Note that for 64k block size filesystems, the freemap entries cannot
         * overflow as they are only be16 fields. However, when checking end
         * pointer of the freemap, we have to be careful to detect overflows and
         * so use uint32_t for those checks.
         */
        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                if (ichdr.freemap[i].base > mp->m_attr_geo->blksize)
                        return __this_address;
                if (ichdr.freemap[i].base & 0x3)
                        return __this_address;
                if (ichdr.freemap[i].size > mp->m_attr_geo->blksize)
                        return __this_address;
                if (ichdr.freemap[i].size & 0x3)
                        return __this_address;

                /* be care of 16 bit overflows here */
                end = (uint32_t)ichdr.freemap[i].base + ichdr.freemap[i].size;
                if (end < ichdr.freemap[i].base)
                        return __this_address;
                if (end > mp->m_attr_geo->blksize)
                        return __this_address;
        }

        fa = xfs_attr_leaf_ichdr_freemaps_verify(&ichdr, leaf);
        if (fa)
                return fa;

        return NULL;
}

xfs_failaddr_t
xfs_attr3_leaf_header_check(
        struct xfs_buf          *bp,
        xfs_ino_t               owner)
{
        struct xfs_mount        *mp = bp->b_mount;

        if (xfs_has_crc(mp)) {
                struct xfs_attr3_leafblock *hdr3 = bp->b_addr;

                if (hdr3->hdr.info.hdr.magic !=
                                cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
                        return __this_address;

                if (be64_to_cpu(hdr3->hdr.info.owner) != owner)
                        return __this_address;
        }

        return NULL;
}

static void
xfs_attr3_leaf_write_verify(
        struct xfs_buf  *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        struct xfs_buf_log_item *bip = bp->b_log_item;
        struct xfs_attr3_leaf_hdr *hdr3 = bp->b_addr;
        xfs_failaddr_t          fa;

        fa = xfs_attr3_leaf_verify(bp);
        if (fa) {
                xfs_verifier_error(bp, -EFSCORRUPTED, fa);
                return;
        }

        if (!xfs_has_crc(mp))
                return;

        if (bip)
                hdr3->info.lsn = cpu_to_be64(bip->bli_item.li_lsn);

        xfs_buf_update_cksum(bp, XFS_ATTR3_LEAF_CRC_OFF);
}

/*
 * leaf/node format detection on trees is sketchy, so a node read can be done on
 * leaf level blocks when detection identifies the tree as a node format tree
 * incorrectly. In this case, we need to swap the verifier to match the correct
 * format of the block being read.
 */
static void
xfs_attr3_leaf_read_verify(
        struct xfs_buf          *bp)
{
        struct xfs_mount        *mp = bp->b_mount;
        xfs_failaddr_t          fa;

        if (xfs_has_crc(mp) &&
             !xfs_buf_verify_cksum(bp, XFS_ATTR3_LEAF_CRC_OFF))
                xfs_verifier_error(bp, -EFSBADCRC, __this_address);
        else {
                fa = xfs_attr3_leaf_verify(bp);
                if (fa)
                        xfs_verifier_error(bp, -EFSCORRUPTED, fa);
        }
}

const struct xfs_buf_ops xfs_attr3_leaf_buf_ops = {
        .name = "xfs_attr3_leaf",
        .magic16 = { cpu_to_be16(XFS_ATTR_LEAF_MAGIC),
                     cpu_to_be16(XFS_ATTR3_LEAF_MAGIC) },
        .verify_read = xfs_attr3_leaf_read_verify,
        .verify_write = xfs_attr3_leaf_write_verify,
        .verify_struct = xfs_attr3_leaf_verify,
};

int
xfs_attr3_leaf_read(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_ino_t               owner,
        xfs_dablk_t             bno,
        struct xfs_buf          **bpp)
{
        xfs_failaddr_t          fa;
        int                     err;

        err = xfs_da_read_buf(tp, dp, bno, 0, bpp, XFS_ATTR_FORK,
                        &xfs_attr3_leaf_buf_ops);
        if (err || !(*bpp))
                return err;

        fa = xfs_attr3_leaf_header_check(*bpp, owner);
        if (fa) {
                __xfs_buf_mark_corrupt(*bpp, fa);
                xfs_trans_brelse(tp, *bpp);
                *bpp = NULL;
                xfs_dirattr_mark_sick(dp, XFS_ATTR_FORK);
                return -EFSCORRUPTED;
        }

        if (tp)
                xfs_trans_buf_set_type(tp, *bpp, XFS_BLFT_ATTR_LEAF_BUF);
        return 0;
}

/*========================================================================
 * Namespace helper routines
 *========================================================================*/

/*
 * If we are in log recovery, then we want the lookup to ignore the INCOMPLETE
 * flag on disk - if there's an incomplete attr then recovery needs to tear it
 * down. If there's no incomplete attr, then recovery needs to tear that attr
 * down to replace it with the attr that has been logged. In this case, the
 * INCOMPLETE flag will not be set in attr->attr_filter, but rather
 * XFS_DA_OP_RECOVERY will be set in args->op_flags.
 */
static inline unsigned int xfs_attr_match_mask(const struct xfs_da_args *args)
{
        if (args->op_flags & XFS_DA_OP_RECOVERY)
                return XFS_ATTR_NSP_ONDISK_MASK;
        return XFS_ATTR_NSP_ONDISK_MASK | XFS_ATTR_INCOMPLETE;
}

static inline bool
xfs_attr_parent_match(
        const struct xfs_da_args        *args,
        const void                      *value,
        unsigned int                    valuelen)
{
        ASSERT(args->value != NULL);

        /* Parent pointers do not use remote values */
        if (!value)
                return false;

        /*
         * The only value we support is a parent rec.  However, we'll accept
         * any valuelen so that offline repair can delete ATTR_PARENT values
         * that are not parent pointers.
         */
        if (valuelen != args->valuelen)
                return false;

        return memcmp(args->value, value, valuelen) == 0;
}

static bool
xfs_attr_match(
        struct xfs_da_args      *args,
        unsigned int            attr_flags,
        const unsigned char     *name,
        unsigned int            namelen,
        const void              *value,
        unsigned int            valuelen)
{
        unsigned int            mask = xfs_attr_match_mask(args);

        if (args->namelen != namelen)
                return false;
        if ((args->attr_filter & mask) != (attr_flags & mask))
                return false;
        if (memcmp(args->name, name, namelen) != 0)
                return false;

        if (attr_flags & XFS_ATTR_PARENT)
                return xfs_attr_parent_match(args, value, valuelen);

        return true;
}

static int
xfs_attr_copy_value(
        struct xfs_da_args      *args,
        unsigned char           *value,
        int                     valuelen)
{
        /*
         * Parent pointer lookups require the caller to specify the name and
         * value, so don't copy anything.
         */
        if (args->attr_filter & XFS_ATTR_PARENT)
                return 0;

        /*
         * No copy if all we have to do is get the length
         */
        if (!args->valuelen) {
                args->valuelen = valuelen;
                return 0;
        }

        /*
         * No copy if the length of the existing buffer is too small
         */
        if (args->valuelen < valuelen) {
                args->valuelen = valuelen;
                return -ERANGE;
        }

        if (!args->value) {
                args->value = kvmalloc(valuelen, GFP_KERNEL | __GFP_NOLOCKDEP);
                if (!args->value)
                        return -ENOMEM;
        }
        args->valuelen = valuelen;

        /* remote block xattr requires IO for copy-in */
        if (args->rmtblkno)
                return xfs_attr_rmtval_get(args);

        /*
         * This is to prevent a GCC warning because the remote xattr case
         * doesn't have a value to pass in. In that case, we never reach here,
         * but GCC can't work that out and so throws a "passing NULL to
         * memcpy" warning.
         */
        if (!value)
                return -EINVAL;
        memcpy(args->value, value, valuelen);
        return 0;
}

/*========================================================================
 * External routines when attribute fork size < XFS_LITINO(mp).
 *========================================================================*/

/*
 * Query whether the total requested number of attr fork bytes of extended
 * attribute space will be able to fit inline.
 *
 * Returns zero if not, else the i_forkoff fork offset to be used in the
 * literal area for attribute data once the new bytes have been added.
 *
 * i_forkoff must be 8 byte aligned, hence is stored as a >>3 value;
 * special case for dev/uuid inodes, they have fixed size data forks.
 */
int
xfs_attr_shortform_bytesfit(
        struct xfs_inode        *dp,
        int                     bytes)
{
        struct xfs_mount        *mp = dp->i_mount;
        int64_t                 dsize;
        int                     minforkoff;
        int                     maxforkoff;
        int                     offset;

        /*
         * Check if the new size could fit at all first:
         */
        if (bytes > XFS_LITINO(mp))
                return 0;

        /* rounded down */
        offset = (XFS_LITINO(mp) - bytes) >> 3;

        if (dp->i_df.if_format == XFS_DINODE_FMT_DEV) {
                minforkoff = roundup(sizeof(xfs_dev_t), 8) >> 3;
                return (offset >= minforkoff) ? minforkoff : 0;
        }

        /*
         * If the requested numbers of bytes is smaller or equal to the
         * current attribute fork size we can always proceed.
         *
         * Note that if_bytes in the data fork might actually be larger than
         * the current data fork size is due to delalloc extents. In that
         * case either the extent count will go down when they are converted
         * to real extents, or the delalloc conversion will take care of the
         * literal area rebalancing.
         */
        if (bytes <= xfs_inode_attr_fork_size(dp))
                return dp->i_forkoff;

        /*
         * For attr2 we can try to move the forkoff if there is space in the
         * literal area
         */
        dsize = dp->i_df.if_bytes;

        switch (dp->i_df.if_format) {
        case XFS_DINODE_FMT_EXTENTS:
                /*
                 * If there is no attr fork and the data fork is extents,
                 * determine if creating the default attr fork will result
                 * in the extents form migrating to btree. If so, the
                 * minimum offset only needs to be the space required for
                 * the btree root.
                 */
                if (!dp->i_forkoff && dp->i_df.if_bytes >
                    xfs_default_attroffset(dp))
                        dsize = xfs_bmdr_space_calc(MINDBTPTRS);
                break;
        case XFS_DINODE_FMT_BTREE:
                /*
                 * If we have a data btree then keep forkoff if we have one,
                 * otherwise we are adding a new attr, so then we set
                 * minforkoff to where the btree root can finish so we have
                 * plenty of room for attrs
                 */
                if (dp->i_forkoff) {
                        if (offset < dp->i_forkoff)
                                return 0;
                        return dp->i_forkoff;
                }
                dsize = xfs_bmap_bmdr_space(dp->i_df.if_broot);
                break;
        }

        /*
         * A data fork btree root must have space for at least
         * MINDBTPTRS key/ptr pairs if the data fork is small or empty.
         */
        minforkoff = max_t(int64_t, dsize, xfs_bmdr_space_calc(MINDBTPTRS));
        minforkoff = roundup(minforkoff, 8) >> 3;

        /* attr fork btree root can have at least this many key/ptr pairs */
        maxforkoff = XFS_LITINO(mp) - xfs_bmdr_space_calc(MINABTPTRS);
        maxforkoff = maxforkoff >> 3;   /* rounded down */

        if (offset >= maxforkoff)
                return maxforkoff;
        if (offset >= minforkoff)
                return offset;
        return 0;
}

/*
 * Switch on the ATTR2 superblock bit (implies also FEATURES2) unless
 * on-disk version bit says it is already set
 */
STATIC void
xfs_sbversion_add_attr2(
        struct xfs_mount        *mp,
        struct xfs_trans        *tp)
{
        if (mp->m_sb.sb_features2 & XFS_SB_VERSION2_ATTR2BIT)
                return;

        spin_lock(&mp->m_sb_lock);
        xfs_add_attr2(mp);
        spin_unlock(&mp->m_sb_lock);
        xfs_log_sb(tp);
}

/*
 * Create the initial contents of a shortform attribute list.
 */
void
xfs_attr_shortform_create(
        struct xfs_da_args      *args)
{
        struct xfs_inode        *dp = args->dp;
        struct xfs_ifork        *ifp = &dp->i_af;
        struct xfs_attr_sf_hdr  *hdr;

        trace_xfs_attr_sf_create(args);

        ASSERT(ifp->if_bytes == 0);
        if (ifp->if_format == XFS_DINODE_FMT_EXTENTS)
                ifp->if_format = XFS_DINODE_FMT_LOCAL;

        hdr = xfs_idata_realloc(dp, sizeof(*hdr), XFS_ATTR_FORK);
        memset(hdr, 0, sizeof(*hdr));
        hdr->totsize = cpu_to_be16(sizeof(*hdr));
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);
}

/*
 * Return the entry if the attr in args is found, or NULL if not.
 */
struct xfs_attr_sf_entry *
xfs_attr_sf_findname(
        struct xfs_da_args              *args)
{
        struct xfs_attr_sf_hdr          *sf = args->dp->i_af.if_data;
        struct xfs_attr_sf_entry        *sfe;

        for (sfe = xfs_attr_sf_firstentry(sf);
             sfe < xfs_attr_sf_endptr(sf);
             sfe = xfs_attr_sf_nextentry(sfe)) {
                if (xfs_attr_match(args, sfe->flags, sfe->nameval,
                                sfe->namelen, &sfe->nameval[sfe->namelen],
                                sfe->valuelen))
                        return sfe;
        }

        return NULL;
}

/*
 * Replace a shortform xattr if it's the right length.  Returns 0 on success,
 * -ENOSPC if the length is wrong, or -ENOATTR if the attr was not found.
 */
int
xfs_attr_shortform_replace(
        struct xfs_da_args              *args)
{
        struct xfs_attr_sf_entry        *sfe;

        ASSERT(args->dp->i_af.if_format == XFS_DINODE_FMT_LOCAL);

        trace_xfs_attr_sf_replace(args);

        sfe = xfs_attr_sf_findname(args);
        if (!sfe)
                return -ENOATTR;

        if (args->attr_filter & XFS_ATTR_PARENT) {
                if (sfe->namelen != args->new_namelen ||
                    sfe->valuelen != args->new_valuelen)
                        return -ENOSPC;

                memcpy(sfe->nameval, args->new_name, sfe->namelen);
                memcpy(&sfe->nameval[sfe->namelen], args->new_value,
                                sfe->valuelen);
        } else {
                if (sfe->valuelen != args->valuelen)
                        return -ENOSPC;
                memcpy(&sfe->nameval[sfe->namelen], args->value,
                                sfe->valuelen);
        }

        xfs_trans_log_inode(args->trans, args->dp,
                        XFS_ILOG_CORE | XFS_ILOG_ADATA);
        return 0;
}

/*
 * Add a name/value pair to the shortform attribute list.
 * Overflow from the inode has already been checked for.
 */
void
xfs_attr_shortform_add(
        struct xfs_da_args              *args,
        int                             forkoff)
{
        struct xfs_inode                *dp = args->dp;
        struct xfs_mount                *mp = dp->i_mount;
        struct xfs_ifork                *ifp = &dp->i_af;
        struct xfs_attr_sf_hdr          *sf = ifp->if_data;
        struct xfs_attr_sf_entry        *sfe;
        int                             size;

        trace_xfs_attr_sf_add(args);

        dp->i_forkoff = forkoff;

        ASSERT(ifp->if_format == XFS_DINODE_FMT_LOCAL);
        ASSERT(!xfs_attr_sf_findname(args));

        size = xfs_attr_sf_entsize_byname(args->namelen, args->valuelen);
        sf = xfs_idata_realloc(dp, size, XFS_ATTR_FORK);

        sfe = xfs_attr_sf_endptr(sf);
        sfe->namelen = args->namelen;
        sfe->valuelen = args->valuelen;
        sfe->flags = args->attr_filter;
        memcpy(sfe->nameval, args->name, args->namelen);
        memcpy(&sfe->nameval[args->namelen], args->value, args->valuelen);
        sf->count++;
        be16_add_cpu(&sf->totsize, size);
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_ADATA);

        xfs_sbversion_add_attr2(mp, args->trans);
}

/*
 * After the last attribute is removed revert to original inode format,
 * making all literal area available to the data fork once more.
 */
void
xfs_attr_fork_remove(
        struct xfs_inode        *ip,
        struct xfs_trans        *tp)
{
        ASSERT(ip->i_af.if_nextents == 0);

        xfs_ifork_zap_attr(ip);
        ip->i_forkoff = 0;
        xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
}

/*
 * Remove an attribute from the shortform attribute list structure.
 */
int
xfs_attr_sf_removename(
        struct xfs_da_args              *args)
{
        struct xfs_inode                *dp = args->dp;
        struct xfs_mount                *mp = dp->i_mount;
        struct xfs_attr_sf_hdr          *sf = dp->i_af.if_data;
        struct xfs_attr_sf_entry        *sfe;
        uint16_t                        totsize = be16_to_cpu(sf->totsize);
        void                            *next, *end;
        int                             size = 0;

        trace_xfs_attr_sf_remove(args);

        sfe = xfs_attr_sf_findname(args);
        if (!sfe) {
                /*
                 * If we are recovering an operation, finding nothing to remove
                 * is not an error, it just means there was nothing to clean up.
                 */
                if (args->op_flags & XFS_DA_OP_RECOVERY)
                        return 0;
                return -ENOATTR;
        }

        /*
         * Fix up the attribute fork data, covering the hole
         */
        size = xfs_attr_sf_entsize(sfe);
        next = xfs_attr_sf_nextentry(sfe);
        end = xfs_attr_sf_endptr(sf);
        if (next < end)
                memmove(sfe, next, end - next);
        sf->count--;
        totsize -= size;
        sf->totsize = cpu_to_be16(totsize);

        /*
         * Fix up the start offset of the attribute fork
         */
        if (totsize == sizeof(struct xfs_attr_sf_hdr) &&
            (dp->i_df.if_format != XFS_DINODE_FMT_BTREE) &&
            !(args->op_flags & (XFS_DA_OP_ADDNAME | XFS_DA_OP_REPLACE)) &&
            !xfs_has_parent(mp)) {
                xfs_attr_fork_remove(dp, args->trans);
        } else {
                xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
                dp->i_forkoff = xfs_attr_shortform_bytesfit(dp, totsize);
                ASSERT(dp->i_forkoff);
                ASSERT(totsize > sizeof(struct xfs_attr_sf_hdr) ||
                                (args->op_flags & XFS_DA_OP_ADDNAME) ||
                                dp->i_df.if_format == XFS_DINODE_FMT_BTREE ||
                                xfs_has_parent(mp));
                xfs_trans_log_inode(args->trans, dp,
                                        XFS_ILOG_CORE | XFS_ILOG_ADATA);
        }

        xfs_sbversion_add_attr2(mp, args->trans);

        return 0;
}

/*
 * Retrieve the attribute value and length.
 *
 * If args->valuelen is zero, only the length needs to be returned.  Unlike a
 * lookup, we only return an error if the attribute does not exist or we can't
 * retrieve the value.
 */
int
xfs_attr_shortform_getvalue(
        struct xfs_da_args              *args)
{
        struct xfs_attr_sf_entry        *sfe;

        ASSERT(args->dp->i_af.if_format == XFS_DINODE_FMT_LOCAL);

        trace_xfs_attr_sf_lookup(args);

        sfe = xfs_attr_sf_findname(args);
        if (!sfe)
                return -ENOATTR;
        return xfs_attr_copy_value(args, &sfe->nameval[args->namelen],
                        sfe->valuelen);
}

/* Convert from using the shortform to the leaf format. */
int
xfs_attr_shortform_to_leaf(
        struct xfs_da_args              *args)
{
        struct xfs_inode                *dp = args->dp;
        struct xfs_ifork                *ifp = &dp->i_af;
        struct xfs_attr_sf_hdr          *sf = ifp->if_data;
        struct xfs_attr_sf_entry        *sfe;
        int                             size = be16_to_cpu(sf->totsize);
        struct xfs_da_args              nargs;
        char                            *tmpbuffer;
        int                             error, i;
        xfs_dablk_t                     blkno;
        struct xfs_buf                  *bp;

        trace_xfs_attr_sf_to_leaf(args);

        tmpbuffer = kmalloc(size, GFP_KERNEL | __GFP_NOFAIL);
        memcpy(tmpbuffer, ifp->if_data, size);
        sf = (struct xfs_attr_sf_hdr *)tmpbuffer;

        xfs_idata_realloc(dp, -size, XFS_ATTR_FORK);
        xfs_bmap_local_to_extents_empty(args->trans, dp, XFS_ATTR_FORK);

        bp = NULL;
        error = xfs_da_grow_inode(args, &blkno);
        if (error)
                goto out;

        ASSERT(blkno == 0);
        error = xfs_attr3_leaf_create(args, blkno, &bp);
        if (error)
                goto out;

        memset((char *)&nargs, 0, sizeof(nargs));
        nargs.dp = dp;
        nargs.geo = args->geo;
        nargs.total = args->total;
        nargs.whichfork = XFS_ATTR_FORK;
        nargs.trans = args->trans;
        nargs.op_flags = XFS_DA_OP_OKNOENT;
        nargs.owner = args->owner;

        sfe = xfs_attr_sf_firstentry(sf);
        for (i = 0; i < sf->count; i++) {
                nargs.name = sfe->nameval;
                nargs.namelen = sfe->namelen;
                nargs.value = &sfe->nameval[nargs.namelen];
                nargs.valuelen = sfe->valuelen;
                nargs.attr_filter = sfe->flags & XFS_ATTR_NSP_ONDISK_MASK;
                if (!xfs_attr_check_namespace(sfe->flags)) {
                        xfs_da_mark_sick(args);
                        error = -EFSCORRUPTED;
                        goto out;
                }
                xfs_attr_sethash(&nargs);
                error = xfs_attr3_leaf_lookup_int(bp, &nargs); /* set a->index */
                ASSERT(error == -ENOATTR);
                if (!xfs_attr3_leaf_add(bp, &nargs))
                        ASSERT(0);
                sfe = xfs_attr_sf_nextentry(sfe);
        }
        error = 0;
out:
        kfree(tmpbuffer);
        return error;
}

/*
 * Check a leaf attribute block to see if all the entries would fit into
 * a shortform attribute list.
 */
int
xfs_attr_shortform_allfit(
        struct xfs_buf          *bp,
        struct xfs_inode        *dp)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr_leaf_entry *entry;
        xfs_attr_leaf_name_local_t *name_loc;
        struct xfs_attr3_icleaf_hdr leafhdr;
        int                     bytes;
        int                     i;
        struct xfs_mount        *mp = bp->b_mount;

        leaf = bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
        entry = xfs_attr3_leaf_entryp(leaf);

        bytes = sizeof(struct xfs_attr_sf_hdr);
        for (i = 0; i < leafhdr.count; entry++, i++) {
                if (entry->flags & XFS_ATTR_INCOMPLETE)
                        continue;               /* don't copy partial entries */
                if (!(entry->flags & XFS_ATTR_LOCAL))
                        return 0;
                name_loc = xfs_attr3_leaf_name_local(leaf, i);
                if (name_loc->namelen >= XFS_ATTR_SF_ENTSIZE_MAX)
                        return 0;
                if (be16_to_cpu(name_loc->valuelen) >= XFS_ATTR_SF_ENTSIZE_MAX)
                        return 0;
                bytes += xfs_attr_sf_entsize_byname(name_loc->namelen,
                                        be16_to_cpu(name_loc->valuelen));
        }
        if ((dp->i_df.if_format != XFS_DINODE_FMT_BTREE) &&
            (bytes == sizeof(struct xfs_attr_sf_hdr)))
                return -1;
        return xfs_attr_shortform_bytesfit(dp, bytes);
}

/* Verify the consistency of a raw inline attribute fork. */
xfs_failaddr_t
xfs_attr_shortform_verify(
        struct xfs_attr_sf_hdr          *sfp,
        size_t                          size)
{
        struct xfs_attr_sf_entry        *sfep = xfs_attr_sf_firstentry(sfp);
        struct xfs_attr_sf_entry        *next_sfep;
        char                            *endp;
        int                             i;

        /*
         * Give up if the attribute is way too short.
         */
        if (size < sizeof(struct xfs_attr_sf_hdr))
                return __this_address;

        endp = (char *)sfp + size;

        /* Check all reported entries */
        for (i = 0; i < sfp->count; i++) {
                /*
                 * struct xfs_attr_sf_entry has a variable length.
                 * Check the fixed-offset parts of the structure are
                 * within the data buffer.
                 * xfs_attr_sf_entry is defined with a 1-byte variable
                 * array at the end, so we must subtract that off.
                 */
                if (((char *)sfep + sizeof(*sfep)) >= endp)
                        return __this_address;

                /* Don't allow names with known bad length. */
                if (sfep->namelen == 0)
                        return __this_address;

                /*
                 * Check that the variable-length part of the structure is
                 * within the data buffer.  The next entry starts after the
                 * name component, so nextentry is an acceptable test.
                 */
                next_sfep = xfs_attr_sf_nextentry(sfep);
                if ((char *)next_sfep > endp)
                        return __this_address;

                /*
                 * Check for unknown flags.  Short form doesn't support
                 * the incomplete or local bits, so we can use the namespace
                 * mask here.
                 */
                if (sfep->flags & ~XFS_ATTR_NSP_ONDISK_MASK)
                        return __this_address;

                /*
                 * Check for invalid namespace combinations.  We only allow
                 * one namespace flag per xattr, so we can just count the
                 * bits (i.e. hweight) here.
                 */
                if (!xfs_attr_check_namespace(sfep->flags))
                        return __this_address;

                sfep = next_sfep;
        }
        if ((void *)sfep != (void *)endp)
                return __this_address;

        return NULL;
}

/*
 * Convert a leaf attribute list to shortform attribute list
 */
int
xfs_attr3_leaf_to_shortform(
        struct xfs_buf          *bp,
        struct xfs_da_args      *args,
        int                     forkoff)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_name_local *name_loc;
        struct xfs_da_args      nargs;
        struct xfs_inode        *dp = args->dp;
        char                    *tmpbuffer;
        int                     error;
        int                     i;

        trace_xfs_attr_leaf_to_sf(args);

        tmpbuffer = kvmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);
        memcpy(tmpbuffer, bp->b_addr, args->geo->blksize);

        leaf = (xfs_attr_leafblock_t *)tmpbuffer;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        entry = xfs_attr3_leaf_entryp(leaf);

        /* XXX (dgc): buffer is about to be marked stale - why zero it? */
        memset(bp->b_addr, 0, args->geo->blksize);

        /*
         * Clean out the prior contents of the attribute list.
         */
        error = xfs_da_shrink_inode(args, 0, bp);
        if (error)
                goto out;

        if (forkoff == -1) {
                /*
                 * Don't remove the attr fork if this operation is the first
                 * part of a attr replace operations. We're going to add a new
                 * attr immediately, so we need to keep the attr fork around in
                 * this case.
                 */
                if (!(args->op_flags & XFS_DA_OP_REPLACE)) {
                        ASSERT(dp->i_df.if_format != XFS_DINODE_FMT_BTREE);
                        xfs_attr_fork_remove(dp, args->trans);
                }
                goto out;
        }

        xfs_attr_shortform_create(args);

        /*
         * Copy the attributes
         */
        memset((char *)&nargs, 0, sizeof(nargs));
        nargs.geo = args->geo;
        nargs.dp = dp;
        nargs.total = args->total;
        nargs.whichfork = XFS_ATTR_FORK;
        nargs.trans = args->trans;
        nargs.op_flags = XFS_DA_OP_OKNOENT;
        nargs.owner = args->owner;

        for (i = 0; i < ichdr.count; entry++, i++) {
                if (entry->flags & XFS_ATTR_INCOMPLETE)
                        continue;       /* don't copy partial entries */
                if (!entry->nameidx)
                        continue;
                ASSERT(entry->flags & XFS_ATTR_LOCAL);
                name_loc = xfs_attr3_leaf_name_local(leaf, i);
                nargs.name = name_loc->nameval;
                nargs.namelen = name_loc->namelen;
                nargs.value = &name_loc->nameval[nargs.namelen];
                nargs.valuelen = be16_to_cpu(name_loc->valuelen);
                nargs.hashval = be32_to_cpu(entry->hashval);
                nargs.attr_filter = entry->flags & XFS_ATTR_NSP_ONDISK_MASK;
                xfs_attr_shortform_add(&nargs, forkoff);
        }
        error = 0;

out:
        kvfree(tmpbuffer);
        return error;
}

/*
 * Convert from using a single leaf to a root node and a leaf.
 */
int
xfs_attr3_leaf_to_node(
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr icleafhdr;
        struct xfs_attr_leaf_entry *entries;
        struct xfs_da3_icnode_hdr icnodehdr;
        struct xfs_da_intnode   *node;
        struct xfs_inode        *dp = args->dp;
        struct xfs_mount        *mp = dp->i_mount;
        struct xfs_buf          *bp1 = NULL;
        struct xfs_buf          *bp2 = NULL;
        xfs_dablk_t             blkno;
        int                     error;

        trace_xfs_attr_leaf_to_node(args);

        if (XFS_TEST_ERROR(mp, XFS_ERRTAG_ATTR_LEAF_TO_NODE)) {
                error = -EIO;
                goto out;
        }

        error = xfs_da_grow_inode(args, &blkno);
        if (error)
                goto out;
        error = xfs_attr3_leaf_read(args->trans, dp, args->owner, 0, &bp1);
        if (error)
                goto out;

        error = xfs_da_get_buf(args->trans, dp, blkno, &bp2, XFS_ATTR_FORK);
        if (error)
                goto out;

        /*
         * Copy leaf to new buffer and log it.
         */
        xfs_da_buf_copy(bp2, bp1, args->geo->blksize);
        xfs_trans_log_buf(args->trans, bp2, 0, args->geo->blksize - 1);

        /*
         * Set up the new root node.
         */
        error = xfs_da3_node_create(args, 0, 1, &bp1, XFS_ATTR_FORK);
        if (error)
                goto out;
        node = bp1->b_addr;
        xfs_da3_node_hdr_from_disk(mp, &icnodehdr, node);

        leaf = bp2->b_addr;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &icleafhdr, leaf);
        entries = xfs_attr3_leaf_entryp(leaf);

        /* both on-disk, don't endian-flip twice */
        icnodehdr.btree[0].hashval = entries[icleafhdr.count - 1].hashval;
        icnodehdr.btree[0].before = cpu_to_be32(blkno);
        icnodehdr.count = 1;
        xfs_da3_node_hdr_to_disk(dp->i_mount, node, &icnodehdr);
        xfs_trans_log_buf(args->trans, bp1, 0, args->geo->blksize - 1);
        error = 0;
out:
        return error;
}

/*========================================================================
 * Routines used for growing the Btree.
 *========================================================================*/

/*
 * Create the initial contents of a leaf attribute list
 * or a leaf in a node attribute list.
 */
STATIC int
xfs_attr3_leaf_create(
        struct xfs_da_args      *args,
        xfs_dablk_t             blkno,
        struct xfs_buf          **bpp)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_inode        *dp = args->dp;
        struct xfs_mount        *mp = dp->i_mount;
        struct xfs_buf          *bp;
        int                     error;

        trace_xfs_attr_leaf_create(args);

        error = xfs_da_get_buf(args->trans, args->dp, blkno, &bp,
                                            XFS_ATTR_FORK);
        if (error)
                return error;
        bp->b_ops = &xfs_attr3_leaf_buf_ops;
        xfs_trans_buf_set_type(args->trans, bp, XFS_BLFT_ATTR_LEAF_BUF);
        leaf = bp->b_addr;
        memset(leaf, 0, args->geo->blksize);

        memset(&ichdr, 0, sizeof(ichdr));
        ichdr.firstused = args->geo->blksize;

        if (xfs_has_crc(mp)) {
                struct xfs_da3_blkinfo *hdr3 = bp->b_addr;

                ichdr.magic = XFS_ATTR3_LEAF_MAGIC;

                hdr3->blkno = cpu_to_be64(xfs_buf_daddr(bp));
                hdr3->owner = cpu_to_be64(args->owner);
                uuid_copy(&hdr3->uuid, &mp->m_sb.sb_meta_uuid);

                ichdr.freemap[0].base = sizeof(struct xfs_attr3_leaf_hdr);
        } else {
                ichdr.magic = XFS_ATTR_LEAF_MAGIC;
                ichdr.freemap[0].base = sizeof(struct xfs_attr_leaf_hdr);
        }
        ichdr.freemap[0].size = ichdr.firstused - ichdr.freemap[0].base;

        xfs_attr3_leaf_hdr_to_disk(args->geo, leaf, &ichdr);
        xfs_trans_log_buf(args->trans, bp, 0, args->geo->blksize - 1);

        *bpp = bp;
        return 0;
}

/*
 * Reinitialize an existing attr fork block as an empty leaf, and attach
 * the buffer to tp.
 */
int
xfs_attr3_leaf_init(
        struct xfs_trans        *tp,
        struct xfs_inode        *dp,
        xfs_dablk_t             blkno)
{
        struct xfs_buf          *bp = NULL;
        struct xfs_da_args      args = {
                .trans          = tp,
                .dp             = dp,
                .owner          = dp->i_ino,
                .geo            = dp->i_mount->m_attr_geo,
        };

        ASSERT(tp != NULL);

        return xfs_attr3_leaf_create(&args, blkno, &bp);
}
/*
 * Split the leaf node, rebalance, then add the new entry.
 *
 * Returns 0 if the entry was added, 1 if a further split is needed or a
 * negative error number otherwise.
 */
int
xfs_attr3_leaf_split(
        struct xfs_da_state     *state,
        struct xfs_da_state_blk *oldblk,
        struct xfs_da_state_blk *newblk)
{
        bool                    added;
        xfs_dablk_t             blkno;
        int                     error;

        trace_xfs_attr_leaf_split(state->args);

        /*
         * Allocate space for a new leaf node.
         */
        ASSERT(oldblk->magic == XFS_ATTR_LEAF_MAGIC);
        error = xfs_da_grow_inode(state->args, &blkno);
        if (error)
                return error;
        error = xfs_attr3_leaf_create(state->args, blkno, &newblk->bp);
        if (error)
                return error;
        newblk->blkno = blkno;
        newblk->magic = XFS_ATTR_LEAF_MAGIC;

        /*
         * Rebalance the entries across the two leaves.
         * NOTE: rebalance() currently depends on the 2nd block being empty.
         */
        xfs_attr3_leaf_rebalance(state, oldblk, newblk);
        error = xfs_da3_blk_link(state, oldblk, newblk);
        if (error)
                return error;

        /*
         * Save info on "old" attribute for "atomic rename" ops, leaf_add()
         * modifies the index/blkno/rmtblk/rmtblkcnt fields to show the
         * "new" attrs info.  Will need the "old" info to remove it later.
         *
         * Insert the "new" entry in the correct block.
         */
        if (state->inleaf) {
                trace_xfs_attr_leaf_add_old(state->args);
                added = xfs_attr3_leaf_add(oldblk->bp, state->args);
        } else {
                trace_xfs_attr_leaf_add_new(state->args);
                added = xfs_attr3_leaf_add(newblk->bp, state->args);
        }

        /*
         * Update last hashval in each block since we added the name.
         */
        oldblk->hashval = xfs_attr_leaf_lasthash(oldblk->bp, NULL);
        newblk->hashval = xfs_attr_leaf_lasthash(newblk->bp, NULL);
        if (!added)
                return 1;
        return 0;
}

/*
 * Add a name to the leaf attribute list structure.
 */
bool
xfs_attr3_leaf_add(
        struct xfs_buf          *bp,
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        int                     tablesize;
        int                     entsize;
        bool                    added = true;
        int                     sum;
        int                     tmp;
        int                     i;

        trace_xfs_attr_leaf_add(args);

        leaf = bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        ASSERT(args->index >= 0 && args->index <= ichdr.count);
        entsize = xfs_attr_leaf_newentsize(args, NULL);

        /*
         * Search through freemap for first-fit on new name length.
         * (may need to figure in size of entry struct too)
         */
        tablesize = xfs_attr_leaf_entries_end(ichdr.count + 1, leaf);
        for (sum = 0, i = XFS_ATTR_LEAF_MAPSIZE - 1; i >= 0; i--) {
                if (tablesize > ichdr.firstused) {
                        sum += ichdr.freemap[i].size;
                        continue;
                }
                if (!ichdr.freemap[i].size)
                        continue;       /* no space in this map */
                tmp = entsize;
                if (ichdr.freemap[i].base < ichdr.firstused)
                        tmp += sizeof(xfs_attr_leaf_entry_t);
                if (ichdr.freemap[i].size >= tmp) {
                        xfs_attr3_leaf_add_work(bp, &ichdr, args, i);
                        goto out_log_hdr;
                }
                sum += ichdr.freemap[i].size;
        }

        /*
         * If there are no holes in the address space of the block,
         * and we don't have enough freespace, then compaction will do us
         * no good and we should just give up.
         */
        if (!ichdr.holes && sum < entsize)
                return false;

        /*
         * Compact the entries to coalesce free space.
         * This may change the hdr->count via dropping INCOMPLETE entries.
         */
        xfs_attr3_leaf_compact(args, &ichdr, bp);

        /*
         * After compaction, the block is guaranteed to have only one
         * free region, in freemap[0].  If it is not big enough, give up.
         */
        if (ichdr.freemap[0].size < (entsize + sizeof(xfs_attr_leaf_entry_t))) {
                added = false;
                goto out_log_hdr;
        }

        xfs_attr3_leaf_add_work(bp, &ichdr, args, 0);

out_log_hdr:
        xfs_attr3_leaf_hdr_to_disk(args->geo, leaf, &ichdr);
        xfs_trans_log_buf(args->trans, bp,
                XFS_DA_LOGRANGE(leaf, &leaf->hdr,
                                xfs_attr3_leaf_hdr_size(leaf)));
        return added;
}

/*
 * Add a name to a leaf attribute list structure.
 */
STATIC void
xfs_attr3_leaf_add_work(
        struct xfs_buf          *bp,
        struct xfs_attr3_icleaf_hdr *ichdr,
        struct xfs_da_args      *args,
        int                     mapindex)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_name_local *name_loc;
        struct xfs_attr_leaf_name_remote *name_rmt;
        struct xfs_mount        *mp;
        int                     old_end, new_end;
        int                     tmp;
        int                     i;

        trace_xfs_attr_leaf_add_work(args);

        leaf = bp->b_addr;
        ASSERT(mapindex >= 0 && mapindex < XFS_ATTR_LEAF_MAPSIZE);
        ASSERT(args->index >= 0 && args->index <= ichdr->count);

        /*
         * Force open some space in the entry array and fill it in.
         */
        entry = &xfs_attr3_leaf_entryp(leaf)[args->index];
        if (args->index < ichdr->count) {
                tmp  = ichdr->count - args->index;
                tmp *= sizeof(xfs_attr_leaf_entry_t);
                memmove(entry + 1, entry, tmp);
                xfs_trans_log_buf(args->trans, bp,
                    XFS_DA_LOGRANGE(leaf, entry, tmp + sizeof(*entry)));
        }
        ichdr->count++;

        /*
         * Allocate space for the new string (at the end of the run).
         */
        mp = args->trans->t_mountp;
        ASSERT(ichdr->freemap[mapindex].base < args->geo->blksize);
        ASSERT((ichdr->freemap[mapindex].base & 0x3) == 0);
        ASSERT(ichdr->freemap[mapindex].size >=
                xfs_attr_leaf_newentsize(args, NULL));
        ASSERT(ichdr->freemap[mapindex].size < args->geo->blksize);
        ASSERT((ichdr->freemap[mapindex].size & 0x3) == 0);

        ichdr->freemap[mapindex].size -= xfs_attr_leaf_newentsize(args, &tmp);

        entry->nameidx = cpu_to_be16(ichdr->freemap[mapindex].base +
                                     ichdr->freemap[mapindex].size);
        entry->hashval = cpu_to_be32(args->hashval);
        entry->flags = args->attr_filter;
        if (tmp)
                entry->flags |= XFS_ATTR_LOCAL;
        if (args->op_flags & XFS_DA_OP_REPLACE) {
                if (!(args->op_flags & XFS_DA_OP_LOGGED))
                        entry->flags |= XFS_ATTR_INCOMPLETE;
                if ((args->blkno2 == args->blkno) &&
                    (args->index2 <= args->index)) {
                        args->index2++;
                }
        }
        xfs_trans_log_buf(args->trans, bp,
                          XFS_DA_LOGRANGE(leaf, entry, sizeof(*entry)));
        ASSERT((args->index == 0) ||
               (be32_to_cpu(entry->hashval) >= be32_to_cpu((entry-1)->hashval)));
        ASSERT((args->index == ichdr->count - 1) ||
               (be32_to_cpu(entry->hashval) <= be32_to_cpu((entry+1)->hashval)));

        /*
         * For "remote" attribute values, simply note that we need to
         * allocate space for the "remote" value.  We can't actually
         * allocate the extents in this transaction, and we can't decide
         * which blocks they should be as we might allocate more blocks
         * as part of this transaction (a split operation for example).
         */
        if (entry->flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf, args->index);
                name_loc->namelen = args->namelen;
                name_loc->valuelen = cpu_to_be16(args->valuelen);
                memcpy((char *)name_loc->nameval, args->name, args->namelen);
                memcpy((char *)&name_loc->nameval[args->namelen], args->value,
                                   be16_to_cpu(name_loc->valuelen));
        } else {
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                name_rmt->namelen = args->namelen;
                memcpy((char *)name_rmt->name, args->name, args->namelen);
                entry->flags |= XFS_ATTR_INCOMPLETE;
                /* just in case */
                name_rmt->valuelen = 0;
                name_rmt->valueblk = 0;
                args->rmtblkno = 1;
                args->rmtblkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
                args->rmtvaluelen = args->valuelen;
        }
        xfs_trans_log_buf(args->trans, bp,
             XFS_DA_LOGRANGE(leaf, xfs_attr3_leaf_name(leaf, args->index),
                                   xfs_attr_leaf_entsize(leaf, args->index)));

        /*
         * Update the control info for this leaf node
         */
        if (be16_to_cpu(entry->nameidx) < ichdr->firstused)
                ichdr->firstused = be16_to_cpu(entry->nameidx);

        new_end = xfs_attr_leaf_entries_end(ichdr->count, leaf);
        old_end = new_end - sizeof(struct xfs_attr_leaf_entry);

        ASSERT(ichdr->firstused >= new_end);

        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                int             diff = 0;

                if (ichdr->freemap[i].base == old_end) {
                        /*
                         * This freemap entry starts at the old end of the
                         * leaf entry array, so we need to adjust its base
                         * upward to accomodate the larger array.
                         */
                        diff = sizeof(struct xfs_attr_leaf_entry);
                } else if (ichdr->freemap[i].size > 0 &&
                           ichdr->freemap[i].base < new_end) {
                        /*
                         * This freemap entry starts in the space claimed by
                         * the new leaf entry.  Adjust its base upward to
                         * reflect that.
                         */
                        diff = new_end - ichdr->freemap[i].base;
                }

                if (diff) {
                        ichdr->freemap[i].base += diff;
                        ichdr->freemap[i].size -=
                                min_t(uint16_t, ichdr->freemap[i].size, diff);
                }

                /*
                 * Don't leave zero-length freemaps with nonzero base lying
                 * around, because we don't want the code in _remove that
                 * matches on base address to get confused and create
                 * overlapping freemaps.  If we end up with no freemap entries
                 * then the next _add will compact the leaf block and
                 * regenerate the freemaps.
                 */
                if (ichdr->freemap[i].size == 0 && ichdr->freemap[i].base > 0) {
                        ichdr->freemap[i].base = 0;
                        ichdr->holes = 1;
                }
        }
        ichdr->usedbytes += xfs_attr_leaf_entsize(leaf, args->index);
}

/*
 * Garbage collect a leaf attribute list block by copying it to a new buffer.
 */
STATIC void
xfs_attr3_leaf_compact(
        struct xfs_da_args      *args,
        struct xfs_attr3_icleaf_hdr *ichdr_dst,
        struct xfs_buf          *bp)
{
        struct xfs_attr_leafblock *leaf_src;
        struct xfs_attr_leafblock *leaf_dst;
        struct xfs_attr3_icleaf_hdr ichdr_src;
        struct xfs_trans        *trans = args->trans;
        char                    *tmpbuffer;

        trace_xfs_attr_leaf_compact(args);

        tmpbuffer = kvmalloc(args->geo->blksize, GFP_KERNEL | __GFP_NOFAIL);
        memcpy(tmpbuffer, bp->b_addr, args->geo->blksize);
        memset(bp->b_addr, 0, args->geo->blksize);
        leaf_src = (xfs_attr_leafblock_t *)tmpbuffer;
        leaf_dst = bp->b_addr;

        /*
         * Copy the on-disk header back into the destination buffer to ensure
         * all the information in the header that is not part of the incore
         * header structure is preserved.
         */
        memcpy(bp->b_addr, tmpbuffer, xfs_attr3_leaf_hdr_size(leaf_src));

        /* Initialise the incore headers */
        ichdr_src = *ichdr_dst; /* struct copy */
        ichdr_dst->firstused = args->geo->blksize;
        ichdr_dst->usedbytes = 0;
        ichdr_dst->count = 0;
        ichdr_dst->holes = 0;
        ichdr_dst->freemap[0].base = xfs_attr3_leaf_hdr_size(leaf_src);
        ichdr_dst->freemap[0].size = ichdr_dst->firstused -
                                                ichdr_dst->freemap[0].base;
        ichdr_dst->freemap[1].base = 0;
        ichdr_dst->freemap[2].base = 0;
        ichdr_dst->freemap[1].size = 0;
        ichdr_dst->freemap[2].size = 0;

        /* write the header back to initialise the underlying buffer */
        xfs_attr3_leaf_hdr_to_disk(args->geo, leaf_dst, ichdr_dst);

        /*
         * Copy all entry's in the same (sorted) order,
         * but allocate name/value pairs packed and in sequence.
         */
        xfs_attr3_leaf_moveents(args, leaf_src, &ichdr_src, 0,
                                leaf_dst, ichdr_dst, 0, ichdr_src.count);
        /*
         * this logs the entire buffer, but the caller must write the header
         * back to the buffer when it is finished modifying it.
         */
        xfs_trans_log_buf(trans, bp, 0, args->geo->blksize - 1);

        kvfree(tmpbuffer);
}

/*
 * Compare two leaf blocks "order".
 * Return 0 unless leaf2 should go before leaf1.
 */
static int
xfs_attr3_leaf_order(
        struct xfs_buf  *leaf1_bp,
        struct xfs_attr3_icleaf_hdr *leaf1hdr,
        struct xfs_buf  *leaf2_bp,
        struct xfs_attr3_icleaf_hdr *leaf2hdr)
{
        struct xfs_attr_leaf_entry *entries1;
        struct xfs_attr_leaf_entry *entries2;

        entries1 = xfs_attr3_leaf_entryp(leaf1_bp->b_addr);
        entries2 = xfs_attr3_leaf_entryp(leaf2_bp->b_addr);
        if (leaf1hdr->count > 0 && leaf2hdr->count > 0 &&
            ((be32_to_cpu(entries2[0].hashval) <
              be32_to_cpu(entries1[0].hashval)) ||
             (be32_to_cpu(entries2[leaf2hdr->count - 1].hashval) <
              be32_to_cpu(entries1[leaf1hdr->count - 1].hashval)))) {
                return 1;
        }
        return 0;
}

int
xfs_attr_leaf_order(
        struct xfs_buf  *leaf1_bp,
        struct xfs_buf  *leaf2_bp)
{
        struct xfs_attr3_icleaf_hdr ichdr1;
        struct xfs_attr3_icleaf_hdr ichdr2;
        struct xfs_mount *mp = leaf1_bp->b_mount;

        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr1, leaf1_bp->b_addr);
        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr2, leaf2_bp->b_addr);
        return xfs_attr3_leaf_order(leaf1_bp, &ichdr1, leaf2_bp, &ichdr2);
}

/*
 * Redistribute the attribute list entries between two leaf nodes,
 * taking into account the size of the new entry.
 *
 * NOTE: if new block is empty, then it will get the upper half of the
 * old block.  At present, all (one) callers pass in an empty second block.
 *
 * This code adjusts the args->index/blkno and args->index2/blkno2 fields
 * to match what it is doing in splitting the attribute leaf block.  Those
 * values are used in "atomic rename" operations on attributes.  Note that
 * the "new" and "old" values can end up in different blocks.
 */
STATIC void
xfs_attr3_leaf_rebalance(
        struct xfs_da_state     *state,
        struct xfs_da_state_blk *blk1,
        struct xfs_da_state_blk *blk2)
{
        struct xfs_da_args      *args;
        struct xfs_attr_leafblock *leaf1;
        struct xfs_attr_leafblock *leaf2;
        struct xfs_attr3_icleaf_hdr ichdr1;
        struct xfs_attr3_icleaf_hdr ichdr2;
        struct xfs_attr_leaf_entry *entries1;
        struct xfs_attr_leaf_entry *entries2;
        int                     count;
        int                     totallen;
        int                     max;
        int                     space;
        int                     swap;

        /*
         * Set up environment.
         */
        ASSERT(blk1->magic == XFS_ATTR_LEAF_MAGIC);
        ASSERT(blk2->magic == XFS_ATTR_LEAF_MAGIC);
        leaf1 = blk1->bp->b_addr;
        leaf2 = blk2->bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(state->args->geo, &ichdr1, leaf1);
        xfs_attr3_leaf_hdr_from_disk(state->args->geo, &ichdr2, leaf2);
        ASSERT(ichdr2.count == 0);
        args = state->args;

        trace_xfs_attr_leaf_rebalance(args);

        /*
         * Check ordering of blocks, reverse if it makes things simpler.
         *
         * NOTE: Given that all (current) callers pass in an empty
         * second block, this code should never set "swap".
         */
        swap = 0;
        if (xfs_attr3_leaf_order(blk1->bp, &ichdr1, blk2->bp, &ichdr2)) {
                swap(blk1, blk2);

                /* swap structures rather than reconverting them */
                swap(ichdr1, ichdr2);

                leaf1 = blk1->bp->b_addr;
                leaf2 = blk2->bp->b_addr;
                swap = 1;
        }

        /*
         * Examine entries until we reduce the absolute difference in
         * byte usage between the two blocks to a minimum.  Then get
         * the direction to copy and the number of elements to move.
         *
         * "inleaf" is true if the new entry should be inserted into blk1.
         * If "swap" is also true, then reverse the sense of "inleaf".
         */
        state->inleaf = xfs_attr3_leaf_figure_balance(state, blk1, &ichdr1,
                                                      blk2, &ichdr2,
                                                      &count, &totallen);
        if (swap)
                state->inleaf = !state->inleaf;

        /*
         * Move any entries required from leaf to leaf:
         */
        if (count < ichdr1.count) {
                /*
                 * Figure the total bytes to be added to the destination leaf.
                 */
                /* number entries being moved */
                count = ichdr1.count - count;
                space  = ichdr1.usedbytes - totallen;
                space += count * sizeof(xfs_attr_leaf_entry_t);

                /*
                 * leaf2 is the destination, compact it if it looks tight.
                 */
                max = ichdr2.firstused -
                                xfs_attr_leaf_entries_end(ichdr2.count, leaf1);
                if (space > max)
                        xfs_attr3_leaf_compact(args, &ichdr2, blk2->bp);

                /*
                 * Move high entries from leaf1 to low end of leaf2.
                 */
                xfs_attr3_leaf_moveents(args, leaf1, &ichdr1,
                                ichdr1.count - count, leaf2, &ichdr2, 0, count);

        } else if (count > ichdr1.count) {
                /*
                 * I assert that since all callers pass in an empty
                 * second buffer, this code should never execute.
                 */
                ASSERT(0);

                /*
                 * Figure the total bytes to be added to the destination leaf.
                 */
                /* number entries being moved */
                count -= ichdr1.count;
                space  = totallen - ichdr1.usedbytes;
                space += count * sizeof(xfs_attr_leaf_entry_t);

                /*
                 * leaf1 is the destination, compact it if it looks tight.
                 */
                max = ichdr1.firstused -
                                xfs_attr_leaf_entries_end(ichdr1.count, leaf1);
                if (space > max)
                        xfs_attr3_leaf_compact(args, &ichdr1, blk1->bp);

                /*
                 * Move low entries from leaf2 to high end of leaf1.
                 */
                xfs_attr3_leaf_moveents(args, leaf2, &ichdr2, 0, leaf1, &ichdr1,
                                        ichdr1.count, count);
        }

        xfs_attr3_leaf_hdr_to_disk(state->args->geo, leaf1, &ichdr1);
        xfs_attr3_leaf_hdr_to_disk(state->args->geo, leaf2, &ichdr2);
        xfs_trans_log_buf(args->trans, blk1->bp, 0, args->geo->blksize - 1);
        xfs_trans_log_buf(args->trans, blk2->bp, 0, args->geo->blksize - 1);

        /*
         * Copy out last hashval in each block for B-tree code.
         */
        entries1 = xfs_attr3_leaf_entryp(leaf1);
        entries2 = xfs_attr3_leaf_entryp(leaf2);
        blk1->hashval = be32_to_cpu(entries1[ichdr1.count - 1].hashval);
        blk2->hashval = be32_to_cpu(entries2[ichdr2.count - 1].hashval);

        /*
         * Adjust the expected index for insertion.
         * NOTE: this code depends on the (current) situation that the
         * second block was originally empty.
         *
         * If the insertion point moved to the 2nd block, we must adjust
         * the index.  We must also track the entry just following the
         * new entry for use in an "atomic rename" operation, that entry
         * is always the "old" entry and the "new" entry is what we are
         * inserting.  The index/blkno fields refer to the "old" entry,
         * while the index2/blkno2 fields refer to the "new" entry.
         */
        if (blk1->index > ichdr1.count) {
                ASSERT(state->inleaf == 0);
                blk2->index = blk1->index - ichdr1.count;
                args->index = args->index2 = blk2->index;
                args->blkno = args->blkno2 = blk2->blkno;
        } else if (blk1->index == ichdr1.count) {
                if (state->inleaf) {
                        args->index = blk1->index;
                        args->blkno = blk1->blkno;
                        args->index2 = 0;
                        args->blkno2 = blk2->blkno;
                } else {
                        /*
                         * On a double leaf split, the original attr location
                         * is already stored in blkno2/index2, so don't
                         * overwrite it overwise we corrupt the tree.
                         */
                        blk2->index = blk1->index - ichdr1.count;
                        args->index = blk2->index;
                        args->blkno = blk2->blkno;
                        if (!state->extravalid) {
                                /*
                                 * set the new attr location to match the old
                                 * one and let the higher level split code
                                 * decide where in the leaf to place it.
                                 */
                                args->index2 = blk2->index;
                                args->blkno2 = blk2->blkno;
                        }
                }
        } else {
                ASSERT(state->inleaf == 1);
                args->index = args->index2 = blk1->index;
                args->blkno = args->blkno2 = blk1->blkno;
        }
}

/*
 * Examine entries until we reduce the absolute difference in
 * byte usage between the two blocks to a minimum.
 * GROT: Is this really necessary?  With other than a 512 byte blocksize,
 * GROT: there will always be enough room in either block for a new entry.
 * GROT: Do a double-split for this case?
 */
STATIC int
xfs_attr3_leaf_figure_balance(
        struct xfs_da_state             *state,
        struct xfs_da_state_blk         *blk1,
        struct xfs_attr3_icleaf_hdr     *ichdr1,
        struct xfs_da_state_blk         *blk2,
        struct xfs_attr3_icleaf_hdr     *ichdr2,
        int                             *countarg,
        int                             *usedbytesarg)
{
        struct xfs_attr_leafblock       *leaf1 = blk1->bp->b_addr;
        struct xfs_attr_leafblock       *leaf2 = blk2->bp->b_addr;
        struct xfs_attr_leaf_entry      *entry;
        int                             count;
        int                             max;
        int                             index;
        int                             totallen = 0;
        int                             half;
        int                             lastdelta;
        int                             foundit = 0;
        int                             tmp;

        /*
         * Examine entries until we reduce the absolute difference in
         * byte usage between the two blocks to a minimum.
         */
        max = ichdr1->count + ichdr2->count;
        half = (max + 1) * sizeof(*entry);
        half += ichdr1->usedbytes + ichdr2->usedbytes +
                        xfs_attr_leaf_newentsize(state->args, NULL);
        half /= 2;
        lastdelta = state->args->geo->blksize;
        entry = xfs_attr3_leaf_entryp(leaf1);
        for (count = index = 0; count < max; entry++, index++, count++) {

#define XFS_ATTR_ABS(A) (((A) < 0) ? -(A) : (A))
                /*
                 * The new entry is in the first block, account for it.
                 */
                if (count == blk1->index) {
                        tmp = totallen + sizeof(*entry) +
                                xfs_attr_leaf_newentsize(state->args, NULL);
                        if (XFS_ATTR_ABS(half - tmp) > lastdelta)
                                break;
                        lastdelta = XFS_ATTR_ABS(half - tmp);
                        totallen = tmp;
                        foundit = 1;
                }

                /*
                 * Wrap around into the second block if necessary.
                 */
                if (count == ichdr1->count) {
                        leaf1 = leaf2;
                        entry = xfs_attr3_leaf_entryp(leaf1);
                        index = 0;
                }

                /*
                 * Figure out if next leaf entry would be too much.
                 */
                tmp = totallen + sizeof(*entry) + xfs_attr_leaf_entsize(leaf1,
                                                                        index);
                if (XFS_ATTR_ABS(half - tmp) > lastdelta)
                        break;
                lastdelta = XFS_ATTR_ABS(half - tmp);
                totallen = tmp;
#undef XFS_ATTR_ABS
        }

        /*
         * Calculate the number of usedbytes that will end up in lower block.
         * If new entry not in lower block, fix up the count.
         */
        totallen -= count * sizeof(*entry);
        if (foundit) {
                totallen -= sizeof(*entry) +
                                xfs_attr_leaf_newentsize(state->args, NULL);
        }

        *countarg = count;
        *usedbytesarg = totallen;
        return foundit;
}

/*========================================================================
 * Routines used for shrinking the Btree.
 *========================================================================*/

/*
 * Check a leaf block and its neighbors to see if the block should be
 * collapsed into one or the other neighbor.  Always keep the block
 * with the smaller block number.
 * If the current block is over 50% full, don't try to join it, return 0.
 * If the block is empty, fill in the state structure and return 2.
 * If it can be collapsed, fill in the state structure and return 1.
 * If nothing can be done, return 0.
 *
 * GROT: allow for INCOMPLETE entries in calculation.
 */
int
xfs_attr3_leaf_toosmall(
        struct xfs_da_state     *state,
        int                     *action)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_da_state_blk *blk;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_buf          *bp;
        xfs_dablk_t             blkno;
        int                     bytes;
        int                     forward;
        int                     error;
        int                     retval;
        int                     i;

        trace_xfs_attr_leaf_toosmall(state->args);

        /*
         * Check for the degenerate case of the block being over 50% full.
         * If so, it's not worth even looking to see if we might be able
         * to coalesce with a sibling.
         */
        blk = &state->path.blk[ state->path.active-1 ];
        leaf = blk->bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(state->args->geo, &ichdr, leaf);
        bytes = xfs_attr_leaf_entries_end(ichdr.count, leaf) + ichdr.usedbytes;
        if (bytes > (state->args->geo->blksize >> 1)) {
                *action = 0;    /* blk over 50%, don't try to join */
                return 0;
        }

        /*
         * Check for the degenerate case of the block being empty.
         * If the block is empty, we'll simply delete it, no need to
         * coalesce it with a sibling block.  We choose (arbitrarily)
         * to merge with the forward block unless it is NULL.
         */
        if (ichdr.count == 0) {
                /*
                 * Make altpath point to the block we want to keep and
                 * path point to the block we want to drop (this one).
                 */
                forward = (ichdr.forw != 0);
                memcpy(&state->altpath, &state->path, sizeof(state->path));
                error = xfs_da3_path_shift(state, &state->altpath, forward,
                                                 0, &retval);
                if (error)
                        return error;
                if (retval) {
                        *action = 0;
                } else {
                        *action = 2;
                }
                return 0;
        }

        /*
         * Examine each sibling block to see if we can coalesce with
         * at least 25% free space to spare.  We need to figure out
         * whether to merge with the forward or the backward block.
         * We prefer coalescing with the lower numbered sibling so as
         * to shrink an attribute list over time.
         */
        /* start with smaller blk num */
        forward = ichdr.forw < ichdr.back;
        for (i = 0; i < 2; forward = !forward, i++) {
                struct xfs_attr3_icleaf_hdr ichdr2;
                if (forward)
                        blkno = ichdr.forw;
                else
                        blkno = ichdr.back;
                if (blkno == 0)
                        continue;
                error = xfs_attr3_leaf_read(state->args->trans, state->args->dp,
                                        state->args->owner, blkno, &bp);
                if (error)
                        return error;

                xfs_attr3_leaf_hdr_from_disk(state->args->geo, &ichdr2, bp->b_addr);

                bytes = state->args->geo->blksize -
                        (state->args->geo->blksize >> 2) -
                        ichdr.usedbytes - ichdr2.usedbytes -
                        xfs_attr_leaf_entries_end(ichdr.count + ichdr2.count,
                                        leaf);

                xfs_trans_brelse(state->args->trans, bp);
                if (bytes >= 0)
                        break;  /* fits with at least 25% to spare */
        }
        if (i >= 2) {
                *action = 0;
                return 0;
        }

        /*
         * Make altpath point to the block we want to keep (the lower
         * numbered block) and path point to the block we want to drop.
         */
        memcpy(&state->altpath, &state->path, sizeof(state->path));
        if (blkno < blk->blkno) {
                error = xfs_da3_path_shift(state, &state->altpath, forward,
                                                 0, &retval);
        } else {
                error = xfs_da3_path_shift(state, &state->path, forward,
                                                 0, &retval);
        }
        if (error)
                return error;
        if (retval) {
                *action = 0;
        } else {
                *action = 1;
        }
        return 0;
}

/*
 * Remove a name from the leaf attribute list structure.
 *
 * Return 1 if leaf is less than 37% full, 0 if >= 37% full.
 * If two leaves are 37% full, when combined they will leave 25% free.
 */
int
xfs_attr3_leaf_remove(
        struct xfs_buf          *bp,
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_attr_leaf_entry *entry;
        int                     before;
        int                     after;
        int                     smallest;
        int                     entsize;
        int                     tablesize;
        int                     tmp;
        int                     i;

        trace_xfs_attr_leaf_remove(args);

        leaf = bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);

        ASSERT(ichdr.count > 0 && ichdr.count < args->geo->blksize / 8);
        ASSERT(args->index >= 0 && args->index < ichdr.count);
        ASSERT(ichdr.firstused >= xfs_attr_leaf_entries_end(ichdr.count, leaf));

        entry = &xfs_attr3_leaf_entryp(leaf)[args->index];

        ASSERT(be16_to_cpu(entry->nameidx) >= ichdr.firstused);
        ASSERT(be16_to_cpu(entry->nameidx) < args->geo->blksize);

        /*
         * Scan through free region table:
         *    check for adjacency of free'd entry with an existing one,
         *    find smallest free region in case we need to replace it,
         *    adjust any map that borders the entry table,
         */
        tablesize = xfs_attr_leaf_entries_end(ichdr.count, leaf);
        tmp = ichdr.freemap[0].size;
        before = after = -1;
        smallest = XFS_ATTR_LEAF_MAPSIZE - 1;
        entsize = xfs_attr_leaf_entsize(leaf, args->index);
        for (i = 0; i < XFS_ATTR_LEAF_MAPSIZE; i++) {
                ASSERT(ichdr.freemap[i].base < args->geo->blksize);
                ASSERT(ichdr.freemap[i].size < args->geo->blksize);
                if (ichdr.freemap[i].base == tablesize) {
                        ichdr.freemap[i].base -= sizeof(xfs_attr_leaf_entry_t);
                        ichdr.freemap[i].size += sizeof(xfs_attr_leaf_entry_t);
                }

                if (ichdr.freemap[i].base + ichdr.freemap[i].size ==
                                be16_to_cpu(entry->nameidx)) {
                        before = i;
                } else if (ichdr.freemap[i].base ==
                                (be16_to_cpu(entry->nameidx) + entsize)) {
                        after = i;
                } else if (ichdr.freemap[i].size < tmp) {
                        tmp = ichdr.freemap[i].size;
                        smallest = i;
                }
        }

        /*
         * Coalesce adjacent freemap regions,
         * or replace the smallest region.
         */
        if ((before >= 0) || (after >= 0)) {
                if ((before >= 0) && (after >= 0)) {
                        ichdr.freemap[before].size += entsize;
                        ichdr.freemap[before].size += ichdr.freemap[after].size;
                        ichdr.freemap[after].base = 0;
                        ichdr.freemap[after].size = 0;
                } else if (before >= 0) {
                        ichdr.freemap[before].size += entsize;
                } else {
                        ichdr.freemap[after].base = be16_to_cpu(entry->nameidx);
                        ichdr.freemap[after].size += entsize;
                }
        } else {
                /*
                 * Replace smallest region (if it is smaller than free'd entry)
                 */
                if (ichdr.freemap[smallest].size < entsize) {
                        ichdr.freemap[smallest].base = be16_to_cpu(entry->nameidx);
                        ichdr.freemap[smallest].size = entsize;
                }
        }

        /*
         * Did we remove the first entry?
         */
        if (be16_to_cpu(entry->nameidx) == ichdr.firstused)
                smallest = 1;
        else
                smallest = 0;

        /*
         * Compress the remaining entries and zero out the removed stuff.
         */
        memset(xfs_attr3_leaf_name(leaf, args->index), 0, entsize);
        ichdr.usedbytes -= entsize;
        xfs_trans_log_buf(args->trans, bp,
             XFS_DA_LOGRANGE(leaf, xfs_attr3_leaf_name(leaf, args->index),
                                   entsize));

        tmp = (ichdr.count - args->index) * sizeof(xfs_attr_leaf_entry_t);
        memmove(entry, entry + 1, tmp);
        ichdr.count--;
        xfs_trans_log_buf(args->trans, bp,
            XFS_DA_LOGRANGE(leaf, entry, tmp + sizeof(xfs_attr_leaf_entry_t)));

        entry = &xfs_attr3_leaf_entryp(leaf)[ichdr.count];
        memset(entry, 0, sizeof(xfs_attr_leaf_entry_t));

        /*
         * If we removed the first entry, re-find the first used byte
         * in the name area.  Note that if the entry was the "firstused",
         * then we don't have a "hole" in our block resulting from
         * removing the name.
         */
        if (smallest) {
                tmp = args->geo->blksize;
                entry = xfs_attr3_leaf_entryp(leaf);
                for (i = ichdr.count - 1; i >= 0; entry++, i--) {
                        ASSERT(be16_to_cpu(entry->nameidx) >= ichdr.firstused);
                        ASSERT(be16_to_cpu(entry->nameidx) < args->geo->blksize);

                        if (be16_to_cpu(entry->nameidx) < tmp)
                                tmp = be16_to_cpu(entry->nameidx);
                }
                ichdr.firstused = tmp;
                ASSERT(ichdr.firstused != 0);
        } else {
                ichdr.holes = 1;        /* mark as needing compaction */
        }
        xfs_attr3_leaf_hdr_to_disk(args->geo, leaf, &ichdr);
        xfs_trans_log_buf(args->trans, bp,
                          XFS_DA_LOGRANGE(leaf, &leaf->hdr,
                                          xfs_attr3_leaf_hdr_size(leaf)));

        /*
         * Check if leaf is less than 50% full, caller may want to
         * "join" the leaf with a sibling if so.
         */
        tmp = ichdr.usedbytes + xfs_attr_leaf_entries_end(ichdr.count, leaf);

        return tmp < args->geo->magicpct; /* leaf is < 37% full */
}

/*
 * Move all the attribute list entries from drop_leaf into save_leaf.
 */
void
xfs_attr3_leaf_unbalance(
        struct xfs_da_state     *state,
        struct xfs_da_state_blk *drop_blk,
        struct xfs_da_state_blk *save_blk)
{
        struct xfs_attr_leafblock *drop_leaf = drop_blk->bp->b_addr;
        struct xfs_attr_leafblock *save_leaf = save_blk->bp->b_addr;
        struct xfs_attr3_icleaf_hdr drophdr;
        struct xfs_attr3_icleaf_hdr savehdr;
        struct xfs_attr_leaf_entry *entry;

        trace_xfs_attr_leaf_unbalance(state->args);

        xfs_attr3_leaf_hdr_from_disk(state->args->geo, &drophdr, drop_leaf);
        xfs_attr3_leaf_hdr_from_disk(state->args->geo, &savehdr, save_leaf);
        entry = xfs_attr3_leaf_entryp(drop_leaf);

        /*
         * Save last hashval from dying block for later Btree fixup.
         */
        drop_blk->hashval = be32_to_cpu(entry[drophdr.count - 1].hashval);

        /*
         * Check if we need a temp buffer, or can we do it in place.
         * Note that we don't check "leaf" for holes because we will
         * always be dropping it, toosmall() decided that for us already.
         */
        if (savehdr.holes == 0) {
                /*
                 * dest leaf has no holes, so we add there.  May need
                 * to make some room in the entry array.
                 */
                if (xfs_attr3_leaf_order(save_blk->bp, &savehdr,
                                         drop_blk->bp, &drophdr)) {
                        xfs_attr3_leaf_moveents(state->args,
                                                drop_leaf, &drophdr, 0,
                                                save_leaf, &savehdr, 0,
                                                drophdr.count);
                } else {
                        xfs_attr3_leaf_moveents(state->args,
                                                drop_leaf, &drophdr, 0,
                                                save_leaf, &savehdr,
                                                savehdr.count, drophdr.count);
                }
        } else {
                /*
                 * Destination has holes, so we make a temporary copy
                 * of the leaf and add them both to that.
                 */
                struct xfs_attr_leafblock *tmp_leaf;
                struct xfs_attr3_icleaf_hdr tmphdr;

                tmp_leaf = kvzalloc(state->args->geo->blksize,
                                GFP_KERNEL | __GFP_NOFAIL);

                /*
                 * Copy the header into the temp leaf so that all the stuff
                 * not in the incore header is present and gets copied back in
                 * once we've moved all the entries.
                 */
                memcpy(tmp_leaf, save_leaf, xfs_attr3_leaf_hdr_size(save_leaf));

                memset(&tmphdr, 0, sizeof(tmphdr));
                tmphdr.magic = savehdr.magic;
                tmphdr.forw = savehdr.forw;
                tmphdr.back = savehdr.back;
                tmphdr.firstused = state->args->geo->blksize;

                /* write the header to the temp buffer to initialise it */
                xfs_attr3_leaf_hdr_to_disk(state->args->geo, tmp_leaf, &tmphdr);

                if (xfs_attr3_leaf_order(save_blk->bp, &savehdr,
                                         drop_blk->bp, &drophdr)) {
                        xfs_attr3_leaf_moveents(state->args,
                                                drop_leaf, &drophdr, 0,
                                                tmp_leaf, &tmphdr, 0,
                                                drophdr.count);
                        xfs_attr3_leaf_moveents(state->args,
                                                save_leaf, &savehdr, 0,
                                                tmp_leaf, &tmphdr, tmphdr.count,
                                                savehdr.count);
                } else {
                        xfs_attr3_leaf_moveents(state->args,
                                                save_leaf, &savehdr, 0,
                                                tmp_leaf, &tmphdr, 0,
                                                savehdr.count);
                        xfs_attr3_leaf_moveents(state->args,
                                                drop_leaf, &drophdr, 0,
                                                tmp_leaf, &tmphdr, tmphdr.count,
                                                drophdr.count);
                }
                memcpy(save_leaf, tmp_leaf, state->args->geo->blksize);
                savehdr = tmphdr; /* struct copy */
                kvfree(tmp_leaf);
        }

        xfs_attr3_leaf_hdr_to_disk(state->args->geo, save_leaf, &savehdr);
        xfs_trans_log_buf(state->args->trans, save_blk->bp, 0,
                                           state->args->geo->blksize - 1);

        /*
         * Copy out last hashval in each block for B-tree code.
         */
        entry = xfs_attr3_leaf_entryp(save_leaf);
        save_blk->hashval = be32_to_cpu(entry[savehdr.count - 1].hashval);
}

/*========================================================================
 * Routines used for finding things in the Btree.
 *========================================================================*/

/*
 * Look up a name in a leaf attribute list structure.
 * This is the internal routine, it uses the caller's buffer.
 *
 * Note that duplicate keys are allowed, but only check within the
 * current leaf node.  The Btree code must check in adjacent leaf nodes.
 *
 * Return in args->index the index into the entry[] array of either
 * the found entry, or where the entry should have been (insert before
 * that entry).
 *
 * Don't change the args->value unless we find the attribute.
 */
int
xfs_attr3_leaf_lookup_int(
        struct xfs_buf          *bp,
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_entry *entries;
        struct xfs_attr_leaf_name_local *name_loc;
        struct xfs_attr_leaf_name_remote *name_rmt;
        xfs_dahash_t            hashval;
        int                     probe;
        int                     span;

        trace_xfs_attr_leaf_lookup(args);

        leaf = bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        entries = xfs_attr3_leaf_entryp(leaf);
        if (ichdr.count >= args->geo->blksize / 8) {
                xfs_buf_mark_corrupt(bp);
                xfs_da_mark_sick(args);
                return -EFSCORRUPTED;
        }

        /*
         * Binary search.  (note: small blocks will skip this loop)
         */
        hashval = args->hashval;
        probe = span = ichdr.count / 2;
        for (entry = &entries[probe]; span > 4; entry = &entries[probe]) {
                span /= 2;
                if (be32_to_cpu(entry->hashval) < hashval)
                        probe += span;
                else if (be32_to_cpu(entry->hashval) > hashval)
                        probe -= span;
                else
                        break;
        }
        if (!(probe >= 0 && (!ichdr.count || probe < ichdr.count))) {
                xfs_buf_mark_corrupt(bp);
                xfs_da_mark_sick(args);
                return -EFSCORRUPTED;
        }
        if (!(span <= 4 || be32_to_cpu(entry->hashval) == hashval)) {
                xfs_buf_mark_corrupt(bp);
                xfs_da_mark_sick(args);
                return -EFSCORRUPTED;
        }

        /*
         * Since we may have duplicate hashval's, find the first matching
         * hashval in the leaf.
         */
        while (probe > 0 && be32_to_cpu(entry->hashval) >= hashval) {
                entry--;
                probe--;
        }
        while (probe < ichdr.count &&
               be32_to_cpu(entry->hashval) < hashval) {
                entry++;
                probe++;
        }
        if (probe == ichdr.count || be32_to_cpu(entry->hashval) != hashval) {
                args->index = probe;
                return -ENOATTR;
        }

        /*
         * Duplicate keys may be present, so search all of them for a match.
         */
        for (; probe < ichdr.count && (be32_to_cpu(entry->hashval) == hashval);
                        entry++, probe++) {
/*
 * GROT: Add code to remove incomplete entries.
 */
                if (entry->flags & XFS_ATTR_LOCAL) {
                        name_loc = xfs_attr3_leaf_name_local(leaf, probe);
                        if (!xfs_attr_match(args, entry->flags,
                                        name_loc->nameval, name_loc->namelen,
                                        &name_loc->nameval[name_loc->namelen],
                                        be16_to_cpu(name_loc->valuelen)))
                                continue;
                        args->index = probe;
                        return -EEXIST;
                } else {
                        unsigned int    valuelen;

                        name_rmt = xfs_attr3_leaf_name_remote(leaf, probe);
                        valuelen = be32_to_cpu(name_rmt->valuelen);
                        if (!xfs_attr_match(args, entry->flags, name_rmt->name,
                                        name_rmt->namelen, NULL, valuelen))
                                continue;
                        args->index = probe;
                        args->rmtvaluelen = valuelen;
                        args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
                        args->rmtblkcnt = xfs_attr3_rmt_blocks(
                                                        args->dp->i_mount,
                                                        args->rmtvaluelen);
                        return -EEXIST;
                }
        }
        args->index = probe;
        return -ENOATTR;
}

/*
 * Get the value associated with an attribute name from a leaf attribute
 * list structure.
 *
 * If args->valuelen is zero, only the length needs to be returned.  Unlike a
 * lookup, we only return an error if the attribute does not exist or we can't
 * retrieve the value.
 */
int
xfs_attr3_leaf_getvalue(
        struct xfs_buf          *bp,
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_name_local *name_loc;
        struct xfs_attr_leaf_name_remote *name_rmt;

        leaf = bp->b_addr;
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        ASSERT(ichdr.count < args->geo->blksize / 8);
        ASSERT(args->index < ichdr.count);

        entry = &xfs_attr3_leaf_entryp(leaf)[args->index];
        if (entry->flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf, args->index);
                ASSERT(name_loc->namelen == args->namelen);
                ASSERT(memcmp(args->name, name_loc->nameval, args->namelen) == 0);
                return xfs_attr_copy_value(args,
                                        &name_loc->nameval[args->namelen],
                                        be16_to_cpu(name_loc->valuelen));
        }

        name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
        ASSERT(name_rmt->namelen == args->namelen);
        ASSERT(memcmp(args->name, name_rmt->name, args->namelen) == 0);
        args->rmtvaluelen = be32_to_cpu(name_rmt->valuelen);
        args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
        args->rmtblkcnt = xfs_attr3_rmt_blocks(args->dp->i_mount,
                                               args->rmtvaluelen);
        return xfs_attr_copy_value(args, NULL, args->rmtvaluelen);
}

/*========================================================================
 * Utility routines.
 *========================================================================*/

/*
 * Move the indicated entries from one leaf to another.
 * NOTE: this routine modifies both source and destination leaves.
 */
/*ARGSUSED*/
STATIC void
xfs_attr3_leaf_moveents(
        struct xfs_da_args              *args,
        struct xfs_attr_leafblock       *leaf_s,
        struct xfs_attr3_icleaf_hdr     *ichdr_s,
        int                             start_s,
        struct xfs_attr_leafblock       *leaf_d,
        struct xfs_attr3_icleaf_hdr     *ichdr_d,
        int                             start_d,
        int                             count)
{
        struct xfs_attr_leaf_entry      *entry_s;
        struct xfs_attr_leaf_entry      *entry_d;
        int                             desti;
        int                             tmp;
        int                             i;

        /*
         * Check for nothing to do.
         */
        if (count == 0)
                return;

        /*
         * Set up environment.
         */
        ASSERT(ichdr_s->magic == XFS_ATTR_LEAF_MAGIC ||
               ichdr_s->magic == XFS_ATTR3_LEAF_MAGIC);
        ASSERT(ichdr_s->magic == ichdr_d->magic);
        ASSERT(ichdr_s->count > 0 && ichdr_s->count < args->geo->blksize / 8);
        ASSERT(ichdr_s->firstused >=
                        xfs_attr_leaf_entries_end(ichdr_s->count, leaf_s));
        ASSERT(ichdr_d->count < args->geo->blksize / 8);
        ASSERT(ichdr_d->firstused >=
                        xfs_attr_leaf_entries_end(ichdr_d->count, leaf_d));

        ASSERT(start_s < ichdr_s->count);
        ASSERT(start_d <= ichdr_d->count);
        ASSERT(count <= ichdr_s->count);


        /*
         * Move the entries in the destination leaf up to make a hole?
         */
        if (start_d < ichdr_d->count) {
                tmp  = ichdr_d->count - start_d;
                tmp *= sizeof(xfs_attr_leaf_entry_t);
                entry_s = &xfs_attr3_leaf_entryp(leaf_d)[start_d];
                entry_d = &xfs_attr3_leaf_entryp(leaf_d)[start_d + count];
                memmove(entry_d, entry_s, tmp);
        }

        /*
         * Copy all entry's in the same (sorted) order,
         * but allocate attribute info packed and in sequence.
         */
        entry_s = &xfs_attr3_leaf_entryp(leaf_s)[start_s];
        entry_d = &xfs_attr3_leaf_entryp(leaf_d)[start_d];
        desti = start_d;
        for (i = 0; i < count; entry_s++, entry_d++, desti++, i++) {
                ASSERT(be16_to_cpu(entry_s->nameidx) >= ichdr_s->firstused);
                tmp = xfs_attr_leaf_entsize(leaf_s, start_s + i);
#ifdef GROT
                /*
                 * Code to drop INCOMPLETE entries.  Difficult to use as we
                 * may also need to change the insertion index.  Code turned
                 * off for 6.2, should be revisited later.
                 */
                if (entry_s->flags & XFS_ATTR_INCOMPLETE) { /* skip partials? */
                        memset(xfs_attr3_leaf_name(leaf_s, start_s + i), 0, tmp);
                        ichdr_s->usedbytes -= tmp;
                        ichdr_s->count -= 1;
                        entry_d--;      /* to compensate for ++ in loop hdr */
                        desti--;
                        if ((start_s + i) < offset)
                                result++;       /* insertion index adjustment */
                } else {
#endif /* GROT */
                        ichdr_d->firstused -= tmp;
                        /* both on-disk, don't endian flip twice */
                        entry_d->hashval = entry_s->hashval;
                        entry_d->nameidx = cpu_to_be16(ichdr_d->firstused);
                        entry_d->flags = entry_s->flags;
                        ASSERT(be16_to_cpu(entry_d->nameidx) + tmp
                                                        <= args->geo->blksize);
                        memmove(xfs_attr3_leaf_name(leaf_d, desti),
                                xfs_attr3_leaf_name(leaf_s, start_s + i), tmp);
                        ASSERT(be16_to_cpu(entry_s->nameidx) + tmp
                                                        <= args->geo->blksize);
                        memset(xfs_attr3_leaf_name(leaf_s, start_s + i), 0, tmp);
                        ichdr_s->usedbytes -= tmp;
                        ichdr_d->usedbytes += tmp;
                        ichdr_s->count -= 1;
                        ichdr_d->count += 1;
                        tmp = xfs_attr_leaf_entries_end(ichdr_d->count, leaf_d);
                        ASSERT(ichdr_d->firstused >= tmp);
#ifdef GROT
                }
#endif /* GROT */
        }

        /*
         * Zero out the entries we just copied.
         */
        if (start_s == ichdr_s->count) {
                tmp = count * sizeof(xfs_attr_leaf_entry_t);
                entry_s = &xfs_attr3_leaf_entryp(leaf_s)[start_s];
                ASSERT(((char *)entry_s + tmp) <=
                       ((char *)leaf_s + args->geo->blksize));
                memset(entry_s, 0, tmp);
        } else {
                /*
                 * Move the remaining entries down to fill the hole,
                 * then zero the entries at the top.
                 */
                tmp  = (ichdr_s->count - count) * sizeof(xfs_attr_leaf_entry_t);
                entry_s = &xfs_attr3_leaf_entryp(leaf_s)[start_s + count];
                entry_d = &xfs_attr3_leaf_entryp(leaf_s)[start_s];
                memmove(entry_d, entry_s, tmp);

                tmp = count * sizeof(xfs_attr_leaf_entry_t);
                entry_s = &xfs_attr3_leaf_entryp(leaf_s)[ichdr_s->count];
                ASSERT(((char *)entry_s + tmp) <=
                       ((char *)leaf_s + args->geo->blksize));
                memset(entry_s, 0, tmp);
        }

        /*
         * Fill in the freemap information
         */
        ichdr_d->freemap[0].base =
                xfs_attr_leaf_entries_end(ichdr_d->count, leaf_d);
        ichdr_d->freemap[0].size = ichdr_d->firstused - ichdr_d->freemap[0].base;
        ichdr_d->freemap[1].base = 0;
        ichdr_d->freemap[2].base = 0;
        ichdr_d->freemap[1].size = 0;
        ichdr_d->freemap[2].size = 0;
        ichdr_s->holes = 1;     /* leaf may not be compact */
}

/*
 * Pick up the last hashvalue from a leaf block.
 */
xfs_dahash_t
xfs_attr_leaf_lasthash(
        struct xfs_buf  *bp,
        int             *count)
{
        struct xfs_attr3_icleaf_hdr ichdr;
        struct xfs_attr_leaf_entry *entries;
        struct xfs_mount *mp = bp->b_mount;

        xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, bp->b_addr);
        entries = xfs_attr3_leaf_entryp(bp->b_addr);
        if (count)
                *count = ichdr.count;
        if (!ichdr.count)
                return 0;
        return be32_to_cpu(entries[ichdr.count - 1].hashval);
}

/*
 * Calculate the number of bytes used to store the indicated attribute
 * (whether local or remote only calculate bytes in this block).
 */
STATIC int
xfs_attr_leaf_entsize(xfs_attr_leafblock_t *leaf, int index)
{
        struct xfs_attr_leaf_entry *entries;
        xfs_attr_leaf_name_local_t *name_loc;
        xfs_attr_leaf_name_remote_t *name_rmt;
        int size;

        entries = xfs_attr3_leaf_entryp(leaf);
        if (entries[index].flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf, index);
                size = xfs_attr_leaf_entsize_local(name_loc->namelen,
                                                   be16_to_cpu(name_loc->valuelen));
        } else {
                name_rmt = xfs_attr3_leaf_name_remote(leaf, index);
                size = xfs_attr_leaf_entsize_remote(name_rmt->namelen);
        }
        return size;
}

/*
 * Calculate the number of bytes that would be required to store the new
 * attribute (whether local or remote only calculate bytes in this block).
 * This routine decides as a side effect whether the attribute will be
 * a "local" or a "remote" attribute.
 */
int
xfs_attr_leaf_newentsize(
        struct xfs_da_args      *args,
        int                     *local)
{
        int                     size;

        size = xfs_attr_leaf_entsize_local(args->namelen, args->valuelen);
        if (size < xfs_attr_leaf_entsize_local_max(args->geo->blksize)) {
                if (local)
                        *local = 1;
                return size;
        }
        if (local)
                *local = 0;
        return xfs_attr_leaf_entsize_remote(args->namelen);
}


/*========================================================================
 * Manage the INCOMPLETE flag in a leaf entry
 *========================================================================*/

/*
 * Clear the INCOMPLETE flag on an entry in a leaf block.
 */
int
xfs_attr3_leaf_clearflag(
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_name_remote *name_rmt;
        struct xfs_buf          *bp;
        int                     error;
#ifdef DEBUG
        struct xfs_attr3_icleaf_hdr ichdr;
        xfs_attr_leaf_name_local_t *name_loc;
        int namelen;
        char *name;
#endif /* DEBUG */

        trace_xfs_attr_leaf_clearflag(args);
        /*
         * Set up the operation.
         */
        error = xfs_attr3_leaf_read(args->trans, args->dp, args->owner,
                        args->blkno, &bp);
        if (error)
                return error;

        leaf = bp->b_addr;
        entry = &xfs_attr3_leaf_entryp(leaf)[args->index];
        ASSERT(entry->flags & XFS_ATTR_INCOMPLETE);

#ifdef DEBUG
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        ASSERT(args->index < ichdr.count);
        ASSERT(args->index >= 0);

        if (entry->flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf, args->index);
                namelen = name_loc->namelen;
                name = (char *)name_loc->nameval;
        } else {
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                namelen = name_rmt->namelen;
                name = (char *)name_rmt->name;
        }
        ASSERT(be32_to_cpu(entry->hashval) == args->hashval);
        ASSERT(namelen == args->namelen);
        ASSERT(memcmp(name, args->name, namelen) == 0);
#endif /* DEBUG */

        entry->flags &= ~XFS_ATTR_INCOMPLETE;
        xfs_trans_log_buf(args->trans, bp,
                         XFS_DA_LOGRANGE(leaf, entry, sizeof(*entry)));

        if (args->rmtblkno) {
                ASSERT((entry->flags & XFS_ATTR_LOCAL) == 0);
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                name_rmt->valueblk = cpu_to_be32(args->rmtblkno);
                name_rmt->valuelen = cpu_to_be32(args->rmtvaluelen);
                xfs_trans_log_buf(args->trans, bp,
                         XFS_DA_LOGRANGE(leaf, name_rmt, sizeof(*name_rmt)));
        }

        return 0;
}

/*
 * Set the INCOMPLETE flag on an entry in a leaf block.
 */
int
xfs_attr3_leaf_setflag(
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf;
        struct xfs_attr_leaf_entry *entry;
        struct xfs_attr_leaf_name_remote *name_rmt;
        struct xfs_buf          *bp;
        int error;
#ifdef DEBUG
        struct xfs_attr3_icleaf_hdr ichdr;
#endif

        trace_xfs_attr_leaf_setflag(args);

        /*
         * Set up the operation.
         */
        error = xfs_attr3_leaf_read(args->trans, args->dp, args->owner,
                        args->blkno, &bp);
        if (error)
                return error;

        leaf = bp->b_addr;
#ifdef DEBUG
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
        ASSERT(args->index < ichdr.count);
        ASSERT(args->index >= 0);
#endif
        entry = &xfs_attr3_leaf_entryp(leaf)[args->index];

        ASSERT((entry->flags & XFS_ATTR_INCOMPLETE) == 0);
        entry->flags |= XFS_ATTR_INCOMPLETE;
        xfs_trans_log_buf(args->trans, bp,
                        XFS_DA_LOGRANGE(leaf, entry, sizeof(*entry)));
        if ((entry->flags & XFS_ATTR_LOCAL) == 0) {
                name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
                name_rmt->valueblk = 0;
                name_rmt->valuelen = 0;
                xfs_trans_log_buf(args->trans, bp,
                         XFS_DA_LOGRANGE(leaf, name_rmt, sizeof(*name_rmt)));
        }

        return 0;
}

/*
 * In a single transaction, clear the INCOMPLETE flag on the leaf entry
 * given by args->blkno/index and set the INCOMPLETE flag on the leaf
 * entry given by args->blkno2/index2.
 *
 * Note that they could be in different blocks, or in the same block.
 */
int
xfs_attr3_leaf_flipflags(
        struct xfs_da_args      *args)
{
        struct xfs_attr_leafblock *leaf1;
        struct xfs_attr_leafblock *leaf2;
        struct xfs_attr_leaf_entry *entry1;
        struct xfs_attr_leaf_entry *entry2;
        struct xfs_attr_leaf_name_remote *name_rmt;
        struct xfs_buf          *bp1;
        struct xfs_buf          *bp2;
        int error;
#ifdef DEBUG
        struct xfs_attr3_icleaf_hdr ichdr1;
        struct xfs_attr3_icleaf_hdr ichdr2;
        xfs_attr_leaf_name_local_t *name_loc;
        int namelen1, namelen2;
        char *name1, *name2;
#endif /* DEBUG */

        trace_xfs_attr_leaf_flipflags(args);

        /*
         * Read the block containing the "old" attr
         */
        error = xfs_attr3_leaf_read(args->trans, args->dp, args->owner,
                        args->blkno, &bp1);
        if (error)
                return error;

        /*
         * Read the block containing the "new" attr, if it is different
         */
        if (args->blkno2 != args->blkno) {
                error = xfs_attr3_leaf_read(args->trans, args->dp, args->owner,
                                args->blkno2, &bp2);
                if (error)
                        return error;
        } else {
                bp2 = bp1;
        }

        leaf1 = bp1->b_addr;
        entry1 = &xfs_attr3_leaf_entryp(leaf1)[args->index];

        leaf2 = bp2->b_addr;
        entry2 = &xfs_attr3_leaf_entryp(leaf2)[args->index2];

#ifdef DEBUG
        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr1, leaf1);
        ASSERT(args->index < ichdr1.count);
        ASSERT(args->index >= 0);

        xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr2, leaf2);
        ASSERT(args->index2 < ichdr2.count);
        ASSERT(args->index2 >= 0);

        if (entry1->flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf1, args->index);
                namelen1 = name_loc->namelen;
                name1 = (char *)name_loc->nameval;
        } else {
                name_rmt = xfs_attr3_leaf_name_remote(leaf1, args->index);
                namelen1 = name_rmt->namelen;
                name1 = (char *)name_rmt->name;
        }
        if (entry2->flags & XFS_ATTR_LOCAL) {
                name_loc = xfs_attr3_leaf_name_local(leaf2, args->index2);
                namelen2 = name_loc->namelen;
                name2 = (char *)name_loc->nameval;
        } else {
                name_rmt = xfs_attr3_leaf_name_remote(leaf2, args->index2);
                namelen2 = name_rmt->namelen;
                name2 = (char *)name_rmt->name;
        }
        ASSERT(be32_to_cpu(entry1->hashval) == be32_to_cpu(entry2->hashval));
        ASSERT(namelen1 == namelen2);
        ASSERT(memcmp(name1, name2, namelen1) == 0);
#endif /* DEBUG */

        ASSERT(entry1->flags & XFS_ATTR_INCOMPLETE);
        ASSERT((entry2->flags & XFS_ATTR_INCOMPLETE) == 0);

        entry1->flags &= ~XFS_ATTR_INCOMPLETE;
        xfs_trans_log_buf(args->trans, bp1,
                          XFS_DA_LOGRANGE(leaf1, entry1, sizeof(*entry1)));
        if (args->rmtblkno) {
                ASSERT((entry1->flags & XFS_ATTR_LOCAL) == 0);
                name_rmt = xfs_attr3_leaf_name_remote(leaf1, args->index);
                name_rmt->valueblk = cpu_to_be32(args->rmtblkno);
                name_rmt->valuelen = cpu_to_be32(args->rmtvaluelen);
                xfs_trans_log_buf(args->trans, bp1,
                         XFS_DA_LOGRANGE(leaf1, name_rmt, sizeof(*name_rmt)));
        }

        entry2->flags |= XFS_ATTR_INCOMPLETE;
        xfs_trans_log_buf(args->trans, bp2,
                          XFS_DA_LOGRANGE(leaf2, entry2, sizeof(*entry2)));
        if ((entry2->flags & XFS_ATTR_LOCAL) == 0) {
                name_rmt = xfs_attr3_leaf_name_remote(leaf2, args->index2);
                name_rmt->valueblk = 0;
                name_rmt->valuelen = 0;
                xfs_trans_log_buf(args->trans, bp2,
                         XFS_DA_LOGRANGE(leaf2, name_rmt, sizeof(*name_rmt)));
        }

        return 0;
}