root/fs/gfs2/xattr.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
 */

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/xattr.h>
#include <linux/gfs2_ondisk.h>
#include <linux/posix_acl_xattr.h>
#include <linux/uaccess.h>

#include "gfs2.h"
#include "incore.h"
#include "acl.h"
#include "xattr.h"
#include "glock.h"
#include "inode.h"
#include "meta_io.h"
#include "quota.h"
#include "rgrp.h"
#include "super.h"
#include "trans.h"
#include "util.h"

/*
 * ea_calc_size - returns the actual number of bytes the request will take up
 *                (not counting any unstuffed data blocks)
 *
 * Returns: 1 if the EA should be stuffed
 */

static int ea_calc_size(struct gfs2_sbd *sdp, unsigned int nsize, size_t dsize,
                        unsigned int *size)
{
        unsigned int jbsize = sdp->sd_jbsize;

        /* Stuffed */
        *size = ALIGN(sizeof(struct gfs2_ea_header) + nsize + dsize, 8);

        if (*size <= jbsize)
                return 1;

        /* Unstuffed */
        *size = ALIGN(sizeof(struct gfs2_ea_header) + nsize +
                      (sizeof(__be64) * DIV_ROUND_UP(dsize, jbsize)), 8);

        return 0;
}

static int ea_check_size(struct gfs2_sbd *sdp, unsigned int nsize, size_t dsize)
{
        unsigned int size;

        if (dsize > GFS2_EA_MAX_DATA_LEN)
                return -ERANGE;

        ea_calc_size(sdp, nsize, dsize, &size);

        /* This can only happen with 512 byte blocks */
        if (size > sdp->sd_jbsize)
                return -ERANGE;

        return 0;
}

static bool gfs2_eatype_valid(struct gfs2_sbd *sdp, u8 type)
{
        switch(sdp->sd_sb.sb_fs_format) {
        case GFS2_FS_FORMAT_MAX:
                return true;

        case GFS2_FS_FORMAT_MIN:
                return type <= GFS2_EATYPE_SECURITY;

        default:
                return false;
        }
}

typedef int (*ea_call_t) (struct gfs2_inode *ip, struct buffer_head *bh,
                          struct gfs2_ea_header *ea,
                          struct gfs2_ea_header *prev, void *private);

static int ea_foreach_i(struct gfs2_inode *ip, struct buffer_head *bh,
                        ea_call_t ea_call, void *data)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_ea_header *ea, *prev = NULL;
        int error = 0;

        if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_EA))
                return -EIO;

        for (ea = GFS2_EA_BH2FIRST(bh);; prev = ea, ea = GFS2_EA2NEXT(ea)) {
                if (!GFS2_EA_REC_LEN(ea)) {
                        gfs2_consist_inode(ip);
                        return -EIO;
                }
                if (!(bh->b_data <= (char *)ea && (char *)GFS2_EA2NEXT(ea) <=
                                                  bh->b_data + bh->b_size)) {
                        gfs2_consist_inode(ip);
                        return -EIO;
                }
                if (!gfs2_eatype_valid(sdp, ea->ea_type)) {
                        gfs2_consist_inode(ip);
                        return -EIO;
                }
                error = ea_call(ip, bh, ea, prev, data);
                if (error)
                        return error;

                if (GFS2_EA_IS_LAST(ea)) {
                        if ((char *)GFS2_EA2NEXT(ea) !=
                            bh->b_data + bh->b_size) {
                                gfs2_consist_inode(ip);
                                return -EIO;
                        }
                        break;
                }
        }

        return error;
}

static int ea_foreach(struct gfs2_inode *ip, ea_call_t ea_call, void *data)
{
        struct buffer_head *bh, *eabh;
        __be64 *eablk, *end;
        int error;

        error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0, &bh);
        if (error)
                return error;

        if (!(ip->i_diskflags & GFS2_DIF_EA_INDIRECT)) {
                error = ea_foreach_i(ip, bh, ea_call, data);
                goto out;
        }

        if (gfs2_metatype_check(GFS2_SB(&ip->i_inode), bh, GFS2_METATYPE_IN)) {
                error = -EIO;
                goto out;
        }

        eablk = (__be64 *)(bh->b_data + sizeof(struct gfs2_meta_header));
        end = eablk + GFS2_SB(&ip->i_inode)->sd_inptrs;

        for (; eablk < end; eablk++) {
                u64 bn;

                if (!*eablk)
                        break;
                bn = be64_to_cpu(*eablk);

                error = gfs2_meta_read(ip->i_gl, bn, DIO_WAIT, 0, &eabh);
                if (error)
                        break;
                error = ea_foreach_i(ip, eabh, ea_call, data);
                brelse(eabh);
                if (error)
                        break;
        }
out:
        brelse(bh);
        return error;
}

struct ea_find {
        int type;
        const char *name;
        size_t namel;
        struct gfs2_ea_location *ef_el;
};

static int ea_find_i(struct gfs2_inode *ip, struct buffer_head *bh,
                     struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
                     void *private)
{
        struct ea_find *ef = private;

        if (ea->ea_type == GFS2_EATYPE_UNUSED)
                return 0;

        if (ea->ea_type == ef->type) {
                if (ea->ea_name_len == ef->namel &&
                    !memcmp(GFS2_EA2NAME(ea), ef->name, ea->ea_name_len)) {
                        struct gfs2_ea_location *el = ef->ef_el;
                        get_bh(bh);
                        el->el_bh = bh;
                        el->el_ea = ea;
                        el->el_prev = prev;
                        return 1;
                }
        }

        return 0;
}

static int gfs2_ea_find(struct gfs2_inode *ip, int type, const char *name,
                        struct gfs2_ea_location *el)
{
        struct ea_find ef;
        int error;

        ef.type = type;
        ef.name = name;
        ef.namel = strlen(name);
        ef.ef_el = el;

        memset(el, 0, sizeof(struct gfs2_ea_location));

        error = ea_foreach(ip, ea_find_i, &ef);
        if (error > 0)
                return 0;

        return error;
}

/*
 * ea_dealloc_unstuffed
 *
 * Take advantage of the fact that all unstuffed blocks are
 * allocated from the same RG.  But watch, this may not always
 * be true.
 *
 * Returns: errno
 */

static int ea_dealloc_unstuffed(struct gfs2_inode *ip, struct buffer_head *bh,
                                struct gfs2_ea_header *ea,
                                struct gfs2_ea_header *prev, void *private)
{
        int *leave = private;
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *rgd;
        struct gfs2_holder rg_gh;
        __be64 *dataptrs;
        u64 bn = 0;
        u64 bstart = 0;
        unsigned int blen = 0;
        unsigned int blks = 0;
        unsigned int x;
        int error;

        error = gfs2_rindex_update(sdp);
        if (error)
                return error;

        if (GFS2_EA_IS_STUFFED(ea))
                return 0;

        dataptrs = GFS2_EA2DATAPTRS(ea);
        for (x = 0; x < ea->ea_num_ptrs; x++, dataptrs++) {
                if (*dataptrs) {
                        blks++;
                        bn = be64_to_cpu(*dataptrs);
                }
        }
        if (!blks)
                return 0;

        rgd = gfs2_blk2rgrpd(sdp, bn, 1);
        if (!rgd) {
                gfs2_consist_inode(ip);
                return -EIO;
        }

        error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,
                                   LM_FLAG_NODE_SCOPE, &rg_gh);
        if (error)
                return error;

        error = gfs2_trans_begin(sdp, rgd->rd_length + RES_DINODE +
                                 RES_EATTR + RES_STATFS + RES_QUOTA, blks);
        if (error)
                goto out_gunlock;

        gfs2_trans_add_meta(ip->i_gl, bh);

        dataptrs = GFS2_EA2DATAPTRS(ea);
        for (x = 0; x < ea->ea_num_ptrs; x++, dataptrs++) {
                if (!*dataptrs)
                        break;
                bn = be64_to_cpu(*dataptrs);

                if (bstart + blen == bn)
                        blen++;
                else {
                        if (bstart)
                                gfs2_free_meta(ip, rgd, bstart, blen);
                        bstart = bn;
                        blen = 1;
                }

                *dataptrs = 0;
                gfs2_add_inode_blocks(&ip->i_inode, -1);
        }
        if (bstart)
                gfs2_free_meta(ip, rgd, bstart, blen);

        if (prev && !leave) {
                u32 len;

                len = GFS2_EA_REC_LEN(prev) + GFS2_EA_REC_LEN(ea);
                prev->ea_rec_len = cpu_to_be32(len);

                if (GFS2_EA_IS_LAST(ea))
                        prev->ea_flags |= GFS2_EAFLAG_LAST;
        } else {
                ea->ea_type = GFS2_EATYPE_UNUSED;
                ea->ea_num_ptrs = 0;
        }

        inode_set_ctime_current(&ip->i_inode);
        __mark_inode_dirty(&ip->i_inode, I_DIRTY_DATASYNC);

        gfs2_trans_end(sdp);

out_gunlock:
        gfs2_glock_dq_uninit(&rg_gh);
        return error;
}

static int ea_remove_unstuffed(struct gfs2_inode *ip, struct buffer_head *bh,
                               struct gfs2_ea_header *ea,
                               struct gfs2_ea_header *prev, int leave)
{
        int error;

        error = gfs2_rindex_update(GFS2_SB(&ip->i_inode));
        if (error)
                return error;

        error = gfs2_quota_hold(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
        if (error)
                goto out_alloc;

        error = ea_dealloc_unstuffed(ip, bh, ea, prev, (leave) ? &error : NULL);

        gfs2_quota_unhold(ip);
out_alloc:
        return error;
}

struct ea_list {
        struct gfs2_ea_request *ei_er;
        unsigned int ei_size;
};

static int ea_list_i(struct gfs2_inode *ip, struct buffer_head *bh,
                     struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
                     void *private)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct ea_list *ei = private;
        struct gfs2_ea_request *er = ei->ei_er;
        unsigned int ea_size;
        char *prefix;
        unsigned int l;

        if (ea->ea_type == GFS2_EATYPE_UNUSED)
                return 0;

        BUG_ON(ea->ea_type > GFS2_EATYPE_SECURITY &&
               sdp->sd_sb.sb_fs_format == GFS2_FS_FORMAT_MIN);
        switch (ea->ea_type) {
        case GFS2_EATYPE_USR:
                prefix = "user.";
                l = 5;
                break;
        case GFS2_EATYPE_SYS:
                prefix = "system.";
                l = 7;
                break;
        case GFS2_EATYPE_SECURITY:
                prefix = "security.";
                l = 9;
                break;
        case GFS2_EATYPE_TRUSTED:
                prefix = "trusted.";
                l = 8;
                break;
        default:
                return 0;
        }

        ea_size = l + ea->ea_name_len + 1;
        if (er->er_data_len) {
                if (ei->ei_size + ea_size > er->er_data_len)
                        return -ERANGE;

                memcpy(er->er_data + ei->ei_size, prefix, l);
                memcpy(er->er_data + ei->ei_size + l, GFS2_EA2NAME(ea),
                       ea->ea_name_len);
                er->er_data[ei->ei_size + ea_size - 1] = 0;
        }

        ei->ei_size += ea_size;

        return 0;
}

/**
 * gfs2_listxattr - List gfs2 extended attributes
 * @dentry: The dentry whose inode we are interested in
 * @buffer: The buffer to write the results
 * @size: The size of the buffer
 *
 * Returns: actual size of data on success, -errno on error
 */

ssize_t gfs2_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
        struct gfs2_inode *ip = GFS2_I(d_inode(dentry));
        struct gfs2_ea_request er;
        struct gfs2_holder i_gh;
        int error;

        memset(&er, 0, sizeof(struct gfs2_ea_request));
        if (size) {
                er.er_data = buffer;
                er.er_data_len = size;
        }

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh);
        if (error)
                return error;

        if (ip->i_eattr) {
                struct ea_list ei = { .ei_er = &er, .ei_size = 0 };

                error = ea_foreach(ip, ea_list_i, &ei);
                if (!error)
                        error = ei.ei_size;
        }

        gfs2_glock_dq_uninit(&i_gh);

        return error;
}

/**
 * gfs2_iter_unstuffed - copies the unstuffed xattr data to/from the
 *                       request buffer
 * @ip: The GFS2 inode
 * @ea: The extended attribute header structure
 * @din: The data to be copied in
 * @dout: The data to be copied out (one of din,dout will be NULL)
 *
 * Returns: errno
 */

static int gfs2_iter_unstuffed(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
                               const char *din, char *dout)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head **bh;
        unsigned int amount = GFS2_EA_DATA_LEN(ea);
        unsigned int nptrs = DIV_ROUND_UP(amount, sdp->sd_jbsize);
        __be64 *dataptrs = GFS2_EA2DATAPTRS(ea);
        unsigned int x;
        int error = 0;
        unsigned char *pos;
        unsigned cp_size;

        bh = kzalloc_objs(struct buffer_head *, nptrs, GFP_NOFS);
        if (!bh)
                return -ENOMEM;

        for (x = 0; x < nptrs; x++) {
                error = gfs2_meta_read(ip->i_gl, be64_to_cpu(*dataptrs), 0, 0,
                                       bh + x);
                if (error) {
                        while (x--)
                                brelse(bh[x]);
                        goto out;
                }
                dataptrs++;
        }

        for (x = 0; x < nptrs; x++) {
                error = gfs2_meta_wait(sdp, bh[x]);
                if (error) {
                        for (; x < nptrs; x++)
                                brelse(bh[x]);
                        goto out;
                }
                if (gfs2_metatype_check(sdp, bh[x], GFS2_METATYPE_ED)) {
                        for (; x < nptrs; x++)
                                brelse(bh[x]);
                        error = -EIO;
                        goto out;
                }

                pos = bh[x]->b_data + sizeof(struct gfs2_meta_header);
                cp_size = (sdp->sd_jbsize > amount) ? amount : sdp->sd_jbsize;

                if (dout) {
                        memcpy(dout, pos, cp_size);
                        dout += sdp->sd_jbsize;
                }

                if (din) {
                        gfs2_trans_add_meta(ip->i_gl, bh[x]);
                        memcpy(pos, din, cp_size);
                        din += sdp->sd_jbsize;
                }

                amount -= sdp->sd_jbsize;
                brelse(bh[x]);
        }

out:
        kfree(bh);
        return error;
}

static int gfs2_ea_get_copy(struct gfs2_inode *ip, struct gfs2_ea_location *el,
                            char *data, size_t size)
{
        int ret;
        size_t len = GFS2_EA_DATA_LEN(el->el_ea);
        if (len > size)
                return -ERANGE;

        if (GFS2_EA_IS_STUFFED(el->el_ea)) {
                memcpy(data, GFS2_EA2DATA(el->el_ea), len);
                return len;
        }
        ret = gfs2_iter_unstuffed(ip, el->el_ea, NULL, data);
        if (ret < 0)
                return ret;
        return len;
}

int gfs2_xattr_acl_get(struct gfs2_inode *ip, const char *name, char **ppdata)
{
        struct gfs2_ea_location el;
        int error;
        int len;
        char *data;

        error = gfs2_ea_find(ip, GFS2_EATYPE_SYS, name, &el);
        if (error)
                return error;
        if (!el.el_ea)
                goto out;
        if (!GFS2_EA_DATA_LEN(el.el_ea))
                goto out;

        len = GFS2_EA_DATA_LEN(el.el_ea);
        data = kmalloc(len, GFP_NOFS);
        error = -ENOMEM;
        if (data == NULL)
                goto out;

        error = gfs2_ea_get_copy(ip, &el, data, len);
        if (error < 0)
                kfree(data);
        else
                *ppdata = data;
out:
        brelse(el.el_bh);
        return error;
}

/**
 * __gfs2_xattr_get - Get a GFS2 extended attribute
 * @inode: The inode
 * @name: The name of the extended attribute
 * @buffer: The buffer to write the result into
 * @size: The size of the buffer
 * @type: The type of extended attribute
 *
 * Returns: actual size of data on success, -errno on error
 */
static int __gfs2_xattr_get(struct inode *inode, const char *name,
                            void *buffer, size_t size, int type)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_ea_location el;
        int error;

        if (!ip->i_eattr)
                return -ENODATA;
        if (strlen(name) > GFS2_EA_MAX_NAME_LEN)
                return -EINVAL;

        error = gfs2_ea_find(ip, type, name, &el);
        if (error)
                return error;
        if (!el.el_ea)
                return -ENODATA;
        if (size)
                error = gfs2_ea_get_copy(ip, &el, buffer, size);
        else
                error = GFS2_EA_DATA_LEN(el.el_ea);
        brelse(el.el_bh);

        return error;
}

static int gfs2_xattr_get(const struct xattr_handler *handler,
                          struct dentry *unused, struct inode *inode,
                          const char *name, void *buffer, size_t size)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_holder gh;
        int ret;

        /* During lookup, SELinux calls this function with the glock locked. */

        if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
                ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &gh);
                if (ret)
                        return ret;
        } else {
                gfs2_holder_mark_uninitialized(&gh);
        }
        ret = __gfs2_xattr_get(inode, name, buffer, size, handler->flags);
        if (gfs2_holder_initialized(&gh))
                gfs2_glock_dq_uninit(&gh);
        return ret;
}

/**
 * ea_alloc_blk - allocates a new block for extended attributes.
 * @ip: A pointer to the inode that's getting extended attributes
 * @bhp: Pointer to pointer to a struct buffer_head
 *
 * Returns: errno
 */

static int ea_alloc_blk(struct gfs2_inode *ip, struct buffer_head **bhp)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_ea_header *ea;
        unsigned int n = 1;
        u64 block;
        int error;

        error = gfs2_alloc_blocks(ip, &block, &n, 0);
        if (error)
                return error;
        gfs2_trans_remove_revoke(sdp, block, 1);
        *bhp = gfs2_meta_new(ip->i_gl, block);
        gfs2_trans_add_meta(ip->i_gl, *bhp);
        gfs2_metatype_set(*bhp, GFS2_METATYPE_EA, GFS2_FORMAT_EA);
        gfs2_buffer_clear_tail(*bhp, sizeof(struct gfs2_meta_header));

        ea = GFS2_EA_BH2FIRST(*bhp);
        ea->ea_rec_len = cpu_to_be32(sdp->sd_jbsize);
        ea->ea_type = GFS2_EATYPE_UNUSED;
        ea->ea_flags = GFS2_EAFLAG_LAST;
        ea->ea_num_ptrs = 0;

        gfs2_add_inode_blocks(&ip->i_inode, 1);

        return 0;
}

/**
 * ea_write - writes the request info to an ea, creating new blocks if
 *            necessary
 * @ip: inode that is being modified
 * @ea: the location of the new ea in a block
 * @er: the write request
 *
 * Note: does not update ea_rec_len or the GFS2_EAFLAG_LAST bin of ea_flags
 *
 * returns : errno
 */

static int ea_write(struct gfs2_inode *ip, struct gfs2_ea_header *ea,
                    struct gfs2_ea_request *er)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        int error;

        ea->ea_data_len = cpu_to_be32(er->er_data_len);
        ea->ea_name_len = er->er_name_len;
        ea->ea_type = er->er_type;
        ea->__pad = 0;

        memcpy(GFS2_EA2NAME(ea), er->er_name, er->er_name_len);

        if (GFS2_EAREQ_SIZE_STUFFED(er) <= sdp->sd_jbsize) {
                ea->ea_num_ptrs = 0;
                memcpy(GFS2_EA2DATA(ea), er->er_data, er->er_data_len);
        } else {
                __be64 *dataptr = GFS2_EA2DATAPTRS(ea);
                const char *data = er->er_data;
                unsigned int data_len = er->er_data_len;
                unsigned int copy;
                unsigned int x;

                ea->ea_num_ptrs = DIV_ROUND_UP(er->er_data_len, sdp->sd_jbsize);
                for (x = 0; x < ea->ea_num_ptrs; x++) {
                        struct buffer_head *bh;
                        u64 block;
                        int mh_size = sizeof(struct gfs2_meta_header);
                        unsigned int n = 1;

                        error = gfs2_alloc_blocks(ip, &block, &n, 0);
                        if (error)
                                return error;
                        gfs2_trans_remove_revoke(sdp, block, 1);
                        bh = gfs2_meta_new(ip->i_gl, block);
                        gfs2_trans_add_meta(ip->i_gl, bh);
                        gfs2_metatype_set(bh, GFS2_METATYPE_ED, GFS2_FORMAT_ED);

                        gfs2_add_inode_blocks(&ip->i_inode, 1);

                        copy = data_len > sdp->sd_jbsize ? sdp->sd_jbsize :
                                                           data_len;
                        memcpy(bh->b_data + mh_size, data, copy);
                        if (copy < sdp->sd_jbsize)
                                memset(bh->b_data + mh_size + copy, 0,
                                       sdp->sd_jbsize - copy);

                        *dataptr++ = cpu_to_be64(bh->b_blocknr);
                        data += copy;
                        data_len -= copy;

                        brelse(bh);
                }

                gfs2_assert_withdraw(sdp, !data_len);
        }

        return 0;
}

typedef int (*ea_skeleton_call_t) (struct gfs2_inode *ip,
                                   struct gfs2_ea_request *er, void *private);

static int ea_alloc_skeleton(struct gfs2_inode *ip, struct gfs2_ea_request *er,
                             unsigned int blks,
                             ea_skeleton_call_t skeleton_call, void *private)
{
        struct gfs2_alloc_parms ap = { .target = blks };
        int error;

        error = gfs2_rindex_update(GFS2_SB(&ip->i_inode));
        if (error)
                return error;

        error = gfs2_quota_lock_check(ip, &ap);
        if (error)
                return error;

        error = gfs2_inplace_reserve(ip, &ap);
        if (error)
                goto out_gunlock_q;

        error = gfs2_trans_begin(GFS2_SB(&ip->i_inode),
                                 blks + gfs2_rg_blocks(ip, blks) +
                                 RES_DINODE + RES_STATFS + RES_QUOTA, 0);
        if (error)
                goto out_ipres;

        error = skeleton_call(ip, er, private);
        if (error)
                goto out_end_trans;

        inode_set_ctime_current(&ip->i_inode);
        __mark_inode_dirty(&ip->i_inode, I_DIRTY_DATASYNC);

out_end_trans:
        gfs2_trans_end(GFS2_SB(&ip->i_inode));
out_ipres:
        gfs2_inplace_release(ip);
out_gunlock_q:
        gfs2_quota_unlock(ip);
        return error;
}

static int ea_init_i(struct gfs2_inode *ip, struct gfs2_ea_request *er,
                     void *private)
{
        struct buffer_head *bh;
        int error;

        error = ea_alloc_blk(ip, &bh);
        if (error)
                return error;

        ip->i_eattr = bh->b_blocknr;
        error = ea_write(ip, GFS2_EA_BH2FIRST(bh), er);

        brelse(bh);

        return error;
}

/*
 * ea_init - initializes a new eattr block
 *
 * Returns: errno
 */
static int ea_init(struct gfs2_inode *ip, int type, const char *name,
                   const void *data, size_t size)
{
        struct gfs2_ea_request er;
        unsigned int jbsize = GFS2_SB(&ip->i_inode)->sd_jbsize;
        unsigned int blks = 1;

        er.er_type = type;
        er.er_name = name;
        er.er_name_len = strlen(name);
        er.er_data = (void *)data;
        er.er_data_len = size;

        if (GFS2_EAREQ_SIZE_STUFFED(&er) > jbsize)
                blks += DIV_ROUND_UP(er.er_data_len, jbsize);

        return ea_alloc_skeleton(ip, &er, blks, ea_init_i, NULL);
}

static struct gfs2_ea_header *ea_split_ea(struct gfs2_ea_header *ea)
{
        u32 ea_size = GFS2_EA_SIZE(ea);
        struct gfs2_ea_header *new = (struct gfs2_ea_header *)((char *)ea +
                                     ea_size);
        u32 new_size = GFS2_EA_REC_LEN(ea) - ea_size;
        int last = ea->ea_flags & GFS2_EAFLAG_LAST;

        ea->ea_rec_len = cpu_to_be32(ea_size);
        ea->ea_flags ^= last;

        new->ea_rec_len = cpu_to_be32(new_size);
        new->ea_flags = last;

        return new;
}

static void ea_set_remove_stuffed(struct gfs2_inode *ip,
                                  struct gfs2_ea_location *el)
{
        struct gfs2_ea_header *ea = el->el_ea;
        struct gfs2_ea_header *prev = el->el_prev;
        u32 len;

        gfs2_trans_add_meta(ip->i_gl, el->el_bh);

        if (!prev || !GFS2_EA_IS_STUFFED(ea)) {
                ea->ea_type = GFS2_EATYPE_UNUSED;
                return;
        } else if (GFS2_EA2NEXT(prev) != ea) {
                prev = GFS2_EA2NEXT(prev);
                gfs2_assert_withdraw(GFS2_SB(&ip->i_inode), GFS2_EA2NEXT(prev) == ea);
        }

        len = GFS2_EA_REC_LEN(prev) + GFS2_EA_REC_LEN(ea);
        prev->ea_rec_len = cpu_to_be32(len);

        if (GFS2_EA_IS_LAST(ea))
                prev->ea_flags |= GFS2_EAFLAG_LAST;
}

struct ea_set {
        int ea_split;

        struct gfs2_ea_request *es_er;
        struct gfs2_ea_location *es_el;

        struct buffer_head *es_bh;
        struct gfs2_ea_header *es_ea;
};

static int ea_set_simple_noalloc(struct gfs2_inode *ip, struct buffer_head *bh,
                                 struct gfs2_ea_header *ea, struct ea_set *es)
{
        struct gfs2_ea_request *er = es->es_er;
        int error;

        error = gfs2_trans_begin(GFS2_SB(&ip->i_inode), RES_DINODE + 2 * RES_EATTR, 0);
        if (error)
                return error;

        gfs2_trans_add_meta(ip->i_gl, bh);

        if (es->ea_split)
                ea = ea_split_ea(ea);

        ea_write(ip, ea, er);

        if (es->es_el)
                ea_set_remove_stuffed(ip, es->es_el);

        inode_set_ctime_current(&ip->i_inode);
        __mark_inode_dirty(&ip->i_inode, I_DIRTY_DATASYNC);

        gfs2_trans_end(GFS2_SB(&ip->i_inode));
        return error;
}

static int ea_set_simple_alloc(struct gfs2_inode *ip,
                               struct gfs2_ea_request *er, void *private)
{
        struct ea_set *es = private;
        struct gfs2_ea_header *ea = es->es_ea;
        int error;

        gfs2_trans_add_meta(ip->i_gl, es->es_bh);

        if (es->ea_split)
                ea = ea_split_ea(ea);

        error = ea_write(ip, ea, er);
        if (error)
                return error;

        if (es->es_el)
                ea_set_remove_stuffed(ip, es->es_el);

        return 0;
}

static int ea_set_simple(struct gfs2_inode *ip, struct buffer_head *bh,
                         struct gfs2_ea_header *ea, struct gfs2_ea_header *prev,
                         void *private)
{
        struct ea_set *es = private;
        unsigned int size;
        int stuffed;
        int error;

        stuffed = ea_calc_size(GFS2_SB(&ip->i_inode), es->es_er->er_name_len,
                               es->es_er->er_data_len, &size);

        if (ea->ea_type == GFS2_EATYPE_UNUSED) {
                if (GFS2_EA_REC_LEN(ea) < size)
                        return 0;
                if (!GFS2_EA_IS_STUFFED(ea)) {
                        error = ea_remove_unstuffed(ip, bh, ea, prev, 1);
                        if (error)
                                return error;
                }
                es->ea_split = 0;
        } else if (GFS2_EA_REC_LEN(ea) - GFS2_EA_SIZE(ea) >= size)
                es->ea_split = 1;
        else
                return 0;

        if (stuffed) {
                error = ea_set_simple_noalloc(ip, bh, ea, es);
                if (error)
                        return error;
        } else {
                unsigned int blks;

                es->es_bh = bh;
                es->es_ea = ea;
                blks = 2 + DIV_ROUND_UP(es->es_er->er_data_len,
                                        GFS2_SB(&ip->i_inode)->sd_jbsize);

                error = ea_alloc_skeleton(ip, es->es_er, blks,
                                          ea_set_simple_alloc, es);
                if (error)
                        return error;
        }

        return 1;
}

static int ea_set_block(struct gfs2_inode *ip, struct gfs2_ea_request *er,
                        void *private)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct buffer_head *indbh, *newbh;
        __be64 *eablk;
        int error;
        int mh_size = sizeof(struct gfs2_meta_header);

        if (ip->i_diskflags & GFS2_DIF_EA_INDIRECT) {
                __be64 *end;

                error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0,
                                       &indbh);
                if (error)
                        return error;

                if (gfs2_metatype_check(sdp, indbh, GFS2_METATYPE_IN)) {
                        error = -EIO;
                        goto out;
                }

                eablk = (__be64 *)(indbh->b_data + mh_size);
                end = eablk + sdp->sd_inptrs;

                for (; eablk < end; eablk++)
                        if (!*eablk)
                                break;

                if (eablk == end) {
                        error = -ENOSPC;
                        goto out;
                }

                gfs2_trans_add_meta(ip->i_gl, indbh);
        } else {
                u64 blk;
                unsigned int n = 1;
                error = gfs2_alloc_blocks(ip, &blk, &n, 0);
                if (error)
                        return error;
                gfs2_trans_remove_revoke(sdp, blk, 1);
                indbh = gfs2_meta_new(ip->i_gl, blk);
                gfs2_trans_add_meta(ip->i_gl, indbh);
                gfs2_metatype_set(indbh, GFS2_METATYPE_IN, GFS2_FORMAT_IN);
                gfs2_buffer_clear_tail(indbh, mh_size);

                eablk = (__be64 *)(indbh->b_data + mh_size);
                *eablk = cpu_to_be64(ip->i_eattr);
                ip->i_eattr = blk;
                ip->i_diskflags |= GFS2_DIF_EA_INDIRECT;
                gfs2_add_inode_blocks(&ip->i_inode, 1);

                eablk++;
        }

        error = ea_alloc_blk(ip, &newbh);
        if (error)
                goto out;

        *eablk = cpu_to_be64((u64)newbh->b_blocknr);
        error = ea_write(ip, GFS2_EA_BH2FIRST(newbh), er);
        brelse(newbh);
        if (error)
                goto out;

        if (private)
                ea_set_remove_stuffed(ip, private);

out:
        brelse(indbh);
        return error;
}

static int ea_set_i(struct gfs2_inode *ip, int type, const char *name,
                    const void *value, size_t size, struct gfs2_ea_location *el)
{
        struct gfs2_ea_request er;
        struct ea_set es;
        unsigned int blks = 2;
        int error;

        er.er_type = type;
        er.er_name = name;
        er.er_data = (void *)value;
        er.er_name_len = strlen(name);
        er.er_data_len = size;

        memset(&es, 0, sizeof(struct ea_set));
        es.es_er = &er;
        es.es_el = el;

        error = ea_foreach(ip, ea_set_simple, &es);
        if (error > 0)
                return 0;
        if (error)
                return error;

        if (!(ip->i_diskflags & GFS2_DIF_EA_INDIRECT))
                blks++;
        if (GFS2_EAREQ_SIZE_STUFFED(&er) > GFS2_SB(&ip->i_inode)->sd_jbsize)
                blks += DIV_ROUND_UP(er.er_data_len, GFS2_SB(&ip->i_inode)->sd_jbsize);

        return ea_alloc_skeleton(ip, &er, blks, ea_set_block, el);
}

static int ea_set_remove_unstuffed(struct gfs2_inode *ip,
                                   struct gfs2_ea_location *el)
{
        if (el->el_prev && GFS2_EA2NEXT(el->el_prev) != el->el_ea) {
                el->el_prev = GFS2_EA2NEXT(el->el_prev);
                gfs2_assert_withdraw(GFS2_SB(&ip->i_inode),
                                     GFS2_EA2NEXT(el->el_prev) == el->el_ea);
        }

        return ea_remove_unstuffed(ip, el->el_bh, el->el_ea, el->el_prev, 0);
}

static int ea_remove_stuffed(struct gfs2_inode *ip, struct gfs2_ea_location *el)
{
        struct gfs2_ea_header *ea = el->el_ea;
        struct gfs2_ea_header *prev = el->el_prev;
        int error;

        error = gfs2_trans_begin(GFS2_SB(&ip->i_inode), RES_DINODE + RES_EATTR, 0);
        if (error)
                return error;

        gfs2_trans_add_meta(ip->i_gl, el->el_bh);

        if (prev) {
                u32 len;

                len = GFS2_EA_REC_LEN(prev) + GFS2_EA_REC_LEN(ea);
                prev->ea_rec_len = cpu_to_be32(len);

                if (GFS2_EA_IS_LAST(ea))
                        prev->ea_flags |= GFS2_EAFLAG_LAST;
        } else {
                ea->ea_type = GFS2_EATYPE_UNUSED;
        }

        inode_set_ctime_current(&ip->i_inode);
        __mark_inode_dirty(&ip->i_inode, I_DIRTY_DATASYNC);

        gfs2_trans_end(GFS2_SB(&ip->i_inode));

        return error;
}

/**
 * gfs2_xattr_remove - Remove a GFS2 extended attribute
 * @ip: The inode
 * @type: The type of the extended attribute
 * @name: The name of the extended attribute
 *
 * This is not called directly by the VFS since we use the (common)
 * scheme of making a "set with NULL data" mean a remove request. Note
 * that this is different from a set with zero length data.
 *
 * Returns: 0, or errno on failure
 */

static int gfs2_xattr_remove(struct gfs2_inode *ip, int type, const char *name)
{
        struct gfs2_ea_location el;
        int error;

        if (!ip->i_eattr)
                return -ENODATA;

        error = gfs2_ea_find(ip, type, name, &el);
        if (error)
                return error;
        if (!el.el_ea)
                return -ENODATA;

        if (GFS2_EA_IS_STUFFED(el.el_ea))
                error = ea_remove_stuffed(ip, &el);
        else
                error = ea_remove_unstuffed(ip, el.el_bh, el.el_ea, el.el_prev, 0);

        brelse(el.el_bh);

        return error;
}

/**
 * __gfs2_xattr_set - Set (or remove) a GFS2 extended attribute
 * @inode: The inode
 * @name: The name of the extended attribute
 * @value: The value of the extended attribute (NULL for remove)
 * @size: The size of the @value argument
 * @flags: Create or Replace
 * @type: The type of the extended attribute
 *
 * See gfs2_xattr_remove() for details of the removal of xattrs.
 *
 * Returns: 0 or errno on failure
 */

int __gfs2_xattr_set(struct inode *inode, const char *name,
                   const void *value, size_t size, int flags, int type)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_sbd *sdp = GFS2_SB(inode);
        struct gfs2_ea_location el;
        unsigned int namel = strlen(name);
        int error;

        if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
                return -EPERM;
        if (namel > GFS2_EA_MAX_NAME_LEN)
                return -ERANGE;

        if (value == NULL) {
                error = gfs2_xattr_remove(ip, type, name);
                if (error == -ENODATA && !(flags & XATTR_REPLACE))
                        error = 0;
                return error;
        }

        if (ea_check_size(sdp, namel, size))
                return -ERANGE;

        if (!ip->i_eattr) {
                if (flags & XATTR_REPLACE)
                        return -ENODATA;
                return ea_init(ip, type, name, value, size);
        }

        error = gfs2_ea_find(ip, type, name, &el);
        if (error)
                return error;

        if (el.el_ea) {
                if (ip->i_diskflags & GFS2_DIF_APPENDONLY) {
                        brelse(el.el_bh);
                        return -EPERM;
                }

                error = -EEXIST;
                if (!(flags & XATTR_CREATE)) {
                        int unstuffed = !GFS2_EA_IS_STUFFED(el.el_ea);
                        error = ea_set_i(ip, type, name, value, size, &el);
                        if (!error && unstuffed)
                                ea_set_remove_unstuffed(ip, &el);
                }

                brelse(el.el_bh);
                return error;
        }

        error = -ENODATA;
        if (!(flags & XATTR_REPLACE))
                error = ea_set_i(ip, type, name, value, size, NULL);

        return error;
}

static int gfs2_xattr_set(const struct xattr_handler *handler,
                          struct mnt_idmap *idmap,
                          struct dentry *unused, struct inode *inode,
                          const char *name, const void *value,
                          size_t size, int flags)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_holder gh;
        int ret;

        ret = gfs2_qa_get(ip);
        if (ret)
                return ret;

        /* May be called from gfs_setattr with the glock locked. */

        if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
                ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
                if (ret)
                        goto out;
        } else {
                if (WARN_ON_ONCE(ip->i_gl->gl_state != LM_ST_EXCLUSIVE)) {
                        ret = -EIO;
                        goto out;
                }
                gfs2_holder_mark_uninitialized(&gh);
        }
        ret = __gfs2_xattr_set(inode, name, value, size, flags, handler->flags);
        if (gfs2_holder_initialized(&gh))
                gfs2_glock_dq_uninit(&gh);
out:
        gfs2_qa_put(ip);
        return ret;
}

static int ea_dealloc_indirect(struct gfs2_inode *ip)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrp_list rlist;
        struct gfs2_rgrpd *rgd;
        struct buffer_head *indbh, *dibh;
        __be64 *eablk, *end;
        unsigned int rg_blocks = 0;
        u64 bstart = 0;
        unsigned int blen = 0;
        unsigned int blks = 0;
        unsigned int x;
        int error;

        error = gfs2_rindex_update(sdp);
        if (error)
                return error;

        memset(&rlist, 0, sizeof(struct gfs2_rgrp_list));

        error = gfs2_meta_read(ip->i_gl, ip->i_eattr, DIO_WAIT, 0, &indbh);
        if (error)
                return error;

        if (gfs2_metatype_check(sdp, indbh, GFS2_METATYPE_IN)) {
                error = -EIO;
                goto out;
        }

        eablk = (__be64 *)(indbh->b_data + sizeof(struct gfs2_meta_header));
        end = eablk + sdp->sd_inptrs;

        for (; eablk < end; eablk++) {
                u64 bn;

                if (!*eablk)
                        break;
                bn = be64_to_cpu(*eablk);

                if (bstart + blen == bn)
                        blen++;
                else {
                        if (bstart)
                                gfs2_rlist_add(ip, &rlist, bstart);
                        bstart = bn;
                        blen = 1;
                }
                blks++;
        }
        if (bstart)
                gfs2_rlist_add(ip, &rlist, bstart);
        else
                goto out;

        gfs2_rlist_alloc(&rlist, LM_ST_EXCLUSIVE, LM_FLAG_NODE_SCOPE);

        for (x = 0; x < rlist.rl_rgrps; x++) {
                rgd = gfs2_glock2rgrp(rlist.rl_ghs[x].gh_gl);
                rg_blocks += rgd->rd_length;
        }

        error = gfs2_glock_nq_m(rlist.rl_rgrps, rlist.rl_ghs);
        if (error)
                goto out_rlist_free;

        error = gfs2_trans_begin(sdp, rg_blocks + RES_DINODE + RES_INDIRECT +
                                 RES_STATFS + RES_QUOTA, blks);
        if (error)
                goto out_gunlock;

        gfs2_trans_add_meta(ip->i_gl, indbh);

        eablk = (__be64 *)(indbh->b_data + sizeof(struct gfs2_meta_header));
        bstart = 0;
        rgd = NULL;
        blen = 0;

        for (; eablk < end; eablk++) {
                u64 bn;

                if (!*eablk)
                        break;
                bn = be64_to_cpu(*eablk);

                if (bstart + blen == bn)
                        blen++;
                else {
                        if (bstart)
                                gfs2_free_meta(ip, rgd, bstart, blen);
                        bstart = bn;
                        rgd = gfs2_blk2rgrpd(sdp, bstart, true);
                        blen = 1;
                }

                *eablk = 0;
                gfs2_add_inode_blocks(&ip->i_inode, -1);
        }
        if (bstart)
                gfs2_free_meta(ip, rgd, bstart, blen);

        ip->i_diskflags &= ~GFS2_DIF_EA_INDIRECT;

        error = gfs2_meta_inode_buffer(ip, &dibh);
        if (!error) {
                gfs2_trans_add_meta(ip->i_gl, dibh);
                gfs2_dinode_out(ip, dibh->b_data);
                brelse(dibh);
        }

        gfs2_trans_end(sdp);

out_gunlock:
        gfs2_glock_dq_m(rlist.rl_rgrps, rlist.rl_ghs);
out_rlist_free:
        gfs2_rlist_free(&rlist);
out:
        brelse(indbh);
        return error;
}

static int ea_dealloc_block(struct gfs2_inode *ip, bool initialized)
{
        struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
        struct gfs2_rgrpd *rgd;
        struct buffer_head *dibh;
        struct gfs2_holder gh;
        int error;

        error = gfs2_rindex_update(sdp);
        if (error)
                return error;

        rgd = gfs2_blk2rgrpd(sdp, ip->i_eattr, 1);
        if (!rgd) {
                gfs2_consist_inode(ip);
                return -EIO;
        }

        error = gfs2_glock_nq_init(rgd->rd_gl, LM_ST_EXCLUSIVE,
                                   LM_FLAG_NODE_SCOPE, &gh);
        if (error)
                return error;

        error = gfs2_trans_begin(sdp, RES_RG_BIT + RES_DINODE + RES_STATFS +
                                 RES_QUOTA, 1);
        if (error)
                goto out_gunlock;

        gfs2_free_meta(ip, rgd, ip->i_eattr, 1);

        ip->i_eattr = 0;
        gfs2_add_inode_blocks(&ip->i_inode, -1);

        if (initialized) {
                error = gfs2_meta_inode_buffer(ip, &dibh);
                if (!error) {
                        gfs2_trans_add_meta(ip->i_gl, dibh);
                        gfs2_dinode_out(ip, dibh->b_data);
                        brelse(dibh);
                }
        }

        gfs2_trans_end(sdp);

out_gunlock:
        gfs2_glock_dq_uninit(&gh);
        return error;
}

/**
 * gfs2_ea_dealloc - deallocate the extended attribute fork
 * @ip: the inode
 * @initialized: xattrs have been initialized
 *
 * Returns: errno
 */

int gfs2_ea_dealloc(struct gfs2_inode *ip, bool initialized)
{
        int error;

        error = gfs2_rindex_update(GFS2_SB(&ip->i_inode));
        if (error)
                return error;

        error = gfs2_quota_hold(ip, NO_UID_QUOTA_CHANGE, NO_GID_QUOTA_CHANGE);
        if (error)
                return error;

        if (initialized) {
                error = ea_foreach(ip, ea_dealloc_unstuffed, NULL);
                if (error)
                        goto out_quota;

                if (ip->i_diskflags & GFS2_DIF_EA_INDIRECT) {
                        error = ea_dealloc_indirect(ip);
                        if (error)
                                goto out_quota;
                }
        }

        error = ea_dealloc_block(ip, initialized);

out_quota:
        gfs2_quota_unhold(ip);
        return error;
}

static const struct xattr_handler gfs2_xattr_user_handler = {
        .prefix = XATTR_USER_PREFIX,
        .flags  = GFS2_EATYPE_USR,
        .get    = gfs2_xattr_get,
        .set    = gfs2_xattr_set,
};

static const struct xattr_handler gfs2_xattr_security_handler = {
        .prefix = XATTR_SECURITY_PREFIX,
        .flags  = GFS2_EATYPE_SECURITY,
        .get    = gfs2_xattr_get,
        .set    = gfs2_xattr_set,
};

static bool
gfs2_xattr_trusted_list(struct dentry *dentry)
{
        return capable(CAP_SYS_ADMIN);
}

static const struct xattr_handler gfs2_xattr_trusted_handler = {
        .prefix = XATTR_TRUSTED_PREFIX,
        .flags  = GFS2_EATYPE_TRUSTED,
        .list   = gfs2_xattr_trusted_list,
        .get    = gfs2_xattr_get,
        .set    = gfs2_xattr_set,
};

const struct xattr_handler * const gfs2_xattr_handlers_max[] = {
        /* GFS2_FS_FORMAT_MAX */
        &gfs2_xattr_trusted_handler,

        /* GFS2_FS_FORMAT_MIN */
        &gfs2_xattr_user_handler,
        &gfs2_xattr_security_handler,
        NULL,
};

const struct xattr_handler * const *gfs2_xattr_handlers_min = gfs2_xattr_handlers_max + 1;