// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/nfs/file.c
 *
 *  Copyright (C) 1992  Rick Sladkey
 */
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/falloc.h>
#include <linux/mount.h>
#include <linux/nfs_fs.h>
#include <linux/nfs_ssc.h>
#include <linux/splice.h>
#include "delegation.h"
#include "internal.h"
#include "iostat.h"
#include "fscache.h"
#include "pnfs.h"

#include "nfstrace.h"

#ifdef CONFIG_NFS_V4_2
#include "nfs42.h"
#endif

#define NFSDBG_FACILITY         NFSDBG_FILE

static int
nfs4_file_open(struct inode *inode, struct file *filp)
{
        struct nfs_open_context *ctx;
        struct dentry *dentry = file_dentry(filp);
        struct dentry *parent = NULL;
        struct inode *dir;
        unsigned openflags = filp->f_flags;
        struct iattr attr;
        int err;

        /*
         * If no cached dentry exists or if it's negative, NFSv4 handled the
         * opens in ->lookup() or ->create().
         *
         * We only get this far for a cached positive dentry.  We skipped
         * revalidation, so handle it here by dropping the dentry and returning
         * -EOPENSTALE.  The VFS will retry the lookup/create/open.
         */

        dprintk("NFS: open file(%pd2)\n", dentry);

        err = nfs_check_flags(openflags);
        if (err)
                return err;

        /* We can't create new files here */
        openflags &= ~(O_CREAT|O_EXCL);

        parent = dget_parent(dentry);
        dir = d_inode(parent);

        ctx = alloc_nfs_open_context(file_dentry(filp),
                                     flags_to_mode(openflags), filp);
        err = PTR_ERR(ctx);
        if (IS_ERR(ctx))
                goto out;

        attr.ia_valid = ATTR_OPEN;
        if (openflags & O_TRUNC) {
                attr.ia_valid |= ATTR_SIZE;
                attr.ia_size = 0;
                filemap_write_and_wait(inode->i_mapping);
        }

        inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, &attr, NULL);
        if (IS_ERR(inode)) {
                err = PTR_ERR(inode);
                switch (err) {
                default:
                        goto out_put_ctx;
                case -ENOENT:
                case -ESTALE:
                case -EISDIR:
                case -ENOTDIR:
                case -ELOOP:
                        goto out_drop;
                }
        }
        if (inode != d_inode(dentry))
                goto out_drop;

        nfs_file_set_open_context(filp, ctx);
        nfs_fscache_open_file(inode, filp);
        err = 0;
        filp->f_mode |= FMODE_CAN_ODIRECT;

out_put_ctx:
        put_nfs_open_context(ctx);
out:
        dput(parent);
        return err;

out_drop:
        d_drop(dentry);
        err = -EOPENSTALE;
        goto out_put_ctx;
}

/*
 * Flush all dirty pages, and check for write errors.
 */
static int
nfs4_file_flush(struct file *file, fl_owner_t id)
{
        struct inode    *inode = file_inode(file);
        errseq_t since;

        dprintk("NFS: flush(%pD2)\n", file);

        nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
        if ((file->f_mode & FMODE_WRITE) == 0)
                return 0;

        /*
         * If we're holding a write delegation, then check if we're required
         * to flush the i/o on close. If not, then just start the i/o now.
         */
        if (!nfs4_delegation_flush_on_close(inode))
                return filemap_fdatawrite(file->f_mapping);

        /* Flush writes to the server and return any errors */
        since = filemap_sample_wb_err(file->f_mapping);
        nfs_wb_all(inode);
        return filemap_check_wb_err(file->f_mapping, since);
}

#ifdef CONFIG_NFS_V4_2
static ssize_t __nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
                                      struct file *file_out, loff_t pos_out,
                                      size_t count, unsigned int flags)
{
        struct nfs42_copy_notify_res *cn_resp = NULL;
        struct nl4_server *nss = NULL;
        nfs4_stateid *cnrs = NULL;
        ssize_t ret;
        bool sync = false;

        /* Only offload copy if superblock is the same */
        if (file_in->f_op != &nfs4_file_operations)
                return -EXDEV;
        if (!nfs_server_capable(file_inode(file_out), NFS_CAP_COPY) ||
            !nfs_server_capable(file_inode(file_in), NFS_CAP_COPY))
                return -EOPNOTSUPP;
        if (file_inode(file_in) == file_inode(file_out))
                return -EOPNOTSUPP;
        /* if the copy size if smaller than 2 RPC payloads, make it
         * synchronous
         */
        if (count <= 2 * NFS_SERVER(file_inode(file_in))->rsize)
                sync = true;
retry:
        if (!nfs42_files_from_same_server(file_in, file_out)) {
                /*
                 * for inter copy, if copy size is too small
                 * then fallback to generic copy.
                 */
                if (sync)
                        return -EOPNOTSUPP;
                cn_resp = kzalloc_obj(struct nfs42_copy_notify_res);
                if (unlikely(cn_resp == NULL))
                        return -ENOMEM;

                ret = nfs42_proc_copy_notify(file_in, file_out, cn_resp);
                if (ret) {
                        ret = -EOPNOTSUPP;
                        goto out;
                }
                nss = &cn_resp->cnr_src;
                cnrs = &cn_resp->cnr_stateid;
        }
        ret = nfs42_proc_copy(file_in, pos_in, file_out, pos_out, count,
                                nss, cnrs, sync);
out:
        kfree(cn_resp);

        if (ret == -EAGAIN)
                goto retry;
        return ret;
}

static ssize_t nfs4_copy_file_range(struct file *file_in, loff_t pos_in,
                                    struct file *file_out, loff_t pos_out,
                                    size_t count, unsigned int flags)
{
        ssize_t ret;

        ret = __nfs4_copy_file_range(file_in, pos_in, file_out, pos_out, count,
                                     flags);
        if (ret == -EOPNOTSUPP || ret == -EXDEV)
                ret = splice_copy_file_range(file_in, pos_in, file_out,
                                             pos_out, count);
        return ret;
}

static loff_t nfs4_file_llseek(struct file *filep, loff_t offset, int whence)
{
        loff_t ret;

        switch (whence) {
        case SEEK_HOLE:
        case SEEK_DATA:
                ret = nfs42_proc_llseek(filep, offset, whence);
                if (ret != -EOPNOTSUPP)
                        return ret;
                fallthrough;
        default:
                return nfs_file_llseek(filep, offset, whence);
        }
}

static long nfs42_fallocate(struct file *filep, int mode, loff_t offset, loff_t len)
{
        struct inode *inode = file_inode(filep);
        long ret;

        if (!S_ISREG(inode->i_mode))
                return -EOPNOTSUPP;

        switch (mode) {
        case 0:
        case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
        case FALLOC_FL_ZERO_RANGE:
                break;
        default:
                return -EOPNOTSUPP;
        }

        ret = inode_newsize_ok(inode, offset + len);
        if (ret < 0)
                return ret;

        if (mode & FALLOC_FL_PUNCH_HOLE)
                return nfs42_proc_deallocate(filep, offset, len);
        else if (mode & FALLOC_FL_ZERO_RANGE)
                return nfs42_proc_zero_range(filep, offset ,len);
        return nfs42_proc_allocate(filep, offset, len);
}

static loff_t nfs42_remap_file_range(struct file *src_file, loff_t src_off,
                struct file *dst_file, loff_t dst_off, loff_t count,
                unsigned int remap_flags)
{
        struct inode *dst_inode = file_inode(dst_file);
        struct nfs_server *server = NFS_SERVER(dst_inode);
        struct inode *src_inode = file_inode(src_file);
        unsigned int bs = server->clone_blksize;
        int ret;

        /* NFS does not support deduplication. */
        if (remap_flags & REMAP_FILE_DEDUP)
                return -EOPNOTSUPP;

        if (remap_flags & ~REMAP_FILE_ADVISORY)
                return -EINVAL;

        if (IS_SWAPFILE(dst_inode) || IS_SWAPFILE(src_inode))
                return -ETXTBSY;

        /* check alignment w.r.t. clone_blksize */
        ret = -EINVAL;
        if (bs) {
                if (!IS_ALIGNED(src_off, bs) || !IS_ALIGNED(dst_off, bs))
                        goto out;
                if (!IS_ALIGNED(count, bs) && i_size_read(src_inode) != (src_off + count))
                        goto out;
        }

        /* XXX: do we lock at all? what if server needs CB_RECALL_LAYOUT? */
        lock_two_nondirectories(src_inode, dst_inode);
        /* flush all pending writes on both src and dst so that server
         * has the latest data */
        nfs_file_block_o_direct(NFS_I(src_inode));
        ret = nfs_sync_inode(src_inode);
        if (ret)
                goto out_unlock;
        nfs_file_block_o_direct(NFS_I(dst_inode));
        ret = nfs_sync_inode(dst_inode);
        if (ret)
                goto out_unlock;

        ret = nfs42_proc_clone(src_file, dst_file, src_off, dst_off, count);

        /* truncate inode page cache of the dst range so that future reads can fetch
         * new data from server */
        if (!ret)
                truncate_inode_pages_range(&dst_inode->i_data, dst_off, dst_off + count - 1);

out_unlock:
        unlock_two_nondirectories(src_inode, dst_inode);
out:
        return ret < 0 ? ret : count;
}

static int read_name_gen = 1;
#define SSC_READ_NAME_BODY "ssc_read_%d"

static struct file *__nfs42_ssc_open(struct vfsmount *ss_mnt,
                struct nfs_fh *src_fh, nfs4_stateid *stateid)
{
        struct nfs_fattr *fattr = nfs_alloc_fattr();
        struct file *filep, *res;
        struct nfs_server *server;
        struct inode *r_ino = NULL;
        struct nfs_open_context *ctx;
        struct nfs4_state_owner *sp;
        char *read_name = NULL;
        int len, status = 0;

        server = NFS_SB(ss_mnt->mnt_sb);

        if (!fattr)
                return ERR_PTR(-ENOMEM);

        status = nfs4_proc_getattr(server, src_fh, fattr, NULL);
        if (status < 0) {
                res = ERR_PTR(status);
                goto out;
        }

        if (!S_ISREG(fattr->mode)) {
                res = ERR_PTR(-EBADF);
                goto out;
        }

        res = ERR_PTR(-ENOMEM);
        len = strlen(SSC_READ_NAME_BODY) + 16;
        read_name = kzalloc(len, GFP_KERNEL);
        if (read_name == NULL)
                goto out;
        snprintf(read_name, len, SSC_READ_NAME_BODY, read_name_gen++);

        r_ino = nfs_fhget(ss_mnt->mnt_sb, src_fh, fattr);
        if (IS_ERR(r_ino)) {
                res = ERR_CAST(r_ino);
                goto out_free_name;
        }

        filep = alloc_file_pseudo(r_ino, ss_mnt, read_name, O_RDONLY,
                                     r_ino->i_fop);
        if (IS_ERR(filep)) {
                res = ERR_CAST(filep);
                iput(r_ino);
                goto out_free_name;
        }

        ctx = alloc_nfs_open_context(filep->f_path.dentry,
                                     flags_to_mode(filep->f_flags), filep);
        if (IS_ERR(ctx)) {
                res = ERR_CAST(ctx);
                goto out_filep;
        }

        res = ERR_PTR(-EINVAL);
        sp = nfs4_get_state_owner(server, ctx->cred, GFP_KERNEL);
        if (sp == NULL)
                goto out_ctx;

        ctx->state = nfs4_get_open_state(r_ino, sp);
        if (ctx->state == NULL)
                goto out_stateowner;

        set_bit(NFS_SRV_SSC_COPY_STATE, &ctx->state->flags);
        memcpy(&ctx->state->open_stateid.other, &stateid->other,
               NFS4_STATEID_OTHER_SIZE);
        update_open_stateid(ctx->state, stateid, NULL, filep->f_mode);
        set_bit(NFS_OPEN_STATE, &ctx->state->flags);

        nfs_file_set_open_context(filep, ctx);
        put_nfs_open_context(ctx);

        file_ra_state_init(&filep->f_ra, filep->f_mapping->host->i_mapping);
        res = filep;
out_free_name:
        kfree(read_name);
out:
        nfs_free_fattr(fattr);
        return res;
out_stateowner:
        nfs4_put_state_owner(sp);
out_ctx:
        put_nfs_open_context(ctx);
out_filep:
        fput(filep);
        goto out_free_name;
}

static void __nfs42_ssc_close(struct file *filep)
{
        struct nfs_open_context *ctx = nfs_file_open_context(filep);

        ctx->state->flags = 0;
}

static const struct nfs4_ssc_client_ops nfs4_ssc_clnt_ops_tbl = {
        .sco_open = __nfs42_ssc_open,
        .sco_close = __nfs42_ssc_close,
};

/**
 * nfs42_ssc_register_ops - Wrapper to register NFS_V4 ops in nfs_common
 *
 * Return values:
 *   None
 */
void nfs42_ssc_register_ops(void)
{
        nfs42_ssc_register(&nfs4_ssc_clnt_ops_tbl);
}

/**
 * nfs42_ssc_unregister_ops - wrapper to un-register NFS_V4 ops in nfs_common
 *
 * Return values:
 *   None.
 */
void nfs42_ssc_unregister_ops(void)
{
        nfs42_ssc_unregister(&nfs4_ssc_clnt_ops_tbl);
}
#endif /* CONFIG_NFS_V4_2 */

static int nfs4_setlease(struct file *file, int arg, struct file_lease **lease,
                         void **priv)
{
        return nfs4_proc_setlease(file, arg, lease, priv);
}

const struct file_operations nfs4_file_operations = {
        .read_iter      = nfs_file_read,
        .write_iter     = nfs_file_write,
        .mmap_prepare   = nfs_file_mmap_prepare,
        .open           = nfs4_file_open,
        .flush          = nfs4_file_flush,
        .release        = nfs_file_release,
        .fsync          = nfs_file_fsync,
        .lock           = nfs_lock,
        .flock          = nfs_flock,
        .splice_read    = nfs_file_splice_read,
        .splice_write   = iter_file_splice_write,
        .check_flags    = nfs_check_flags,
        .setlease       = nfs4_setlease,
#ifdef CONFIG_NFS_V4_2
        .copy_file_range = nfs4_copy_file_range,
        .llseek         = nfs4_file_llseek,
        .fallocate      = nfs42_fallocate,
        .remap_file_range = nfs42_remap_file_range,
#else
        .llseek         = nfs_file_llseek,
#endif
        .fop_flags      = FOP_DONTCACHE,
};