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linux/fs/9p/vfs_inode.c
NeilBrown 88d5baf690
Change inode_operations.mkdir to return struct dentry * 
Some filesystems, such as NFS, cifs, ceph, and fuse, do not have
complete control of sequencing on the actual filesystem (e.g.  on a
different server) and may find that the inode created for a mkdir
request already exists in the icache and dcache by the time the mkdir
request returns.  For example, if the filesystem is mounted twice the
directory could be visible on the other mount before it is on the
original mount, and a pair of name_to_handle_at(), open_by_handle_at()
calls could instantiate the directory inode with an IS_ROOT() dentry
before the first mkdir returns.

This means that the dentry passed to ->mkdir() may not be the one that
is associated with the inode after the ->mkdir() completes.  Some
callers need to interact with the inode after the ->mkdir completes and
they currently need to perform a lookup in the (rare) case that the
dentry is no longer hashed.

This lookup-after-mkdir requires that the directory remains locked to
avoid races.  Planned future patches to lock the dentry rather than the
directory will mean that this lookup cannot be performed atomically with
the mkdir.

To remove this barrier, this patch changes ->mkdir to return the
resulting dentry if it is different from the one passed in.
Possible returns are:
  NULL - the directory was created and no other dentry was used
  ERR_PTR() - an error occurred
  non-NULL - this other dentry was spliced in

This patch only changes file-systems to return "ERR_PTR(err)" instead of
"err" or equivalent transformations.  Subsequent patches will make
further changes to some file-systems to return a correct dentry.

Not all filesystems reliably result in a positive hashed dentry:

- NFS, cifs, hostfs will sometimes need to perform a lookup of
  the name to get inode information.  Races could result in this
  returning something different. Note that this lookup is
  non-atomic which is what we are trying to avoid.  Placing the
  lookup in filesystem code means it only happens when the filesystem
  has no other option.
- kernfs and tracefs leave the dentry negative and the ->revalidate
  operation ensures that lookup will be called to correctly populate
  the dentry.  This could be fixed but I don't think it is important
  to any of the users of vfs_mkdir() which look at the dentry.

The recommendation to use
    d_drop();d_splice_alias()
is ugly but fits with current practice.  A planned future patch will
change this.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: NeilBrown <neilb@suse.de>
Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 20:00:17 +01:00

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// SPDX-License-Identifier: GPL-2.0-only
/*
* This file contains vfs inode ops for the 9P2000 protocol.
*
* Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com>
* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/pagemap.h>
#include <linux/stat.h>
#include <linux/string.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include "v9fs.h"
#include "v9fs_vfs.h"
#include "fid.h"
#include "cache.h"
#include "xattr.h"
#include "acl.h"
static const struct inode_operations v9fs_dir_inode_operations;
static const struct inode_operations v9fs_dir_inode_operations_dotu;
static const struct inode_operations v9fs_file_inode_operations;
static const struct inode_operations v9fs_symlink_inode_operations;
/**
* unixmode2p9mode - convert unix mode bits to plan 9
* @v9ses: v9fs session information
* @mode: mode to convert
*
*/
static u32 unixmode2p9mode(struct v9fs_session_info *v9ses, umode_t mode)
{
int res;
res = mode & 0777;
if (S_ISDIR(mode))
res |= P9_DMDIR;
if (v9fs_proto_dotu(v9ses)) {
if (v9ses->nodev == 0) {
if (S_ISSOCK(mode))
res |= P9_DMSOCKET;
if (S_ISFIFO(mode))
res |= P9_DMNAMEDPIPE;
if (S_ISBLK(mode))
res |= P9_DMDEVICE;
if (S_ISCHR(mode))
res |= P9_DMDEVICE;
}
if ((mode & S_ISUID) == S_ISUID)
res |= P9_DMSETUID;
if ((mode & S_ISGID) == S_ISGID)
res |= P9_DMSETGID;
if ((mode & S_ISVTX) == S_ISVTX)
res |= P9_DMSETVTX;
}
return res;
}
/**
* p9mode2perm- convert plan9 mode bits to unix permission bits
* @v9ses: v9fs session information
* @stat: p9_wstat from which mode need to be derived
*
*/
static int p9mode2perm(struct v9fs_session_info *v9ses,
struct p9_wstat *stat)
{
int res;
int mode = stat->mode;
res = mode & 0777; /* S_IRWXUGO */
if (v9fs_proto_dotu(v9ses)) {
if ((mode & P9_DMSETUID) == P9_DMSETUID)
res |= S_ISUID;
if ((mode & P9_DMSETGID) == P9_DMSETGID)
res |= S_ISGID;
if ((mode & P9_DMSETVTX) == P9_DMSETVTX)
res |= S_ISVTX;
}
return res;
}
/**
* p9mode2unixmode- convert plan9 mode bits to unix mode bits
* @v9ses: v9fs session information
* @stat: p9_wstat from which mode need to be derived
* @rdev: major number, minor number in case of device files.
*
*/
static umode_t p9mode2unixmode(struct v9fs_session_info *v9ses,
struct p9_wstat *stat, dev_t *rdev)
{
int res, r;
u32 mode = stat->mode;
*rdev = 0;
res = p9mode2perm(v9ses, stat);
if ((mode & P9_DMDIR) == P9_DMDIR)
res |= S_IFDIR;
else if ((mode & P9_DMSYMLINK) && (v9fs_proto_dotu(v9ses)))
res |= S_IFLNK;
else if ((mode & P9_DMSOCKET) && (v9fs_proto_dotu(v9ses))
&& (v9ses->nodev == 0))
res |= S_IFSOCK;
else if ((mode & P9_DMNAMEDPIPE) && (v9fs_proto_dotu(v9ses))
&& (v9ses->nodev == 0))
res |= S_IFIFO;
else if ((mode & P9_DMDEVICE) && (v9fs_proto_dotu(v9ses))
&& (v9ses->nodev == 0)) {
char type = 0;
int major = -1, minor = -1;
r = sscanf(stat->extension, "%c %i %i", &type, &major, &minor);
if (r != 3) {
p9_debug(P9_DEBUG_ERROR,
"invalid device string, umode will be bogus: %s\n",
stat->extension);
return res;
}
switch (type) {
case 'c':
res |= S_IFCHR;
break;
case 'b':
res |= S_IFBLK;
break;
default:
p9_debug(P9_DEBUG_ERROR, "Unknown special type %c %s\n",
type, stat->extension);
}
*rdev = MKDEV(major, minor);
} else
res |= S_IFREG;
return res;
}
/**
* v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
* @uflags: flags to convert
* @extended: if .u extensions are active
*/
int v9fs_uflags2omode(int uflags, int extended)
{
int ret;
switch (uflags&3) {
default:
case O_RDONLY:
ret = P9_OREAD;
break;
case O_WRONLY:
ret = P9_OWRITE;
break;
case O_RDWR:
ret = P9_ORDWR;
break;
}
if (uflags & O_TRUNC)
ret |= P9_OTRUNC;
if (extended) {
if (uflags & O_EXCL)
ret |= P9_OEXCL;
if (uflags & O_APPEND)
ret |= P9_OAPPEND;
}
return ret;
}
/**
* v9fs_blank_wstat - helper function to setup a 9P stat structure
* @wstat: structure to initialize
*
*/
void
v9fs_blank_wstat(struct p9_wstat *wstat)
{
wstat->type = ~0;
wstat->dev = ~0;
wstat->qid.type = ~0;
wstat->qid.version = ~0;
*((long long *)&wstat->qid.path) = ~0;
wstat->mode = ~0;
wstat->atime = ~0;
wstat->mtime = ~0;
wstat->length = ~0;
wstat->name = NULL;
wstat->uid = NULL;
wstat->gid = NULL;
wstat->muid = NULL;
wstat->n_uid = INVALID_UID;
wstat->n_gid = INVALID_GID;
wstat->n_muid = INVALID_UID;
wstat->extension = NULL;
}
/**
* v9fs_alloc_inode - helper function to allocate an inode
* @sb: The superblock to allocate the inode from
*/
struct inode *v9fs_alloc_inode(struct super_block *sb)
{
struct v9fs_inode *v9inode;
v9inode = alloc_inode_sb(sb, v9fs_inode_cache, GFP_KERNEL);
if (!v9inode)
return NULL;
v9inode->cache_validity = 0;
mutex_init(&v9inode->v_mutex);
return &v9inode->netfs.inode;
}
/**
* v9fs_free_inode - destroy an inode
* @inode: The inode to be freed
*/
void v9fs_free_inode(struct inode *inode)
{
kmem_cache_free(v9fs_inode_cache, V9FS_I(inode));
}
/*
* Set parameters for the netfs library
*/
void v9fs_set_netfs_context(struct inode *inode)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
netfs_inode_init(&v9inode->netfs, &v9fs_req_ops, true);
}
int v9fs_init_inode(struct v9fs_session_info *v9ses,
struct inode *inode, umode_t mode, dev_t rdev)
{
int err = 0;
inode_init_owner(&nop_mnt_idmap, inode, NULL, mode);
inode->i_blocks = 0;
inode->i_rdev = rdev;
simple_inode_init_ts(inode);
inode->i_mapping->a_ops = &v9fs_addr_operations;
inode->i_private = NULL;
switch (mode & S_IFMT) {
case S_IFIFO:
case S_IFBLK:
case S_IFCHR:
case S_IFSOCK:
if (v9fs_proto_dotl(v9ses)) {
inode->i_op = &v9fs_file_inode_operations_dotl;
} else if (v9fs_proto_dotu(v9ses)) {
inode->i_op = &v9fs_file_inode_operations;
} else {
p9_debug(P9_DEBUG_ERROR,
"special files without extended mode\n");
err = -EINVAL;
goto error;
}
init_special_inode(inode, inode->i_mode, inode->i_rdev);
break;
case S_IFREG:
if (v9fs_proto_dotl(v9ses)) {
inode->i_op = &v9fs_file_inode_operations_dotl;
inode->i_fop = &v9fs_file_operations_dotl;
} else {
inode->i_op = &v9fs_file_inode_operations;
inode->i_fop = &v9fs_file_operations;
}
break;
case S_IFLNK:
if (!v9fs_proto_dotu(v9ses) && !v9fs_proto_dotl(v9ses)) {
p9_debug(P9_DEBUG_ERROR,
"extended modes used with legacy protocol\n");
err = -EINVAL;
goto error;
}
if (v9fs_proto_dotl(v9ses))
inode->i_op = &v9fs_symlink_inode_operations_dotl;
else
inode->i_op = &v9fs_symlink_inode_operations;
break;
case S_IFDIR:
inc_nlink(inode);
if (v9fs_proto_dotl(v9ses))
inode->i_op = &v9fs_dir_inode_operations_dotl;
else if (v9fs_proto_dotu(v9ses))
inode->i_op = &v9fs_dir_inode_operations_dotu;
else
inode->i_op = &v9fs_dir_inode_operations;
if (v9fs_proto_dotl(v9ses))
inode->i_fop = &v9fs_dir_operations_dotl;
else
inode->i_fop = &v9fs_dir_operations;
break;
default:
p9_debug(P9_DEBUG_ERROR, "BAD mode 0x%hx S_IFMT 0x%x\n",
mode, mode & S_IFMT);
err = -EINVAL;
goto error;
}
error:
return err;
}
/**
* v9fs_evict_inode - Remove an inode from the inode cache
* @inode: inode to release
*
*/
void v9fs_evict_inode(struct inode *inode)
{
struct v9fs_inode __maybe_unused *v9inode = V9FS_I(inode);
__le32 __maybe_unused version;
if (!is_bad_inode(inode)) {
netfs_wait_for_outstanding_io(inode);
truncate_inode_pages_final(&inode->i_data);
version = cpu_to_le32(v9inode->qid.version);
netfs_clear_inode_writeback(inode, &version);
clear_inode(inode);
filemap_fdatawrite(&inode->i_data);
#ifdef CONFIG_9P_FSCACHE
if (v9fs_inode_cookie(v9inode))
fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
#endif
} else
clear_inode(inode);
}
static int v9fs_test_inode(struct inode *inode, void *data)
{
int umode;
dev_t rdev;
struct v9fs_inode *v9inode = V9FS_I(inode);
struct p9_wstat *st = (struct p9_wstat *)data;
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
umode = p9mode2unixmode(v9ses, st, &rdev);
/* don't match inode of different type */
if (inode_wrong_type(inode, umode))
return 0;
/* compare qid details */
if (memcmp(&v9inode->qid.version,
&st->qid.version, sizeof(v9inode->qid.version)))
return 0;
if (v9inode->qid.type != st->qid.type)
return 0;
if (v9inode->qid.path != st->qid.path)
return 0;
return 1;
}
static int v9fs_test_new_inode(struct inode *inode, void *data)
{
return 0;
}
static int v9fs_set_inode(struct inode *inode, void *data)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
struct p9_wstat *st = (struct p9_wstat *)data;
memcpy(&v9inode->qid, &st->qid, sizeof(st->qid));
return 0;
}
static struct inode *v9fs_qid_iget(struct super_block *sb,
struct p9_qid *qid,
struct p9_wstat *st,
int new)
{
dev_t rdev;
int retval;
umode_t umode;
struct inode *inode;
struct v9fs_session_info *v9ses = sb->s_fs_info;
int (*test)(struct inode *inode, void *data);
if (new)
test = v9fs_test_new_inode;
else
test = v9fs_test_inode;
inode = iget5_locked(sb, QID2INO(qid), test, v9fs_set_inode, st);
if (!inode)
return ERR_PTR(-ENOMEM);
if (!(inode->i_state & I_NEW))
return inode;
/*
* initialize the inode with the stat info
* FIXME!! we may need support for stale inodes
* later.
*/
inode->i_ino = QID2INO(qid);
umode = p9mode2unixmode(v9ses, st, &rdev);
retval = v9fs_init_inode(v9ses, inode, umode, rdev);
if (retval)
goto error;
v9fs_stat2inode(st, inode, sb, 0);
v9fs_set_netfs_context(inode);
v9fs_cache_inode_get_cookie(inode);
unlock_new_inode(inode);
return inode;
error:
iget_failed(inode);
return ERR_PTR(retval);
}
struct inode *
v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
struct super_block *sb, int new)
{
struct p9_wstat *st;
struct inode *inode = NULL;
st = p9_client_stat(fid);
if (IS_ERR(st))
return ERR_CAST(st);
inode = v9fs_qid_iget(sb, &st->qid, st, new);
p9stat_free(st);
kfree(st);
return inode;
}
/**
* v9fs_at_to_dotl_flags- convert Linux specific AT flags to
* plan 9 AT flag.
* @flags: flags to convert
*/
static int v9fs_at_to_dotl_flags(int flags)
{
int rflags = 0;
if (flags & AT_REMOVEDIR)
rflags |= P9_DOTL_AT_REMOVEDIR;
return rflags;
}
/**
* v9fs_dec_count - helper functon to drop i_nlink.
*
* If a directory had nlink <= 2 (including . and ..), then we should not drop
* the link count, which indicates the underlying exported fs doesn't maintain
* nlink accurately. e.g.
* - overlayfs sets nlink to 1 for merged dir
* - ext4 (with dir_nlink feature enabled) sets nlink to 1 if a dir has more
* than EXT4_LINK_MAX (65000) links.
*
* @inode: inode whose nlink is being dropped
*/
static void v9fs_dec_count(struct inode *inode)
{
if (!S_ISDIR(inode->i_mode) || inode->i_nlink > 2)
drop_nlink(inode);
}
/**
* v9fs_remove - helper function to remove files and directories
* @dir: directory inode that is being deleted
* @dentry: dentry that is being deleted
* @flags: removing a directory
*
*/
static int v9fs_remove(struct inode *dir, struct dentry *dentry, int flags)
{
struct inode *inode;
int retval = -EOPNOTSUPP;
struct p9_fid *v9fid, *dfid;
struct v9fs_session_info *v9ses;
p9_debug(P9_DEBUG_VFS, "inode: %p dentry: %p rmdir: %x\n",
dir, dentry, flags);
v9ses = v9fs_inode2v9ses(dir);
inode = d_inode(dentry);
dfid = v9fs_parent_fid(dentry);
if (IS_ERR(dfid)) {
retval = PTR_ERR(dfid);
p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", retval);
return retval;
}
if (v9fs_proto_dotl(v9ses))
retval = p9_client_unlinkat(dfid, dentry->d_name.name,
v9fs_at_to_dotl_flags(flags));
p9_fid_put(dfid);
if (retval == -EOPNOTSUPP) {
/* Try the one based on path */
v9fid = v9fs_fid_clone(dentry);
if (IS_ERR(v9fid))
return PTR_ERR(v9fid);
retval = p9_client_remove(v9fid);
}
if (!retval) {
/*
* directories on unlink should have zero
* link count
*/
if (flags & AT_REMOVEDIR) {
clear_nlink(inode);
v9fs_dec_count(dir);
} else
v9fs_dec_count(inode);
v9fs_invalidate_inode_attr(inode);
v9fs_invalidate_inode_attr(dir);
/* invalidate all fids associated with dentry */
/* NOTE: This will not include open fids */
dentry->d_op->d_release(dentry);
}
return retval;
}
/**
* v9fs_create - Create a file
* @v9ses: session information
* @dir: directory that dentry is being created in
* @dentry: dentry that is being created
* @extension: 9p2000.u extension string to support devices, etc.
* @perm: create permissions
* @mode: open mode
*
*/
static struct p9_fid *
v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
struct dentry *dentry, char *extension, u32 perm, u8 mode)
{
int err;
const unsigned char *name;
struct p9_fid *dfid, *ofid = NULL, *fid = NULL;
struct inode *inode;
p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
name = dentry->d_name.name;
dfid = v9fs_parent_fid(dentry);
if (IS_ERR(dfid)) {
err = PTR_ERR(dfid);
p9_debug(P9_DEBUG_VFS, "fid lookup failed %d\n", err);
return ERR_PTR(err);
}
/* clone a fid to use for creation */
ofid = clone_fid(dfid);
if (IS_ERR(ofid)) {
err = PTR_ERR(ofid);
p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
goto error;
}
err = p9_client_fcreate(ofid, name, perm, mode, extension);
if (err < 0) {
p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n", err);
goto error;
}
if (!(perm & P9_DMLINK)) {
/* now walk from the parent so we can get unopened fid */
fid = p9_client_walk(dfid, 1, &name, 1);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
p9_debug(P9_DEBUG_VFS,
"p9_client_walk failed %d\n", err);
goto error;
}
/*
* instantiate inode and assign the unopened fid to the dentry
*/
inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
if (IS_ERR(inode)) {
err = PTR_ERR(inode);
p9_debug(P9_DEBUG_VFS,
"inode creation failed %d\n", err);
goto error;
}
v9fs_fid_add(dentry, &fid);
d_instantiate(dentry, inode);
}
p9_fid_put(dfid);
return ofid;
error:
p9_fid_put(dfid);
p9_fid_put(ofid);
p9_fid_put(fid);
return ERR_PTR(err);
}
/**
* v9fs_vfs_create - VFS hook to create a regular file
* @idmap: idmap of the mount
* @dir: The parent directory
* @dentry: The name of file to be created
* @mode: The UNIX file mode to set
* @excl: True if the file must not yet exist
*
* open(.., O_CREAT) is handled in v9fs_vfs_atomic_open(). This is only called
* for mknod(2).
*
*/
static int
v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, bool excl)
{
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
u32 perm = unixmode2p9mode(v9ses, mode);
struct p9_fid *fid;
/* P9_OEXCL? */
fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_ORDWR);
if (IS_ERR(fid))
return PTR_ERR(fid);
v9fs_invalidate_inode_attr(dir);
p9_fid_put(fid);
return 0;
}
/**
* v9fs_vfs_mkdir - VFS mkdir hook to create a directory
* @idmap: idmap of the mount
* @dir: inode that is being unlinked
* @dentry: dentry that is being unlinked
* @mode: mode for new directory
*
*/
static struct dentry *v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode)
{
int err;
u32 perm;
struct p9_fid *fid;
struct v9fs_session_info *v9ses;
p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
err = 0;
v9ses = v9fs_inode2v9ses(dir);
perm = unixmode2p9mode(v9ses, mode | S_IFDIR);
fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
fid = NULL;
} else {
inc_nlink(dir);
v9fs_invalidate_inode_attr(dir);
}
if (fid)
p9_fid_put(fid);
return ERR_PTR(err);
}
/**
* v9fs_vfs_lookup - VFS lookup hook to "walk" to a new inode
* @dir: inode that is being walked from
* @dentry: dentry that is being walked to?
* @flags: lookup flags (unused)
*
*/
struct dentry *v9fs_vfs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags)
{
struct dentry *res;
struct v9fs_session_info *v9ses;
struct p9_fid *dfid, *fid;
struct inode *inode;
const unsigned char *name;
p9_debug(P9_DEBUG_VFS, "dir: %p dentry: (%pd) %p flags: %x\n",
dir, dentry, dentry, flags);
if (dentry->d_name.len > NAME_MAX)
return ERR_PTR(-ENAMETOOLONG);
v9ses = v9fs_inode2v9ses(dir);
/* We can walk d_parent because we hold the dir->i_mutex */
dfid = v9fs_parent_fid(dentry);
if (IS_ERR(dfid))
return ERR_CAST(dfid);
/*
* Make sure we don't use a wrong inode due to parallel
* unlink. For cached mode create calls request for new
* inode. But with cache disabled, lookup should do this.
*/
name = dentry->d_name.name;
fid = p9_client_walk(dfid, 1, &name, 1);
p9_fid_put(dfid);
if (fid == ERR_PTR(-ENOENT))
inode = NULL;
else if (IS_ERR(fid))
inode = ERR_CAST(fid);
else if (v9ses->cache & (CACHE_META|CACHE_LOOSE))
inode = v9fs_get_inode_from_fid(v9ses, fid, dir->i_sb);
else
inode = v9fs_get_new_inode_from_fid(v9ses, fid, dir->i_sb);
/*
* If we had a rename on the server and a parallel lookup
* for the new name, then make sure we instantiate with
* the new name. ie look up for a/b, while on server somebody
* moved b under k and client parallely did a lookup for
* k/b.
*/
res = d_splice_alias(inode, dentry);
if (!IS_ERR(fid)) {
if (!res)
v9fs_fid_add(dentry, &fid);
else if (!IS_ERR(res))
v9fs_fid_add(res, &fid);
else
p9_fid_put(fid);
}
return res;
}
static int
v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, unsigned int flags, umode_t mode)
{
int err;
u32 perm;
struct v9fs_inode __maybe_unused *v9inode;
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
struct dentry *res = NULL;
struct inode *inode;
int p9_omode;
if (d_in_lookup(dentry)) {
res = v9fs_vfs_lookup(dir, dentry, 0);
if (IS_ERR(res))
return PTR_ERR(res);
if (res)
dentry = res;
}
/* Only creates */
if (!(flags & O_CREAT) || d_really_is_positive(dentry))
return finish_no_open(file, res);
v9ses = v9fs_inode2v9ses(dir);
perm = unixmode2p9mode(v9ses, mode);
p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
if ((v9ses->cache & CACHE_WRITEBACK) && (p9_omode & P9_OWRITE)) {
p9_omode = (p9_omode & ~P9_OWRITE) | P9_ORDWR;
p9_debug(P9_DEBUG_CACHE,
"write-only file with writeback enabled, creating w/ O_RDWR\n");
}
fid = v9fs_create(v9ses, dir, dentry, NULL, perm, p9_omode);
if (IS_ERR(fid)) {
err = PTR_ERR(fid);
goto error;
}
v9fs_invalidate_inode_attr(dir);
inode = d_inode(dentry);
v9inode = V9FS_I(inode);
err = finish_open(file, dentry, generic_file_open);
if (err)
goto error;
file->private_data = fid;
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cache & CACHE_FSCACHE)
fscache_use_cookie(v9fs_inode_cookie(v9inode),
file->f_mode & FMODE_WRITE);
#endif
v9fs_fid_add_modes(fid, v9ses->flags, v9ses->cache, file->f_flags);
v9fs_open_fid_add(inode, &fid);
file->f_mode |= FMODE_CREATED;
out:
dput(res);
return err;
error:
p9_fid_put(fid);
goto out;
}
/**
* v9fs_vfs_unlink - VFS unlink hook to delete an inode
* @i: inode that is being unlinked
* @d: dentry that is being unlinked
*
*/
int v9fs_vfs_unlink(struct inode *i, struct dentry *d)
{
return v9fs_remove(i, d, 0);
}
/**
* v9fs_vfs_rmdir - VFS unlink hook to delete a directory
* @i: inode that is being unlinked
* @d: dentry that is being unlinked
*
*/
int v9fs_vfs_rmdir(struct inode *i, struct dentry *d)
{
return v9fs_remove(i, d, AT_REMOVEDIR);
}
/**
* v9fs_vfs_rename - VFS hook to rename an inode
* @idmap: The idmap of the mount
* @old_dir: old dir inode
* @old_dentry: old dentry
* @new_dir: new dir inode
* @new_dentry: new dentry
* @flags: RENAME_* flags
*
*/
int
v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags)
{
int retval;
struct inode *old_inode;
struct inode *new_inode;
struct v9fs_session_info *v9ses;
struct p9_fid *oldfid = NULL, *dfid = NULL;
struct p9_fid *olddirfid = NULL;
struct p9_fid *newdirfid = NULL;
struct p9_wstat wstat;
if (flags)
return -EINVAL;
p9_debug(P9_DEBUG_VFS, "\n");
old_inode = d_inode(old_dentry);
new_inode = d_inode(new_dentry);
v9ses = v9fs_inode2v9ses(old_inode);
oldfid = v9fs_fid_lookup(old_dentry);
if (IS_ERR(oldfid))
return PTR_ERR(oldfid);
dfid = v9fs_parent_fid(old_dentry);
olddirfid = clone_fid(dfid);
p9_fid_put(dfid);
dfid = NULL;
if (IS_ERR(olddirfid)) {
retval = PTR_ERR(olddirfid);
goto error;
}
dfid = v9fs_parent_fid(new_dentry);
newdirfid = clone_fid(dfid);
p9_fid_put(dfid);
dfid = NULL;
if (IS_ERR(newdirfid)) {
retval = PTR_ERR(newdirfid);
goto error;
}
down_write(&v9ses->rename_sem);
if (v9fs_proto_dotl(v9ses)) {
retval = p9_client_renameat(olddirfid, old_dentry->d_name.name,
newdirfid, new_dentry->d_name.name);
if (retval == -EOPNOTSUPP)
retval = p9_client_rename(oldfid, newdirfid,
new_dentry->d_name.name);
if (retval != -EOPNOTSUPP)
goto error_locked;
}
if (old_dentry->d_parent != new_dentry->d_parent) {
/*
* 9P .u can only handle file rename in the same directory
*/
p9_debug(P9_DEBUG_ERROR, "old dir and new dir are different\n");
retval = -EXDEV;
goto error_locked;
}
v9fs_blank_wstat(&wstat);
wstat.muid = v9ses->uname;
wstat.name = new_dentry->d_name.name;
retval = p9_client_wstat(oldfid, &wstat);
error_locked:
if (!retval) {
if (new_inode) {
if (S_ISDIR(new_inode->i_mode))
clear_nlink(new_inode);
else
v9fs_dec_count(new_inode);
}
if (S_ISDIR(old_inode->i_mode)) {
if (!new_inode)
inc_nlink(new_dir);
v9fs_dec_count(old_dir);
}
v9fs_invalidate_inode_attr(old_inode);
v9fs_invalidate_inode_attr(old_dir);
v9fs_invalidate_inode_attr(new_dir);
/* successful rename */
d_move(old_dentry, new_dentry);
}
up_write(&v9ses->rename_sem);
error:
p9_fid_put(newdirfid);
p9_fid_put(olddirfid);
p9_fid_put(oldfid);
return retval;
}
/**
* v9fs_vfs_getattr - retrieve file metadata
* @idmap: idmap of the mount
* @path: Object to query
* @stat: metadata structure to populate
* @request_mask: Mask of STATX_xxx flags indicating the caller's interests
* @flags: AT_STATX_xxx setting
*
*/
static int
v9fs_vfs_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int flags)
{
struct dentry *dentry = path->dentry;
struct inode *inode = d_inode(dentry);
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
struct p9_wstat *st;
p9_debug(P9_DEBUG_VFS, "dentry: %p\n", dentry);
v9ses = v9fs_dentry2v9ses(dentry);
if (v9ses->cache & (CACHE_META|CACHE_LOOSE)) {
generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
return 0;
} else if (v9ses->cache & CACHE_WRITEBACK) {
if (S_ISREG(inode->i_mode)) {
int retval = filemap_fdatawrite(inode->i_mapping);
if (retval)
p9_debug(P9_DEBUG_ERROR,
"flushing writeback during getattr returned %d\n", retval);
}
}
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
st = p9_client_stat(fid);
p9_fid_put(fid);
if (IS_ERR(st))
return PTR_ERR(st);
v9fs_stat2inode(st, d_inode(dentry), dentry->d_sb, 0);
generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
p9stat_free(st);
kfree(st);
return 0;
}
/**
* v9fs_vfs_setattr - set file metadata
* @idmap: idmap of the mount
* @dentry: file whose metadata to set
* @iattr: metadata assignment structure
*
*/
static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *iattr)
{
int retval, use_dentry = 0;
struct inode *inode = d_inode(dentry);
struct v9fs_session_info *v9ses;
struct p9_fid *fid = NULL;
struct p9_wstat wstat;
p9_debug(P9_DEBUG_VFS, "\n");
retval = setattr_prepare(&nop_mnt_idmap, dentry, iattr);
if (retval)
return retval;
v9ses = v9fs_dentry2v9ses(dentry);
if (iattr->ia_valid & ATTR_FILE) {
fid = iattr->ia_file->private_data;
WARN_ON(!fid);
}
if (!fid) {
fid = v9fs_fid_lookup(dentry);
use_dentry = 1;
}
if (IS_ERR(fid))
return PTR_ERR(fid);
v9fs_blank_wstat(&wstat);
if (iattr->ia_valid & ATTR_MODE)
wstat.mode = unixmode2p9mode(v9ses, iattr->ia_mode);
if (iattr->ia_valid & ATTR_MTIME)
wstat.mtime = iattr->ia_mtime.tv_sec;
if (iattr->ia_valid & ATTR_ATIME)
wstat.atime = iattr->ia_atime.tv_sec;
if (iattr->ia_valid & ATTR_SIZE)
wstat.length = iattr->ia_size;
if (v9fs_proto_dotu(v9ses)) {
if (iattr->ia_valid & ATTR_UID)
wstat.n_uid = iattr->ia_uid;
if (iattr->ia_valid & ATTR_GID)
wstat.n_gid = iattr->ia_gid;
}
/* Write all dirty data */
if (d_is_reg(dentry)) {
retval = filemap_fdatawrite(inode->i_mapping);
if (retval)
p9_debug(P9_DEBUG_ERROR,
"flushing writeback during setattr returned %d\n", retval);
}
retval = p9_client_wstat(fid, &wstat);
if (use_dentry)
p9_fid_put(fid);
if (retval < 0)
return retval;
if ((iattr->ia_valid & ATTR_SIZE) &&
iattr->ia_size != i_size_read(inode)) {
truncate_setsize(inode, iattr->ia_size);
netfs_resize_file(netfs_inode(inode), iattr->ia_size, true);
#ifdef CONFIG_9P_FSCACHE
if (v9ses->cache & CACHE_FSCACHE) {
struct v9fs_inode *v9inode = V9FS_I(inode);
fscache_resize_cookie(v9fs_inode_cookie(v9inode), iattr->ia_size);
}
#endif
}
v9fs_invalidate_inode_attr(inode);
setattr_copy(&nop_mnt_idmap, inode, iattr);
mark_inode_dirty(inode);
return 0;
}
/**
* v9fs_stat2inode - populate an inode structure with mistat info
* @stat: Plan 9 metadata (mistat) structure
* @inode: inode to populate
* @sb: superblock of filesystem
* @flags: control flags (e.g. V9FS_STAT2INODE_KEEP_ISIZE)
*
*/
void
v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
struct super_block *sb, unsigned int flags)
{
umode_t mode;
struct v9fs_session_info *v9ses = sb->s_fs_info;
struct v9fs_inode *v9inode = V9FS_I(inode);
inode_set_atime(inode, stat->atime, 0);
inode_set_mtime(inode, stat->mtime, 0);
inode_set_ctime(inode, stat->mtime, 0);
inode->i_uid = v9ses->dfltuid;
inode->i_gid = v9ses->dfltgid;
if (v9fs_proto_dotu(v9ses)) {
inode->i_uid = stat->n_uid;
inode->i_gid = stat->n_gid;
}
if ((S_ISREG(inode->i_mode)) || (S_ISDIR(inode->i_mode))) {
if (v9fs_proto_dotu(v9ses)) {
unsigned int i_nlink;
/*
* Hadlink support got added later to the .u extension.
* So there can be a server out there that doesn't
* support this even with .u extension. That would
* just leave us with stat->extension being an empty
* string, though.
*/
/* HARDLINKCOUNT %u */
if (sscanf(stat->extension,
" HARDLINKCOUNT %u", &i_nlink) == 1)
set_nlink(inode, i_nlink);
}
}
mode = p9mode2perm(v9ses, stat);
mode |= inode->i_mode & ~S_IALLUGO;
inode->i_mode = mode;
v9inode->netfs.remote_i_size = stat->length;
if (!(flags & V9FS_STAT2INODE_KEEP_ISIZE))
v9fs_i_size_write(inode, stat->length);
/* not real number of blocks, but 512 byte ones ... */
inode->i_blocks = (stat->length + 512 - 1) >> 9;
v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
}
/**
* v9fs_vfs_get_link - follow a symlink path
* @dentry: dentry for symlink
* @inode: inode for symlink
* @done: delayed call for when we are done with the return value
*/
static const char *v9fs_vfs_get_link(struct dentry *dentry,
struct inode *inode,
struct delayed_call *done)
{
struct v9fs_session_info *v9ses;
struct p9_fid *fid;
struct p9_wstat *st;
char *res;
if (!dentry)
return ERR_PTR(-ECHILD);
v9ses = v9fs_dentry2v9ses(dentry);
if (!v9fs_proto_dotu(v9ses))
return ERR_PTR(-EBADF);
p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return ERR_CAST(fid);
st = p9_client_stat(fid);
p9_fid_put(fid);
if (IS_ERR(st))
return ERR_CAST(st);
if (!(st->mode & P9_DMSYMLINK)) {
p9stat_free(st);
kfree(st);
return ERR_PTR(-EINVAL);
}
res = st->extension;
st->extension = NULL;
if (strlen(res) >= PATH_MAX)
res[PATH_MAX - 1] = '\0';
p9stat_free(st);
kfree(st);
set_delayed_call(done, kfree_link, res);
return res;
}
/**
* v9fs_vfs_mkspecial - create a special file
* @dir: inode to create special file in
* @dentry: dentry to create
* @perm: mode to create special file
* @extension: 9p2000.u format extension string representing special file
*
*/
static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
u32 perm, const char *extension)
{
struct p9_fid *fid;
struct v9fs_session_info *v9ses;
v9ses = v9fs_inode2v9ses(dir);
if (!v9fs_proto_dotu(v9ses)) {
p9_debug(P9_DEBUG_ERROR, "not extended\n");
return -EPERM;
}
fid = v9fs_create(v9ses, dir, dentry, (char *) extension, perm,
P9_OREAD);
if (IS_ERR(fid))
return PTR_ERR(fid);
v9fs_invalidate_inode_attr(dir);
p9_fid_put(fid);
return 0;
}
/**
* v9fs_vfs_symlink - helper function to create symlinks
* @idmap: idmap of the mount
* @dir: directory inode containing symlink
* @dentry: dentry for symlink
* @symname: symlink data
*
* See Also: 9P2000.u RFC for more information
*
*/
static int
v9fs_vfs_symlink(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, const char *symname)
{
p9_debug(P9_DEBUG_VFS, " %lu,%pd,%s\n",
dir->i_ino, dentry, symname);
return v9fs_vfs_mkspecial(dir, dentry, P9_DMSYMLINK, symname);
}
#define U32_MAX_DIGITS 10
/**
* v9fs_vfs_link - create a hardlink
* @old_dentry: dentry for file to link to
* @dir: inode destination for new link
* @dentry: dentry for link
*
*/
static int
v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
struct dentry *dentry)
{
int retval;
char name[1 + U32_MAX_DIGITS + 2]; /* sign + number + \n + \0 */
struct p9_fid *oldfid;
p9_debug(P9_DEBUG_VFS, " %lu,%pd,%pd\n",
dir->i_ino, dentry, old_dentry);
oldfid = v9fs_fid_clone(old_dentry);
if (IS_ERR(oldfid))
return PTR_ERR(oldfid);
sprintf(name, "%d\n", oldfid->fid);
retval = v9fs_vfs_mkspecial(dir, dentry, P9_DMLINK, name);
if (!retval) {
v9fs_refresh_inode(oldfid, d_inode(old_dentry));
v9fs_invalidate_inode_attr(dir);
}
p9_fid_put(oldfid);
return retval;
}
/**
* v9fs_vfs_mknod - create a special file
* @idmap: idmap of the mount
* @dir: inode destination for new link
* @dentry: dentry for file
* @mode: mode for creation
* @rdev: device associated with special file
*
*/
static int
v9fs_vfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
struct dentry *dentry, umode_t mode, dev_t rdev)
{
struct v9fs_session_info *v9ses = v9fs_inode2v9ses(dir);
int retval;
char name[2 + U32_MAX_DIGITS + 1 + U32_MAX_DIGITS + 1];
u32 perm;
p9_debug(P9_DEBUG_VFS, " %lu,%pd mode: %x MAJOR: %u MINOR: %u\n",
dir->i_ino, dentry, mode,
MAJOR(rdev), MINOR(rdev));
/* build extension */
if (S_ISBLK(mode))
sprintf(name, "b %u %u", MAJOR(rdev), MINOR(rdev));
else if (S_ISCHR(mode))
sprintf(name, "c %u %u", MAJOR(rdev), MINOR(rdev));
else
*name = 0;
perm = unixmode2p9mode(v9ses, mode);
retval = v9fs_vfs_mkspecial(dir, dentry, perm, name);
return retval;
}
int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
{
int umode;
dev_t rdev;
struct p9_wstat *st;
struct v9fs_session_info *v9ses;
unsigned int flags;
v9ses = v9fs_inode2v9ses(inode);
st = p9_client_stat(fid);
if (IS_ERR(st))
return PTR_ERR(st);
/*
* Don't update inode if the file type is different
*/
umode = p9mode2unixmode(v9ses, st, &rdev);
if (inode_wrong_type(inode, umode))
goto out;
/*
* We don't want to refresh inode->i_size,
* because we may have cached data
*/
flags = (v9ses->cache & CACHE_LOOSE) ?
V9FS_STAT2INODE_KEEP_ISIZE : 0;
v9fs_stat2inode(st, inode, inode->i_sb, flags);
out:
p9stat_free(st);
kfree(st);
return 0;
}
static const struct inode_operations v9fs_dir_inode_operations_dotu = {
.create = v9fs_vfs_create,
.lookup = v9fs_vfs_lookup,
.atomic_open = v9fs_vfs_atomic_open,
.symlink = v9fs_vfs_symlink,
.link = v9fs_vfs_link,
.unlink = v9fs_vfs_unlink,
.mkdir = v9fs_vfs_mkdir,
.rmdir = v9fs_vfs_rmdir,
.mknod = v9fs_vfs_mknod,
.rename = v9fs_vfs_rename,
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
};
static const struct inode_operations v9fs_dir_inode_operations = {
.create = v9fs_vfs_create,
.lookup = v9fs_vfs_lookup,
.atomic_open = v9fs_vfs_atomic_open,
.unlink = v9fs_vfs_unlink,
.mkdir = v9fs_vfs_mkdir,
.rmdir = v9fs_vfs_rmdir,
.mknod = v9fs_vfs_mknod,
.rename = v9fs_vfs_rename,
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
};
static const struct inode_operations v9fs_file_inode_operations = {
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
};
static const struct inode_operations v9fs_symlink_inode_operations = {
.get_link = v9fs_vfs_get_link,
.getattr = v9fs_vfs_getattr,
.setattr = v9fs_vfs_setattr,
};
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