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fanotify: Split fsid check from other fid mode checks

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[ Upstream commit 8299212cbdb01a5867e230e961f82e5c02a6de34 ]

FAN_FS_ERROR will require fsid, but not necessarily require the
filesystem to expose a file handle.  Split those checks into different
functions, so they can be used separately when setting up an event.

While there, update a comment about tmpfs having 0 fsid, which is no
longer true.

Link: https://lore.kernel.org/r/20211025192746.66445-7-krisman@collabora.com
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Gabriel Krisman Bertazi
2021-10-25 16:27:21 -03:00
committed by Greg Kroah-Hartman
parent 326be73a59
commit 9539a89f28
1 changed files with 18 additions and 9 deletions
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27
fs/notify/fanotify/fanotify_user.c
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@@ -1295,16 +1295,15 @@ out_destroy_group:
return fd; return fd;
} }
/* Check if filesystem can encode a unique fid */ static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid)
static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
{ {
__kernel_fsid_t root_fsid; __kernel_fsid_t root_fsid;
int err; int err;
/* /*
* Make sure path is not in filesystem with zero fsid (e.g. tmpfs). * Make sure dentry is not of a filesystem with zero fsid (e.g. fuse).
*/ */
err = vfs_get_fsid(path->dentry, fsid); err = vfs_get_fsid(dentry, fsid);
if (err) if (err)
return err; return err;
@@ -1312,10 +1311,10 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
return -ENODEV; return -ENODEV;
/* /*
* Make sure path is not inside a filesystem subvolume (e.g. btrfs) * Make sure dentry is not of a filesystem subvolume (e.g. btrfs)
* which uses a different fsid than sb root. * which uses a different fsid than sb root.
*/ */
err = vfs_get_fsid(path->dentry->d_sb->s_root, &root_fsid); err = vfs_get_fsid(dentry->d_sb->s_root, &root_fsid);
if (err) if (err)
return err; return err;
@@ -1323,6 +1322,12 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
root_fsid.val[1] != fsid->val[1]) root_fsid.val[1] != fsid->val[1])
return -EXDEV; return -EXDEV;
return 0;
}
/* Check if filesystem can encode a unique fid */
static int fanotify_test_fid(struct dentry *dentry)
{
/* /*
* We need to make sure that the file system supports at least * We need to make sure that the file system supports at least
* encoding a file handle so user can use name_to_handle_at() to * encoding a file handle so user can use name_to_handle_at() to
@@ -1330,8 +1335,8 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid)
* objects. However, name_to_handle_at() requires that the * objects. However, name_to_handle_at() requires that the
* filesystem also supports decoding file handles. * filesystem also supports decoding file handles.
*/ */
if (!path->dentry->d_sb->s_export_op || if (!dentry->d_sb->s_export_op ||
!path->dentry->d_sb->s_export_op->fh_to_dentry) !dentry->d_sb->s_export_op->fh_to_dentry)
return -EOPNOTSUPP; return -EOPNOTSUPP;
return 0; return 0;
@@ -1500,7 +1505,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
} }
if (fid_mode) { if (fid_mode) {
ret = fanotify_test_fid(&path, &__fsid); ret = fanotify_test_fsid(path.dentry, &__fsid);
if (ret)
goto path_put_and_out;
ret = fanotify_test_fid(path.dentry);
if (ret) if (ret)
goto path_put_and_out; goto path_put_and_out;