Re: [PATCH v3 03/15] fanotify: Split fsid check from other fid mode checks
From: Amir Goldstein <amir73il@gmail.com>
Date: 2021-06-30 03:14:25
Also in:
linux-fsdevel
On Tue, Jun 29, 2021 at 10:12 PM Gabriel Krisman Bertazi [off-list ref] wrote:
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. Signed-off-by: Gabriel Krisman Bertazi <redacted>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
quoted hunk ↗ jump to hunk
--- Changes since v2: - FAN_ERROR -> FAN_FS_ERROR (Amir) - Update comment (Amir) Changes since v1: (Amir) - Sort hunks to simplify diff. Changes since RFC: (Amir) - Rename fanotify_check_path_fsid -> fanotify_test_fsid. - Use dentry directly instead of path. --- fs/notify/fanotify/fanotify_user.c | 27 ++++++++++++++++++--------- 1 file changed, 18 insertions(+), 9 deletions(-)diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 68a53d3534f8..67b18dfe0025 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c@@ -1192,16 +1192,15 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags) return fd; } -/* Check if filesystem can encode a unique fid */ -static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid) +static int fanotify_test_fsid(struct dentry *dentry, __kernel_fsid_t *fsid) { __kernel_fsid_t root_fsid; 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) return err;@@ -1209,10 +1208,10 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid) 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. */ - 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) return err;@@ -1220,6 +1219,12 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid) root_fsid.val[1] != fsid->val[1]) 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 * encoding a file handle so user can use name_to_handle_at() to@@ -1227,8 +1232,8 @@ static int fanotify_test_fid(struct path *path, __kernel_fsid_t *fsid) * objects. However, name_to_handle_at() requires that the * filesystem also supports decoding file handles. */ - if (!path->dentry->d_sb->s_export_op || - !path->dentry->d_sb->s_export_op->fh_to_dentry) + if (!dentry->d_sb->s_export_op || + !dentry->d_sb->s_export_op->fh_to_dentry) return -EOPNOTSUPP; return 0;@@ -1379,7 +1384,11 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask, } 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) goto path_put_and_out; --2.32.0