On Mon 07-03-22 17:57:40, Amir Goldstein wrote:
> Similar to inotify's IN_MARK_CREATE, adding an fanotify mark with flag
> FAN_MARK_CREATE will fail with error EEXIST if an fanotify mark already
> exists on the object.
>
> Unlike inotify's IN_MARK_CREATE, FAN_MARK_CREATE has to supplied in
> combination with FAN_MARK_ADD (FAN_MARK_ADD is like inotify_add_watch()
> and the behavior of IN_MARK_ADD is the default for fanotify_mark()).
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
What I'm missing in this changelog is "why". Is it just about feature
parity with inotify? I don't find this feature particularly useful...
Honza
> ---
> fs/notify/fanotify/fanotify_user.c | 13 ++++++++++---
> include/linux/fanotify.h | 8 +++++---
> include/uapi/linux/fanotify.h | 1 +
> 3 files changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
> index 9b32b76a9c30..99c5ced6abd8 100644
> --- a/fs/notify/fanotify/fanotify_user.c
> +++ b/fs/notify/fanotify/fanotify_user.c
> @@ -1185,6 +1185,9 @@ static int fanotify_add_mark(struct fsnotify_group *group,
> mutex_unlock(&group->mark_mutex);
> return PTR_ERR(fsn_mark);
> }
> + } else if (flags & FAN_MARK_CREATE) {
> + ret = -EEXIST;
> + goto out;
> }
>
> /*
> @@ -1510,6 +1513,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> __kernel_fsid_t __fsid, *fsid = NULL;
> u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
> unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
> + unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
> bool ignored = flags & FAN_MARK_IGNORED_MASK;
> unsigned int obj_type, fid_mode;
> u32 umask = 0;
> @@ -1539,7 +1543,10 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> return -EINVAL;
> }
>
> - switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE | FAN_MARK_FLUSH)) {
> + if (flags & FAN_MARK_CREATE && mark_cmd != FAN_MARK_ADD)
> + return -EINVAL;
> +
> + switch (mark_cmd) {
> case FAN_MARK_ADD:
> case FAN_MARK_REMOVE:
> if (!mask)
> @@ -1671,7 +1678,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
> }
>
> /* create/update an inode mark */
> - switch (flags & (FAN_MARK_ADD | FAN_MARK_REMOVE)) {
> + switch (mark_cmd) {
> case FAN_MARK_ADD:
> if (mark_type == FAN_MARK_MOUNT)
> ret = fanotify_add_vfsmount_mark(group, mnt, mask,
> @@ -1749,7 +1756,7 @@ static int __init fanotify_user_setup(void)
>
> BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
> BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
> - BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
> + BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 10);
>
> fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
> SLAB_PANIC|SLAB_ACCOUNT);
> diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
> index 419cadcd7ff5..780f4b17d4c9 100644
> --- a/include/linux/fanotify.h
> +++ b/include/linux/fanotify.h
> @@ -59,14 +59,16 @@
> #define FANOTIFY_MARK_TYPE_BITS (FAN_MARK_INODE | FAN_MARK_MOUNT | \
> FAN_MARK_FILESYSTEM)
>
> +#define FANOTIFY_MARK_CMD_BITS (FAN_MARK_ADD | FAN_MARK_REMOVE | \
> + FAN_MARK_FLUSH)
> +
> #define FANOTIFY_MARK_FLAGS (FANOTIFY_MARK_TYPE_BITS | \
> - FAN_MARK_ADD | \
> - FAN_MARK_REMOVE | \
> + FANOTIFY_MARK_CMD_BITS | \
> FAN_MARK_DONT_FOLLOW | \
> FAN_MARK_ONLYDIR | \
> FAN_MARK_IGNORED_MASK | \
> FAN_MARK_IGNORED_SURV_MODIFY | \
> - FAN_MARK_FLUSH)
> + FAN_MARK_CREATE)
>
> /*
> * Events that can be reported with data type FSNOTIFY_EVENT_PATH.
> diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
> index e8ac38cc2fd6..c41feac21fe9 100644
> --- a/include/uapi/linux/fanotify.h
> +++ b/include/uapi/linux/fanotify.h
> @@ -82,6 +82,7 @@
> #define FAN_MARK_IGNORED_SURV_MODIFY 0x00000040
> #define FAN_MARK_FLUSH 0x00000080
> /* FAN_MARK_FILESYSTEM is 0x00000100 */
> +#define FAN_MARK_CREATE 0x00000200
>
> /* These are NOT bitwise flags. Both bits can be used togther. */
> #define FAN_MARK_INODE 0x00000000
> --
> 2.25.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
