summaryrefslogtreecommitdiff
path: root/fs/notify
diff options
context:
space:
mode:
authorAmir Goldstein <amir73il@gmail.com>2021-11-29 23:15:29 +0300
committerJan Kara <jack@suse.cz>2021-12-15 16:04:25 +0300
commitd61fd650e9d206a71fda789f02a1ced4b19944c4 (patch)
tree7e0cc3f9013fd0cee3f25131fed0f486dc767956 /fs/notify
parent1c9007d62bea6fd164285314f7553f73e5308863 (diff)
downloadlinux-d61fd650e9d206a71fda789f02a1ced4b19944c4.tar.xz
fanotify: introduce group flag FAN_REPORT_TARGET_FID
FAN_REPORT_FID is ambiguous in that it reports the fid of the child for some events and the fid of the parent for create/delete/move events. The new FAN_REPORT_TARGET_FID flag is an implicit request to report the fid of the target object of the operation (a.k.a the child inode) also in create/delete/move events in addition to the fid of the parent and the name of the child. To reduce the test matrix for uninteresting use cases, the new FAN_REPORT_TARGET_FID flag requires both FAN_REPORT_NAME and FAN_REPORT_FID. The convenience macro FAN_REPORT_DFID_NAME_TARGET combines FAN_REPORT_TARGET_FID with all the required flags. Link: https://lore.kernel.org/r/20211129201537.1932819-4-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify')
-rw-r--r--fs/notify/fanotify/fanotify.c48
-rw-r--r--fs/notify/fanotify/fanotify_user.c11
2 files changed, 46 insertions, 13 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 652fe84cb8ac..85e542b164c8 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -458,17 +458,41 @@ out_err:
}
/*
- * The inode to use as identifier when reporting fid depends on the event.
- * Report the modified directory inode on dirent modification events.
- * Report the "victim" inode otherwise.
+ * FAN_REPORT_FID is ambiguous in that it reports the fid of the child for
+ * some events and the fid of the parent for create/delete/move events.
+ *
+ * With the FAN_REPORT_TARGET_FID flag, the fid of the child is reported
+ * also in create/delete/move events in addition to the fid of the parent
+ * and the name of the child.
+ */
+static inline bool fanotify_report_child_fid(unsigned int fid_mode, u32 mask)
+{
+ if (mask & ALL_FSNOTIFY_DIRENT_EVENTS)
+ return (fid_mode & FAN_REPORT_TARGET_FID);
+
+ return (fid_mode & FAN_REPORT_FID) && !(mask & FAN_ONDIR);
+}
+
+/*
+ * The inode to use as identifier when reporting fid depends on the event
+ * and the group flags.
+ *
+ * With the group flag FAN_REPORT_TARGET_FID, always report the child fid.
+ *
+ * Without the group flag FAN_REPORT_TARGET_FID, report the modified directory
+ * fid on dirent events and the child fid otherwise.
+ *
* For example:
- * FS_ATTRIB reports the child inode even if reported on a watched parent.
- * FS_CREATE reports the modified dir inode and not the created inode.
+ * FS_ATTRIB reports the child fid even if reported on a watched parent.
+ * FS_CREATE reports the modified dir fid without FAN_REPORT_TARGET_FID.
+ * and reports the created child fid with FAN_REPORT_TARGET_FID.
*/
static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
- int data_type, struct inode *dir)
+ int data_type, struct inode *dir,
+ unsigned int fid_mode)
{
- if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
+ if ((event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) &&
+ !(fid_mode & FAN_REPORT_TARGET_FID))
return dir;
return fsnotify_data_inode(data, data_type);
@@ -647,10 +671,11 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
{
struct fanotify_event *event = NULL;
gfp_t gfp = GFP_KERNEL_ACCOUNT;
- struct inode *id = fanotify_fid_inode(mask, data, data_type, dir);
+ unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
+ struct inode *id = fanotify_fid_inode(mask, data, data_type, dir,
+ fid_mode);
struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
const struct path *path = fsnotify_data_path(data, data_type);
- unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
struct mem_cgroup *old_memcg;
struct inode *child = NULL;
bool name_event = false;
@@ -660,11 +685,10 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
/*
- * With both flags FAN_REPORT_DIR_FID and FAN_REPORT_FID, we
- * report the child fid for events reported on a non-dir child
+ * For certain events and group flags, report the child fid
* in addition to reporting the parent fid and maybe child name.
*/
- if ((fid_mode & FAN_REPORT_FID) && id != dirid && !ondir)
+ if (fanotify_report_child_fid(fid_mode, mask) && id != dirid)
child = id;
id = dirid;
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index ab24c37f1fdf..00bbc29712bb 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1275,6 +1275,15 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
if ((fid_mode & FAN_REPORT_NAME) && !(fid_mode & FAN_REPORT_DIR_FID))
return -EINVAL;
+ /*
+ * FAN_REPORT_TARGET_FID requires FAN_REPORT_NAME and FAN_REPORT_FID
+ * and is used as an indication to report both dir and child fid on all
+ * dirent events.
+ */
+ if ((fid_mode & FAN_REPORT_TARGET_FID) &&
+ (!(fid_mode & FAN_REPORT_NAME) || !(fid_mode & FAN_REPORT_FID)))
+ return -EINVAL;
+
f_flags = O_RDWR | FMODE_NONOTIFY;
if (flags & FAN_CLOEXEC)
f_flags |= O_CLOEXEC;
@@ -1667,7 +1676,7 @@ static int __init fanotify_user_setup(void)
FANOTIFY_DEFAULT_MAX_USER_MARKS);
BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
- BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 11);
+ BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 12);
BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,