inotify generates unsolicited IN_UNMOUNT events for every inode
mark before the filesystem containing the inode is shutdown.
Unlike IN_UNMOUNT, FAN_UNMOUNT is an opt-in event that can only be
set on a mount mark and is generated when the mount is unmounted.
FAN_UNMOUNT requires FAN_REPORT_FID and reports an fid info record
with fsid of the filesystem and an empty file handle.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify.c | 10 +++++++---
fs/notify/fanotify/fanotify.h | 6 ++++--
fs/notify/fanotify/fanotify_user.c | 10 ++++++++++
include/linux/fanotify.h | 3 ++-
include/linux/fsnotify.h | 16 ++++++++++++++++
include/uapi/linux/fanotify.h | 1 +
6 files changed, 40 insertions(+), 6 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 90d9210dc0d2..384d2b2e55e7 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -713,7 +713,7 @@ static struct fanotify_event *fanotify_alloc_error_event(
inode = report->inode;
fh_len = fanotify_encode_fh_len(inode);
- /* Bad fh_len. Fallback to using an invalid fh. Should never happen. */
+ /* Record empty fh for errors not associated with specific inode */
if (!fh_len && inode)
inode = NULL;
@@ -745,7 +745,10 @@ static struct fanotify_event *fanotify_alloc_event(
bool ondir = mask & FAN_ONDIR;
struct pid *pid;
- if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
+ if (mask & FAN_UNMOUNT && !WARN_ON_ONCE(!path || !fid_mode)) {
+ /* Record fid event with fsid and empty fh */
+ id = NULL;
+ } else if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
/*
* For certain events and group flags, report the child fid
* in addition to reporting the parent fid and maybe child name.
@@ -951,10 +954,11 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR);
BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
+ BUILD_BUG_ON(FAN_UNMOUNT != FS_UNMOUNT);
BUILD_BUG_ON(FAN_FS_ERROR != FS_ERROR);
BUILD_BUG_ON(FAN_RENAME != FS_RENAME);
- BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 21);
+ BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 22);
mask = fanotify_group_event_mask(group, iter_info, &match_mask,
mask, data, data_type, dir);
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 7f0bf00a90f0..f98dcf5b7a19 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -382,10 +382,12 @@ static inline int fanotify_event_dir2_fh_len(struct fanotify_event *event)
return info ? fanotify_info_dir2_fh_len(info) : 0;
}
+/* For error and unmount events, fsid with empty fh are reported. */
+#define FANOTIFY_EMPTY_FH_EVENTS (FAN_FS_ERROR | FAN_UNMOUNT)
+
static inline bool fanotify_event_has_object_fh(struct fanotify_event *event)
{
- /* For error events, even zeroed fh are reported. */
- if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR)
+ if (event->mask & FANOTIFY_EMPTY_FH_EVENTS)
return true;
return fanotify_event_object_fh_len(event) > 0;
}
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 554b335b1733..0b3de6218c56 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1766,6 +1766,16 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
(!fid_mode || mark_type == FAN_MARK_MOUNT))
goto fput_and_out;
+ /*
+ * inotify sends unsoliciled IN_UNMOUNT per marked inode on sb shutdown.
+ * FAN_UNMOUNT event is about unmount of a mount, not about sb shutdown,
+ * so allow setting it only in mount mark mask.
+ * FAN_UNMOUNT requires FAN_REPORT_FID to report fsid with empty fh.
+ */
+ if (mask & FAN_UNMOUNT &&
+ (!(fid_mode & FAN_REPORT_FID) || mark_type != FAN_MARK_MOUNT))
+ goto fput_and_out;
+
/*
* FAN_RENAME uses special info type records to report the old and
* new parent+name. Reporting only old and new parent id is less
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index 4c6f40a701c2..a64c26d9626f 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -80,7 +80,8 @@
* FSNOTIFY_EVENT_INODE.
*/
#define FANOTIFY_PATH_EVENTS (FAN_ACCESS | FAN_MODIFY | \
- FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC)
+ FAN_CLOSE | FAN_OPEN | FAN_OPEN_EXEC | \
+ FAN_UNMOUNT)
/*
* Directory entry modification events - reported only to directory
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index bb8467cd11ae..3898bf858407 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -176,11 +176,27 @@ static inline void fsnotify_inode_delete(struct inode *inode)
__fsnotify_inode_delete(inode);
}
+/*
+ * fsnotify_unmount - mount was unmounted.
+ */
+static inline int fsnotify_unmount(struct vfsmount *mnt)
+{
+ struct path path = { .mnt = mnt, .dentry = mnt->mnt_root };
+
+ if (atomic_long_read(&mnt->mnt_sb->s_fsnotify_connectors) == 0)
+ return 0;
+
+ return fsnotify(FS_UNMOUNT, &path, FSNOTIFY_EVENT_PATH, NULL, NULL,
+ d_inode(path.dentry), 0);
+}
+
/*
* fsnotify_vfsmount_delete - a vfsmount is being destroyed, clean up is needed
*/
static inline void fsnotify_vfsmount_delete(struct vfsmount *mnt)
{
+ /* Send FS_UNMOUNT to groups and then clear mount marks */
+ fsnotify_unmount(mnt);
__fsnotify_vfsmount_delete(mnt);
}
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index 014e9682bd76..70f2d43e8ba4 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -19,6 +19,7 @@
#define FAN_MOVE_SELF 0x00000800 /* Self was moved */
#define FAN_OPEN_EXEC 0x00001000 /* File was opened for exec */
+#define FAN_UNMOUNT 0x00002000 /* Filesystem unmounted */
#define FAN_Q_OVERFLOW 0x00004000 /* Event queued overflowed */
#define FAN_FS_ERROR 0x00008000 /* Filesystem error */
--
2.34.1
