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-rw-r--r--fs/notify/fanotify/fanotify.h2
-rw-r--r--fs/notify/fanotify/fanotify_user.c38
-rw-r--r--include/uapi/linux/fanotify.h1
3 files changed, 39 insertions, 2 deletions
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 87142bc0131a..80e0ec95b113 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -497,6 +497,8 @@ static inline unsigned int fanotify_mark_user_flags(struct fsnotify_mark *mark)
if (mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)
mflags |= FAN_MARK_IGNORED_SURV_MODIFY;
+ if (mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)
+ mflags |= FAN_MARK_EVICTABLE;
return mflags;
}
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 4005ee8e6e2c..ae36138afead 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1084,6 +1084,7 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group,
static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
unsigned int fan_flags)
{
+ bool want_iref = !(fan_flags & FAN_MARK_EVICTABLE);
bool recalc = false;
/*
@@ -1099,7 +1100,18 @@ static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
recalc = true;
}
- return recalc;
+ if (fsn_mark->connector->type != FSNOTIFY_OBJ_TYPE_INODE ||
+ want_iref == !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
+ return recalc;
+
+ /*
+ * NO_IREF may be removed from a mark, but not added.
+ * When removed, fsnotify_recalc_mask() will take the inode ref.
+ */
+ WARN_ON_ONCE(!want_iref);
+ fsn_mark->flags &= ~FSNOTIFY_MARK_FLAG_NO_IREF;
+
+ return true;
}
static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
@@ -1125,6 +1137,7 @@ static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
fsnotify_connp_t *connp,
unsigned int obj_type,
+ unsigned int fan_flags,
__kernel_fsid_t *fsid)
{
struct ucounts *ucounts = group->fanotify_data.ucounts;
@@ -1147,6 +1160,9 @@ static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
}
fsnotify_init_mark(mark, group);
+ if (fan_flags & FAN_MARK_EVICTABLE)
+ mark->flags |= FSNOTIFY_MARK_FLAG_NO_IREF;
+
ret = fsnotify_add_mark_locked(mark, connp, obj_type, 0, fsid);
if (ret) {
fsnotify_put_mark(mark);
@@ -1183,7 +1199,8 @@ static int fanotify_add_mark(struct fsnotify_group *group,
mutex_lock(&group->mark_mutex);
fsn_mark = fsnotify_find_mark(connp, group);
if (!fsn_mark) {
- fsn_mark = fanotify_add_new_mark(group, connp, obj_type, fsid);
+ fsn_mark = fanotify_add_new_mark(group, connp, obj_type,
+ fan_flags, fsid);
if (IS_ERR(fsn_mark)) {
mutex_unlock(&group->mark_mutex);
return PTR_ERR(fsn_mark);
@@ -1191,6 +1208,15 @@ static int fanotify_add_mark(struct fsnotify_group *group,
}
/*
+ * Non evictable mark cannot be downgraded to evictable mark.
+ */
+ if (fan_flags & FAN_MARK_EVICTABLE &&
+ !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF)) {
+ ret = -EEXIST;
+ goto out;
+ }
+
+ /*
* Error events are pre-allocated per group, only if strictly
* needed (i.e. FAN_FS_ERROR was requested).
*/
@@ -1602,6 +1628,14 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
goto fput_and_out;
/*
+ * Evictable is only relevant for inode marks, because only inode object
+ * can be evicted on memory pressure.
+ */
+ if (flags & FAN_MARK_EVICTABLE &&
+ mark_type != FAN_MARK_INODE)
+ goto fput_and_out;
+
+ /*
* Events that do not carry enough information to report
* event->fd require a group that supports reporting fid. Those
* events are not supported on a mount mark, because they do not
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index e8ac38cc2fd6..f1f89132d60e 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_EVICTABLE 0x00000200
/* These are NOT bitwise flags. Both bits can be used togther. */
#define FAN_MARK_INODE 0x00000000