fsnotify: generalize handle_inode_event()

The handle_inode_event() interface was added as (quoting comment):
"a simple variant of handle_event() for groups that only have inode
marks and don't have ignore mask".

In other words, all backends except fanotify.  The inotify backend
also falls under this category, but because it required extra arguments
it was left out of the initial pass of backends conversion to the
simple interface.

This results in code duplication between the generic helper
fsnotify_handle_event() and the inotify_handle_event() callback
which also happen to be buggy code.

Generalize the handle_inode_event() arguments and add the check for
FS_EXCL_UNLINK flag to the generic helper, so inotify backend could
be converted to use the simple interface.

Link: https://lore.kernel.org/r/20201202120713.702387-2-amir73il@gmail.com
CC: stable@vger.kernel.org
Fixes: b9a1b9772509 ("fsnotify: create method handle_inode_event() in fsnotify_operations")
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>

3 files changed, 26 insertions, 9 deletions

diff --git a/fs/nfsd/filecache.c b/fs/nfsd/filecache.c
index 3c6c2f7d1688..5849c1bd88f1 100644
--- a/fs/nfsd/filecache.c
+++ b/fs/nfsd/filecache.c
@@ -600,7 +600,7 @@ static struct notifier_block nfsd_file_lease_notifier = {
 static int
 nfsd_file_fsnotify_handle_event(struct fsnotify_mark *mark, u32 mask,
 				struct inode *inode, struct inode *dir,
-				const struct qstr *name)
+				const struct qstr *name, u32 cookie)
 {
 	trace_nfsd_file_fsnotify_handle_event(inode, mask);
 
diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c
index 5dcda8f20c04..e45ca6ecba95 100644
--- a/fs/notify/dnotify/dnotify.c
+++ b/fs/notify/dnotify/dnotify.c
@@ -72,7 +72,7 @@ static void dnotify_recalc_inode_mask(struct fsnotify_mark *fsn_mark)
  */
 static int dnotify_handle_event(struct fsnotify_mark *inode_mark, u32 mask,
 				struct inode *inode, struct inode *dir,
-				const struct qstr *name)
+				const struct qstr *name, u32 cookie)
 {
 	struct dnotify_mark *dn_mark;
 	struct dnotify_struct *dn;
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
index 8d3ad5ef2925..c5c68bcbaadf 100644
--- a/fs/notify/fsnotify.c
+++ b/fs/notify/fsnotify.c
@@ -232,6 +232,26 @@ notify:
 }
 EXPORT_SYMBOL_GPL(__fsnotify_parent);
 
+static int fsnotify_handle_inode_event(struct fsnotify_group *group,
+				       struct fsnotify_mark *inode_mark,
+				       u32 mask, const void *data, int data_type,
+				       struct inode *dir, const struct qstr *name,
+				       u32 cookie)
+{
+	const struct path *path = fsnotify_data_path(data, data_type);
+	struct inode *inode = fsnotify_data_inode(data, data_type);
+	const struct fsnotify_ops *ops = group->ops;
+
+	if (WARN_ON_ONCE(!ops->handle_inode_event))
+		return 0;
+
+	if ((inode_mark->mask & FS_EXCL_UNLINK) &&
+	    path && d_unlinked(path->dentry))
+		return 0;
+
+	return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie);
+}
+
 static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
 				 const void *data, int data_type,
 				 struct inode *dir, const struct qstr *name,
@@ -239,13 +259,8 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
 {
 	struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info);
 	struct fsnotify_mark *child_mark = fsnotify_iter_child_mark(iter_info);
-	struct inode *inode = fsnotify_data_inode(data, data_type);
-	const struct fsnotify_ops *ops = group->ops;
 	int ret;
 
-	if (WARN_ON_ONCE(!ops->handle_inode_event))
-		return 0;
-
 	if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) ||
 	    WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info)))
 		return 0;
@@ -262,7 +277,8 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
 		name = NULL;
 	}
 
-	ret = ops->handle_inode_event(inode_mark, mask, inode, dir, name);
+	ret = fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type,
+					  dir, name, cookie);
 	if (ret || !child_mark)
 		return ret;
 
@@ -272,7 +288,8 @@ static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask,
 	 * report the event once to parent dir with name and once to child
 	 * without name.
 	 */
-	return ops->handle_inode_event(child_mark, mask, inode, NULL, NULL);
+	return fsnotify_handle_inode_event(group, child_mark, mask, data, data_type,
+					   NULL, NULL, 0);
 }
 
 static int send_to_group(__u32 mask, const void *data, int data_type,