Commit 29335033 authored by Gabriel Krisman Bertazi's avatar Gabriel Krisman Bertazi Committed by Jan Kara
Browse files

fsnotify: Retrieve super block from the data field 

Some file system events (i.e. FS_ERROR) might not be associated with an
inode or directory.  For these, we can retrieve the super block from the
data field.  But, since the super_block is available in the data field
on every event type, simplify the code to always retrieve it from there,
through a new helper.

Link: https://lore.kernel.org/r/20211025192746.66445-11-krisman@collabora.com


Suggested-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarAmir Goldstein <amir73il@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarGabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 1ad03c3a

fs/notify/fsnotify.c

+3 −4
Original line number Diff line number Diff line
@@ -455,16 +455,16 @@ static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info) 
 *		@file_name is relative to

 * @file_name:	optional file name associated with event

 * @inode:	optional inode associated with event -

 *		either @dir or @inode must be non-NULL.

 *		if both are non-NULL event may be reported to both.

 *		If @dir and @inode are both non-NULL, event may be

 *		reported to both.

 * @cookie:	inotify rename cookie

 */

int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir,

	     const struct qstr *file_name, struct inode *inode, u32 cookie)

{

	const struct path *path = fsnotify_data_path(data, data_type);

	struct super_block *sb = fsnotify_data_sb(data, data_type);

	struct fsnotify_iter_info iter_info = {};

	struct super_block *sb;

	struct mount *mnt = NULL;

	struct inode *parent = NULL;

	int ret = 0;
@@ -483,7 +483,6 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, 
		 */

		parent = dir;

	}

	sb = inode->i_sb;



	/*

	 * Optimization: srcu_read_lock() has a memory barrier which can

include/linux/fsnotify_backend.h

+15 −0
Original line number Diff line number Diff line
@@ -289,6 +289,21 @@ static inline const struct path *fsnotify_data_path(const void *data, 
	}

}



static inline struct super_block *fsnotify_data_sb(const void *data,

						   int data_type)

{

	switch (data_type) {

	case FSNOTIFY_EVENT_INODE:

		return ((struct inode *)data)->i_sb;

	case FSNOTIFY_EVENT_DENTRY:

		return ((struct dentry *)data)->d_sb;

	case FSNOTIFY_EVENT_PATH:

		return ((const struct path *)data)->dentry->d_sb;

	default:

		return NULL;

	}

}



enum fsnotify_obj_type {

	FSNOTIFY_OBJ_TYPE_INODE,

	FSNOTIFY_OBJ_TYPE_PARENT,