On Wed 22-07-20 15:58:46, Amir Goldstein wrote:
> The arguments of fsnotify() are overloaded and mean different things
> for different event types.
>
> Replace the to_tell argument with separate arguments @dir and @inode,
> because we may be sending to both dir and child. Using the @data
> argument to pass the child is not enough, because dirent events pass
> this argument (for audit), but we do not report to child.
>
> Document the new fsnotify() function argumenets.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Thanks, applied!
Honza
> ---
> fs/kernfs/file.c | 5 +--
> fs/notify/fsnotify.c | 54 ++++++++++++++++++++++----------
> include/linux/fsnotify.h | 9 +++---
> include/linux/fsnotify_backend.h | 10 +++---
> 4 files changed, 52 insertions(+), 26 deletions(-)
>
> diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
> index 1d185bffc52f..f277d023ebcd 100644
> --- a/fs/kernfs/file.c
> +++ b/fs/kernfs/file.c
> @@ -902,8 +902,9 @@ static void kernfs_notify_workfn(struct work_struct *work)
> if (parent) {
> p_inode = ilookup(info->sb, kernfs_ino(parent));
> if (p_inode) {
> - fsnotify(p_inode, FS_MODIFY | FS_EVENT_ON_CHILD,
> - inode, FSNOTIFY_EVENT_INODE, &name, 0);
> + fsnotify(FS_MODIFY | FS_EVENT_ON_CHILD,
> + inode, FSNOTIFY_EVENT_INODE,
> + p_inode, &name, inode, 0);
> iput(p_inode);
> }
>
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 834775f61f6b..3b805e05c02d 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -179,7 +179,7 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> struct dentry *parent;
> bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED;
> __u32 p_mask;
> - struct inode *p_inode;
> + struct inode *p_inode = NULL;
> struct name_snapshot name;
> struct qstr *file_name = NULL;
> int ret = 0;
> @@ -213,14 +213,13 @@ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type));
>
> /* Notify both parent and child with child name info */
> - inode = p_inode;
> take_dentry_name_snapshot(&name, dentry);
> file_name = &name.name;
> mask |= FS_EVENT_ON_CHILD;
> }
>
> notify:
> - ret = fsnotify(inode, mask, data, data_type, file_name, 0);
> + ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0);
>
> if (file_name)
> release_dentry_name_snapshot(&name);
> @@ -354,18 +353,31 @@ static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info)
> }
>
> /*
> - * This is the main call to fsnotify. The VFS calls into hook specific functions
> - * in linux/fsnotify.h. Those functions then in turn call here. Here will call
> - * out to all of the registered fsnotify_group. Those groups can then use the
> - * notification event in whatever means they feel necessary.
> + * fsnotify - This is the main call to fsnotify.
> + *
> + * The VFS calls into hook specific functions in linux/fsnotify.h.
> + * Those functions then in turn call here. Here will call out to all of the
> + * registered fsnotify_group. Those groups can then use the notification event
> + * in whatever means they feel necessary.
> + *
> + * @mask: event type and flags
> + * @data: object that event happened on
> + * @data_type: type of object for fanotify_data_XXX() accessors
> + * @dir: optional directory associated with event -
> + * if @file_name is not NULL, this is the directory that
> + * @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.
> + * @cookie: inotify rename cookie
> */
> -int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> - const struct qstr *file_name, u32 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 fsnotify_iter_info iter_info = {};
> - struct super_block *sb = to_tell->i_sb;
> - struct inode *dir = file_name ? to_tell : NULL;
> + struct super_block *sb;
> struct mount *mnt = NULL;
> struct inode *child = NULL;
> int ret = 0;
> @@ -374,8 +386,18 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> if (path)
> mnt = real_mount(path->mnt);
>
> - if (mask & FS_EVENT_ON_CHILD)
> - child = fsnotify_data_inode(data, data_type);
> + if (!inode) {
> + /* Dirent event - report on TYPE_INODE to dir */
> + inode = dir;
> + } else if (mask & FS_EVENT_ON_CHILD) {
> + /*
> + * Event on child - report on TYPE_INODE to dir
> + * and on TYPE_CHILD to child.
> + */
> + child = inode;
> + inode = dir;
> + }
> + sb = inode->i_sb;
>
> /*
> * Optimization: srcu_read_lock() has a memory barrier which can
> @@ -384,12 +406,12 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> * SRCU because we have no references to any objects and do not
> * need SRCU to keep them "alive".
> */
> - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks &&
> + if (!inode->i_fsnotify_marks && !sb->s_fsnotify_marks &&
> (!mnt || !mnt->mnt_fsnotify_marks) &&
> (!child || !child->i_fsnotify_marks))
> return 0;
>
> - marks_mask = to_tell->i_fsnotify_mask | sb->s_fsnotify_mask;
> + marks_mask = inode->i_fsnotify_mask | sb->s_fsnotify_mask;
> if (mnt)
> marks_mask |= mnt->mnt_fsnotify_mask;
> if (child)
> @@ -407,7 +429,7 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_type,
> iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu);
>
> iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] =
> - fsnotify_first_mark(&to_tell->i_fsnotify_marks);
> + fsnotify_first_mark(&inode->i_fsnotify_marks);
> iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] =
> fsnotify_first_mark(&sb->s_fsnotify_marks);
> if (mnt) {
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index 01b71ad91339..d9b26c6552ee 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -23,13 +23,14 @@
> * have changed (i.e. renamed over).
> *
> * Unlike fsnotify_parent(), the event will be reported regardless of the
> - * FS_EVENT_ON_CHILD mask on the parent inode.
> + * FS_EVENT_ON_CHILD mask on the parent inode and will not be reported if only
> + * the child is interested and not the parent.
> */
> static inline void fsnotify_name(struct inode *dir, __u32 mask,
> struct inode *child,
> const struct qstr *name, u32 cookie)
> {
> - fsnotify(dir, mask, child, FSNOTIFY_EVENT_INODE, name, cookie);
> + fsnotify(mask, child, FSNOTIFY_EVENT_INODE, dir, name, NULL, cookie);
> }
>
> static inline void fsnotify_dirent(struct inode *dir, struct dentry *dentry,
> @@ -43,7 +44,7 @@ static inline void fsnotify_inode(struct inode *inode, __u32 mask)
> if (S_ISDIR(inode->i_mode))
> mask |= FS_ISDIR;
>
> - fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE, NULL, 0);
> + fsnotify(mask, inode, FSNOTIFY_EVENT_INODE, NULL, NULL, inode, 0);
> }
>
> /* Notify this dentry's parent about a child's events. */
> @@ -67,7 +68,7 @@ static inline int fsnotify_parent(struct dentry *dentry, __u32 mask,
> return __fsnotify_parent(dentry, mask, data, data_type);
>
> notify_child:
> - return fsnotify(inode, mask, data, data_type, NULL, 0);
> + return fsnotify(mask, data, data_type, NULL, NULL, inode, 0);
> }
>
> /*
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index d94a50e0445a..32104cfc27a5 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -398,8 +398,9 @@ struct fsnotify_mark {
> /* called from the vfs helpers */
>
> /* main fsnotify call to send events */
> -extern int fsnotify(struct inode *to_tell, __u32 mask, const void *data,
> - int data_type, const struct qstr *name, u32 cookie);
> +extern int fsnotify(__u32 mask, const void *data, int data_type,
> + struct inode *dir, const struct qstr *name,
> + struct inode *inode, u32 cookie);
> extern int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data,
> int data_type);
> extern void __fsnotify_inode_delete(struct inode *inode);
> @@ -569,8 +570,9 @@ static inline void fsnotify_init_event(struct fsnotify_event *event,
>
> #else
>
> -static inline int fsnotify(struct inode *to_tell, __u32 mask, const void *data,
> - int data_type, const struct qstr *name, u32 cookie)
> +static inline int fsnotify(__u32 mask, const void *data, int data_type,
> + struct inode *dir, const struct qstr *name,
> + struct inode *inode, u32 cookie)
> {
> return 0;
> }
> --
> 2.17.1
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
