diff options
| -rw-r--r-- | fs/notify/fsnotify.c | 74 | ||||
| -rw-r--r-- | include/linux/fsnotify.h | 10 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 32 |
3 files changed, 97 insertions, 19 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 4a762c8c4a29..494d5d70323f 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -142,38 +142,81 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) spin_unlock(&inode->i_lock); } +/* Are inode/sb/mount interested in parent and name info with this event? */ +static bool fsnotify_event_needs_parent(struct inode *inode, struct mount *mnt, + __u32 mask) +{ + __u32 marks_mask = 0; + + /* We only send parent/name to inode/sb/mount for events on non-dir */ + if (mask & FS_ISDIR) + return false; + + /* Did either inode/sb/mount subscribe for events with parent/name? */ + marks_mask |= fsnotify_parent_needed_mask(inode->i_fsnotify_mask); + marks_mask |= fsnotify_parent_needed_mask(inode->i_sb->s_fsnotify_mask); + if (mnt) + marks_mask |= fsnotify_parent_needed_mask(mnt->mnt_fsnotify_mask); + + /* Did they subscribe for this event with parent/name info? */ + return mask & marks_mask; +} + /* * Notify this dentry's parent about a child's events with child name info - * if parent is watching. - * Notify only the child without name info if parent is not watching. + * if parent is watching or if inode/sb/mount are interested in events with + * parent and name info. + * + * Notify only the child without name info if parent is not watching and + * inode/sb/mount are not interested in events with parent and name info. */ int __fsnotify_parent(struct dentry *dentry, __u32 mask, const void *data, int data_type) { + const struct path *path = fsnotify_data_path(data, data_type); + struct mount *mnt = path ? real_mount(path->mnt) : NULL; struct inode *inode = d_inode(dentry); struct dentry *parent; + bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED; + __u32 p_mask; struct inode *p_inode = NULL; struct name_snapshot name; struct qstr *file_name = NULL; int ret = 0; + /* + * Do inode/sb/mount care about parent and name info on non-dir? + * Do they care about any event at all? + */ + if (!inode->i_fsnotify_marks && !inode->i_sb->s_fsnotify_marks && + (!mnt || !mnt->mnt_fsnotify_marks) && !parent_watched) + return 0; + parent = NULL; - if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) + if (!parent_watched && !fsnotify_event_needs_parent(inode, mnt, mask)) goto notify; + /* Does parent inode care about events on children? */ parent = dget_parent(dentry); p_inode = parent->d_inode; - - if (unlikely(!fsnotify_inode_watches_children(p_inode))) { + p_mask = fsnotify_inode_watches_children(p_inode); + if (unlikely(parent_watched && !p_mask)) __fsnotify_update_child_dentry_flags(p_inode); - } else if (p_inode->i_fsnotify_mask & mask & ALL_FSNOTIFY_EVENTS) { + + /* + * Include parent/name in notification either if some notification + * groups require parent info (!parent_watched case) or the parent is + * interested in this event. + */ + if (!parent_watched || (mask & p_mask & ALL_FSNOTIFY_EVENTS)) { /* When notifying parent, child should be passed as data */ WARN_ON_ONCE(inode != fsnotify_data_inode(data, data_type)); /* Notify both parent and child with child name info */ take_dentry_name_snapshot(&name, dentry); file_name = &name.name; - mask |= FS_EVENT_ON_CHILD; + if (parent_watched) + mask |= FS_EVENT_ON_CHILD; } notify: @@ -349,8 +392,8 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *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. + * Event on child - report on TYPE_INODE to dir if it is + * watching children and on TYPE_CHILD to child. */ child = inode; inode = dir; @@ -364,14 +407,17 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, * SRCU because we have no references to any objects and do not * need SRCU to keep them "alive". */ - if (!inode->i_fsnotify_marks && !sb->s_fsnotify_marks && + if (!sb->s_fsnotify_marks && (!mnt || !mnt->mnt_fsnotify_marks) && + (!inode || !inode->i_fsnotify_marks) && (!child || !child->i_fsnotify_marks)) return 0; - marks_mask = inode->i_fsnotify_mask | sb->s_fsnotify_mask; + marks_mask = sb->s_fsnotify_mask; if (mnt) marks_mask |= mnt->mnt_fsnotify_mask; + if (inode) + marks_mask |= inode->i_fsnotify_mask; if (child) marks_mask |= child->i_fsnotify_mask; @@ -386,14 +432,16 @@ int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = - fsnotify_first_mark(&inode->i_fsnotify_marks); iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = fsnotify_first_mark(&sb->s_fsnotify_marks); if (mnt) { iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = fsnotify_first_mark(&mnt->mnt_fsnotify_marks); } + if (inode) { + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = + fsnotify_first_mark(&inode->i_fsnotify_marks); + } if (child) { iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] = fsnotify_first_mark(&child->i_fsnotify_marks); diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 99922cac4fcd..6e63f7e10da0 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -53,10 +53,16 @@ static inline int fsnotify_parent(struct dentry *dentry, __u32 mask, { struct inode *inode = d_inode(dentry); - if (S_ISDIR(inode->i_mode)) + if (S_ISDIR(inode->i_mode)) { mask |= FS_ISDIR; - if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) + /* sb/mount marks are not interested in name of directory */ + if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) + goto notify_child; + } + + /* disconnected dentry cannot notify parent */ + if (IS_ROOT(dentry)) goto notify_child; return __fsnotify_parent(dentry, mask, data, data_type); diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 152520635bd3..32104cfc27a5 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -49,8 +49,11 @@ #define FS_OPEN_EXEC_PERM 0x00040000 /* open/exec event in a permission hook */ #define FS_EXCL_UNLINK 0x04000000 /* do not send events if object is unlinked */ -/* This inode cares about things that happen to its children. Always set for - * dnotify and inotify. */ +/* + * Set on inode mark that cares about things that happen to its children. + * Always set for dnotify and inotify. + * Set on inode/sb/mount marks that care about parent/name info. + */ #define FS_EVENT_ON_CHILD 0x08000000 #define FS_DN_RENAME 0x10000000 /* file renamed */ @@ -72,14 +75,22 @@ FS_OPEN_EXEC_PERM) /* - * This is a list of all events that may get sent to a parent based on fs event - * happening to inodes inside that directory. + * This is a list of all events that may get sent to a parent that is watching + * with flag FS_EVENT_ON_CHILD based on fs event on a child of that directory. */ #define FS_EVENTS_POSS_ON_CHILD (ALL_FSNOTIFY_PERM_EVENTS | \ FS_ACCESS | FS_MODIFY | FS_ATTRIB | \ FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | \ FS_OPEN | FS_OPEN_EXEC) +/* + * This is a list of all events that may get sent with the parent inode as the + * @to_tell argument of fsnotify(). + * It may include events that can be sent to an inode/sb/mount mark, but cannot + * be sent to a parent watching children. + */ +#define FS_EVENTS_POSS_TO_PARENT (FS_EVENTS_POSS_ON_CHILD) + /* Events that can be reported to backends */ #define ALL_FSNOTIFY_EVENTS (ALL_FSNOTIFY_DIRENT_EVENTS | \ FS_EVENTS_POSS_ON_CHILD | \ @@ -397,6 +408,19 @@ extern void __fsnotify_vfsmount_delete(struct vfsmount *mnt); extern void fsnotify_sb_delete(struct super_block *sb); extern u32 fsnotify_get_cookie(void); +static inline __u32 fsnotify_parent_needed_mask(__u32 mask) +{ + /* FS_EVENT_ON_CHILD is set on marks that want parent/name info */ + if (!(mask & FS_EVENT_ON_CHILD)) + return 0; + /* + * This object might be watched by a mark that cares about parent/name + * info, does it care about the specific set of events that can be + * reported with parent/name info? + */ + return mask & FS_EVENTS_POSS_TO_PARENT; +} + static inline int fsnotify_inode_watches_children(struct inode *inode) { /* FS_EVENT_ON_CHILD is set if the inode may care */ |