Messages in this thread Patch in this message | | | From | Eric Paris <> | Subject | [PATCH -v1 04/11] fsnotify: parent event notification | Date | Mon, 09 Feb 2009 16:15:43 -0500 |
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inotify and dnotify both use a similar parent notification mechanism. We add a generic parent notification mechanism to fsnotify for both of these to use. This new machanism also adds the dentry flag optimization which exists for inotify to dnotify.
Signed-off-by: Eric Paris <eparis@redhat.com> ---
fs/notify/inode_mark.c | 4 + include/linux/dcache.h | 3 + include/linux/fsnotify.h | 111 +++++++++++++++++++++++++++++++++++++- include/linux/fsnotify_backend.h | 5 ++ 4 files changed, 119 insertions(+), 4 deletions(-)
diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 9a65fbc..840bd91 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -78,6 +78,8 @@ void fsnotify_recalc_inode_mask(struct inode *inode) spin_lock(&inode->i_lock); fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); + + fsnotify_update_dentry_child_flags(inode); } void fsnotify_clear_marks_by_group(struct fsnotify_group *group) @@ -232,6 +234,8 @@ int fsnotify_add_mark(struct fsnotify_mark_entry *entry) if (lentry) { ret = -EEXIST; fsnotify_put_mark(lentry); + } else { + fsnotify_update_dentry_child_flags(inode); } return ret; diff --git a/include/linux/dcache.h b/include/linux/dcache.h index c66d224..2b935f2 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -180,7 +180,8 @@ d_iput: no no no yes #define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */ #define DCACHE_UNHASHED 0x0010 -#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched */ +#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 /* Parent inode is watched by inotify */ +#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x0040 /* Parent inode is watched by some fsnotify listener */ #define DCACHE_COOKIE 0x0040 /* For use by dcookie subsystem */ diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h index 6ae332f..736bb28 100644 --- a/include/linux/fsnotify.h +++ b/include/linux/fsnotify.h @@ -16,14 +16,102 @@ #include <linux/fsnotify_backend.h> #include <linux/audit.h> +static inline int fsnotify_inode_watches_children(struct inode *inode) +{ + if (inode->i_fsnotify_mask & (FS_EVENTS_WITH_CHILD << 32)) + return 1; + return 0; +} + +/* + * Get child dentry flag into synch with parent inode. + * Flag should always be clear for negative dentrys.A + * + * It's possible the flag could lie (false positive). fsnotify only + * automatically updates the flag when a new mark is added. The flag is NOT + * automatically updated when marks are removed because of the horrid tactics + * that would be needed to do this. When we remove marks from an inode we have + * no idea if that inode is sticking around aside from holding the i_lock. We + * clearly can't hold the i_lock across this function. It doesn't really + * matter though. The whole point is just to short cut the parent lookup for + * performance. False positives hurt perf, but they aren't a bad thing. + */ +static inline void fsnotify_update_dentry_child_flags(struct inode *inode) +{ + struct dentry *alias; + int watched = fsnotify_inode_watches_children(inode); + + spin_lock(&dcache_lock); + list_for_each_entry(alias, &inode->i_dentry, d_alias) { + struct dentry *child; + + list_for_each_entry(child, &alias->d_subdirs, d_u.d_child) { + if (!child->d_inode) + continue; + + spin_lock(&child->d_lock); + if (watched) + child->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; + else + child->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; + spin_unlock(&child->d_lock); + } + } + spin_unlock(&dcache_lock); +} + /* * fsnotify_d_instantiate - instantiate a dentry for inode * Called with dcache_lock held. */ -static inline void fsnotify_d_instantiate(struct dentry *entry, - struct inode *inode) +static inline void fsnotify_d_instantiate(struct dentry *dentry, struct inode *inode) { - inotify_d_instantiate(entry, inode); + struct dentry *parent; + struct inode *p_inode; + + if (!inode) + return; + + spin_lock(&dentry->d_lock); + parent = dentry->d_parent; + p_inode = parent->d_inode; + + if (p_inode && fsnotify_inode_watches_children(p_inode)) + dentry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; + spin_unlock(&dentry->d_lock); + + /* call the legacy inotify shit */ + inotify_d_instantiate(dentry, inode); +} + +/* Notify this dentry's parent about a child's events. */ +static inline void fsnotify_parent(struct dentry *dentry, __u64 orig_mask) +{ + struct dentry *parent; + struct inode *p_inode; + __u64 mask; + + if (!(dentry->d_flags | DCACHE_FSNOTIFY_PARENT_WATCHED)) + return; + + /* we are notifying a parent so come up with the new mask which + * specifies these are events which came from a child. */ + mask = (orig_mask & FS_EVENTS_WITH_CHILD) << 32; + /* need to remember if the child was a dir */ + mask |= (orig_mask & FS_IN_ISDIR); + + spin_lock(&dentry->d_lock); + parent = dentry->d_parent; + p_inode = parent->d_inode; + + if (p_inode && (p_inode->i_fsnotify_mask & mask)) { + dget(parent); + spin_unlock(&dentry->d_lock); + fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE); + dput(parent); + } else { + spin_unlock(&dentry->d_lock); + } } /* @@ -32,6 +120,14 @@ static inline void fsnotify_d_instantiate(struct dentry *entry, */ static inline void fsnotify_d_move(struct dentry *entry) { + struct dentry *parent; + + parent = entry->d_parent; + if (fsnotify_inode_watches_children(parent->d_inode)) + entry->d_flags |= DCACHE_FSNOTIFY_PARENT_WATCHED; + else + entry->d_flags &= ~DCACHE_FSNOTIFY_PARENT_WATCHED; + inotify_d_move(entry); } @@ -96,6 +192,8 @@ static inline void fsnotify_nameremove(struct dentry *dentry, int isdir) isdir = IN_ISDIR; dnotify_parent(dentry, DN_DELETE); inotify_dentry_parent_queue_event(dentry, IN_DELETE|isdir, 0, dentry->d_name.name); + + fsnotify_parent(dentry, FS_DELETE|isdir); } /* @@ -185,6 +283,7 @@ static inline void fsnotify_access(struct dentry *dentry) inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + fsnotify_parent(dentry, mask); fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } @@ -203,6 +302,7 @@ static inline void fsnotify_modify(struct dentry *dentry) inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + fsnotify_parent(dentry, mask); fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } @@ -220,6 +320,7 @@ static inline void fsnotify_open(struct dentry *dentry) inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + fsnotify_parent(dentry, mask); fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } @@ -240,6 +341,7 @@ static inline void fsnotify_close(struct file *file) inotify_dentry_parent_queue_event(dentry, mask, 0, name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + fsnotify_parent(dentry, mask); fsnotify(inode, mask, file, FSNOTIFY_EVENT_FILE); } @@ -257,6 +359,7 @@ static inline void fsnotify_xattr(struct dentry *dentry) inotify_dentry_parent_queue_event(dentry, mask, 0, dentry->d_name.name); inotify_inode_queue_event(inode, mask, 0, NULL, NULL); + fsnotify_parent(dentry, mask); fsnotify(inode, mask, inode, FSNOTIFY_EVENT_INODE); } @@ -307,6 +410,8 @@ static inline void fsnotify_change(struct dentry *dentry, unsigned int ia_valid) inotify_inode_queue_event(inode, in_mask, 0, NULL, NULL); inotify_dentry_parent_queue_event(dentry, in_mask, 0, dentry->d_name.name); + + fsnotify_parent(dentry, in_mask); fsnotify(inode, in_mask, inode, FSNOTIFY_EVENT_INODE); } } diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index a9508c5..ad7294f 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -63,6 +63,11 @@ #define FS_DN_RENAME 0x1000000000000000ull /* file renamed */ #define FS_DN_MULTISHOT 0x2000000000000000ull /* dnotify multishot */ +#define FS_EVENTS_WITH_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\ + FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\ + FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\ + FS_DELETE) + /* when calling fsnotify tell it if the data is a path or inode */ #define FSNOTIFY_EVENT_PATH 1 #define FSNOTIFY_EVENT_INODE 2
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