diff options
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/dnotify/dnotify.c | 14 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 8 | ||||
| -rw-r--r-- | fs/notify/fdinfo.c | 3 | ||||
| -rw-r--r-- | fs/notify/fsnotify.c | 11 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 21 | ||||
| -rw-r--r-- | fs/notify/inode_mark.c | 20 | ||||
| -rw-r--r-- | fs/notify/mark.c | 141 | ||||
| -rw-r--r-- | fs/notify/vfsmount_mark.c | 19 |
8 files changed, 132 insertions, 105 deletions
diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index 44523f4a6084..6faaf710e563 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -154,6 +154,7 @@ void dnotify_flush(struct file *filp, fl_owner_t id) struct dnotify_struct *dn; struct dnotify_struct **prev; struct inode *inode; + bool free = false; inode = file_inode(filp); if (!S_ISDIR(inode->i_mode)) @@ -182,11 +183,15 @@ void dnotify_flush(struct file *filp, fl_owner_t id) /* nothing else could have found us thanks to the dnotify_groups mark_mutex */ - if (dn_mark->dn == NULL) - fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); + if (dn_mark->dn == NULL) { + fsnotify_detach_mark(fsn_mark); + free = true; + } mutex_unlock(&dnotify_group->mark_mutex); + if (free) + fsnotify_free_mark(fsn_mark); fsnotify_put_mark(fsn_mark); } @@ -362,9 +367,10 @@ out: spin_unlock(&fsn_mark->lock); if (destroy) - fsnotify_destroy_mark_locked(fsn_mark, dnotify_group); - + fsnotify_detach_mark(fsn_mark); mutex_unlock(&dnotify_group->mark_mutex); + if (destroy) + fsnotify_free_mark(fsn_mark); fsnotify_put_mark(fsn_mark); out_err: if (new_fsn_mark) diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index cf275500a665..8e8e6bcd1d43 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -529,8 +529,10 @@ static int fanotify_remove_vfsmount_mark(struct fsnotify_group *group, removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, &destroy_mark); if (destroy_mark) - fsnotify_destroy_mark_locked(fsn_mark, group); + fsnotify_detach_mark(fsn_mark); mutex_unlock(&group->mark_mutex); + if (destroy_mark) + fsnotify_free_mark(fsn_mark); fsnotify_put_mark(fsn_mark); if (removed & real_mount(mnt)->mnt_fsnotify_mask) @@ -557,8 +559,10 @@ static int fanotify_remove_inode_mark(struct fsnotify_group *group, removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags, &destroy_mark); if (destroy_mark) - fsnotify_destroy_mark_locked(fsn_mark, group); + fsnotify_detach_mark(fsn_mark); mutex_unlock(&group->mark_mutex); + if (destroy_mark) + fsnotify_free_mark(fsn_mark); /* matches the fsnotify_find_inode_mark() */ fsnotify_put_mark(fsn_mark); diff --git a/fs/notify/fdinfo.c b/fs/notify/fdinfo.c index 58b7cdb63da9..6b6f0d472ae8 100644 --- a/fs/notify/fdinfo.c +++ b/fs/notify/fdinfo.c @@ -76,7 +76,8 @@ static void inotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark) struct inotify_inode_mark *inode_mark; struct inode *inode; - if (!(mark->flags & (FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_INODE))) + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE) || + !(mark->flags & FSNOTIFY_MARK_FLAG_INODE)) return; inode_mark = container_of(mark, struct inotify_inode_mark, fsn_mark); diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index dd3fb0b17be7..db39de2dd4cb 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -26,7 +26,6 @@ #include <linux/fsnotify_backend.h> #include "fsnotify.h" -#include "../mount.h" /* * Clear all of the marks on an inode when it is being evicted from core @@ -205,6 +204,16 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, mnt = NULL; /* + * Optimization: srcu_read_lock() has a memory barrier which can + * be expensive. It protects walking the *_fsnotify_marks lists. + * However, if we do not walk the lists, we do not have to do + * SRCU because we have no references to any objects and do not + * need SRCU to keep them "alive". + */ + if (hlist_empty(&to_tell->i_fsnotify_marks) && + (!mnt || hlist_empty(&mnt->mnt_fsnotify_marks))) + return 0; + /* * if this is a modify event we may need to clear the ignored masks * otherwise return if neither the inode nor the vfsmount care about * this type of event. diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 13a00be516d2..b44c68a857e7 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -6,6 +6,8 @@ #include <linux/srcu.h> #include <linux/types.h> +#include "../mount.h" + /* destroy all events sitting in this groups notification queue */ extern void fsnotify_flush_notify(struct fsnotify_group *group); @@ -38,15 +40,22 @@ extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark); /* inode specific destruction of a mark */ extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); -/* Destroy all marks in the given list */ -extern void fsnotify_destroy_marks(struct list_head *to_free); /* Find mark belonging to given group in the list of marks */ extern struct fsnotify_mark *fsnotify_find_mark(struct hlist_head *head, struct fsnotify_group *group); -/* run the list of all marks associated with inode and flag them to be freed */ -extern void fsnotify_clear_marks_by_inode(struct inode *inode); -/* run the list of all marks associated with vfsmount and flag them to be freed */ -extern void fsnotify_clear_marks_by_mount(struct vfsmount *mnt); +/* Destroy all marks in the given list protected by 'lock' */ +extern void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock); +/* run the list of all marks associated with inode and destroy them */ +static inline void fsnotify_clear_marks_by_inode(struct inode *inode) +{ + fsnotify_destroy_marks(&inode->i_fsnotify_marks, &inode->i_lock); +} +/* run the list of all marks associated with vfsmount and destroy them */ +static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) +{ + fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks, + &mnt->mnt_root->d_lock); +} /* * update the dentry->d_flags of all of inode's children to indicate if inode cares * about events that happen to its children. diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 3daf513ee99e..474a3ce1b5e1 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -65,26 +65,6 @@ void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) } /* - * Given an inode, destroy all of the marks associated with that inode. - */ -void fsnotify_clear_marks_by_inode(struct inode *inode) -{ - struct fsnotify_mark *mark; - struct hlist_node *n; - LIST_HEAD(free_list); - - spin_lock(&inode->i_lock); - hlist_for_each_entry_safe(mark, n, &inode->i_fsnotify_marks, obj_list) { - list_add(&mark->free_list, &free_list); - hlist_del_init_rcu(&mark->obj_list); - fsnotify_get_mark(mark); - } - spin_unlock(&inode->i_lock); - - fsnotify_destroy_marks(&free_list); -} - -/* * Given a group clear all of the inode marks associated with that group. */ void fsnotify_clear_inode_marks_by_group(struct fsnotify_group *group) diff --git a/fs/notify/mark.c b/fs/notify/mark.c index 92e48c70f0f0..fc0df4442f7b 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -122,26 +122,27 @@ u32 fsnotify_recalc_mask(struct hlist_head *head) } /* - * Any time a mark is getting freed we end up here. - * The caller had better be holding a reference to this mark so we don't actually - * do the final put under the mark->lock + * Remove mark from inode / vfsmount list, group list, drop inode reference + * if we got one. + * + * Must be called with group->mark_mutex held. */ -void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, - struct fsnotify_group *group) +void fsnotify_detach_mark(struct fsnotify_mark *mark) { struct inode *inode = NULL; + struct fsnotify_group *group = mark->group; BUG_ON(!mutex_is_locked(&group->mark_mutex)); spin_lock(&mark->lock); /* something else already called this function on this mark */ - if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ATTACHED)) { spin_unlock(&mark->lock); return; } - mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + mark->flags &= ~FSNOTIFY_MARK_FLAG_ATTACHED; if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) { inode = mark->inode; @@ -150,6 +151,12 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, fsnotify_destroy_vfsmount_mark(mark); else BUG(); + /* + * Note that we didn't update flags telling whether inode cares about + * what's happening with children. We update these flags from + * __fsnotify_parent() lazily when next event happens on one of our + * children. + */ list_del_init(&mark->g_list); @@ -157,18 +164,32 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, if (inode && (mark->flags & FSNOTIFY_MARK_FLAG_OBJECT_PINNED)) iput(inode); - /* release lock temporarily */ - mutex_unlock(&group->mark_mutex); + + atomic_dec(&group->num_marks); +} + +/* + * Free fsnotify mark. The freeing is actually happening from a kthread which + * first waits for srcu period end. Caller must have a reference to the mark + * or be protected by fsnotify_mark_srcu. + */ +void fsnotify_free_mark(struct fsnotify_mark *mark) +{ + struct fsnotify_group *group = mark->group; + + spin_lock(&mark->lock); + /* something else already called this function on this mark */ + if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE)) { + spin_unlock(&mark->lock); + return; + } + mark->flags &= ~FSNOTIFY_MARK_FLAG_ALIVE; + spin_unlock(&mark->lock); spin_lock(&destroy_lock); list_add(&mark->g_list, &destroy_list); spin_unlock(&destroy_lock); wake_up(&destroy_waitq); - /* - * We don't necessarily have a ref on mark from caller so the above destroy - * may have actually freed it, unless this group provides a 'freeing_mark' - * function which must be holding a reference. - */ /* * Some groups like to know that marks are being freed. This is a @@ -177,50 +198,45 @@ void fsnotify_destroy_mark_locked(struct fsnotify_mark *mark, */ if (group->ops->freeing_mark) group->ops->freeing_mark(mark, group); - - /* - * __fsnotify_update_child_dentry_flags(inode); - * - * I really want to call that, but we can't, we have no idea if the inode - * still exists the second we drop the mark->lock. - * - * The next time an event arrive to this inode from one of it's children - * __fsnotify_parent will see that the inode doesn't care about it's - * children and will update all of these flags then. So really this - * is just a lazy update (and could be a perf win...) - */ - - atomic_dec(&group->num_marks); - - mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); } void fsnotify_destroy_mark(struct fsnotify_mark *mark, struct fsnotify_group *group) { mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); - fsnotify_destroy_mark_locked(mark, group); + fsnotify_detach_mark(mark); mutex_unlock(&group->mark_mutex); + fsnotify_free_mark(mark); } -/* - * Destroy all marks in the given list. The marks must be already detached from - * the original inode / vfsmount. - */ -void fsnotify_destroy_marks(struct list_head *to_free) +void fsnotify_destroy_marks(struct hlist_head *head, spinlock_t *lock) { - struct fsnotify_mark *mark, *lmark; - struct fsnotify_group *group; - - list_for_each_entry_safe(mark, lmark, to_free, free_list) { - spin_lock(&mark->lock); - fsnotify_get_group(mark->group); - group = mark->group; - spin_unlock(&mark->lock); + struct fsnotify_mark *mark; - fsnotify_destroy_mark(mark, group); + while (1) { + /* + * We have to be careful since we can race with e.g. + * fsnotify_clear_marks_by_group() and once we drop 'lock', + * mark can get removed from the obj_list and destroyed. But + * we are holding mark reference so mark cannot be freed and + * calling fsnotify_destroy_mark() more than once is fine. + */ + spin_lock(lock); + if (hlist_empty(head)) { + spin_unlock(lock); + break; + } + mark = hlist_entry(head->first, struct fsnotify_mark, obj_list); + /* + * We don't update i_fsnotify_mask / mnt_fsnotify_mask here + * since inode / mount is going away anyway. So just remove + * mark from the list. + */ + hlist_del_init_rcu(&mark->obj_list); + fsnotify_get_mark(mark); + spin_unlock(lock); + fsnotify_destroy_mark(mark, mark->group); fsnotify_put_mark(mark); - fsnotify_put_group(group); } } @@ -332,7 +348,7 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark, * inode->i_lock */ spin_lock(&mark->lock); - mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE; + mark->flags |= FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_ATTACHED; fsnotify_get_group(group); mark->group = group; @@ -412,16 +428,37 @@ void fsnotify_clear_marks_by_group_flags(struct fsnotify_group *group, unsigned int flags) { struct fsnotify_mark *lmark, *mark; + LIST_HEAD(to_free); + /* + * We have to be really careful here. Anytime we drop mark_mutex, e.g. + * fsnotify_clear_marks_by_inode() can come and free marks. Even in our + * to_free list so we have to use mark_mutex even when accessing that + * list. And freeing mark requires us to drop mark_mutex. So we can + * reliably free only the first mark in the list. That's why we first + * move marks to free to to_free list in one go and then free marks in + * to_free list one by one. + */ mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { - if (mark->flags & flags) { - fsnotify_get_mark(mark); - fsnotify_destroy_mark_locked(mark, group); - fsnotify_put_mark(mark); - } + if (mark->flags & flags) + list_move(&mark->g_list, &to_free); } mutex_unlock(&group->mark_mutex); + + while (1) { + mutex_lock_nested(&group->mark_mutex, SINGLE_DEPTH_NESTING); + if (list_empty(&to_free)) { + mutex_unlock(&group->mark_mutex); + break; + } + mark = list_first_entry(&to_free, struct fsnotify_mark, g_list); + fsnotify_get_mark(mark); + fsnotify_detach_mark(mark); + mutex_unlock(&group->mark_mutex); + fsnotify_free_mark(mark); + fsnotify_put_mark(mark); + } } /* diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c index 326b148e623c..a8fcab68faef 100644 --- a/fs/notify/vfsmount_mark.c +++ b/fs/notify/vfsmount_mark.c @@ -28,25 +28,6 @@ #include <linux/fsnotify_backend.h> #include "fsnotify.h" -#include "../mount.h" - -void fsnotify_clear_marks_by_mount(struct vfsmount *mnt) -{ - struct fsnotify_mark *mark; - struct hlist_node *n; - struct mount *m = real_mount(mnt); - LIST_HEAD(free_list); - - spin_lock(&mnt->mnt_root->d_lock); - hlist_for_each_entry_safe(mark, n, &m->mnt_fsnotify_marks, obj_list) { - list_add(&mark->free_list, &free_list); - hlist_del_init_rcu(&mark->obj_list); - fsnotify_get_mark(mark); - } - spin_unlock(&mnt->mnt_root->d_lock); - - fsnotify_destroy_marks(&free_list); -} void fsnotify_clear_vfsmount_marks_by_group(struct fsnotify_group *group) { |