diff options
| -rw-r--r-- | fs/notify/Makefile | 3 | ||||
| -rw-r--r-- | fs/notify/dnotify/dnotify.c | 12 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify.c | 2 | ||||
| -rw-r--r-- | fs/notify/fanotify/fanotify_user.c | 8 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 7 | ||||
| -rw-r--r-- | fs/notify/inode_mark.c | 246 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_fsnotify.c | 4 | ||||
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 4 | ||||
| -rw-r--r-- | fs/notify/mark.c | 294 | ||||
| -rw-r--r-- | include/linux/fsnotify_backend.h | 5 | ||||
| -rw-r--r-- | kernel/audit_tree.c | 8 | ||||
| -rw-r--r-- | kernel/audit_watch.c | 6 |
12 files changed, 347 insertions, 252 deletions
diff --git a/fs/notify/Makefile b/fs/notify/Makefile index 396a387..8f7f3b0 100644 --- a/fs/notify/Makefile +++ b/fs/notify/Makefile @@ -1,4 +1,5 @@ -obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o +obj-$(CONFIG_FSNOTIFY) += fsnotify.o notification.o group.o inode_mark.o \ + mark.o obj-y += dnotify/ obj-y += inotify/ diff --git a/fs/notify/dnotify/dnotify.c b/fs/notify/dnotify/dnotify.c index cac2eb8..69f42df 100644 --- a/fs/notify/dnotify/dnotify.c +++ b/fs/notify/dnotify/dnotify.c @@ -95,7 +95,7 @@ static int dnotify_handle_event(struct fsnotify_group *group, to_tell = event->to_tell; - fsn_mark = fsnotify_find_mark(group, to_tell); + fsn_mark = fsnotify_find_inode_mark(group, to_tell); if (unlikely(!fsn_mark)) return 0; dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); @@ -143,14 +143,14 @@ static bool dnotify_should_send_event(struct fsnotify_group *group, if (!S_ISDIR(inode->i_mode)) return false; - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return false; mask = (mask & ~FS_EVENT_ON_CHILD); send = (mask & fsn_mark->mask); - fsnotify_put_mark(fsn_mark); /* matches fsnotify_find_mark */ + fsnotify_put_mark(fsn_mark); /* matches fsnotify_find_inode_mark */ return send; } @@ -193,7 +193,7 @@ void dnotify_flush(struct file *filp, fl_owner_t id) if (!S_ISDIR(inode->i_mode)) return; - fsn_mark = fsnotify_find_mark(dnotify_group, inode); + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); if (!fsn_mark) return; dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); @@ -346,12 +346,12 @@ int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg) mutex_lock(&dnotify_mark_mutex); /* add the new_fsn_mark or find an old one. */ - fsn_mark = fsnotify_find_mark(dnotify_group, inode); + fsn_mark = fsnotify_find_inode_mark(dnotify_group, inode); if (fsn_mark) { dn_mark = container_of(fsn_mark, struct dnotify_mark, fsn_mark); spin_lock(&fsn_mark->lock); } else { - fsnotify_add_mark(new_fsn_mark, dnotify_group, inode, 0); + fsnotify_add_mark(new_fsn_mark, dnotify_group, inode, NULL, 0); spin_lock(&new_fsn_mark->lock); fsn_mark = new_fsn_mark; dn_mark = new_dn_mark; diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 881067d..aa5e926 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -118,7 +118,7 @@ static bool fanotify_should_send_event(struct fsnotify_group *group, struct inod if (data_type != FSNOTIFY_EVENT_PATH) return false; - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return false; diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c index 66e38fc..0535193 100644 --- a/fs/notify/fanotify/fanotify_user.c +++ b/fs/notify/fanotify/fanotify_user.c @@ -305,7 +305,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group, pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, mask); - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return -ENOENT; @@ -321,7 +321,7 @@ static int fanotify_remove_mark(struct fsnotify_group *group, fsnotify_recalc_group_mask(group); - /* matches the fsnotify_find_mark() */ + /* matches the fsnotify_find_inode_mark() */ fsnotify_put_mark(fsn_mark); return 0; @@ -338,7 +338,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, mask); - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) { struct fsnotify_mark *new_fsn_mark; @@ -348,7 +348,7 @@ static int fanotify_add_mark(struct fsnotify_group *group, goto out; fsnotify_init_mark(new_fsn_mark, fanotify_free_mark); - ret = fsnotify_add_mark(new_fsn_mark, group, inode, 0); + ret = fsnotify_add_mark(new_fsn_mark, group, inode, NULL, 0); if (ret) { fanotify_free_mark(new_fsn_mark); goto out; diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 2ba5915..7c7a904 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -20,6 +20,11 @@ extern __u32 fsnotify_vfsmount_mask; /* destroy all events sitting in this groups notification queue */ extern void fsnotify_flush_notify(struct fsnotify_group *group); +/* add a mark to an inode */ +extern int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups); + /* add a group to the inode group list */ extern void fsnotify_add_inode_group(struct fsnotify_group *group); /* add a group to the vfsmount group list */ @@ -27,6 +32,8 @@ extern void fsnotify_add_vfsmount_group(struct fsnotify_group *group); /* final kfree of a group */ extern void fsnotify_final_destroy_group(struct fsnotify_group *group); +/* inode specific destruction of a mark */ +extern void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark); /* 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); /* diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index ba6f983..c925579 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -16,72 +16,6 @@ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ -/* - * fsnotify inode mark locking/lifetime/and refcnting - * - * REFCNT: - * The mark->refcnt tells how many "things" in the kernel currently are - * referencing this object. The object typically will live inside the kernel - * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task - * which can find this object holding the appropriete locks, can take a reference - * and the object itself is guarenteed to survive until the reference is dropped. - * - * LOCKING: - * There are 3 spinlocks involved with fsnotify inode marks and they MUST - * be taken in order as follows: - * - * mark->lock - * group->mark_lock - * inode->i_lock - * - * mark->lock protects 2 things, mark->group and mark->inode. You must hold - * that lock to dereference either of these things (they could be NULL even with - * the lock) - * - * group->mark_lock protects the marks_list anchored inside a given group - * and each mark is hooked via the g_list. It also sorta protects the - * free_g_list, which when used is anchored by a private list on the stack of the - * task which held the group->mark_lock. - * - * inode->i_lock protects the i_fsnotify_marks list anchored inside a - * given inode and each mark is hooked via the i_list. (and sorta the - * free_i_list) - * - * - * LIFETIME: - * Inode marks survive between when they are added to an inode and when their - * refcnt==0. - * - * The inode mark can be cleared for a number of different reasons including: - * - The inode is unlinked for the last time. (fsnotify_inode_remove) - * - The inode is being evicted from cache. (fsnotify_inode_delete) - * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) - * - Something explicitly requests that it be removed. (fsnotify_destroy_mark) - * - The fsnotify_group associated with the mark is going away and all such marks - * need to be cleaned up. (fsnotify_clear_marks_by_group) - * - * Worst case we are given an inode and need to clean up all the marks on that - * inode. We take i_lock and walk the i_fsnotify_marks safely. For each - * mark on the list we take a reference (so the mark can't disappear under us). - * We remove that mark form the inode's list of marks and we add this mark to a - * private list anchored on the stack using i_free_list; At this point we no - * longer fear anything finding the mark using the inode's list of marks. - * - * We can safely and locklessly run the private list on the stack of everything - * we just unattached from the original inode. For each mark on the private list - * we grab the mark-> and can thus dereference mark->group and mark->inode. If - * we see the group and inode are not NULL we take those locks. Now holding all - * 3 locks we can completely remove the mark from other tasks finding it in the - * future. Remember, 10 things might already be referencing this mark, but they - * better be holding a ref. We drop our reference we took before we unhooked it - * from the inode. When the ref hits 0 we can free the mark. - * - * Very similarly for freeing by group, except we use free_g_list. - * - * This has the very interesting property of being able to run concurrently with - * any (or all) other directions. - */ - #include <linux/fs.h> #include <linux/init.h> #include <linux/kernel.h> @@ -95,17 +29,6 @@ #include <linux/fsnotify_backend.h> #include "fsnotify.h" -void fsnotify_get_mark(struct fsnotify_mark *mark) -{ - atomic_inc(&mark->refcnt); -} - -void fsnotify_put_mark(struct fsnotify_mark *mark) -{ - if (atomic_dec_and_test(&mark->refcnt)) - mark->free_mark(mark); -} - /* * Recalculate the mask of events relevant to a given inode locked. */ @@ -135,44 +58,18 @@ void fsnotify_recalc_inode_mask(struct inode *inode) __fsnotify_update_child_dentry_flags(inode); } -/* - * 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 - */ -void fsnotify_destroy_mark(struct fsnotify_mark *mark) +void fsnotify_destroy_inode_mark(struct fsnotify_mark *mark) { - struct fsnotify_group *group; - struct inode *inode; - - spin_lock(&mark->lock); + struct inode *inode = mark->i.inode; - group = mark->group; - inode = mark->i.inode; + assert_spin_locked(&mark->lock); + assert_spin_locked(&mark->group->mark_lock); - BUG_ON(group && !inode); - BUG_ON(!group && inode); - - /* if !group something else already marked this to die */ - if (!group) { - spin_unlock(&mark->lock); - return; - } - - /* 1 from caller and 1 for being on i_list/g_list */ - BUG_ON(atomic_read(&mark->refcnt) < 2); - - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); hlist_del_init(&mark->i.i_list); mark->i.inode = NULL; - list_del_init(&mark->g_list); - mark->group = NULL; - - fsnotify_put_mark(mark); /* for i_list and g_list */ - /* * this mark is now off the inode->i_fsnotify_marks list and we * hold the inode->i_lock, so this is the perfect time to update the @@ -181,61 +78,6 @@ void fsnotify_destroy_mark(struct fsnotify_mark *mark) fsnotify_recalc_inode_mask_locked(inode); spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&mark->lock); - - /* - * Some groups like to know that marks are being freed. This is a - * callback to the group function to let it know that this mark - * is being freed. - */ - 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...) - */ - - - iput(inode); - - /* - * it's possible that this group tried to destroy itself, but this - * this mark was simultaneously being freed by inode. If that's the - * case, we finish freeing the group here. - */ - if (unlikely(atomic_dec_and_test(&group->num_marks))) - fsnotify_final_destroy_group(group); -} - -/* - * Given a group, destroy all of the marks associated with that group. - */ -void fsnotify_clear_marks_by_group(struct fsnotify_group *group) -{ - struct fsnotify_mark *lmark, *mark; - LIST_HEAD(free_list); - - spin_lock(&group->mark_lock); - list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { - list_add(&mark->free_g_list, &free_list); - list_del_init(&mark->g_list); - fsnotify_get_mark(mark); - } - spin_unlock(&group->mark_lock); - - list_for_each_entry_safe(mark, lmark, &free_list, free_g_list) { - fsnotify_destroy_mark(mark); - fsnotify_put_mark(mark); - } } /* @@ -261,8 +103,12 @@ void fsnotify_clear_marks_by_inode(struct inode *inode) } } -static struct fsnotify_mark *fsnotify_find_mark_locked(struct fsnotify_group *group, - struct inode *inode) +/* + * given a group and inode, find the mark associated with that combination. + * if found take a reference to that mark and return it, else return NULL + */ +struct fsnotify_mark *fsnotify_find_inode_mark_locked(struct fsnotify_group *group, + struct inode *inode) { struct fsnotify_mark *mark; struct hlist_node *pos; @@ -282,50 +128,26 @@ static struct fsnotify_mark *fsnotify_find_mark_locked(struct fsnotify_group *gr * given a group and inode, find the mark associated with that combination. * if found take a reference to that mark and return it, else return NULL */ -struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group, - struct inode *inode) +struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, + struct inode *inode) { struct fsnotify_mark *mark; spin_lock(&inode->i_lock); - mark = fsnotify_find_mark_locked(group, inode); + mark = fsnotify_find_inode_mark_locked(group, inode); spin_unlock(&inode->i_lock); return mark; } -void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) -{ - assert_spin_locked(&old->lock); - new->i.inode = old->i.inode; - new->group = old->group; - new->mask = old->mask; - new->free_mark = old->free_mark; -} - -/* - * Nothing fancy, just initialize lists and locks and counters. - */ -void fsnotify_init_mark(struct fsnotify_mark *mark, - void (*free_mark)(struct fsnotify_mark *mark)) -{ - spin_lock_init(&mark->lock); - atomic_set(&mark->refcnt, 1); - INIT_HLIST_NODE(&mark->i.i_list); - mark->group = NULL; - mark->mask = 0; - mark->i.inode = NULL; - mark->free_mark = free_mark; -} - /* * Attach an initialized mark mark to a given group and inode. * These marks may be used for the fsnotify backend to determine which * event types should be delivered to which group and for which inodes. */ -int fsnotify_add_mark(struct fsnotify_mark *mark, - struct fsnotify_group *group, struct inode *inode, - int allow_dups) +int fsnotify_add_inode_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + int allow_dups) { struct fsnotify_mark *lmark = NULL; int ret = 0; @@ -336,56 +158,26 @@ int fsnotify_add_mark(struct fsnotify_mark *mark, mark->flags = FSNOTIFY_MARK_FLAG_INODE; - /* - * if this group isn't being testing for inode type events we need - * to start testing - */ - if (unlikely(list_empty(&group->inode_group_list))) - fsnotify_add_inode_group(group); - /* - * XXX This is where we could also do the fsnotify_add_vfsmount_group - * if we are setting and vfsmount mark.... - - if (unlikely(list_empty(&group->vfsmount_group_list))) - fsnotify_add_vfsmount_group(group); - */ + assert_spin_locked(&mark->lock); + assert_spin_locked(&group->mark_lock); - /* - * LOCKING ORDER!!!! - * mark->lock - * group->mark_lock - * inode->i_lock - */ - spin_lock(&mark->lock); - spin_lock(&group->mark_lock); spin_lock(&inode->i_lock); if (!allow_dups) - lmark = fsnotify_find_mark_locked(group, inode); + lmark = fsnotify_find_inode_mark_locked(group, inode); if (!lmark) { - mark->group = group; mark->i.inode = inode; hlist_add_head(&mark->i.i_list, &inode->i_fsnotify_marks); - list_add(&mark->g_list, &group->marks_list); - - fsnotify_get_mark(mark); /* for i_list and g_list */ - - atomic_inc(&group->num_marks); fsnotify_recalc_inode_mask_locked(inode); } spin_unlock(&inode->i_lock); - spin_unlock(&group->mark_lock); - spin_unlock(&mark->lock); if (lmark) { ret = -EEXIST; iput(inode); - fsnotify_put_mark(lmark); - } else { - __fsnotify_update_child_dentry_flags(inode); } return ret; diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index cc8f6bc..1d237e1 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -97,7 +97,7 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev to_tell = event->to_tell; - fsn_mark = fsnotify_find_mark(group, to_tell); + fsn_mark = fsnotify_find_inode_mark(group, to_tell); /* race with watch removal? We already passes should_send */ if (unlikely(!fsn_mark)) return 0; @@ -145,7 +145,7 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode struct fsnotify_mark *fsn_mark; bool send; - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return false; diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index ad5a1ea..a12315a 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -566,7 +566,7 @@ static int inotify_update_existing_watch(struct fsnotify_group *group, if (unlikely(!mask)) return -EINVAL; - fsn_mark = fsnotify_find_mark(group, inode); + fsn_mark = fsnotify_find_inode_mark(group, inode); if (!fsn_mark) return -ENOENT; @@ -644,7 +644,7 @@ static int inotify_new_watch(struct fsnotify_group *group, goto out_err; /* we are on the idr, now get on the inode */ - ret = fsnotify_add_mark(&tmp_i_mark->fsn_mark, group, inode, 0); + ret = fsnotify_add_mark(&tmp_i_mark->fsn_mark, group, inode, NULL, 0); if (ret) { /* we failed to get on the inode, get off the idr */ inotify_remove_from_idr(group, tmp_i_mark); diff --git a/fs/notify/mark.c b/fs/notify/mark.c new file mode 100644 index 0000000..e56e876 --- /dev/null +++ b/fs/notify/mark.c @@ -0,0 +1,294 @@ +/* + * Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; see the file COPYING. If not, write to + * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +/* + * fsnotify inode mark locking/lifetime/and refcnting + * + * REFCNT: + * The mark->refcnt tells how many "things" in the kernel currently are + * referencing this object. The object typically will live inside the kernel + * with a refcnt of 2, one for each list it is on (i_list, g_list). Any task + * which can find this object holding the appropriete locks, can take a reference + * and the object itself is guarenteed to survive until the reference is dropped. + * + * LOCKING: + * There are 3 spinlocks involved with fsnotify inode marks and they MUST + * be taken in order as follows: + * + * mark->lock + * group->mark_lock + * inode->i_lock + * + * mark->lock protects 2 things, mark->group and mark->inode. You must hold + * that lock to dereference either of these things (they could be NULL even with + * the lock) + * + * group->mark_lock protects the marks_list anchored inside a given group + * and each mark is hooked via the g_list. It also sorta protects the + * free_g_list, which when used is anchored by a private list on the stack of the + * task which held the group->mark_lock. + * + * inode->i_lock protects the i_fsnotify_marks list anchored inside a + * given inode and each mark is hooked via the i_list. (and sorta the + * free_i_list) + * + * + * LIFETIME: + * Inode marks survive between when they are added to an inode and when their + * refcnt==0. + * + * The inode mark can be cleared for a number of different reasons including: + * - The inode is unlinked for the last time. (fsnotify_inode_remove) + * - The inode is being evicted from cache. (fsnotify_inode_delete) + * - The fs the inode is on is unmounted. (fsnotify_inode_delete/fsnotify_unmount_inodes) + * - Something explicitly requests that it be removed. (fsnotify_destroy_mark) + * - The fsnotify_group associated with the mark is going away and all such marks + * need to be cleaned up. (fsnotify_clear_marks_by_group) + * + * Worst case we are given an inode and need to clean up all the marks on that + * inode. We take i_lock and walk the i_fsnotify_marks safely. For each + * mark on the list we take a reference (so the mark can't disappear under us). + * We remove that mark form the inode's list of marks and we add this mark to a + * private list anchored on the stack using i_free_list; At this point we no + * longer fear anything finding the mark using the inode's list of marks. + * + * We can safely and locklessly run the private list on the stack of everything + * we just unattached from the original inode. For each mark on the private list + * we grab the mark-> and can thus dereference mark->group and mark->inode. If + * we see the group and inode are not NULL we take those locks. Now holding all + * 3 locks we can completely remove the mark from other tasks finding it in the + * future. Remember, 10 things might already be referencing this mark, but they + * better be holding a ref. We drop our reference we took before we unhooked it + * from the inode. When the ref hits 0 we can free the mark. + * + * Very similarly for freeing by group, except we use free_g_list. + * + * This has the very interesting property of being able to run concurrently with + * any (or all) other directions. + */ + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/writeback.h> /* for inode_lock */ + +#include <asm/atomic.h> + +#include <linux/fsnotify_backend.h> +#include "fsnotify.h" + +void fsnotify_get_mark(struct fsnotify_mark *mark) +{ + atomic_inc(&mark->refcnt); +} + +void fsnotify_put_mark(struct fsnotify_mark *mark) +{ + if (atomic_dec_and_test(&mark->refcnt)) + mark->free_mark(mark); +} + +/* + * 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 + */ +void fsnotify_destroy_mark(struct fsnotify_mark *mark) +{ + struct fsnotify_group *group; + struct inode *inode; + + spin_lock(&mark->lock); + + group = mark->group; + inode = mark->i.inode; + + BUG_ON(group && !inode); + BUG_ON(!group && inode); + + /* if !group something else already marked this to die */ + if (!group) { + spin_unlock(&mark->lock); + return; + } + + /* 1 from caller and 1 for being on i_list/g_list */ + BUG_ON(atomic_read(&mark->refcnt) < 2); + + spin_lock(&group->mark_lock); + + if (mark->flags & FSNOTIFY_MARK_FLAG_INODE) + fsnotify_destroy_inode_mark(mark); + else + BUG(); + + list_del_init(&mark->g_list); + mark->group = NULL; + + fsnotify_put_mark(mark); /* for i_list and g_list */ + + spin_unlock(&group->mark_lock); + spin_unlock(&mark->lock); + + /* + * Some groups like to know that marks are being freed. This is a + * callback to the group function to let it know that this mark + * is being freed. + */ + 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...) + */ + + + iput(inode); + + /* + * it's possible that this group tried to destroy itself, but this + * this mark was simultaneously being freed by inode. If that's the + * case, we finish freeing the group here. + */ + if (unlikely(atomic_dec_and_test(&group->num_marks))) + fsnotify_final_destroy_group(group); +} + +/* + * Attach an initialized mark to a given group and fs object. + * These marks may be used for the fsnotify backend to determine which + * event types should be delivered to which group. + */ +int fsnotify_add_mark(struct fsnotify_mark *mark, + struct fsnotify_group *group, struct inode *inode, + struct vfsmount *mnt, int allow_dups) +{ + int ret = 0; + + BUG_ON(mnt); + BUG_ON(inode && mnt); + BUG_ON(!inode && !mnt); + + /* + * if this group isn't being testing for inode type events we need + * to start testing + */ + if (inode && unlikely(list_empty(&group->inode_group_list))) + fsnotify_add_inode_group(group); + else if (mnt && unlikely(list_empty(&group->vfsmount_group_list))) + fsnotify_add_vfsmount_group(group); + + /* + * LOCKING ORDER!!!! + * mark->lock + * group->mark_lock + * inode->i_lock + */ + spin_lock(&mark->lock); + spin_lock(&group->mark_lock); + + mark->group = group; + list_add(&mark->g_list, &group->marks_list); + atomic_inc(&group->num_marks); + fsnotify_get_mark(mark); /* for i_list and g_list */ + + if (inode) { + ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups); + if (ret) + goto err; + } else { + BUG(); + } + + spin_unlock(&group->mark_lock); + spin_unlock(&mark->lock); + + if (inode) + __fsnotify_update_child_dentry_flags(inode); + + return ret; +err: + mark->group = NULL; + list_del_init(&mark->g_list); + atomic_dec(&group->num_marks); + fsnotify_put_mark(mark); + + spin_unlock(&group->mark_lock); + spin_unlock(&mark->lock); + + return ret; +} + +/* + * Given a group, destroy all of the marks associated with that group. + */ +void fsnotify_clear_marks_by_group(struct fsnotify_group *group) +{ + struct fsnotify_mark *lmark, *mark; + LIST_HEAD(free_list); + + spin_lock(&group->mark_lock); + list_for_each_entry_safe(mark, lmark, &group->marks_list, g_list) { + list_add(&mark->free_g_list, &free_list); + list_del_init(&mark->g_list); + fsnotify_get_mark(mark); + } + spin_unlock(&group->mark_lock); + + list_for_each_entry_safe(mark, lmark, &free_list, free_g_list) { + fsnotify_destroy_mark(mark); + fsnotify_put_mark(mark); + } +} + +void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old) +{ + assert_spin_locked(&old->lock); + new->i.inode = old->i.inode; + new->m.mnt = old->m.mnt; + new->group = old->group; + new->mask = old->mask; + new->free_mark = old->free_mark; +} + +/* + * Nothing fancy, just initialize lists and locks and counters. + */ +void fsnotify_init_mark(struct fsnotify_mark *mark, + void (*free_mark)(struct fsnotify_mark *mark)) +{ + spin_lock_init(&mark->lock); + atomic_set(&mark->refcnt, 1); + INIT_HLIST_NODE(&mark->i.i_list); + mark->group = NULL; + mark->mask = 0; + mark->i.inode = NULL; + mark->free_mark = free_mark; +} diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 7d93572..27cccbe 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -364,11 +364,12 @@ extern struct fsnotify_event *fsnotify_remove_notify_event(struct fsnotify_group extern void fsnotify_recalc_inode_mask(struct inode *inode); extern void fsnotify_init_mark(struct fsnotify_mark *mark, void (*free_mark)(struct fsnotify_mark *mark)); /* find (and take a reference) to a mark associated with group and inode */ -extern struct fsnotify_mark *fsnotify_find_mark(struct fsnotify_group *group, struct inode *inode); +extern struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group, struct inode *inode); /* copy the values from old into new */ extern void fsnotify_duplicate_mark(struct fsnotify_mark *new, struct fsnotify_mark *old); /* attach the mark to both the group and the inode */ -extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, struct inode *inode, int allow_dups); +extern int fsnotify_add_mark(struct fsnotify_mark *mark, struct fsnotify_group *group, + struct inode *inode, struct vfsmount *mnt, int allow_dups); /* given a mark, flag it to be freed when all references are dropped */ extern void fsnotify_destroy_mark(struct fsnotify_mark *mark); /* run all the marks in a group, and flag them to be freed */ diff --git a/kernel/audit_tree.c b/kernel/audit_tree.c index 80f8ac3..cfb97d7 100644 --- a/kernel/audit_tree.c +++ b/kernel/audit_tree.c @@ -259,7 +259,7 @@ static void untag_chunk(struct node *p) if (!new) goto Fallback; fsnotify_duplicate_mark(&new->mark, entry); - if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.i.inode, 1)) { + if (fsnotify_add_mark(&new->mark, new->mark.group, new->mark.i.inode, NULL, 1)) { free_chunk(new); goto Fallback; } @@ -322,7 +322,7 @@ static int create_chunk(struct inode *inode, struct audit_tree *tree) return -ENOMEM; entry = &chunk->mark; - if (fsnotify_add_mark(entry, audit_tree_group, inode, 0)) { + if (fsnotify_add_mark(entry, audit_tree_group, inode, NULL, 0)) { free_chunk(chunk); return -ENOSPC; } @@ -360,7 +360,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) struct node *p; int n; - old_entry = fsnotify_find_mark(audit_tree_group, inode); + old_entry = fsnotify_find_inode_mark(audit_tree_group, inode); if (!old_entry) return create_chunk(inode, tree); @@ -395,7 +395,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree) } fsnotify_duplicate_mark(chunk_entry, old_entry); - if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->i.inode, 1)) { + if (fsnotify_add_mark(chunk_entry, chunk_entry->group, chunk_entry->i.inode, NULL, 1)) { spin_unlock(&old_entry->lock); free_chunk(chunk); fsnotify_put_mark(old_entry); diff --git a/kernel/audit_watch.c b/kernel/audit_watch.c index d85fa53..7499397 100644 --- a/kernel/audit_watch.c +++ b/kernel/audit_watch.c @@ -101,7 +101,7 @@ static inline struct audit_parent *audit_find_parent(struct inode *inode) struct audit_parent *parent = NULL; struct fsnotify_mark *entry; - entry = fsnotify_find_mark(audit_watch_group, inode); + entry = fsnotify_find_inode_mark(audit_watch_group, inode); if (entry) parent = container_of(entry, struct audit_parent, mark); @@ -158,7 +158,7 @@ static struct audit_parent *audit_init_parent(struct nameidata *ndp) fsnotify_init_mark(&parent->mark, audit_watch_free_mark); parent->mark.mask = AUDIT_FS_WATCH; - ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, 0); + ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode, NULL, 0); if (ret < 0) { audit_free_parent(parent); return ERR_PTR(ret); @@ -517,7 +517,7 @@ static bool audit_watch_should_send_event(struct fsnotify_group *group, struct i struct fsnotify_mark *entry; bool send; - entry = fsnotify_find_mark(group, inode); + entry = fsnotify_find_inode_mark(group, inode); if (!entry) return false; |