diff options
Diffstat (limited to 'fs/notify')
| -rw-r--r-- | fs/notify/fsnotify.c | 36 | ||||
| -rw-r--r-- | fs/notify/fsnotify.h | 4 | ||||
| -rw-r--r-- | fs/notify/inode_mark.c | 25 | ||||
| -rw-r--r-- | fs/notify/mark.c | 36 | ||||
| -rw-r--r-- | fs/notify/vfsmount_mark.c | 8 |
5 files changed, 78 insertions, 31 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 700129940c6e..41e39102743a 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -229,8 +229,16 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, &fsnotify_mark_srcu); } + /* + * We need to merge inode & vfsmount mark lists so that inode mark + * ignore masks are properly reflected for mount mark notifications. + * That's why this traversal is so complicated... + */ while (inode_node || vfsmount_node) { - inode_group = vfsmount_group = NULL; + inode_group = NULL; + inode_mark = NULL; + vfsmount_group = NULL; + vfsmount_mark = NULL; if (inode_node) { inode_mark = hlist_entry(srcu_dereference(inode_node, &fsnotify_mark_srcu), @@ -244,21 +252,19 @@ int fsnotify(struct inode *to_tell, __u32 mask, void *data, int data_is, vfsmount_group = vfsmount_mark->group; } - if (inode_group > vfsmount_group) { - /* handle inode */ - ret = send_to_group(to_tell, inode_mark, NULL, mask, - data, data_is, cookie, file_name); - /* we didn't use the vfsmount_mark */ - vfsmount_group = NULL; - } else if (vfsmount_group > inode_group) { - ret = send_to_group(to_tell, NULL, vfsmount_mark, mask, - data, data_is, cookie, file_name); - inode_group = NULL; - } else { - ret = send_to_group(to_tell, inode_mark, vfsmount_mark, - mask, data, data_is, cookie, - file_name); + if (inode_group && vfsmount_group) { + int cmp = fsnotify_compare_groups(inode_group, + vfsmount_group); + if (cmp > 0) { + inode_group = NULL; + inode_mark = NULL; + } else if (cmp < 0) { + vfsmount_group = NULL; + vfsmount_mark = NULL; + } } + ret = send_to_group(to_tell, inode_mark, vfsmount_mark, mask, + data, data_is, cookie, file_name); if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) goto out; diff --git a/fs/notify/fsnotify.h b/fs/notify/fsnotify.h index 9c0898c4cfe1..3b68b0ae0a97 100644 --- a/fs/notify/fsnotify.h +++ b/fs/notify/fsnotify.h @@ -12,6 +12,10 @@ extern void fsnotify_flush_notify(struct fsnotify_group *group); /* protects reads of inode and vfsmount marks list */ extern struct srcu_struct fsnotify_mark_srcu; +/* compare two groups for sorting of marks lists */ +extern int fsnotify_compare_groups(struct fsnotify_group *a, + struct fsnotify_group *b); + extern void fsnotify_set_inode_mark_mask_locked(struct fsnotify_mark *fsn_mark, __u32 mask); /* add a mark to an inode */ diff --git a/fs/notify/inode_mark.c b/fs/notify/inode_mark.c index 9ce062218de9..dfbf5447eea4 100644 --- a/fs/notify/inode_mark.c +++ b/fs/notify/inode_mark.c @@ -194,6 +194,7 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, { struct fsnotify_mark *lmark, *last = NULL; int ret = 0; + int cmp; mark->flags |= FSNOTIFY_MARK_FLAG_INODE; @@ -219,11 +220,8 @@ int fsnotify_add_inode_mark(struct fsnotify_mark *mark, goto out; } - if (mark->group->priority < lmark->group->priority) - continue; - - if ((mark->group->priority == lmark->group->priority) && - (mark->group < lmark->group)) + cmp = fsnotify_compare_groups(lmark->group, mark->group); + if (cmp < 0) continue; hlist_add_before_rcu(&mark->i.i_list, &lmark->i.i_list); @@ -288,20 +286,25 @@ void fsnotify_unmount_inodes(struct list_head *list) spin_unlock(&inode->i_lock); /* In case the dropping of a reference would nuke next_i. */ - if ((&next_i->i_sb_list != list) && - atomic_read(&next_i->i_count)) { + while (&next_i->i_sb_list != list) { spin_lock(&next_i->i_lock); - if (!(next_i->i_state & (I_FREEING | I_WILL_FREE))) { + if (!(next_i->i_state & (I_FREEING | I_WILL_FREE)) && + atomic_read(&next_i->i_count)) { __iget(next_i); need_iput = next_i; + spin_unlock(&next_i->i_lock); + break; } spin_unlock(&next_i->i_lock); + next_i = list_entry(next_i->i_sb_list.next, + struct inode, i_sb_list); } /* - * We can safely drop inode_sb_list_lock here because we hold - * references on both inode and next_i. Also no new inodes - * will be added since the umount has begun. + * We can safely drop inode_sb_list_lock here because either + * we actually hold references on both inode and next_i or + * end of list. Also no new inodes will be added since the + * umount has begun. */ spin_unlock(&inode_sb_list_lock); diff --git a/fs/notify/mark.c b/fs/notify/mark.c index d90deaa08e78..34c38fabf514 100644 --- a/fs/notify/mark.c +++ b/fs/notify/mark.c @@ -210,6 +210,42 @@ void fsnotify_set_mark_ignored_mask_locked(struct fsnotify_mark *mark, __u32 mas } /* + * Sorting function for lists of fsnotify marks. + * + * Fanotify supports different notification classes (reflected as priority of + * notification group). Events shall be passed to notification groups in + * decreasing priority order. To achieve this marks in notification lists for + * inodes and vfsmounts are sorted so that priorities of corresponding groups + * are descending. + * + * Furthermore correct handling of the ignore mask requires processing inode + * and vfsmount marks of each group together. Using the group address as + * further sort criterion provides a unique sorting order and thus we can + * merge inode and vfsmount lists of marks in linear time and find groups + * present in both lists. + * + * A return value of 1 signifies that b has priority over a. + * A return value of 0 signifies that the two marks have to be handled together. + * A return value of -1 signifies that a has priority over b. + */ +int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b) +{ + if (a == b) + return 0; + if (!a) + return 1; + if (!b) + return -1; + if (a->priority < b->priority) + return 1; + if (a->priority > b->priority) + return -1; + if (a < b) + return 1; + return -1; +} + +/* * 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. diff --git a/fs/notify/vfsmount_mark.c b/fs/notify/vfsmount_mark.c index ac851e8376b1..faefa72a11eb 100644 --- a/fs/notify/vfsmount_mark.c +++ b/fs/notify/vfsmount_mark.c @@ -153,6 +153,7 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, struct mount *m = real_mount(mnt); struct fsnotify_mark *lmark, *last = NULL; int ret = 0; + int cmp; mark->flags |= FSNOTIFY_MARK_FLAG_VFSMOUNT; @@ -178,11 +179,8 @@ int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark, goto out; } - if (mark->group->priority < lmark->group->priority) - continue; - - if ((mark->group->priority == lmark->group->priority) && - (mark->group < lmark->group)) + cmp = fsnotify_compare_groups(lmark->group, mark->group); + if (cmp < 0) continue; hlist_add_before_rcu(&mark->m.m_list, &lmark->m.m_list); |