diff options
Diffstat (limited to 'fs/notify/fsnotify.c')
-rw-r--r-- | fs/notify/fsnotify.c | 406 |
1 files changed, 302 insertions, 104 deletions
diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c index 46f225580009..7974e91ffe13 100644 --- a/fs/notify/fsnotify.c +++ b/fs/notify/fsnotify.c @@ -70,11 +70,10 @@ static void fsnotify_unmount_inodes(struct super_block *sb) spin_unlock(&inode->i_lock); spin_unlock(&sb->s_inode_list_lock); - if (iput_inode) - iput(iput_inode); + iput(iput_inode); /* for each watch, send FS_UNMOUNT and then remove it */ - fsnotify(inode, FS_UNMOUNT, inode, FSNOTIFY_EVENT_INODE, NULL, 0); + fsnotify_inode(inode, FS_UNMOUNT); fsnotify_inode_delete(inode); @@ -85,24 +84,23 @@ static void fsnotify_unmount_inodes(struct super_block *sb) } spin_unlock(&sb->s_inode_list_lock); - if (iput_inode) - iput(iput_inode); - /* Wait for outstanding inode references from connectors */ - wait_var_event(&sb->s_fsnotify_inode_refs, - !atomic_long_read(&sb->s_fsnotify_inode_refs)); + iput(iput_inode); } void fsnotify_sb_delete(struct super_block *sb) { fsnotify_unmount_inodes(sb); fsnotify_clear_marks_by_sb(sb); + /* Wait for outstanding object references from connectors */ + wait_var_event(&sb->s_fsnotify_connectors, + !atomic_long_read(&sb->s_fsnotify_connectors)); } /* * Given an inode, first check if we care what happens to our children. Inotify * and dnotify both tell their parents about events. If we care about any event * on a child we run all of our children and set a dentry flag saying that the - * parent cares. Thus when an event happens on a child it can quickly tell if + * parent cares. Thus when an event happens on a child it can quickly tell * if there is a need to find a parent and send the event to the parent. */ void __fsnotify_update_child_dentry_flags(struct inode *inode) @@ -142,97 +140,229 @@ void __fsnotify_update_child_dentry_flags(struct inode *inode) spin_unlock(&inode->i_lock); } -/* Notify this dentry's parent about a child's events. */ -int __fsnotify_parent(const struct path *path, struct dentry *dentry, __u32 mask) +/* 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; + + /* + * All events that are possible on child can also may be reported with + * parent/name info to inode/sb/mount. Otherwise, a watching parent + * could result in events reported with unexpected name info to sb/mount. + */ + BUILD_BUG_ON(FS_EVENTS_POSS_ON_CHILD & ~FS_EVENTS_POSS_TO_PARENT); + + /* 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 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; - struct inode *p_inode; + bool parent_watched = dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED; + bool parent_needed, parent_interested; + __u32 p_mask; + struct inode *p_inode = NULL; + struct name_snapshot name; + struct qstr *file_name = NULL; int ret = 0; - if (!dentry) - dentry = path->dentry; - - if (!(dentry->d_flags & DCACHE_FSNOTIFY_PARENT_WATCHED)) + /* + * 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; + parent_needed = fsnotify_event_needs_parent(inode, mnt, mask); + if (!parent_watched && !parent_needed) + 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) { - struct name_snapshot name; - /* we are notifying a parent so come up with the new mask which - * specifies these are events which came from a child. */ - mask |= FS_EVENT_ON_CHILD; + /* + * Include parent/name in notification either if some notification + * groups require parent info or the parent is interested in this event. + */ + parent_interested = mask & p_mask & ALL_FSNOTIFY_EVENTS; + if (parent_needed || parent_interested) { + /* 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); - if (path) - ret = fsnotify(p_inode, mask, path, FSNOTIFY_EVENT_PATH, - &name.name, 0); - else - ret = fsnotify(p_inode, mask, dentry->d_inode, FSNOTIFY_EVENT_INODE, - &name.name, 0); - release_dentry_name_snapshot(&name); + file_name = &name.name; + if (parent_interested) + mask |= FS_EVENT_ON_CHILD; } +notify: + ret = fsnotify(mask, data, data_type, p_inode, file_name, inode, 0); + + if (file_name) + release_dentry_name_snapshot(&name); dput(parent); return ret; } EXPORT_SYMBOL_GPL(__fsnotify_parent); -static int send_to_group(struct inode *to_tell, - __u32 mask, const void *data, - int data_is, u32 cookie, - const struct qstr *file_name, - struct fsnotify_iter_info *iter_info) +static int fsnotify_handle_inode_event(struct fsnotify_group *group, + struct fsnotify_mark *inode_mark, + u32 mask, const void *data, int data_type, + struct inode *dir, const struct qstr *name, + u32 cookie) +{ + const struct path *path = fsnotify_data_path(data, data_type); + struct inode *inode = fsnotify_data_inode(data, data_type); + const struct fsnotify_ops *ops = group->ops; + + if (WARN_ON_ONCE(!ops->handle_inode_event)) + return 0; + + if (WARN_ON_ONCE(!inode && !dir)) + return 0; + + if ((inode_mark->flags & FSNOTIFY_MARK_FLAG_EXCL_UNLINK) && + path && d_unlinked(path->dentry)) + return 0; + + /* Check interest of this mark in case event was sent with two marks */ + if (!(mask & inode_mark->mask & ALL_FSNOTIFY_EVENTS)) + return 0; + + return ops->handle_inode_event(inode_mark, mask, inode, dir, name, cookie); +} + +static int fsnotify_handle_event(struct fsnotify_group *group, __u32 mask, + const void *data, int data_type, + struct inode *dir, const struct qstr *name, + u32 cookie, struct fsnotify_iter_info *iter_info) +{ + struct fsnotify_mark *inode_mark = fsnotify_iter_inode_mark(iter_info); + struct fsnotify_mark *parent_mark = fsnotify_iter_parent_mark(iter_info); + int ret; + + if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) || + WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info))) + return 0; + + /* + * For FS_RENAME, 'dir' is old dir and 'data' is new dentry. + * The only ->handle_inode_event() backend that supports FS_RENAME is + * dnotify, where it means file was renamed within same parent. + */ + if (mask & FS_RENAME) { + struct dentry *moved = fsnotify_data_dentry(data, data_type); + + if (dir != moved->d_parent->d_inode) + return 0; + } + + if (parent_mark) { + ret = fsnotify_handle_inode_event(group, parent_mark, mask, + data, data_type, dir, name, 0); + if (ret) + return ret; + } + + if (!inode_mark) + return 0; + + if (mask & FS_EVENT_ON_CHILD) { + /* + * Some events can be sent on both parent dir and child marks + * (e.g. FS_ATTRIB). If both parent dir and child are + * watching, report the event once to parent dir with name (if + * interested) and once to child without name (if interested). + * The child watcher is expecting an event without a file name + * and without the FS_EVENT_ON_CHILD flag. + */ + mask &= ~FS_EVENT_ON_CHILD; + dir = NULL; + name = NULL; + } + + return fsnotify_handle_inode_event(group, inode_mark, mask, data, data_type, + dir, name, cookie); +} + +static int send_to_group(__u32 mask, const void *data, int data_type, + struct inode *dir, const struct qstr *file_name, + u32 cookie, struct fsnotify_iter_info *iter_info) { struct fsnotify_group *group = NULL; __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); __u32 marks_mask = 0; - __u32 marks_ignored_mask = 0; + __u32 marks_ignore_mask = 0; + bool is_dir = mask & FS_ISDIR; struct fsnotify_mark *mark; int type; - if (WARN_ON(!iter_info->report_mask)) + if (!iter_info->report_mask) return 0; /* clear ignored on inode modification */ if (mask & FS_MODIFY) { - fsnotify_foreach_obj_type(type) { - if (!fsnotify_iter_should_report_type(iter_info, type)) - continue; - mark = iter_info->marks[type]; - if (mark && - !(mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) - mark->ignored_mask = 0; + fsnotify_foreach_iter_mark_type(iter_info, mark, type) { + if (!(mark->flags & + FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) + mark->ignore_mask = 0; } } - fsnotify_foreach_obj_type(type) { - if (!fsnotify_iter_should_report_type(iter_info, type)) - continue; - mark = iter_info->marks[type]; - /* does the object mark tell us to do something? */ - if (mark) { - group = mark->group; - marks_mask |= mark->mask; - marks_ignored_mask |= mark->ignored_mask; - } + /* Are any of the group marks interested in this event? */ + fsnotify_foreach_iter_mark_type(iter_info, mark, type) { + group = mark->group; + marks_mask |= mark->mask; + marks_ignore_mask |= + fsnotify_effective_ignore_mask(mark, is_dir, type); } - pr_debug("%s: group=%p to_tell=%p mask=%x marks_mask=%x marks_ignored_mask=%x" - " data=%p data_is=%d cookie=%d\n", - __func__, group, to_tell, mask, marks_mask, marks_ignored_mask, - data, data_is, cookie); + pr_debug("%s: group=%p mask=%x marks_mask=%x marks_ignore_mask=%x data=%p data_type=%d dir=%p cookie=%d\n", + __func__, group, mask, marks_mask, marks_ignore_mask, + data, data_type, dir, cookie); - if (!(test_mask & marks_mask & ~marks_ignored_mask)) + if (!(test_mask & marks_mask & ~marks_ignore_mask)) return 0; - return group->ops->handle_event(group, to_tell, mask, data, data_is, - file_name, cookie, iter_info); + if (group->ops->handle_event) { + return group->ops->handle_event(group, mask, data, data_type, dir, + file_name, cookie, iter_info); + } + + return fsnotify_handle_event(group, mask, data, data_type, dir, + file_name, cookie, iter_info); } static struct fsnotify_mark *fsnotify_first_mark(struct fsnotify_mark_connector **connp) @@ -260,11 +390,11 @@ static struct fsnotify_mark *fsnotify_next_mark(struct fsnotify_mark *mark) /* * iter_info is a multi head priority queue of marks. - * Pick a subset of marks from queue heads, all with the - * same group and set the report_mask for selected subset. - * Returns the report_mask of the selected subset. + * Pick a subset of marks from queue heads, all with the same group + * and set the report_mask to a subset of the selected marks. + * Returns false if there are no more groups to iterate. */ -static unsigned int fsnotify_iter_select_report_types( +static bool fsnotify_iter_select_report_types( struct fsnotify_iter_info *iter_info) { struct fsnotify_group *max_prio_group = NULL; @@ -272,7 +402,7 @@ static unsigned int fsnotify_iter_select_report_types( int type; /* Choose max prio group among groups of all queue heads */ - fsnotify_foreach_obj_type(type) { + fsnotify_foreach_iter_type(type) { mark = iter_info->marks[type]; if (mark && fsnotify_compare_groups(max_prio_group, mark->group) > 0) @@ -280,58 +410,107 @@ static unsigned int fsnotify_iter_select_report_types( } if (!max_prio_group) - return 0; + return false; /* Set the report mask for marks from same group as max prio group */ + iter_info->current_group = max_prio_group; iter_info->report_mask = 0; - fsnotify_foreach_obj_type(type) { + fsnotify_foreach_iter_type(type) { mark = iter_info->marks[type]; - if (mark && - fsnotify_compare_groups(max_prio_group, mark->group) == 0) + if (mark && mark->group == iter_info->current_group) { + /* + * FSNOTIFY_ITER_TYPE_PARENT indicates that this inode + * is watching children and interested in this event, + * which is an event possible on child. + * But is *this mark* watching children? + */ + if (type == FSNOTIFY_ITER_TYPE_PARENT && + !(mark->mask & FS_EVENT_ON_CHILD) && + !(fsnotify_ignore_mask(mark) & FS_EVENT_ON_CHILD)) + continue; + fsnotify_iter_set_report_type(iter_info, type); + } } - return iter_info->report_mask; + return true; } /* - * Pop from iter_info multi head queue, the marks that were iterated in the + * Pop from iter_info multi head queue, the marks that belong to the group of * current iteration step. */ static void fsnotify_iter_next(struct fsnotify_iter_info *iter_info) { + struct fsnotify_mark *mark; int type; - fsnotify_foreach_obj_type(type) { - if (fsnotify_iter_should_report_type(iter_info, type)) + /* + * We cannot use fsnotify_foreach_iter_mark_type() here because we + * may need to advance a mark of type X that belongs to current_group + * but was not selected for reporting. + */ + fsnotify_foreach_iter_type(type) { + mark = iter_info->marks[type]; + if (mark && mark->group == iter_info->current_group) iter_info->marks[type] = fsnotify_next_mark(iter_info->marks[type]); } } /* - * This is the main call to fsnotify. The VFS calls into hook specific functions - * in linux/fsnotify.h. Those functions then in turn call here. Here will call - * out to all of the registered fsnotify_group. Those groups can then use the - * notification event in whatever means they feel necessary. + * fsnotify - This is the main call to fsnotify. + * + * The VFS calls into hook specific functions in linux/fsnotify.h. + * Those functions then in turn call here. Here will call out to all of the + * registered fsnotify_group. Those groups can then use the notification event + * in whatever means they feel necessary. + * + * @mask: event type and flags + * @data: object that event happened on + * @data_type: type of object for fanotify_data_XXX() accessors + * @dir: optional directory associated with event - + * if @file_name is not NULL, this is the directory that + * @file_name is relative to + * @file_name: optional file name associated with event + * @inode: optional inode associated with event - + * If @dir and @inode are both non-NULL, event may be + * reported to both. + * @cookie: inotify rename cookie */ -int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, - const struct qstr *file_name, u32 cookie) +int fsnotify(__u32 mask, const void *data, int data_type, struct inode *dir, + const struct qstr *file_name, struct inode *inode, u32 cookie) { + const struct path *path = fsnotify_data_path(data, data_type); + struct super_block *sb = fsnotify_data_sb(data, data_type); struct fsnotify_iter_info iter_info = {}; - struct super_block *sb = to_tell->i_sb; struct mount *mnt = NULL; - __u32 mnt_or_sb_mask = sb->s_fsnotify_mask; + struct inode *inode2 = NULL; + struct dentry *moved; + int inode2_type; int ret = 0; - __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); - - if (data_is == FSNOTIFY_EVENT_PATH) { - mnt = real_mount(((const struct path *)data)->mnt); - mnt_or_sb_mask |= mnt->mnt_fsnotify_mask; + __u32 test_mask, marks_mask; + + if (path) + mnt = real_mount(path->mnt); + + if (!inode) { + /* Dirent event - report on TYPE_INODE to dir */ + inode = dir; + /* For FS_RENAME, inode is old_dir and inode2 is new_dir */ + if (mask & FS_RENAME) { + moved = fsnotify_data_dentry(data, data_type); + inode2 = moved->d_parent->d_inode; + inode2_type = FSNOTIFY_ITER_TYPE_INODE2; + } + } else if (mask & FS_EVENT_ON_CHILD) { + /* + * Event on child - report on TYPE_PARENT to dir if it is + * watching children and on TYPE_INODE to child. + */ + inode2 = dir; + inode2_type = FSNOTIFY_ITER_TYPE_PARENT; } - /* An event "on child" is not intended for a mount/sb mark */ - if (mask & FS_EVENT_ON_CHILD) - mnt_or_sb_mask = 0; /* * Optimization: srcu_read_lock() has a memory barrier which can @@ -340,28 +519,47 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, * SRCU because we have no references to any objects and do not * need SRCU to keep them "alive". */ - if (!to_tell->i_fsnotify_marks && !sb->s_fsnotify_marks && - (!mnt || !mnt->mnt_fsnotify_marks)) + if (!sb->s_fsnotify_marks && + (!mnt || !mnt->mnt_fsnotify_marks) && + (!inode || !inode->i_fsnotify_marks) && + (!inode2 || !inode2->i_fsnotify_marks)) return 0; + + marks_mask = sb->s_fsnotify_mask; + if (mnt) + marks_mask |= mnt->mnt_fsnotify_mask; + if (inode) + marks_mask |= inode->i_fsnotify_mask; + if (inode2) + marks_mask |= inode2->i_fsnotify_mask; + + /* - * if this is a modify event we may need to clear the ignored masks - * otherwise return if neither the inode nor the vfsmount/sb care about - * this type of event. + * If this is a modify event we may need to clear some ignore masks. + * In that case, the object with ignore masks will have the FS_MODIFY + * event in its mask. + * Otherwise, return if none of the marks care about this type of event. */ - if (!(mask & FS_MODIFY) && - !(test_mask & (to_tell->i_fsnotify_mask | mnt_or_sb_mask))) + test_mask = (mask & ALL_FSNOTIFY_EVENTS); + if (!(test_mask & marks_mask)) return 0; iter_info.srcu_idx = srcu_read_lock(&fsnotify_mark_srcu); - iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = - fsnotify_first_mark(&to_tell->i_fsnotify_marks); - iter_info.marks[FSNOTIFY_OBJ_TYPE_SB] = + iter_info.marks[FSNOTIFY_ITER_TYPE_SB] = fsnotify_first_mark(&sb->s_fsnotify_marks); if (mnt) { - iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = + iter_info.marks[FSNOTIFY_ITER_TYPE_VFSMOUNT] = fsnotify_first_mark(&mnt->mnt_fsnotify_marks); } + if (inode) { + iter_info.marks[FSNOTIFY_ITER_TYPE_INODE] = + fsnotify_first_mark(&inode->i_fsnotify_marks); + } + if (inode2) { + iter_info.marks[inode2_type] = + fsnotify_first_mark(&inode2->i_fsnotify_marks); + } /* * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark @@ -369,8 +567,8 @@ int fsnotify(struct inode *to_tell, __u32 mask, const void *data, int data_is, * That's why this traversal is so complicated... */ while (fsnotify_iter_select_report_types(&iter_info)) { - ret = send_to_group(to_tell, mask, data, data_is, cookie, - file_name, &iter_info); + ret = send_to_group(mask, data, data_type, dir, file_name, + cookie, &iter_info); if (ret && (mask & ALL_FSNOTIFY_PERM_EVENTS)) goto out; @@ -389,7 +587,7 @@ static __init int fsnotify_init(void) { int ret; - BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 25); + BUILD_BUG_ON(HWEIGHT32(ALL_FSNOTIFY_BITS) != 23); ret = init_srcu_struct(&fsnotify_mark_srcu); if (ret) |