--- zzzz-none-000/linux-5.4.213/fs/notify/fsnotify.c 2022-09-15 10:04:56.000000000 +0000 +++ miami-7690-761/linux-5.4.213/fs/notify/fsnotify.c 2024-05-29 11:20:02.000000000 +0000 @@ -74,7 +74,7 @@ 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); @@ -142,52 +142,142 @@ 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; + + /* 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_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 *child_mark = fsnotify_iter_child_mark(iter_info); + struct inode *inode = fsnotify_data_inode(data, data_type); + const struct fsnotify_ops *ops = group->ops; + int ret; + + if (WARN_ON_ONCE(!ops->handle_inode_event)) + return 0; + + if (WARN_ON_ONCE(fsnotify_iter_sb_mark(iter_info)) || + WARN_ON_ONCE(fsnotify_iter_vfsmount_mark(iter_info))) + return 0; + + /* + * An event can be sent on child mark iterator instead of inode mark + * iterator because of other groups that have interest of this inode + * and have marks on both parent and child. We can simplify this case. + */ + if (!inode_mark) { + inode_mark = child_mark; + child_mark = NULL; + dir = NULL; + name = NULL; + } + + ret = ops->handle_inode_event(inode_mark, mask, inode, dir, name); + if (ret || !child_mark) + return ret; + + /* + * 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 and once to child + * without name. + */ + return ops->handle_inode_event(child_mark, mask, inode, NULL, NULL); +} + +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); @@ -223,16 +313,20 @@ } } - 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_ignored_mask=%x data=%p data_type=%d dir=%p cookie=%d\n", + __func__, group, mask, marks_mask, marks_ignored_mask, + data, data_type, dir, cookie); if (!(test_mask & marks_mask & ~marks_ignored_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) @@ -310,28 +404,51 @@ } /* - * 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 - + * either @dir or @inode must be non-NULL. + * if both are 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 fsnotify_iter_info iter_info = {}; - struct super_block *sb = to_tell->i_sb; + struct super_block *sb; struct mount *mnt = NULL; - __u32 mnt_or_sb_mask = sb->s_fsnotify_mask; + struct inode *child = NULL; int ret = 0; - __u32 test_mask = (mask & ALL_FSNOTIFY_EVENTS); + __u32 test_mask, marks_mask; - if (data_is == FSNOTIFY_EVENT_PATH) { - mnt = real_mount(((const struct path *)data)->mnt); - mnt_or_sb_mask |= mnt->mnt_fsnotify_mask; - } - /* An event "on child" is not intended for a mount/sb mark */ - if (mask & FS_EVENT_ON_CHILD) - mnt_or_sb_mask = 0; + if (path) + mnt = real_mount(path->mnt); + + if (!inode) { + /* Dirent event - report on TYPE_INODE to dir */ + inode = dir; + } else if (mask & FS_EVENT_ON_CHILD) { + /* + * Event on child - report on TYPE_INODE to dir if it is + * watching children and on TYPE_CHILD to child. + */ + child = inode; + inode = dir; + } + sb = inode->i_sb; /* * Optimization: srcu_read_lock() has a memory barrier which can @@ -340,28 +457,45 @@ * 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) && + (!child || !child->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 (child) + marks_mask |= child->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. + * 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 (!(mask & FS_MODIFY) && !(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] = fsnotify_first_mark(&sb->s_fsnotify_marks); if (mnt) { iter_info.marks[FSNOTIFY_OBJ_TYPE_VFSMOUNT] = fsnotify_first_mark(&mnt->mnt_fsnotify_marks); } + if (inode) { + iter_info.marks[FSNOTIFY_OBJ_TYPE_INODE] = + fsnotify_first_mark(&inode->i_fsnotify_marks); + } + if (child) { + iter_info.marks[FSNOTIFY_OBJ_TYPE_CHILD] = + fsnotify_first_mark(&child->i_fsnotify_marks); + } /* * We need to merge inode/vfsmount/sb mark lists so that e.g. inode mark @@ -369,8 +503,8 @@ * 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; @@ -385,8 +519,6 @@ } EXPORT_SYMBOL_GPL(fsnotify); -extern struct kmem_cache *fsnotify_mark_connector_cachep; - static __init int fsnotify_init(void) { int ret;