diff options
Diffstat (limited to 'kernel/fs/notify/inotify/inotify_fsnotify.c')
| -rw-r--r-- | kernel/fs/notify/inotify/inotify_fsnotify.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/kernel/fs/notify/inotify/inotify_fsnotify.c b/kernel/fs/notify/inotify/inotify_fsnotify.c new file mode 100644 index 000000000..2cd900c2c --- /dev/null +++ b/kernel/fs/notify/inotify/inotify_fsnotify.c @@ -0,0 +1,184 @@ +/* + * fs/inotify_user.c - inotify support for userspace + * + * Authors: + * John McCutchan <ttb@tentacle.dhs.org> + * Robert Love <rml@novell.com> + * + * Copyright (C) 2005 John McCutchan + * Copyright 2006 Hewlett-Packard Development Company, L.P. + * + * Copyright (C) 2009 Eric Paris <Red Hat Inc> + * inotify was largely rewriten to make use of the fsnotify infrastructure + * + * 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. + */ + +#include <linux/dcache.h> /* d_unlinked */ +#include <linux/fs.h> /* struct inode */ +#include <linux/fsnotify_backend.h> +#include <linux/inotify.h> +#include <linux/path.h> /* struct path */ +#include <linux/slab.h> /* kmem_* */ +#include <linux/types.h> +#include <linux/sched.h> + +#include "inotify.h" + +/* + * Check if 2 events contain the same information. + */ +static bool event_compare(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) +{ + struct inotify_event_info *old, *new; + + if (old_fsn->mask & FS_IN_IGNORED) + return false; + old = INOTIFY_E(old_fsn); + new = INOTIFY_E(new_fsn); + if ((old_fsn->mask == new_fsn->mask) && + (old_fsn->inode == new_fsn->inode) && + (old->name_len == new->name_len) && + (!old->name_len || !strcmp(old->name, new->name))) + return true; + return false; +} + +static int inotify_merge(struct list_head *list, + struct fsnotify_event *event) +{ + struct fsnotify_event *last_event; + + last_event = list_entry(list->prev, struct fsnotify_event, list); + return event_compare(last_event, event); +} + +int inotify_handle_event(struct fsnotify_group *group, + struct inode *inode, + struct fsnotify_mark *inode_mark, + struct fsnotify_mark *vfsmount_mark, + u32 mask, void *data, int data_type, + const unsigned char *file_name, u32 cookie) +{ + struct inotify_inode_mark *i_mark; + struct inotify_event_info *event; + struct fsnotify_event *fsn_event; + int ret; + int len = 0; + int alloc_len = sizeof(struct inotify_event_info); + + BUG_ON(vfsmount_mark); + + if ((inode_mark->mask & FS_EXCL_UNLINK) && + (data_type == FSNOTIFY_EVENT_PATH)) { + struct path *path = data; + + if (d_unlinked(path->dentry)) + return 0; + } + if (file_name) { + len = strlen(file_name); + alloc_len += len + 1; + } + + pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, + mask); + + i_mark = container_of(inode_mark, struct inotify_inode_mark, + fsn_mark); + + event = kmalloc(alloc_len, GFP_KERNEL); + if (unlikely(!event)) + return -ENOMEM; + + fsn_event = &event->fse; + fsnotify_init_event(fsn_event, inode, mask); + event->wd = i_mark->wd; + event->sync_cookie = cookie; + event->name_len = len; + if (len) + strcpy(event->name, file_name); + + ret = fsnotify_add_event(group, fsn_event, inotify_merge); + if (ret) { + /* Our event wasn't used in the end. Free it. */ + fsnotify_destroy_event(group, fsn_event); + } + + if (inode_mark->mask & IN_ONESHOT) + fsnotify_destroy_mark(inode_mark, group); + + return 0; +} + +static void inotify_freeing_mark(struct fsnotify_mark *fsn_mark, struct fsnotify_group *group) +{ + inotify_ignored_and_remove_idr(fsn_mark, group); +} + +/* + * This is NEVER supposed to be called. Inotify marks should either have been + * removed from the idr when the watch was removed or in the + * fsnotify_destroy_mark_by_group() call when the inotify instance was being + * torn down. This is only called if the idr is about to be freed but there + * are still marks in it. + */ +static int idr_callback(int id, void *p, void *data) +{ + struct fsnotify_mark *fsn_mark; + struct inotify_inode_mark *i_mark; + static bool warned = false; + + if (warned) + return 0; + + warned = true; + fsn_mark = p; + i_mark = container_of(fsn_mark, struct inotify_inode_mark, fsn_mark); + + WARN(1, "inotify closing but id=%d for fsn_mark=%p in group=%p still in " + "idr. Probably leaking memory\n", id, p, data); + + /* + * I'm taking the liberty of assuming that the mark in question is a + * valid address and I'm dereferencing it. This might help to figure + * out why we got here and the panic is no worse than the original + * BUG() that was here. + */ + if (fsn_mark) + printk(KERN_WARNING "fsn_mark->group=%p inode=%p wd=%d\n", + fsn_mark->group, fsn_mark->inode, i_mark->wd); + return 0; +} + +static void inotify_free_group_priv(struct fsnotify_group *group) +{ + /* ideally the idr is empty and we won't hit the BUG in the callback */ + idr_for_each(&group->inotify_data.idr, idr_callback, group); + idr_destroy(&group->inotify_data.idr); + if (group->inotify_data.user) { + atomic_dec(&group->inotify_data.user->inotify_devs); + free_uid(group->inotify_data.user); + } +} + +static void inotify_free_event(struct fsnotify_event *fsn_event) +{ + kfree(INOTIFY_E(fsn_event)); +} + +const struct fsnotify_ops inotify_fsnotify_ops = { + .handle_event = inotify_handle_event, + .free_group_priv = inotify_free_group_priv, + .free_event = inotify_free_event, + .freeing_mark = inotify_freeing_mark, +}; |