Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify: inotify: Ensure we alwasy write the terminating NULL. inotify: fix locking around inotify watching in the idr inotify: do not BUG on idr entries at inotify destruction inotify: seperate new watch creation updating existing watches
This commit is contained in:
Linus Torvalds
commit
9c504cadc4
2 changed files with 178 additions and 86 deletions
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@ -105,16 +105,45 @@ static bool inotify_should_send_event(struct fsnotify_group *group, struct inode
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return send;
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}
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/*
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* This is NEVER supposed to be called. Inotify marks should either have been
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* removed from the idr when the watch was removed or in the
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* fsnotify_destroy_mark_by_group() call when the inotify instance was being
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* torn down. This is only called if the idr is about to be freed but there
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* are still marks in it.
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*/
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static int idr_callback(int id, void *p, void *data)
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{
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BUG();
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struct fsnotify_mark_entry *entry;
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struct inotify_inode_mark_entry *ientry;
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static bool warned = false;
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if (warned)
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return 0;
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warned = false;
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entry = p;
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ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
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WARN(1, "inotify closing but id=%d for entry=%p in group=%p still in "
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"idr. Probably leaking memory\n", id, p, data);
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/*
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* I'm taking the liberty of assuming that the mark in question is a
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* valid address and I'm dereferencing it. This might help to figure
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* out why we got here and the panic is no worse than the original
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* BUG() that was here.
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*/
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if (entry)
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printk(KERN_WARNING "entry->group=%p inode=%p wd=%d\n",
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entry->group, entry->inode, ientry->wd);
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return 0;
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}
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static void inotify_free_group_priv(struct fsnotify_group *group)
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{
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/* ideally the idr is empty and we won't hit the BUG in teh callback */
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idr_for_each(&group->inotify_data.idr, idr_callback, NULL);
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idr_for_each(&group->inotify_data.idr, idr_callback, group);
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idr_remove_all(&group->inotify_data.idr);
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idr_destroy(&group->inotify_data.idr);
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}
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@ -47,9 +47,6 @@
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static struct vfsmount *inotify_mnt __read_mostly;
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/* this just sits here and wastes global memory. used to just pad userspace messages with zeros */
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static struct inotify_event nul_inotify_event;
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/* these are configurable via /proc/sys/fs/inotify/ */
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static int inotify_max_user_instances __read_mostly;
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static int inotify_max_queued_events __read_mostly;
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@ -199,8 +196,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
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inotify_free_event_priv(fsn_priv);
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}
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/* round up event->name_len so it is a multiple of event_size */
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name_len = roundup(event->name_len, event_size);
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/* round up event->name_len so it is a multiple of event_size
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* plus an extra byte for the terminating '\0'.
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*/
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name_len = roundup(event->name_len + 1, event_size);
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inotify_event.len = name_len;
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inotify_event.mask = inotify_mask_to_arg(event->mask);
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@ -224,8 +223,8 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
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return -EFAULT;
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buf += event->name_len;
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/* fill userspace with 0's from nul_inotify_event */
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if (copy_to_user(buf, &nul_inotify_event, len_to_zero))
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/* fill userspace with 0's */
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if (clear_user(buf, len_to_zero))
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return -EFAULT;
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buf += len_to_zero;
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event_size += name_len;
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@ -364,20 +363,53 @@ static int inotify_find_inode(const char __user *dirname, struct path *path, uns
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return error;
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}
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/*
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* Remove the mark from the idr (if present) and drop the reference
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* on the mark because it was in the idr.
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*/
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static void inotify_remove_from_idr(struct fsnotify_group *group,
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struct inotify_inode_mark_entry *ientry)
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{
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struct idr *idr;
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struct fsnotify_mark_entry *entry;
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struct inotify_inode_mark_entry *found_ientry;
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int wd;
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spin_lock(&group->inotify_data.idr_lock);
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idr = &group->inotify_data.idr;
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idr_remove(idr, ientry->wd);
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spin_unlock(&group->inotify_data.idr_lock);
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wd = ientry->wd;
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if (wd == -1)
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goto out;
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entry = idr_find(&group->inotify_data.idr, wd);
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if (unlikely(!entry))
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goto out;
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found_ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
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if (unlikely(found_ientry != ientry)) {
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/* We found an entry in the idr with the right wd, but it's
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* not the entry we were told to remove. eparis seriously
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* fucked up somewhere. */
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WARN_ON(1);
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ientry->wd = -1;
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goto out;
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}
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/* One ref for being in the idr, one ref held by the caller */
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BUG_ON(atomic_read(&entry->refcnt) < 2);
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idr_remove(idr, wd);
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ientry->wd = -1;
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/* removed from the idr, drop that ref */
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fsnotify_put_mark(entry);
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out:
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spin_unlock(&group->inotify_data.idr_lock);
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}
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/*
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* Send IN_IGNORED for this wd, remove this wd from the idr, and drop the
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* internal reference help on the mark because it is in the idr.
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* Send IN_IGNORED for this wd, remove this wd from the idr.
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*/
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void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
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struct fsnotify_group *group)
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@ -417,9 +449,6 @@ skip_send_ignore:
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/* remove this entry from the idr */
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inotify_remove_from_idr(group, ientry);
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/* removed from idr, drop that reference */
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fsnotify_put_mark(entry);
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atomic_dec(&group->inotify_data.user->inotify_watches);
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}
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@ -431,80 +460,29 @@ static void inotify_free_mark(struct fsnotify_mark_entry *entry)
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kmem_cache_free(inotify_inode_mark_cachep, ientry);
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}
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static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
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static int inotify_update_existing_watch(struct fsnotify_group *group,
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struct inode *inode,
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u32 arg)
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{
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struct fsnotify_mark_entry *entry = NULL;
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struct fsnotify_mark_entry *entry;
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struct inotify_inode_mark_entry *ientry;
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struct inotify_inode_mark_entry *tmp_ientry;
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int ret = 0;
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int add = (arg & IN_MASK_ADD);
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__u32 mask;
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__u32 old_mask, new_mask;
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__u32 mask;
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int add = (arg & IN_MASK_ADD);
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int ret;
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/* don't allow invalid bits: we don't want flags set */
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mask = inotify_arg_to_mask(arg);
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if (unlikely(!mask))
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return -EINVAL;
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tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
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if (unlikely(!tmp_ientry))
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return -ENOMEM;
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/* we set the mask at the end after attaching it */
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fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
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tmp_ientry->wd = -1;
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find_entry:
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spin_lock(&inode->i_lock);
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entry = fsnotify_find_mark_entry(group, inode);
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spin_unlock(&inode->i_lock);
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if (entry) {
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ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
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} else {
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ret = -ENOSPC;
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if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
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goto out_err;
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retry:
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ret = -ENOMEM;
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if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
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goto out_err;
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if (!entry)
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return -ENOENT;
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spin_lock(&group->inotify_data.idr_lock);
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ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry,
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group->inotify_data.last_wd,
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&tmp_ientry->wd);
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spin_unlock(&group->inotify_data.idr_lock);
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if (ret) {
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if (ret == -EAGAIN)
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goto retry;
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goto out_err;
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}
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ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
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if (ret) {
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inotify_remove_from_idr(group, tmp_ientry);
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if (ret == -EEXIST)
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goto find_entry;
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goto out_err;
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}
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/* tmp_ientry has been added to the inode, so we are all set up.
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* now we just need to make sure tmp_ientry doesn't get freed and
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* we need to set up entry and ientry so the generic code can
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* do its thing. */
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ientry = tmp_ientry;
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entry = &ientry->fsn_entry;
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tmp_ientry = NULL;
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atomic_inc(&group->inotify_data.user->inotify_watches);
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/* update the idr hint */
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group->inotify_data.last_wd = ientry->wd;
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/* we put the mark on the idr, take a reference */
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fsnotify_get_mark(entry);
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}
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ret = ientry->wd;
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ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry);
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spin_lock(&entry->lock);
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@ -536,19 +514,104 @@ retry:
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fsnotify_recalc_group_mask(group);
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}
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/* this either matches fsnotify_find_mark_entry, or init_mark_entry
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* depending on which path we took... */
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/* return the wd */
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ret = ientry->wd;
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/* match the get from fsnotify_find_mark_entry() */
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fsnotify_put_mark(entry);
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out_err:
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/* could be an error, could be that we found an existing mark */
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if (tmp_ientry) {
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/* on the idr but didn't make it on the inode */
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if (tmp_ientry->wd != -1)
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inotify_remove_from_idr(group, tmp_ientry);
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kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry);
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return ret;
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}
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static int inotify_new_watch(struct fsnotify_group *group,
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struct inode *inode,
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u32 arg)
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{
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struct inotify_inode_mark_entry *tmp_ientry;
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__u32 mask;
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int ret;
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/* don't allow invalid bits: we don't want flags set */
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mask = inotify_arg_to_mask(arg);
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if (unlikely(!mask))
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return -EINVAL;
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tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL);
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if (unlikely(!tmp_ientry))
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return -ENOMEM;
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fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark);
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tmp_ientry->fsn_entry.mask = mask;
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tmp_ientry->wd = -1;
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ret = -ENOSPC;
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if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches)
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goto out_err;
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retry:
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ret = -ENOMEM;
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if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL)))
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goto out_err;
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spin_lock(&group->inotify_data.idr_lock);
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ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry,
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group->inotify_data.last_wd,
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&tmp_ientry->wd);
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spin_unlock(&group->inotify_data.idr_lock);
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if (ret) {
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/* idr was out of memory allocate and try again */
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if (ret == -EAGAIN)
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goto retry;
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goto out_err;
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}
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/* we put the mark on the idr, take a reference */
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fsnotify_get_mark(&tmp_ientry->fsn_entry);
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/* we are on the idr, now get on the inode */
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ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode);
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if (ret) {
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/* we failed to get on the inode, get off the idr */
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inotify_remove_from_idr(group, tmp_ientry);
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goto out_err;
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}
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/* update the idr hint, who cares about races, it's just a hint */
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group->inotify_data.last_wd = tmp_ientry->wd;
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/* increment the number of watches the user has */
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atomic_inc(&group->inotify_data.user->inotify_watches);
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/* return the watch descriptor for this new entry */
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ret = tmp_ientry->wd;
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/* match the ref from fsnotify_init_markentry() */
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fsnotify_put_mark(&tmp_ientry->fsn_entry);
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out_err:
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if (ret < 0)
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kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry);
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return ret;
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}
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static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg)
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{
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int ret = 0;
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retry:
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/* try to update and existing watch with the new arg */
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ret = inotify_update_existing_watch(group, inode, arg);
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/* no mark present, try to add a new one */
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if (ret == -ENOENT)
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ret = inotify_new_watch(group, inode, arg);
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/*
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* inotify_new_watch could race with another thread which did an
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* inotify_new_watch between the update_existing and the add watch
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* here, go back and try to update an existing mark again.
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*/
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if (ret == -EEXIST)
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goto retry;
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return ret;
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}
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