diff options
| -rw-r--r-- | fs/notify/inotify/inotify_user.c | 172 |
1 files changed, 103 insertions, 69 deletions
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index dc32ed8323ba..d8f73c253073 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -431,80 +431,29 @@ static void inotify_free_mark(struct fsnotify_mark_entry *entry) kmem_cache_free(inotify_inode_mark_cachep, ientry); } -static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) +static int inotify_update_existing_watch(struct fsnotify_group *group, + struct inode *inode, + u32 arg) { - struct fsnotify_mark_entry *entry = NULL; + struct fsnotify_mark_entry *entry; struct inotify_inode_mark_entry *ientry; - struct inotify_inode_mark_entry *tmp_ientry; - int ret = 0; - int add = (arg & IN_MASK_ADD); - __u32 mask; __u32 old_mask, new_mask; + __u32 mask; + int add = (arg & IN_MASK_ADD); + int ret; /* don't allow invalid bits: we don't want flags set */ mask = inotify_arg_to_mask(arg); if (unlikely(!mask)) return -EINVAL; - tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); - if (unlikely(!tmp_ientry)) - return -ENOMEM; - /* we set the mask at the end after attaching it */ - fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark); - tmp_ientry->wd = -1; - -find_entry: spin_lock(&inode->i_lock); entry = fsnotify_find_mark_entry(group, inode); spin_unlock(&inode->i_lock); - if (entry) { - ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); - } else { - ret = -ENOSPC; - if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) - goto out_err; -retry: - ret = -ENOMEM; - if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) - goto out_err; - - spin_lock(&group->inotify_data.idr_lock); - ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, - group->inotify_data.last_wd, - &tmp_ientry->wd); - spin_unlock(&group->inotify_data.idr_lock); - if (ret) { - if (ret == -EAGAIN) - goto retry; - goto out_err; - } + if (!entry) + return -ENOENT; - ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); - if (ret) { - inotify_remove_from_idr(group, tmp_ientry); - if (ret == -EEXIST) - goto find_entry; - goto out_err; - } - - /* tmp_ientry has been added to the inode, so we are all set up. - * now we just need to make sure tmp_ientry doesn't get freed and - * we need to set up entry and ientry so the generic code can - * do its thing. */ - ientry = tmp_ientry; - entry = &ientry->fsn_entry; - tmp_ientry = NULL; - - atomic_inc(&group->inotify_data.user->inotify_watches); - - /* update the idr hint */ - group->inotify_data.last_wd = ientry->wd; - - /* we put the mark on the idr, take a reference */ - fsnotify_get_mark(entry); - } - - ret = ientry->wd; + ientry = container_of(entry, struct inotify_inode_mark_entry, fsn_entry); spin_lock(&entry->lock); @@ -536,18 +485,103 @@ retry: fsnotify_recalc_group_mask(group); } - /* this either matches fsnotify_find_mark_entry, or init_mark_entry - * depending on which path we took... */ + /* return the wd */ + ret = ientry->wd; + + /* match the get from fsnotify_find_mark_entry() */ fsnotify_put_mark(entry); + return ret; +} + +static int inotify_new_watch(struct fsnotify_group *group, + struct inode *inode, + u32 arg) +{ + struct inotify_inode_mark_entry *tmp_ientry; + __u32 mask; + int ret; + + /* don't allow invalid bits: we don't want flags set */ + mask = inotify_arg_to_mask(arg); + if (unlikely(!mask)) + return -EINVAL; + + tmp_ientry = kmem_cache_alloc(inotify_inode_mark_cachep, GFP_KERNEL); + if (unlikely(!tmp_ientry)) + return -ENOMEM; + + fsnotify_init_mark(&tmp_ientry->fsn_entry, inotify_free_mark); + tmp_ientry->fsn_entry.mask = mask; + tmp_ientry->wd = -1; + + ret = -ENOSPC; + if (atomic_read(&group->inotify_data.user->inotify_watches) >= inotify_max_user_watches) + goto out_err; +retry: + ret = -ENOMEM; + if (unlikely(!idr_pre_get(&group->inotify_data.idr, GFP_KERNEL))) + goto out_err; + + spin_lock(&group->inotify_data.idr_lock); + ret = idr_get_new_above(&group->inotify_data.idr, &tmp_ientry->fsn_entry, + group->inotify_data.last_wd, + &tmp_ientry->wd); + spin_unlock(&group->inotify_data.idr_lock); + if (ret) { + /* idr was out of memory allocate and try again */ + if (ret == -EAGAIN) + goto retry; + goto out_err; + } + + /* we are on the idr, now get on the inode */ + ret = fsnotify_add_mark(&tmp_ientry->fsn_entry, group, inode); + if (ret) { + /* we failed to get on the inode, get off the idr */ + inotify_remove_from_idr(group, tmp_ientry); + goto out_err; + } + + /* we put the mark on the idr, take a reference */ + fsnotify_get_mark(&tmp_ientry->fsn_entry); + + /* update the idr hint, who cares about races, it's just a hint */ + group->inotify_data.last_wd = tmp_ientry->wd; + + /* increment the number of watches the user has */ + atomic_inc(&group->inotify_data.user->inotify_watches); + + /* return the watch descriptor for this new entry */ + ret = tmp_ientry->wd; + + /* match the ref from fsnotify_init_markentry() */ + fsnotify_put_mark(&tmp_ientry->fsn_entry); + out_err: - /* could be an error, could be that we found an existing mark */ - if (tmp_ientry) { - /* on the idr but didn't make it on the inode */ - if (tmp_ientry->wd != -1) - inotify_remove_from_idr(group, tmp_ientry); + if (ret < 0) kmem_cache_free(inotify_inode_mark_cachep, tmp_ientry); - } + + return ret; +} + +static int inotify_update_watch(struct fsnotify_group *group, struct inode *inode, u32 arg) +{ + int ret = 0; + +retry: + /* try to update and existing watch with the new arg */ + ret = inotify_update_existing_watch(group, inode, arg); + /* no mark present, try to add a new one */ + if (ret == -ENOENT) + ret = inotify_new_watch(group, inode, arg); + /* + * inotify_new_watch could race with another thread which did an + * inotify_new_watch between the update_existing and the add watch + * here, go back and try to update an existing mark again. + */ + if (ret == -EEXIST) + goto retry; return ret; } |