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* inotify: fix coalesce duplicate events into a single event in special caseWei Yongjun2009-10-181-1/+1
| | | | | | | | | | | | | | If we do rename a dir entry, like this: rename("/tmp/ino7UrgoJ.rename1", "/tmp/ino7UrgoJ.rename2") rename("/tmp/ino7UrgoJ.rename2", "/tmp/ino7UrgoJ") The duplicate events should be coalesced into a single event. But those two events do not be coalesced into a single event, due to some bad check in event_compare(). It can not match the two NULL inodes as the same event. Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* inotify: tail drop inotify q_overflow eventsEric Paris2009-08-171-0/+4
| | | | | | | | | | | In f44aebcc the tail drop logic of events with no file backing (q_overflow and in_ignored) was reversed so IN_IGNORED events would never be tail dropped. This now means that Q_OVERFLOW events are NOT tail dropped. The fix is to not tail drop IN_IGNORED, but to tail drop Q_OVERFLOW. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* notify: unused event private raceEric Paris2009-08-171-4/+3
| | | | | | | | | | | | inotify decides if private data it passed to get added to an event was used by checking list_empty(). But it's possible that the event may have been dequeued and the private event removed so it would look empty. The fix is to use the return code from fsnotify_add_notify_event rather than looking at the list. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* inotify: use GFP_NOFS under potential memory pressureEric Paris2009-07-211-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | inotify can have a watchs removed under filesystem reclaim. ================================= [ INFO: inconsistent lock state ] 2.6.31-rc2 #16 --------------------------------- inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage. khubd/217 [HC0[0]:SC0[0]:HE1:SE1] takes: (iprune_mutex){+.+.?.}, at: [<c10ba899>] invalidate_inodes+0x20/0xe3 {IN-RECLAIM_FS-W} state was registered at: [<c10536ab>] __lock_acquire+0x2c9/0xac4 [<c1053f45>] lock_acquire+0x9f/0xc2 [<c1308872>] __mutex_lock_common+0x2d/0x323 [<c1308c00>] mutex_lock_nested+0x2e/0x36 [<c10ba6ff>] shrink_icache_memory+0x38/0x1b2 [<c108bfb6>] shrink_slab+0xe2/0x13c [<c108c3e1>] kswapd+0x3d1/0x55d [<c10449b5>] kthread+0x66/0x6b [<c1003fdf>] kernel_thread_helper+0x7/0x10 [<ffffffff>] 0xffffffff Two things are needed to fix this. First we need a method to tell fsnotify_create_event() to use GFP_NOFS and second we need to stop using one global IN_IGNORED event and allocate them one at a time. This solves current issues with multiple IN_IGNORED on a queue having tail drop problems and simplifies the allocations since we don't have to worry about two tasks opperating on the IGNORED event concurrently. Signed-off-by: Eric Paris <eparis@redhat.com>
* fsnotify: fix inotify tail drop check with path entriesEric Paris2009-07-211-0/+1
| | | | | | | | | | | | fsnotify drops new events when they are the same as the tail event on the queue to be sent to userspace. The problem is that if the event comes with a path we forget to break out of the switch statement and fall into the code path which matches on events that do not have any type of file backed information (things like IN_UNMOUNT and IN_Q_OVERFLOW). The problem is that this code thinks all such events should be dropped. Fix is to add a break. Signed-off-by: Eric Paris <eparis@redhat.com>
* inotify: check filename before dropping repeat eventsEric Paris2009-07-211-2/+7
| | | | | | | | | | | | | | | | | | | | inotify drops events if the last event on the queue is the same as the current event. But it does 2 things wrong. First it is comparing old->inode with new->inode. But after an event if put on the queue the ->inode is no longer allowed to be used. It's possible between the last event and this new event the inode could be reused and we would falsely match the inode's memory address between two differing events. The second problem is that when a file is removed fsnotify is passed the negative dentry for the removed object rather than the postive dentry from immediately before the removal. This mean the (broken) inotify tail drop code was matching the NULL ->inode of differing events. The fix is to check the file name which is stored with events when doing the tail drop instead of wrongly checking the address of the stored ->inode. Reported-by: Scott James Remnant <scott@ubuntu.com> Signed-off-by: Eric Paris <eparis@redhat.com>
* fsnotify: allow groups to add private data to eventsEric Paris2009-06-111-4/+48
| | | | | | | | | | inotify needs per group information attached to events. This patch allows groups to attach private information and implements a callback so that information can be freed when an event is being destroyed. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
* fsnotify: add correlations between eventsEric Paris2009-06-111-2/+18
| | | | | | | | | | | As part of the standard inotify events it includes a correlation cookie between two dentry move operations. This patch includes the same behaviour in fsnotify events. It is needed so that inotify userspace can be implemented on top of fsnotify. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
* fsnotify: include pathnames with entries when possibleEric Paris2009-06-111-1/+15
| | | | | | | | | | When inotify wants to send events to a directory about a child it includes the name of the original file. This patch collects that filename and makes it available for notification. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
* fsnotify: generic notification queue and waitqEric Paris2009-06-111-7/+223
| | | | | | | | | | | inotify needs to do asyc notification in which event information is stored on a queue until the listener is ready to receive it. This patch implements a generic notification queue for inotify (and later fanotify) to store events to be sent at a later time. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
* fsnotify: unified filesystem notification backendEric Paris2009-06-111-0/+121
fsnotify is a backend for filesystem notification. fsnotify does not provide any userspace interface but does provide the basis needed for other notification schemes such as dnotify. fsnotify can be extended to be the backend for inotify or the upcoming fanotify. fsnotify provides a mechanism for "groups" to register for some set of filesystem events and to then deliver those events to those groups for processing. fsnotify has a number of benefits, the first being actually shrinking the size of an inode. Before fsnotify to support both dnotify and inotify an inode had unsigned long i_dnotify_mask; /* Directory notify events */ struct dnotify_struct *i_dnotify; /* for directory notifications */ struct list_head inotify_watches; /* watches on this inode */ struct mutex inotify_mutex; /* protects the watches list But with fsnotify this same functionallity (and more) is done with just __u32 i_fsnotify_mask; /* all events for this inode */ struct hlist_head i_fsnotify_mark_entries; /* marks on this inode */ That's right, inotify, dnotify, and fanotify all in 64 bits. We used that much space just in inotify_watches alone, before this patch set. fsnotify object lifetime and locking is MUCH better than what we have today. inotify locking is incredibly complex. See 8f7b0ba1c8539 as an example of what's been busted since inception. inotify needs to know internal semantics of superblock destruction and unmounting to function. The inode pinning and vfs contortions are horrible. no fsnotify implementers do allocation under locks. This means things like f04b30de3 which (due to an overabundance of caution) changes GFP_KERNEL to GFP_NOFS can be reverted. There are no longer any allocation rules when using or implementing your own fsnotify listener. fsnotify paves the way for fanotify. In brief fanotify is a notification mechanism that delivers the lisener both an 'event' and an open file descriptor to the object in question. This means that fanotify is pathname agnostic. Some on lkml may not care for the original companies or users that pushed for TALPA, but fanotify was designed with flexibility and input for other users in mind. The readahead group expressed interest in fanotify as it could be used to profile disk access on boot without breaking the audit system. The desktop search groups have also expressed interest in fanotify as it solves a number of the race conditions and problems present with managing inotify when more than a limited number of specific files are of interest. fanotify can provide for a userspace access control system which makes it a clean interface for AV vendors to hook without trying to do binary patching on the syscall table, LSM, and everywhere else they do their things today. With this patch series fanotify can be implemented in less than 1200 lines of easy to review code. Almost all of which is the socket based user interface. This patch series builds fsnotify to the point that it can implement dnotify and inotify_user. Patches exist and will be sent soon after acceptance to finish the in kernel inotify conversion (audit) and implement fanotify. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>