path: root/fs/notify/group.c
AgeCommit message (Collapse)AuthorFilesLines
2012-12-11fsnotify: make fasync generic for both inotify and fanotifyEric Paris1-0/+7
inotify is supposed to support async signal notification when information is available on the inotify fd. This patch moves that support to generic fsnotify functions so it can be used by all notification mechanisms. Signed-off-by: Eric Paris <eparis@redhat.com>
2012-12-11fsnotify: use a mutex instead of a spinlock to protect a groups mark listLino Sanfilippo1-1/+1
Replaces the groups mark_lock spinlock with a mutex. Using a mutex instead of a spinlock results in more flexibility (i.e it allows to sleep while the lock is held). Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-12-11fsnotify: use reference counting for groupsLino Sanfilippo1-18/+10
Get a group ref for each mark that is added to the groups list and release that ref when the mark is freed in fsnotify_put_mark(). We also use get a group reference for duplicated marks and for private event data. Now we dont free a group any more when the number of marks becomes 0 but when the groups ref count does. Since this will only happen when all marks are removed from a groups mark list, we dont have to set the groups number of marks to 1 at group creation. Beside clearing all marks in fsnotify_destroy_group() we do also flush the groups event queue. This is since events may hold references to groups (due to private event data) and we have to put those references first before we get a chance to put the final ref, which will result in a call to fsnotify_final_destroy_group(). Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-12-11fsnotify: introduce fsnotify_get_group()Lino Sanfilippo1-0/+8
Introduce fsnotify_get_group() which increments the reference counter of a group. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2012-12-11inotify, fanotify: replace fsnotify_put_group() with fsnotify_destroy_group()Lino Sanfilippo1-1/+1
Currently in fsnotify_put_group() the ref count of a group is decremented and if it becomes 0 fsnotify_destroy_group() is called. Since a groups ref count is only at group creation set to 1 and never increased after that a call to fsnotify_put_group() always results in a call to fsnotify_destroy_group(). With this patch fsnotify_destroy_group() is called directly. Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de> Signed-off-by: Eric Paris <eparis@redhat.com>
2011-07-26atomic: use <linux/atomic.h>Arun Sharma1-1/+1
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-07-28fsnotify: remove global fsnotify groups listsEric Paris1-105/+2
The global fsnotify groups lists were invented as a way to increase the performance of fsnotify by shortcutting events which were not interesting. With the changes to walk the object lists rather than global groups lists these shortcuts are not useful. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: remove group->maskEric Paris1-16/+0
group->mask is now useless. It was originally a shortcut for fsnotify to save on performance. These checks are now redundant, so we remove them. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: remove the global masksEric Paris1-37/+2
Because we walk the object->fsnotify_marks list instead of the global fsnotify groups list we don't need the fsnotify_inode_mask and fsnotify_vfsmount_mask as these were simply shortcuts in fsnotify() for performance. They are now extra checks, rip them out. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: srcu to protect read side of inode and vfsmount locksEric Paris1-11/+5
Currently reading the inode->i_fsnotify_marks or vfsmount->mnt_fsnotify_marks lists are protected by a spinlock on both the read and the write side. This patch protects the read side of those lists with a new single srcu. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fanotify: drop the useless priority argumentEric Paris1-7/+3
The priority argument in fanotify is useless. Kill it. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: add group prioritiesEric Paris1-2/+38
This introduces an ordering to fsnotify groups. With purely asynchronous notification based "things" implementing fsnotify (inotify, dnotify) ordering isn't particularly important. But if people want to use fsnotify for the basis of sycronous notification or blocking notification ordering becomes important. eg. A Hierarchical Storage Management listener would need to get its event before an AV scanner could get its event (since the HSM would need to bring the data in for the AV scanner to scan.) Typically asynchronous notification would want to run after the AV scanner made any relevant access decisions so as to not send notification about an event that was denied. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: rename mark_entry to just markEric Paris1-3/+3
previously I used mark_entry when talking about marks on inodes. The _entry is pretty useless. Just use "mark" instead. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: rename fsnotify_mark_entry to just fsnotify_markEric Paris1-4/+4
The name is long and it serves no real purpose. So rename fsnotify_mark_entry to just fsnotify_mark. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: mount point listeners list and global maskEric Paris1-4/+29
currently all of the notification systems implemented select which inodes they care about and receive messages only about those inodes (or the children of those inodes.) This patch begins to flesh out fsnotify support for the concept of listeners that want to hear notification for an inode accessed below a given monut point. This patch implements a second list of fsnotify groups to hold these types of groups and a second global mask to hold the events of interest for this type of group. The reason we want a second group list and mask is because the inode based notification should_send_event support which makes each group look for a mark on the given inode. With one nfsmount listener that means that every group would have to take the inode->i_lock, look for their mark, not find one, and return for every operation. By seperating vfsmount from inode listeners only when there is a inode listener will the inode groups have to look for their mark and take the inode lock. vfsmount listeners will have to grab the lock and look for a mark but there should be fewer of them, and one vfsmount listener won't cause the i_lock to be grabbed and released for every fsnotify group on every io operation. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: add groups to fsnotify_inode_groups when registering inode watchEric Paris1-10/+8
Currently all fsnotify groups are added immediately to the fsnotify_inode_groups list upon creation. This means, even groups with no watches (common for audit) will be on the global tracking list and will get checked for every event. This patch adds groups to the global list on when the first inode mark is added to the group. Signed-of-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: initialize the group->num_marks in a better placeEric Paris1-3/+7
Currently the comments say that group->num_marks is held because the group is on the fsnotify_group list. This isn't strictly the case, we really just hold the num_marks for the life of the group (any time group->refcnt is != 0) This patch moves the initialization stuff and makes it clear when it is really being held. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: rename fsnotify_groups to fsnotify_inode_groupsEric Paris1-11/+19
Simple renaming patch. fsnotify is about to support mount point listeners so I am renaming fsnotify_groups and fsnotify_mask to indicate these are lists used only for groups which have watches on inodes. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: drop mask argument from fsnotify_alloc_groupEric Paris1-7/+1
Nothing uses the mask argument to fsnotify_alloc_group. This patch drops that argument. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: fsnotify_obtain_group should be fsnotify_alloc_groupEric Paris1-7/+3
fsnotify_obtain_group was intended to be able to find an already existing group. Nothing uses that functionality. This just renames it to fsnotify_alloc_group so it is clear what it is doing. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: fsnotify_obtain_group kzalloc cleanupEric Paris1-3/+0
fsnotify_obtain_group uses kzalloc but then proceedes to set things to 0. This patch just deletes those useless lines. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: remove group_num altogetherEric Paris1-46/+2
The original fsnotify interface has a group-num which was intended to be able to find a group after it was added. I no longer think this is a necessary thing to do and so we remove the group_num. Signed-off-by: Eric Paris <eparis@redhat.com>
2010-07-28fsnotify: kzalloc fsnotify groupsEric Paris1-1/+1
Use kzalloc for fsnotify_groups so that none of the fields can leak any information accidentally. Signed-off-by: Eric Paris <eparis@redhat.com>
2009-06-11fsnotify: generic notification queue and waitqEric Paris1-0/+9
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>
2009-06-11fsnotify: add marks to inodes so groups can interpret how to handle those inodesEric Paris1-1/+48
This patch creates a way for fsnotify groups to attach marks to inodes. These marks have little meaning to the generic fsnotify infrastructure and thus their meaning should be interpreted by the group that attached them to the inode's list. dnotify and inotify will make use of these markings to indicate which inodes are of interest to their respective groups. But this implementation has the useful property that in the future other listeners could actually use the marks for the exact opposite reason, aka to indicate which inodes it had NO interest in. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
2009-06-11fsnotify: unified filesystem notification backendEric Paris1-0/+198
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>