Add a ->sync_fs method for data integrity syncs. Factor out common code
between affs_put_super, affs_write_super and the new affs_sync_fs into
a helper.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Mon, 8 Jun 2009 05:22:00 +0000 (01:22 -0400)]
sanitize ->fsync() for affs
unfortunately, for affs (especially for affs directories) we have
no real way to keep track of metadata ownership. So we have to
do more or less what file_fsync() does, but we do *not* need to
call write_super() there.
Al Viro [Sun, 7 Jun 2009 17:44:36 +0000 (13:44 -0400)]
Sanitize ->fsync() for FAT
* mark directory data blocks as assoc. metadata
* add new inode to deal with FAT, mark FAT blocks as assoc. metadata of that
* now ->fsync() is trivial both for files and directories
Al Viro [Sun, 7 Jun 2009 13:30:08 +0000 (09:30 -0400)]
Sanitize qnx4 fsync handling
* have directory operations use mark_buffer_dirty_inode(),
so that sync_mapping_buffers() would get those.
* make qnx4_write_inode() honour its last argument.
* get rid of insane copies of very ancient "walk the indirect blocks"
in qnx4/fsync - they never matched the actual fs layout and, fortunately,
never'd been called. Again, all this junk is not needed; ->fsync()
should just do sync_mapping_buffers + sync_inode (and if we implement
block allocation for qnx4, we'll need to use mark_buffer_dirty_inode()
for extent blocks)
Al Viro [Sun, 7 Jun 2009 18:56:44 +0000 (14:56 -0400)]
New helper - simple_fsync()
writes associated buffers, then does sync_inode() to write
the inode itself (and to make it clean). Depends on
->write_inode() honouring the second argument.
Nick Piggin [Thu, 28 May 2009 07:01:15 +0000 (09:01 +0200)]
fs: block_dump missing dentry locking
I think the block_dump output in __mark_inode_dirty is missing dentry locking.
Surely the i_dentry list can change any time, so we may not even *get* a
dentry there. If we do get one by chance, then it would appear to be able to
go away or get renamed at any time...
Nick Piggin [Tue, 2 Jun 2009 10:07:47 +0000 (12:07 +0200)]
fs: remove incorrect I_NEW warnings
Some filesystems can call in to sync an inode that is still in the
I_NEW state (eg. ext family, when mounted with -osync). This is OK
because the filesystem has sole access to the new inode, so it can
modify i_state without races (because no other thread should be
modifying it, by definition of I_NEW). Ie. a false positive, so
remove the warnings.
xfs: remove ->write_super and stop maintaining ->s_dirt
the write_super method is used for
(1) writing back the superblock periodically from pdflush
(2) called just before ->sync_fs for data integerity syncs
We don't need (1) because we have our own peridoc writeout through xfssyncd,
and we don't need (2) because xfs_fs_sync_fs performs a proper synchronous
superblock writeout after all other data and metadata has been written out.
Also remove ->s_dirt tracking as it's only used to decide when too call
->write_super.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Eric Sandeen <sandeen@sandeen.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Theodore Ts'o [Thu, 21 May 2009 20:01:00 +0000 (16:01 -0400)]
fs: Remove i_cindex from struct inode
The only user of the i_cindex element in the inode structure is used
is by the firewire drivers. As part of an attempt to slim down the
inode structure to save memory --- since a typical Linux system will
have hundreds of thousands if not millions of inodes cached, a
reduction in the size inode has high leverage.
The firewire driver does not need i_cindex in any fast path, so it's
simple enough to calculate when it is needed, instead of wasting space
in the inode structure.
Push down lock_super into ->write_super instances and remove it from the
caller.
Following filesystem don't need ->s_lock in ->write_super and are skipped:
* bfs, nilfs2 - no other uses of s_lock and have internal locks in
->write_super
* ext2 - uses BKL in ext2_write_super and has internal calls without s_lock
* reiserfs - no other uses of s_lock as has reiserfs_write_lock (BKL) in
->write_super
* xfs - no other uses of s_lock and uses internal lock (buffer lock on
superblock buffer) to serialize ->write_super. Also xfs_fs_write_super
is superflous and will go away in the next merge window
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Wed, 6 May 2009 14:43:07 +0000 (10:43 -0400)]
Push lock_super() into the ->remount_fs() of filesystems that care about it
Note that since we can't run into contention between remount_fs and write_super
(due to exclusion on s_umount), we have to care only about filesystems that
touch lock_super() on their own. Out of those ext3, ext4, hpfs, sysv and ufs
do need it; fat doesn't since its ->remount_fs() only accesses assign-once
data (basically, it's "we have no atime on directories and only have atime on
files for vfat; force nodiratime and possibly noatime into *flags").
Move BKL into ->put_super from the only caller. A couple of
filesystems had trivial enough ->put_super (only kfree and NULLing of
s_fs_info + stuff in there) to not get any locking: coda, cramfs, efs,
hugetlbfs, omfs, qnx4, shmem, all others got the full treatment. Most
of them probably don't need it, but I'd rather sort that out individually.
Preferably after all the other BKL pushdowns in that area.
[AV: original used to move lock_super() down as well; these changes are
removed since we don't do lock_super() at all in generic_shutdown_super()
now]
[AV: fuse, btrfs and xfs are known to need no damn BKL, exempt]
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Wed, 6 May 2009 02:10:44 +0000 (22:10 -0400)]
No need to do lock_super() for exclusion in generic_shutdown_super()
We can't run into contention on it. All other callers of lock_super()
either hold s_umount (and we have it exclusive) or hold an active
reference to superblock in question, which prevents the call of
generic_shutdown_super() while the reference is held. So we can
replace lock_super(s) with get_fs_excl() in generic_shutdown_super()
(and corresponding change for unlock_super(), of course).
Since ext4 expects s_lock held for its put_super, take lock_super()
into it. The rest of filesystems do not care at all.
enforce ->sync_fs is only called for rw superblock
Make sure a superblock really is writeable by checking MS_RDONLY
under s_umount. sync_filesystems needed some re-arragement for
that, but all but one sync_filesystem caller had the correct locking
already so that we could add that check there. cachefiles grew
s_umount locking.
I've also added a WARN_ON to sync_filesystem to assert this for
future callers.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Merge the write_super helper into sync_super and move the check for
->write_super earlier so that we can avoid grabbing a reference to
a superblock that doesn't have it.
While we're at it also add a little comment documenting sync_supers.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Alexey Dobriyan [Sun, 3 May 2009 23:32:03 +0000 (03:32 +0400)]
dcache: extrace and use d_unlinked()
d_unlinked() will be used in middle-term to ban checkpointing when opened
but unlinked file is detected, and in long term, to detect such situation
and special case on it.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
remove ->write_super call in generic_shutdown_super
We just did a full fs writeout using sync_filesystem before, and if
that's not enough for the filesystem it can perform it's own writeout
in ->put_super, which many filesystems already do.
Move a call to foofs_write_super into every foofs_put_super for now to
guarantee identical behaviour until it's cleaned up by the individual
filesystem maintainers.
Exceptions:
- affs already has identical copy & pasted code at the beginning of
affs_put_super so no need to do it twice.
- xfs does the right thing without it and I have changes pending for
the xfs tree touching this are so I don't really need conflicts
here..
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jan Kara [Mon, 27 Apr 2009 14:43:55 +0000 (16:43 +0200)]
quota: Introduce writeout_quota_sb() (version 4)
Introduce this function which just writes all the quota structures but
avoids all the syncing and cache pruning work to expose quota structures
to userspace. Use this function from __sync_filesystem when wait == 0.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently the VFS calls vfs_dq_sync to sync out disk quotas for a given
superblock. This is a small wrapper around sync_dquots which for the
case of a non-NULL superblock is a small wrapper around quota_sync_sb.
Just make quota_sync_sb global (rename it to sync_quota_sb) and call it
directly. Also call it directly for those cases in quota.c that have a
superblock and leave sync_dquots purely an iterator over sync_quota_sb and
remove it's superblock argument.
To make this nicer move the check for the lack of a quota_sync method
from the callers into sync_quota_sb.
[folded build fix from Alexander Beregalov <a.beregalov@gmail.com>]
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jan Kara [Mon, 27 Apr 2009 14:43:51 +0000 (16:43 +0200)]
vfs: Make sys_sync() use fsync_super() (version 4)
It is unnecessarily fragile to have two places (fsync_super() and do_sync())
doing data integrity sync of the filesystem. Alter __fsync_super() to
accommodate needs of both callers and use it. So after this patch
__fsync_super() is the only place where we gather all the calls needed to
properly send all data on a filesystem to disk.
Nice bonus is that we get a complete livelock avoidance and write_supers()
is now only used for periodic writeback of superblocks.
sync_blockdevs() introduced a couple of patches ago is gone now.
[build fixes folded]
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jan Kara [Mon, 27 Apr 2009 14:43:50 +0000 (16:43 +0200)]
vfs: Make __fsync_super() a static function (version 4)
__fsync_super() does the same thing as fsync_super(). So change the only
caller to use fsync_super() and make __fsync_super() static. This removes
unnecessarily duplicated call to sync_blockdev() and prepares ground
for the changes to __fsync_super() in the following patches.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jan Kara [Mon, 27 Apr 2009 14:43:49 +0000 (16:43 +0200)]
vfs: Call ->sync_fs() even if s_dirt is 0 (version 4)
sync_filesystems() has a condition that if wait == 0 and s_dirt == 0, then
->sync_fs() isn't called. This does not really make much sence since s_dirt is
generally used by a filesystem to mean that ->write_super() needs to be called.
But ->sync_fs() does different things. I even suspect that some filesystems
(btrfs?) sets s_dirt just to fool this logic.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Jan Kara [Mon, 27 Apr 2009 14:43:48 +0000 (16:43 +0200)]
vfs: Fix sys_sync() and fsync_super() reliability (version 4)
So far, do_sync() called:
sync_inodes(0);
sync_supers();
sync_filesystems(0);
sync_filesystems(1);
sync_inodes(1);
This ordering makes it kind of hard for filesystems as sync_inodes(0) need not
submit all the IO (for example it skips inodes with I_SYNC set) so e.g. forcing
transaction to disk in ->sync_fs() is not really enough. Therefore sys_sync has
not been completely reliable on some filesystems (ext3, ext4, reiserfs, ocfs2
and others are hit by this) when racing e.g. with background writeback. A
similar problem hits also other filesystems (e.g. ext2) because of
write_supers() being called before the sync_inodes(1).
Change the ordering of calls in do_sync() - this requires a new function
sync_blockdevs() to preserve the property that block devices are always synced
after write_super() / sync_fs() call.
The same issue is fixed in __fsync_super() function used on umount /
remount read-only.
[AV: build fixes]
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Remove the unused s_async_list in the superblock, a leftover of the
broken async inode deletion code that leaked into mainline. Having this
in the middle of the sync/unmount path is not helpful for the following
cleanups.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This patch speeds up lmbench lat_mmap test by about another 2% after the
first patch.
Before:
avg = 462.286
std = 5.46106
After:
avg = 453.12
std = 9.58257
(50 runs of each, stddev gives a reasonable confidence)
It does this by introducing mnt_clone_write, which avoids some heavyweight
operations of mnt_want_write if called on a vfsmount which we know already
has a write count; and mnt_want_write_file, which can call mnt_clone_write
if the file is open for write.
After these two patches, mnt_want_write and mnt_drop_write go from 7% on
the profile down to 1.3% (including mnt_clone_write).
[AV: mnt_want_write_file() should take file alone and derive mnt from it;
not only all callers have that form, but that's the only mnt about which
we know that it's already held for write if file is opened for write]
Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This patch speeds up lmbench lat_mmap test by about 8%. lat_mmap is set up
basically to mmap a 64MB file on tmpfs, fault in its pages, then unmap it.
A microbenchmark yes, but it exercises some important paths in the mm.
Before:
avg = 501.9
std = 14.7773
After:
avg = 462.286
std = 5.46106
(50 runs of each, stddev gives a reasonable confidence, but there is quite
a bit of variation there still)
It does this by removing the complex per-cpu locking and counter-cache and
replaces it with a percpu counter in struct vfsmount. This makes the code
much simpler, and avoids spinlocks (although the msync is still pretty
costly, unfortunately). It results in about 900 bytes smaller code too. It
does increase the size of a vfsmount, however.
It should also give a speedup on large systems if CPUs are frequently operating
on different mounts (because the existing scheme has to operate on an atomic in
the struct vfsmount when switching between mounts). But I'm most interested in
the single threaded path performance for the moment.
[AV: minor cleanup]
Cc: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro [Tue, 7 Apr 2009 16:21:18 +0000 (12:21 -0400)]
Don't bother with check_mnt() in do_add_mount() on shrinkable ones
These guys are what we add as submounts; checks for "is that attached in
our namespace" are simply irrelevant for those and counterproductive for
use of private vfsmount trees a-la what NFS folks want.
Al Viro [Tue, 7 Apr 2009 15:49:53 +0000 (11:49 -0400)]
Cache root in nameidata
New field: nd->root. When pathname resolution wants to know the root,
check if nd->root.mnt is non-NULL; use nd->root if it is, otherwise
copy current->fs->root there. After path_walk() is finished, we check
if we'd got a cached value in nd->root and drop it. Before calling
path_walk() we should either set nd->root.mnt to NULL *or* copy (and
pin down) some path to nd->root. In the latter case we won't be
looking at current->fs->root at all.
Al Viro [Tue, 7 Apr 2009 15:44:16 +0000 (11:44 -0400)]
Preparations to caching root in path_walk()
Split do_path_lookup(), opencode the call from do_filp_open()
do_filp_open() is the only caller of do_path_lookup() that
cares about root afterwards (it keeps resolving symlinks on
O_CREAT path after it'd done LOOKUP_PARENT walk). So when
we start caching fs->root in path_walk(), it'll need a different
treatment.
* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (23 commits)
Btrfs: fix extent_buffer leak during tree log replay
Btrfs: fix oops when btrfs_inherit_iflags called with a NULL dir
Btrfs: fix -o nodatasum printk spelling
Btrfs: check duplicate backrefs for both data and metadata
Btrfs: init worker struct fields before kthread-run
Btrfs: pin buffers during write_dev_supers
Btrfs: avoid races between super writeout and device list updates
Fix btrfs when ACLs are configured out
Btrfs: fdatasync should skip metadata writeout
Btrfs: remove crc32c.h and use libcrc32c directly.
Btrfs: implement FS_IOC_GETFLAGS/SETFLAGS/GETVERSION
Btrfs: autodetect SSD devices
Btrfs: add mount -o ssd_spread to spread allocations out
Btrfs: avoid allocation clusters that are too spread out
Btrfs: Add mount -o nossd
Btrfs: avoid IO stalls behind congested devices in a multi-device FS
Btrfs: don't allow WRITE_SYNC bios to starve out regular writes
Btrfs: fix metadata dirty throttling limits
Btrfs: reduce mount -o ssd CPU usage
Btrfs: balance btree more often
...
Linus Torvalds [Thu, 11 Jun 2009 21:22:55 +0000 (14:22 -0700)]
Merge branch 'for-linus' of git://git.infradead.org/users/eparis/notify
* 'for-linus' of git://git.infradead.org/users/eparis/notify:
fsnotify: allow groups to set freeing_mark to null
inotify/dnotify: should_send_event shouldn't match on FS_EVENT_ON_CHILD
dnotify: do not bother to lock entry->lock when reading mask
dnotify: do not use ?true:false when assigning to a bool
fsnotify: move events should indicate the event was on a child
inotify: reimplement inotify using fsnotify
fsnotify: handle filesystem unmounts with fsnotify marks
fsnotify: fsnotify marks on inodes pin them in core
fsnotify: allow groups to add private data to events
fsnotify: add correlations between events
fsnotify: include pathnames with entries when possible
fsnotify: generic notification queue and waitq
dnotify: reimplement dnotify using fsnotify
fsnotify: parent event notification
fsnotify: add marks to inodes so groups can interpret how to handle those inodes
fsnotify: unified filesystem notification backend
Linus Torvalds [Thu, 11 Jun 2009 21:15:57 +0000 (14:15 -0700)]
Merge branch 'for-linus' of git://linux-arm.org/linux-2.6
* 'for-linus' of git://linux-arm.org/linux-2.6:
kmemleak: Add the corresponding MAINTAINERS entry
kmemleak: Simple testing module for kmemleak
kmemleak: Enable the building of the memory leak detector
kmemleak: Remove some of the kmemleak false positives
kmemleak: Add modules support
kmemleak: Add kmemleak_alloc callback from alloc_large_system_hash
kmemleak: Add the vmalloc memory allocation/freeing hooks
kmemleak: Add the slub memory allocation/freeing hooks
kmemleak: Add the slob memory allocation/freeing hooks
kmemleak: Add the slab memory allocation/freeing hooks
kmemleak: Add documentation on the memory leak detector
kmemleak: Add the base support
Linus Torvalds [Thu, 11 Jun 2009 21:01:07 +0000 (14:01 -0700)]
Merge branch 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (574 commits)
perf_counter: Turn off by default
perf_counter: Add counter->id to the throttle event
perf_counter: Better align code
perf_counter: Rename L2 to LL cache
perf_counter: Standardize event names
perf_counter: Rename enums
perf_counter tools: Clean up u64 usage
perf_counter: Rename perf_counter_limit sysctl
perf_counter: More paranoia settings
perf_counter: powerpc: Implement generalized cache events for POWER processors
perf_counters: powerpc: Add support for POWER7 processors
perf_counter: Accurate period data
perf_counter: Introduce struct for sample data
perf_counter tools: Normalize data using per sample period data
perf_counter: Annotate exit ctx recursion
perf_counter tools: Propagate signals properly
perf_counter tools: Small frequency related fixes
perf_counter: More aggressive frequency adjustment
perf_counter/x86: Fix the model number of Intel Core2 processors
perf_counter, x86: Correct some event and umask values for Intel processors
...
Linus Torvalds [Thu, 11 Jun 2009 19:25:06 +0000 (12:25 -0700)]
Merge branch 'topic/slab/earlyboot' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6
* 'topic/slab/earlyboot' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
vgacon: use slab allocator instead of the bootmem allocator
irq: use kcalloc() instead of the bootmem allocator
sched: use slab in cpupri_init()
sched: use alloc_cpumask_var() instead of alloc_bootmem_cpumask_var()
memcg: don't use bootmem allocator in setup code
irq/cpumask: make memoryless node zero happy
x86: remove some alloc_bootmem_cpumask_var calling
vt: use kzalloc() instead of the bootmem allocator
sched: use kzalloc() instead of the bootmem allocator
init: introduce mm_init()
vmalloc: use kzalloc() instead of alloc_bootmem()
slab: setup allocators earlier in the boot sequence
bootmem: fix slab fallback on numa
bootmem: use slab if bootmem is no longer available
Eric Paris [Thu, 11 Jun 2009 15:09:48 +0000 (11:09 -0400)]
fsnotify: allow groups to set freeing_mark to null
Most fsnotify listeners (all but inotify) do not care about marks being
freed. Allow groups to set freeing_mark to null and do not call any
function if it is set that way.
Eric Paris [Thu, 11 Jun 2009 15:09:47 +0000 (11:09 -0400)]
inotify/dnotify: should_send_event shouldn't match on FS_EVENT_ON_CHILD
inotify and dnotify will both indicate that they want any event which came
from a child inode. The fix is to mask off FS_EVENT_ON_CHILD when deciding
if inotify or dnotify is interested in a given event.
Eric Paris [Thu, 11 Jun 2009 15:09:47 +0000 (11:09 -0400)]
dnotify: do not bother to lock entry->lock when reading mask
entry->lock is needed to make sure entry->mask does not change while
manipulating it. In dnotify_should_send_event() we don't care if we get an
old or a new mask value out of this entry so there is no point it taking
the lock.
Eric Paris [Thu, 11 Jun 2009 15:09:47 +0000 (11:09 -0400)]
fsnotify: move events should indicate the event was on a child
fsnotify tells its listeners explicitly when an event happened on the given
inode verses on the child of the given inode. (see __fsnotify_parent)
However, the semantics of fsnotify_move() are such that we deliver events
directly to the two parent directories in question (old_dir and new_dir)
directly without using the __fsnotify_parent() call. fsnotify should be
adding FS_EVENT_ON_CHILD for the notifications to these parents.
Eric Paris [Thu, 21 May 2009 21:02:01 +0000 (17:02 -0400)]
inotify: reimplement inotify using fsnotify
Reimplement inotify_user using fsnotify. This should be feature for feature
exactly the same as the original inotify_user. This does not make any changes
to the in kernel inotify feature used by audit. Those patches (and the eventual
removal of in kernel inotify) will come after the new inotify_user proves to be
working correctly.
Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
Eric Paris [Thu, 21 May 2009 21:01:58 +0000 (17:01 -0400)]
fsnotify: handle filesystem unmounts with fsnotify marks
When an fs is unmounted with an fsnotify mark entry attached to one of its
inodes we need to destroy that mark entry and we also (like inotify) send
an unmount event.
Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
Eric Paris [Thu, 21 May 2009 21:01:54 +0000 (17:01 -0400)]
fsnotify: fsnotify marks on inodes pin them in core
This patch pins any inodes with an fsnotify mark in core. The idea is that
as soon as the mark is removed from the inode->fsnotify_mark_entries list
the inode will be iput. In reality is doesn't quite work exactly this way.
The igrab will happen when the mark is added to an inode, but the iput will
happen when the inode pointer is NULL'd inside the mark.
It's possible that 2 racing things will try to remove the mark from
different directions. One may try to remove the mark because of an
explicit request and one might try to remove it because the inode was
deleted. It's possible that the removal because of inode deletion will
remove the mark from the inode's list, but the removal by explicit request
will actually set entry->inode == NULL; and call the iput. This is safe.
Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
Eric Paris [Thu, 21 May 2009 21:01:50 +0000 (17:01 -0400)]
fsnotify: allow groups to add private data to events
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>
Eric Paris [Thu, 21 May 2009 21:01:47 +0000 (17:01 -0400)]
fsnotify: add correlations between events
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>
Eric Paris [Thu, 21 May 2009 21:01:43 +0000 (17:01 -0400)]
fsnotify: include pathnames with entries when possible
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>
Eric Paris [Thu, 21 May 2009 21:01:37 +0000 (17:01 -0400)]
fsnotify: generic notification queue and waitq
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>
Eric Paris [Thu, 21 May 2009 21:01:29 +0000 (17:01 -0400)]
fsnotify: parent event notification
inotify and dnotify both use a similar parent notification mechanism. We
add a generic parent notification mechanism to fsnotify for both of these
to use. This new machanism also adds the dentry flag optimization which
exists for inotify to dnotify.
Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de>
Eric Paris [Thu, 21 May 2009 21:01:26 +0000 (17:01 -0400)]
fsnotify: add marks to inodes so groups can interpret how to handle those inodes
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>
Eric Paris [Thu, 21 May 2009 21:01:20 +0000 (17:01 -0400)]
fsnotify: unified filesystem notification backend
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>
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