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path: root/fs/sync.c
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2012-09-26switch simple cases of fget_light to fdgetAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22vfs: Avoid unnecessary WB_SYNC_NONE writeback during sys_sync and reorder ↵Jan Kara
sync passes wakeup_flusher_threads(0) will queue work doing complete writeback for each flusher thread. Thus there is not much point in submitting another work doing full inode WB_SYNC_NONE writeback by writeback_inodes_sb(). After this change it does not make sense to call nonblocking ->sync_fs and block device flush before calling sync_inodes_sb() because wakeup_flusher_threads() is completely asynchronous and thus these functions would be called in parallel with inode writeback running which will effectively void any work they do. So we move sync_inodes_sb() call before these two functions. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22vfs: Remove unnecessary flushing of block devicesJan Kara
It is not necessary to write block devices twice. The reason why we first did flush and then proper sync is that for_each_bdev() { write_bdev() wait_for_completion() } is much slower than for_each_bdev() write_bdev() for_each_bdev() wait_for_completion() when there is bigger amount of data. But as is seen in the above, there's no real need to scan pages and submit them twice. We just need to separate the submission and waiting part. This patch does that. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22vfs: Make sys_sync writeout also block device inodesJan Kara
In case block device does not have filesystem mounted on it, sys_sync will just ignore it and doesn't writeout its dirty pages. This is because writeback code avoids writing inodes from superblock without backing device and blockdev_superblock is such a superblock. Since it's unexpected that sync doesn't writeout dirty data for block devices be nice to users and change the behavior to do so. So now we iterate over all block devices on blockdev_super instead of iterating over all superblocks when syncing block devices. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22vfs: Reorder operations during sys_syncJan Kara
Change the order of operations during sync from for_each_sb { writeback_inodes_sb(); sync_fs(nowait); __sync_blockdev(nowait); } for_each_sb { sync_inodes_sb(); sync_fs(wait); __sync_blockdev(wait); } to for_each_sb writeback_inodes_sb(); for_each_sb sync_fs(nowait); for_each_sb __sync_blockdev(nowait); for_each_sb sync_inodes_sb(); for_each_sb sync_fs(wait); for_each_sb __sync_blockdev(wait); This is a preparation for the following patches in this series. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22quota: Move quota syncing to ->sync_fs methodJan Kara
Since the moment writes to quota files are using block device page cache and space for quota structures is reserved at the moment they are first accessed we have no reason to sync quota before inode writeback. In fact this order is now only harmful since quota information can easily change during inode writeback (either because conversion of delayed-allocated extents or simply because of allocation of new blocks for simple filesystems not using page_mkwrite). So move syncing of quota information after writeback of inodes into ->sync_fs method. This way we do not have to use ->quota_sync callback which is primarily intended for use by quotactl syscall anyway and we get rid of calling ->sync_fs() twice unnecessarily. We skip quota syncing for OCFS2 since it does proper quota journalling in all cases (unlike ext3, ext4, and reiserfs which also support legacy non-journalled quotas) and thus there are no dirty quota structures. CC: "Theodore Ts'o" <tytso@mit.edu> CC: Joel Becker <jlbec@evilplan.org> CC: reiserfs-devel@vger.kernel.org Acked-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Dave Kleikamp <shaggy@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22quota: Split dquot_quota_sync() to writeback and cache flushing partJan Kara
Split off part of dquot_quota_sync() which writes dquots into a quota file to a separate function. In the next patch we will use the function from filesystems and we do not want to abuse ->quota_sync quotactl callback more than necessary. Acked-by: Steven Whitehouse <swhiteho@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-07-22vfs: Move noop_backing_dev_info check from sync into writebackJan Kara
In principle, a filesystem may want to have ->sync_fs() called during sync(1) although it does not have a bdi (i.e. s_bdi is set to noop_backing_dev_info). Only writeback code really needs bdi set to something reasonable. So move the checks where they are more logical. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-05-29switch do_fsync() to fget_light()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-02-28fs: reduce the use of module.h wherever possiblePaul Gortmaker
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map them onto including export.h -- or if the file isn't even using those, then just delete the include. Fix up any implicit include dependencies that were being masked by module.h along the way. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2012-01-03fs: move code out of buffer.cAl Viro
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export kill_bdev as well, so brd doesn't have to open code it. Reduce buffer_head.h requirement accordingly. Removed a rather large comment from invalidate_bdev, as it looked a bit obsolete to bother moving. The small comment replacing it says enough. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-10-31writeback: Add a 'reason' to wb_writeback_workCurt Wohlgemuth
This creates a new 'reason' field in a wb_writeback_work structure, which unambiguously identifies who initiates writeback activity. A 'wb_reason' enumeration has been added to writeback.h, to enumerate the possible reasons. The 'writeback_work_class' and tracepoint event class and 'writeback_queue_io' tracepoints are updated to include the symbolic 'reason' in all trace events. And the 'writeback_inodes_sbXXX' family of routines has had a wb_stats parameter added to them, so callers can specify why writeback is being started. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
2011-07-20fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlersJosef Bacik
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-24Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
2011-03-21introduce sys_syncfs to sync a single file systemSage Weil
It is frequently useful to sync a single file system, instead of all mounted file systems via sync(2): - On machines with many mounts, it is not at all uncommon for some of them to hang (e.g. unresponsive NFS server). sync(2) will get stuck on those and may never get to the one you do care about (e.g., /). - Some applications write lots of data to the file system and then want to make sure it is flushed to disk. Calling fsync(2) on each file introduces unnecessary ordering constraints that result in a large amount of sub-optimal writeback/flush/commit behavior by the file system. There are currently two ways (that I know of) to sync a single super_block: - BLKFLSBUF ioctl on the block device: That also invalidates the bdev mapping, which isn't usually desirable, and doesn't work for non-block file systems. - 'mount -o remount,rw' will call sync_filesystem as an artifact of the current implemention. Relying on this little-known side effect for something like data safety sounds foolish. Both of these approaches require root privileges, which some applications do not have (nor should they need?) given that sync(2) is an unprivileged operation. This patch introduces a new system call syncfs(2) that takes an fd and syncs only the file system it references. Maybe someday we can $ sync /some/path and not get sync: ignoring all arguments The syscall is motivated by comments by Al and Christoph at the last LSF. syncfs(2) seems like an appropriate name given statfs(2). A similar ioctl was also proposed a while back, see http://marc.info/?l=linux-fsdevel&m=127970513829285&w=2 Signed-off-by: Sage Weil <sage@newdream.net> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-03-17fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going awayJens Axboe
We don't have proper reference counting for this yet, so we run into cases where the device is pulled and we OOPS on flushing the fs data. This happens even though the dirty inodes have already been migrated to the default_backing_dev_info. Reported-by: Torsten Hilbrich <torsten.hilbrich@secunet.com> Tested-by: Torsten Hilbrich <torsten.hilbrich@secunet.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-09get rid of file_fsync()Al Viro
Copy and simplify in the only two users remaining. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-06-01Merge branch 'master' into for-linusJens Axboe
Conflicts: fs/pipe.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-06-01Revert "writeback: fix WB_SYNC_NONE writeback from umount"Jens Axboe
This reverts commit e913fc825dc685a444cb4c1d0f9d32f372f59861. We are investigating a hang associated with the WB_SYNC_NONE changes, so revert them for now. Conflicts: fs/fs-writeback.c mm/page-writeback.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-05-27drop unused dentry argument to ->fsyncChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (69 commits) fix handling of offsets in cris eeprom.c, get rid of fake on-stack files get rid of home-grown mutex in cris eeprom.c switch ecryptfs_write() to struct inode *, kill on-stack fake files switch ecryptfs_get_locked_page() to struct inode * simplify access to ecryptfs inodes in ->readpage() and friends AFS: Don't put struct file on the stack Ban ecryptfs over ecryptfs logfs: replace inode uid,gid,mode initialization with helper function ufs: replace inode uid,gid,mode initialization with helper function udf: replace inode uid,gid,mode init with helper ubifs: replace inode uid,gid,mode initialization with helper function sysv: replace inode uid,gid,mode initialization with helper function reiserfs: replace inode uid,gid,mode initialization with helper function ramfs: replace inode uid,gid,mode initialization with helper function omfs: replace inode uid,gid,mode initialization with helper function bfs: replace inode uid,gid,mode initialization with helper function ocfs2: replace inode uid,gid,mode initialization with helper function nilfs2: replace inode uid,gid,mode initialization with helper function minix: replace inode uid,gid,mode init with helper ext4: replace inode uid,gid,mode init with helper ... Trivial conflict in fs/fs-writeback.c (mark bitfields unsigned)
2010-05-21sanitize vfs_fsync calling conventionsChristoph Hellwig
Now that the last user passing a NULL file pointer is gone we can remove the redundant dentry argument and associated hacks inside vfs_fsynmc_range. The next step will be removig the dentry argument from ->fsync, but given the luck with the last round of method prototype changes I'd rather defer this until after the main merge window. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21new helper: iterate_supers()Al Viro
... and switch the simple "loop over superblocks and do something" loops to it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21get rid of restarts in sync_filesystems()Al Viro
At the same time we can kill s_need_restart and local mutex in there. __put_super() made public for a while; will be gone later. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-21Leave superblocks on s_list until the endAl Viro
We used to remove from s_list and s_instances at the same time. So let's *not* do the former and skip superblocks that have empty s_instances in the loops over s_list. The next step, of course, will be to get rid of rescan logics in those loops. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-17writeback: fix WB_SYNC_NONE writeback from umountJens Axboe
When umount calls sync_filesystem(), we first do a WB_SYNC_NONE writeback to kick off writeback of pending dirty inodes, then follow that up with a WB_SYNC_ALL to wait for it. Since umount already holds the sb s_umount mutex, WB_SYNC_NONE ends up doing nothing and all writeback happens as WB_SYNC_ALL. This can greatly slow down umount, since WB_SYNC_ALL writeback is a data integrity operation and thus a bigger hammer than simple WB_SYNC_NONE. For barrier aware file systems it's a lot slower. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-04-25Catch filesystems lacking s_bdiJörn Engel
noop_backing_dev_info is used only as a flag to mark filesystems that don't have any backing store, like tmpfs, procfs, spufs, etc. Signed-off-by: Joern Engel <joern@logfs.org> Changed the BUG_ON() to a WARN_ON(). Note that adding dirty inodes to the noop_backing_dev_info is not legal and will not result in them being flushed, but we already catch this condition in __mark_inode_dirty() when checking for a registered bdi. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-05quota: move code from sync_quota_sb into vfs_quota_syncChristoph Hellwig
Currenly sync_quota_sb does a lot of sync and truncate action that only applies to "VFS" style quotas and is actively harmful for the sync performance in XFS. Move it into vfs_quota_sync and add a wait parameter to ->quota_sync to tell if we need it or not. My audit of the GFS2 code says it's also not needed given the way GFS2 implements quotas, but I'd be happy if this can get a detailed review. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2009-12-17fold do_sync_file_range into sys_sync_file_rangeChristoph Hellwig
We recently go rid of all callers of do_sync_file_range as they're better served with vfs_fsync or the filemap_write_and_wait. Now that do_sync_file_range is down to a single caller fold it into it so that people don't start using it again accidentally. While at it also switch it from using __filemap_fdatawrite_range(..., WB_SYNC_ALL) to the more clear filemap_fdatawrite_range(). Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-10kill wait_on_page_writeback_rangeChristoph Hellwig
All callers really want the more logical filemap_fdatawait_range interface, so convert them to use it and merge wait_on_page_writeback_range into filemap_fdatawait_range. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2009-12-10vfs: Implement proper O_SYNC semanticsChristoph Hellwig
While Linux provided an O_SYNC flag basically since day 1, it took until Linux 2.4.0-test12pre2 to actually get it implemented for filesystems, since that day we had generic_osync_around with only minor changes and the great "For now, when the user asks for O_SYNC, we'll actually give O_DSYNC" comment. This patch intends to actually give us real O_SYNC semantics in addition to the O_DSYNC semantics. After Jan's O_SYNC patches which are required before this patch it's actually surprisingly simple, we just need to figure out when to set the datasync flag to vfs_fsync_range and when not. This patch renames the existing O_SYNC flag to O_DSYNC while keeping it's numerical value to keep binary compatibility, and adds a new real O_SYNC flag. To guarantee backwards compatiblity it is defined as expanding to both the O_DSYNC and the new additional binary flag (__O_SYNC) to make sure we are backwards-compatible when compiled against the new headers. This also means that all places that don't care about the differences can just check O_DSYNC and get the right behaviour for O_SYNC, too - only places that actuall care need to check __O_SYNC in addition. Drivers and network filesystems have been updated in a fail safe way to always do the full sync magic if O_DSYNC is set. The few places setting O_SYNC for lower layers are kept that way for now to stay failsafe. We enforce that O_DSYNC is set when __O_SYNC is set early in the open path to make sure we always get these sane options. Note that parisc really screwed up their headers as they already define a O_DSYNC that has always been a no-op. We try to repair it by using it for the new O_DSYNC and redefinining O_SYNC to send both the traditional O_SYNC numerical value _and_ the O_DSYNC one. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Grant Grundler <grundler@parisc-linux.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andreas Dilger <adilger@sun.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Kyle McMartin <kyle@mcmartin.ca> Acked-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jan Kara <jack@suse.cz>
2009-09-23fs/buffer.c: clean up EXPORT* macrosH Hartley Sweeten
According to Documentation/CodingStyle the EXPORT* macro should follow immediately after the closing function brace line. Also, mark_buffer_async_write_endio() and do_thaw_all() are not used elsewhere so they should be marked as static. In addition, file_fsync() is actually in fs/sync.c so move the EXPORT* to that file. Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-16fs: Assign bdi in super_blockJens Axboe
We do this automatically in get_sb_bdev() from the set_bdev_super() callback. Filesystems that have their own private backing_dev_info must assign that in ->fill_super(). Note that ->s_bdi assignment is required for proper writeback! Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14fsync: wait for data writeout completion before calling ->fsyncChristoph Hellwig
Currenly vfs_fsync(_range) first calls filemap_fdatawrite to write out the data, the calls into ->fsync to write out the metadata and then finally calls filemap_fdatawait to wait for the data I/O to complete. What sounds like a clever micro-optimization actually is nast trap for many filesystems. For many modern filesystems i_size or other inode information is only updated on I/O completion and we need to wait for I/O to finish before we can write out the metadata. For old fashionen filesystems that instanciate blocks during the actual write and also update the metadata at that point it opens up a large window were we could expose uninitialized blocks after a crash. While a few filesystems that need it already wait for the I/O to finish inside their ->fsync methods it is rather suboptimal as it is done under the i_mutex and also always for the whole file instead of just a part as we could do for O_SYNC handling. Here is a small audit of all fsync instances in the tree: - spufs_mfc_fsync: - ps3flash_fsync: - vol_cdev_fsync: - printer_fsync: - fb_deferred_io_fsync: - bad_file_fsync: - simple_sync_file: don't care - filesystems/drivers do't use the page cache or are purely in-memory. - simple_fsync: - file_fsync: - affs_file_fsync: - fat_file_fsync: - jfs_fsync: - ubifs_fsync: - reiserfs_dir_fsync: - reiserfs_sync_file: never touch pagecache themselves. We need to wait before if we do not want to expose stale data after an allocation. - afs_fsync: - fuse_fsync_common: do the waiting writeback itself in awkward ways, would benefit from proper semantics - block_fsync: Does a filemap_write_and_wait on the block device inode. Because we now have f_mapping that is the same inode we call it on in vfs_fsync. So just removing it and letting the VFS do the work in one go would be an improvement. - btrfs_sync_file: - cifs_fsync: - xfs_file_fsync: need the wait first and currently do it themselves. would benefit from doing it outside i_mutex. - coda_fsync: - ecryptfs_fsync: - exofs_file_fsync: - shm_fsync: only passes the fsync through to the lower layer - ext3_sync_file: doesn't seem to care, comments are confusing. - ext4_sync_file: would need the wait to work correctly for delalloc mode with late i_size updates. Otherwise the ext3 comment applies. currently implemens it's own writeback and wait in an odd way, could benefit from doing it properly. - gfs2_fsync: not needed for journaled data mode, but probably harmless there. Currently writes back data asynchronously itself. Needs some major audit. - hostfs_fsync: just calls fsync/datasync on the host FD. Without the wait before data might not even be inflight yet if we're unlucky. - hpfs_file_fsync: - ncp_fsync: no-ops. Dangerous before and after. - jffs2_fsync: just calls jffs2_flush_wbuf_gc, not sure how this relates to data. - nfs_fsync_dir: just increments stats, claims all directory operations are synchronous - nfs_file_fsync: only writes out data??? Looks very odd. - nilfs_sync_file: looks like it expects all data done, but not sure from the code - ntfs_dir_fsync: - ntfs_file_fsync: appear to do their own data writeback. Very convoluted code. - ocfs2_sync_file: does it's own data writeback, but no wait. probably needs the wait. - smb_fsync: according to a comment expects all pages written already, probably needs the wait before. This patch only changes vfs_fsync_range, removal of the wait in the methods that have it is left to the filesystem maintainers. Note that most filesystems really do need an audit for their fsync methods given the gems found in this very brief audit. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2009-09-14vfs: Introduce new helpers for syncing after writing to O_SYNC file or ↵Jan Kara
IS_SYNC inode Introduce new function for generic inode syncing (vfs_fsync_range) and use it from fsync() path. Introduce also new helper for syncing after a sync write (generic_write_sync) using the generic function. Use these new helpers for syncing from generic VFS functions. This makes O_SYNC writes to block devices acquire i_mutex for syncing. If we really care about this, we can make block_fsync() drop the i_mutex and reacquire it before it returns. CC: Evgeniy Polyakov <zbr@ioremap.net> CC: ocfs2-devel@oss.oracle.com CC: Joel Becker <joel.becker@oracle.com> CC: Felix Blyakher <felixb@sgi.com> CC: xfs@oss.sgi.com CC: Anton Altaparmakov <aia21@cantab.net> CC: linux-ntfs-dev@lists.sourceforge.net CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> CC: linux-ext4@vger.kernel.org CC: tytso@mit.edu Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2009-09-11writeback: switch to per-bdi threads for flushing dataJens Axboe
This gets rid of pdflush for bdi writeout and kupdated style cleaning. pdflush writeout suffers from lack of locality and also requires more threads to handle the same workload, since it has to work in a non-blocking fashion against each queue. This also introduces lumpy behaviour and potential request starvation, since pdflush can be starved for queue access if others are accessing it. A sample ffsb workload that does random writes to files is about 8% faster here on a simple SATA drive during the benchmark phase. File layout also seems a LOT more smooth in vmstat: r b swpd free buff cache si so bi bo in cs us sy id wa 0 1 0 608848 2652 375372 0 0 0 71024 604 24 1 10 48 42 0 1 0 549644 2712 433736 0 0 0 60692 505 27 1 8 48 44 1 0 0 476928 2784 505192 0 0 4 29540 553 24 0 9 53 37 0 1 0 457972 2808 524008 0 0 0 54876 331 16 0 4 38 58 0 1 0 366128 2928 614284 0 0 4 92168 710 58 0 13 53 34 0 1 0 295092 3000 684140 0 0 0 62924 572 23 0 9 53 37 0 1 0 236592 3064 741704 0 0 4 58256 523 17 0 8 48 44 0 1 0 165608 3132 811464 0 0 0 57460 560 21 0 8 54 38 0 1 0 102952 3200 873164 0 0 4 74748 540 29 1 10 48 41 0 1 0 48604 3252 926472 0 0 0 53248 469 29 0 7 47 45 where vanilla tends to fluctuate a lot in the creation phase: r b swpd free buff cache si so bi bo in cs us sy id wa 1 1 0 678716 5792 303380 0 0 0 74064 565 50 1 11 52 36 1 0 0 662488 5864 319396 0 0 4 352 302 329 0 2 47 51 0 1 0 599312 5924 381468 0 0 0 78164 516 55 0 9 51 40 0 1 0 519952 6008 459516 0 0 4 78156 622 56 1 11 52 37 1 1 0 436640 6092 541632 0 0 0 82244 622 54 0 11 48 41 0 1 0 436640 6092 541660 0 0 0 8 152 39 0 0 51 49 0 1 0 332224 6200 644252 0 0 4 102800 728 46 1 13 49 36 1 0 0 274492 6260 701056 0 0 4 12328 459 49 0 7 50 43 0 1 0 211220 6324 763356 0 0 0 106940 515 37 1 10 51 39 1 0 0 160412 6376 813468 0 0 0 8224 415 43 0 6 49 45 1 1 0 85980 6452 886556 0 0 4 113516 575 39 1 11 54 34 0 2 0 85968 6452 886620 0 0 0 1640 158 211 0 0 46 54 A 10 disk test with btrfs performs 26% faster with per-bdi flushing. A SSD based writeback test on XFS performs over 20% better as well, with the throughput being very stable around 1GB/sec, where pdflush only manages 750MB/sec and fluctuates wildly while doing so. Random buffered writes to many files behave a lot better as well, as does random mmap'ed writes. A separate thread is added to sync the super blocks. In the long term, adding sync_supers_bdi() functionality could get rid of this thread again. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11writeback: get rid of generic_sync_sb_inodes() exportJens Axboe
This adds two new exported functions: - writeback_inodes_sb(), which only attempts to writeback dirty inodes on this super_block, for WB_SYNC_NONE writeout. - sync_inodes_sb(), which writes out all dirty inodes on this super_block and also waits for the IO to complete. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-06sys_sync(): fix 16% performance regression in ffsb create_4k testZhang, Yanmin
I run many ffsb test cases on JBODs (typically 13/12 disks). Comparing with kernel 2.6.30, 2.6.31-rc1 has about 16% regression with ffsb_create_4k. The sub test case creates files continuously for 10 minitues and every file is 1MB. Bisect located below patch. 5cee5815d1564bbbd505fea86f4550f1efdb5cd0 is first bad commit commit 5cee5815d1564bbbd505fea86f4550f1efdb5cd0 Author: Jan Kara <jack@suse.cz> Date: Mon Apr 27 16:43:51 2009 +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. As a matter of fact, ffsb calls sys_sync in the end to make sure all data is flushed to disks and the flushing is counted into the result. vmstat shows ffsb is blocked when syncing for a long time. With 2.6.30, ffsb is blocked for a short time. I checked the patch and did experiments to recover the original methods. Eventually, the root cause is the patch deletes the calling to wakeup_pdflush when syncing, so only ffsb is blocked on disk I/O. wakeup_pdflush could ask pdflush to write back pages with ffsb at the same time. [akpm@linux-foundation.org: restore comment too] Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11remove the call to ->write_super in __sync_filesystemChristoph Hellwig
Now that all filesystems provide ->sync_fs methods we can change __sync_filesystem to only call ->sync_fs. This gives us a clear separation between periodic writeouts which are driven by ->write_super and data integrity syncs that go through ->sync_fs. (modulo file_fsync which is also going away) Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11->write_super lock_super pushdownChristoph Hellwig
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>
2009-06-11enforce ->sync_fs is only called for rw superblockChristoph Hellwig
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>
2009-06-11quota: Introduce writeout_quota_sb() (version 4)Jan Kara
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>
2009-06-11quota: cleanup dquota sync functions (version 4)Christoph Hellwig
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>
2009-06-11vfs: Rename fsync_super() to sync_filesystem() (version 4)Jan Kara
Rename the function so that it better describe what it really does. Also remove the unnecessary include of buffer_head.h. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11vfs: Move syncing code from super.c to sync.c (version 4)Jan Kara
Move sync_filesystems(), __fsync_super(), fsync_super() from super.c to sync.c where it fits better. [build fixes folded] Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-06-11vfs: Make sys_sync() use fsync_super() (version 4)Jan Kara
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>
2009-06-11vfs: Fix sys_sync() and fsync_super() reliability (version 4)Jan Kara
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>
2009-03-27Merge branch 'for_linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6 * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-quota-2.6: (27 commits) ext2: Zero our b_size in ext2_quota_read() trivial: fix typos/grammar errors in fs/Kconfig quota: Coding style fixes quota: Remove superfluous inlines quota: Remove uppercase aliases for quota functions. nfsd: Use lowercase names of quota functions jfs: Use lowercase names of quota functions udf: Use lowercase names of quota functions ufs: Use lowercase names of quota functions reiserfs: Use lowercase names of quota functions ext4: Use lowercase names of quota functions ext3: Use lowercase names of quota functions ext2: Use lowercase names of quota functions ramfs: Remove quota call vfs: Use lowercase names of quota functions quota: Remove dqbuf_t and other cleanups quota: Remove NODQUOT macro quota: Make global quota locks cacheline aligned quota: Move quota files into separate directory ext4: quota reservation for delayed allocation ...
2009-03-26Get rid of pdflush_operation() in emergency sync and remountJens Axboe
Opencode a cheasy approach with kevent. The idea here is that we'll add some generic delayed work infrastructure, which probably wont be based on pdflush (or maybe it will, in which case we can just add it back). This is in preparation for getting rid of pdflush completely. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>