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* simplify checks for I_CLEAR/I_FREEINGAl Viro2010-08-091-4/+4
| | | | | | | | | | | | | | add I_CLEAR instead of replacing I_FREEING with it. I_CLEAR is equivalent to I_FREEING for almost all code looking at either; it's there to keep track of having called clear_inode() exactly once per inode lifetime, at some point after having set I_FREEING. I_CLEAR and I_FREEING never get set at the same time with the current code, so we can switch to setting i_flags to I_FREEING | I_CLEAR instead of I_CLEAR without loss of information. As the result of such change, checks become simpler and the amount of code that needs to know about I_CLEAR shrinks a lot. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* writeback: simplify the write back thread queueChristoph Hellwig2010-07-061-184/+69
| | | | | | | | | | | | | | | | | | First remove items from work_list as soon as we start working on them. This means we don't have to track any pending or visited state and can get rid of all the RCU magic freeing the work items - we can simply free them once the operation has finished. Second use a real completion for tracking synchronous requests - if the caller sets the completion pointer we complete it, otherwise use it as a boolean indicator that we can free the work item directly. Third unify struct wb_writeback_args and struct bdi_work into a single data structure, wb_writeback_work. Previous we set all parameters into a struct wb_writeback_args, copied it into struct bdi_work, copied it again on the stack to use it there. Instead of just allocate one structure dynamically or on the stack and use it all the way through the stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: split writeback_inodes_wbChristoph Hellwig2010-07-061-36/+46
| | | | | | | | | | | | | The case where we have a superblock doesn't require a loop here as we scan over all inodes in writeback_sb_inodes. Split it out into a separate helper to make the code simpler. This also allows to get rid of the sb member in struct writeback_control, which was rather out of place there. Also update the comments in writeback_sb_inodes that explain the handling of inodes from wrong superblocks. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: remove writeback_inodes_wbcChristoph Hellwig2010-07-061-10/+2
| | | | | | | | | This was just an odd wrapper around writeback_inodes_wb. Removing this also allows to get rid of the bdi member of struct writeback_control which was rather out of place there. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* fs-writeback: fix kernel-doc warningsRandy Dunlap2010-07-011-1/+1
| | | | | | | | | | | Fix kernel-doc to match the function's changed args. Warning(fs/fs-writeback.c:190): No description found for parameter 'args' Warning(fs/fs-writeback.c:190): Excess function parameter 'sb' description in 'bdi_queue_work_onstack' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: fix pin_sb_for_writebackChristoph Hellwig2010-06-111-8/+10
| | | | | | | | | | We need to check for s_instances to make sure we don't bother working against a filesystem that is beeing unmounted, and we need to call put_super to make sure a superblock is freed when we race against umount. Also no need to keep sb_lock after we got a reference on it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: add missing requeue_io in writeback_inodes_wbChristoph Hellwig2010-06-111-1/+3
| | | | | | | | | | In "writeback: fix writeback_inodes_wb from writeback_inodes_sb" I accidentally removed the requeue_io if we need to skip a superblock because we can't pin it. Add it back, otherwise we're getting spurious lockups after multiple xfstests runs. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: simplify and split bdi_start_writebackChristoph Hellwig2010-06-111-12/+20
| | | | | | | | | bdi_start_writeback now never gets a superblock passed, so we can just remove that case. And to further untangle the code and flatten the call stack split it into two trivial helpers for it's two callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: simplify wakeup_flusher_threadsChristoph Hellwig2010-06-111-21/+11
| | | | | | | | bdi_writeback_all only has one caller, so fold it to simplify the code and flatten the call stack. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: fix writeback_inodes_wb from writeback_inodes_sbChristoph Hellwig2010-06-111-38/+23
| | | | | | | | | | | | | When we call writeback_inodes_wb from writeback_inodes_sb we always have s_umount held, which currently makes the whole operation a no-op. But if we are called to write out inodes for a specific superblock we always have s_umount held, so replace the incorrect logic checking for WB_SYNC_ALL which only worked by coincidence with the proper check for an explicit superblock argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: enforce s_umount locking in writeback_inodes_sbChristoph Hellwig2010-06-111-0/+6
| | | | | | | | | | Make sure that not only sync_filesystem but all callers of writeback_inodes_sb have the superblock protected against remount. As-is this disables all functionality for these callers, but the next patch relies on this locking to fix writeback_inodes_sb for sync_filesystem. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: queue work on stack in writeback_inodes_sbChristoph Hellwig2010-06-111-19/+21
| | | | | | | | | | If we want to rely on s_umount in the caller we need to wait for completion of the I/O submission before returning to the caller. Refactor bdi_sync_writeback into a bdi_queue_work_onstack helper and use it for this case. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* writeback: fix writeback completion notificationsChristoph Hellwig2010-06-111-50/+15
| | | | | | | | | | | | | | | | | | | | | | | The code dealing with bdi_work->state and completion of a bdi_work is a major mess currently. This patch makes sure we directly use one set of flags to deal with it, and use it consistently, which means: - always notify about completion from the rcu callback. We only ever wait for it from on-stack callers, so this simplification does not even cause a theoretical slowdown currently. It also makes sure we don't miss out on the notification if we ever add other callers to wait for it. - make earlier completion notification depending on the on-stack allocation, not the sync mode. If we introduce new callers that want to do WB_SYNC_NONE writeback from on-stack callers this will be nessecary. Also rename bdi_wait_on_work_clear to bdi_wait_on_work_done and inline a few small functions into their only caller to make the code understandable. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'master' into for-linusJens Axboe2010-06-011-2/+2
|\ | | | | | | | | | | | | Conflicts: fs/pipe.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * fs-writeback: check sync bit earlier in inode_wait_for_writebackRichard Kennedy2010-05-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When wb_writeback() hasn't written anything it will re-acquire the inode lock before calling inode_wait_for_writeback. This change tests the sync bit first so that is doesn't need to drop & re-acquire the lock if the inode became available while wb_writeback() was waiting to get the lock. Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Revert "writeback: fix WB_SYNC_NONE writeback from umount"Jens Axboe2010-06-011-37/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | Revert "writeback: ensure that WB_SYNC_NONE writeback with sb pinned is sync"Jens Axboe2010-06-011-11/+5
|/ | | | | | | | | This reverts commit 7c8a3554c683f512dbcee26faedb42e4c05f12fa. We are investigating a hang associated with the WB_SYNC_NONE changes, so revert them for now. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-05-211-4/+4
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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)
| * fs-writeback.c: bitfields should be unsignedH Hartley Sweeten2010-05-211-3/+3
| | | | | | | | | | | | | | | | | | This fixes sparse noise: error: dubious one-bit signed bitfield Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | writeback: bdi_writeback_task() must set task state before calling schedule()Jens Axboe2010-05-211-2/+7
| | | | | | | | | | | | | | | | | | | | Calling schedule without setting the task state to non-running will return immediately, so ensure that we set it properly and check our sleep conditions after doing so. This is a fixup for commit 69b62d01. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | writeback: ensure that WB_SYNC_NONE writeback with sb pinned is syncJens Axboe2010-05-211-5/+11
| | | | | | | | | | | | | | | | | | | | Even if the writeout itself isn't a data integrity operation, we need to ensure that the caller doesn't drop the sb umount sem before we have actually done the writeback. This is a fixup for commit e913fc82. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | writeback: Update dirty flags in two stepsDmitry Monakhov2010-05-171-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | Filesystems with delalloc support may dirty inode during writepages. As result inode will have dirty metadata flags even after write_inode. In fact we have two dedicated functions for proper data and metadata writeback. It is reasonable to separate flags updates in two stages. https://bugzilla.kernel.org/show_bug.cgi?id=15906 Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | writeback: fix WB_SYNC_NONE writeback from umountJens Axboe2010-05-171-11/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* | writeback: disable periodic old data writeback for !dirty_writeback_centisecsJens Axboe2010-05-171-2/+12
|/ | | | | | | | | | | Prior to 2.6.32, setting /proc/sys/vm/dirty_writeback_centisecs disabled periodic dirty writeback from kupdate. This got broken and now causes excessive sys CPU usage if set to zero, as we'll keep beating on schedule(). Cc: stable@kernel.org Reported-by: Justin Maggard <jmaggard10@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2010-04-091-60/+73
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/linux-2.6-block: (34 commits) cfq-iosched: Fix the incorrect timeslice accounting with forced_dispatch loop: Update mtime when writing using aops block: expose the statistics in blkio.time and blkio.sectors for the root cgroup backing-dev: Handle class_create() failure Block: Fix block/elevator.c elevator_get() off-by-one error drbd: lc_element_by_index() never returns NULL cciss: unlock on error path cfq-iosched: Do not merge queues of BE and IDLE classes cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging i2o: Remove the dangerous kobj_to_i2o_device macro block: remove 16 bytes of padding from struct request on 64bits cfq-iosched: fix a kbuild regression block: make CONFIG_BLK_CGROUP visible Remove GENHD_FL_DRIVERFS block: Export max number of segments and max segment size in sysfs block: Finalize conversion of block limits functions block: Fix overrun in lcm() and move it to lib vfs: improve writeback_inodes_wb() paride: fix off-by-one test drbd: fix al-to-on-disk-bitmap for 4k logical_block_size ...
| * vfs: improve writeback_inodes_wb()Edward Shishkin2010-03-121-60/+73
| | | | | | | | | | | | | | | | | | | | | | | | Do not pin/unpin superblock for every inode in writeback_inodes_wb(), pin it for the whole group of inodes which belong to the same superblock and call writeback_sb_inodes() handler for them. Signed-off-by: Edward Shishkin <edward.shishkin@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-301-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* pass writeback_control to ->write_inodeChristoph Hellwig2010-03-051-6/+5
| | | | | | | | | | This gives the filesystem more information about the writeback that is happening. Trond requested this for the NFS unstable write handling, and other filesystems might benefit from this too by beeing able to distinguish between the different callers in more detail. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* make sure data is on disk before calling ->write_inodeChristoph Hellwig2010-03-051-5/+10
| | | | | | | | | | | | | | | | | Similar to the fsync issue fixed a while ago in commit 2daea67e966dc0c42067ebea015ddac6834cef88 we need to write for data to actually hit the disk before writing out the metadata to guarantee data integrity for filesystems that modify the inode in the data I/O completion path. Currently XFS and NFS handle this manually, and AFS has a write_inode method that does nothing but waiting for data, while others are possibly missing out on this. Fortunately this change has a lot less impact than the fsync change as none of the write_inode methods starts data writeout of any form by itself. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* writeback: add missing kernel-doc notationJaswinder Singh Rajput2010-01-021-0/+1
| | | | | | | | | | | | | | Fix the following htmldocs warning: Warning(fs/fs-writeback.c:255): No description found for parameter 'sb' Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs-writeback: Add helper function to start writeback if idleEric Sandeen2009-12-231-0/+17
| | | | | | | | | | | | | | | | | | | ext4, at least, would like to start pushing on writeback if it starts to get close to ENOSPC when reserving worst-case blocks for delalloc writes. Writing out delalloc data will convert those worst-case predictions into usually smaller actual usage, freeing up space before we hit ENOSPC based on this speculation. Thanks to Jens for the suggestion for the helper function, & the naming help. I've made the helper return status on whether writeback was started even though I don't plan to use it in the ext4 patch; it seems like it would be potentially useful to test this in some cases. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Acked-by: Jan Kara <jack@suse.cz>
* writeback: remove unused nonblocking and congestion checksWu Fengguang2009-12-031-9/+0
| | | | | | | | | | | | | | | | | | | - no one is calling wb_writeback and write_cache_pages with wbc.nonblocking=1 any more - lumpy pageout will want to do nonblocking writeback without the congestion wait So remove the congestion checks as suggested by Chris. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Evgeniy Polyakov <zbr@ioremap.net> Cc: Alex Elder <aelder@sgi.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: introduce wbc.for_backgroundWu Fengguang2009-12-031-0/+1
| | | | | | | | | | It will lower the flush priority for NFS, and maybe more in future. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: remove the always false bdi_cap_writeback_dirty() testWu Fengguang2009-12-031-18/+0
| | | | | | | | | | | This is dead code because no bdi flush thread will be started for !bdi_cap_writeback_dirty bdi. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: pass in super_block to bdi_start_writeback()Jens Axboe2009-09-261-2/+4
| | | | | | | | | | | Sometimes we only want to write pages from a specific super_block, so allow that to be passed in. This fixes a problem with commit 56a131dcf7ed36c3c6e36bea448b674ea85ed5bb causing writeback on all super_blocks on a bdi, where we only really want to sync a specific sb from writeback_inodes_sb(). Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: writeback_inodes_sb() should use bdi_start_writeback()Jens Axboe2009-09-251-1/+1
| | | | | | | Pointless to iterate other devices looking for a super, when we have a bdi mapping. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: don't delay inodes redirtied by a fast dirtierWu Fengguang2009-09-251-3/+9
| | | | | | | | | | | | | | | | | | | | | | | | | Debug traces show that in per-bdi writeback, the inode under writeback almost always get redirtied by a busy dirtier. We used to call redirty_tail() in this case, which could delay inode for up to 30s. This is unacceptable because it now happens so frequently for plain cp/dd, that the accumulated delays could make writeback of big files very slow. So let's distinguish between data redirty and metadata only redirty. The first one is caused by a busy dirtier, while the latter one could happen in XFS, NFS, etc. when they are doing delalloc or updating isize. The inode being busy dirtied will now be requeued for next io, while the inode being redirtied by fs will continue to be delayed to avoid repeated IO. CC: Jan Kara <jack@suse.cz> CC: Theodore Ts'o <tytso@mit.edu> CC: Dave Chinner <david@fromorbit.com> CC: Chris Mason <chris.mason@oracle.com> CC: Christoph Hellwig <hch@infradead.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: make the super_block pinning more efficientJens Axboe2009-09-251-17/+29
| | | | | | | | | | Currently we pin the inode->i_sb for every single inode. This increases cache traffic on sb->s_umount sem. Lets instead cache the inode sb pin state and keep the super_block pinned for as long as keep writing out inodes from the same super_block. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: don't resort for a single super_block in move_expired_inodes()Jens Axboe2009-09-251-1/+11
| | | | | | | If we only moved inodes from a single super_block to the temporary list, there's no point in doing a resort for multiple super_blocks. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: move inodes from one super_block togetherShaohua Li2009-09-251-3/+18
| | | | | | | | | | | | | | | | | | | __mark_inode_dirty adds inode to wb dirty list in random order. If a disk has several partitions, writeback might keep spindle moving between partitions. To reduce the move, better write big chunk of one partition and then move to another. Inodes from one fs usually are in one partion, so idealy move indoes from one fs together should reduce spindle move. This patch tries to address this. Before per-bdi writeback is added, the behavior is write indoes from one fs first and then another, so the patch restores previous behavior. The loop in the patch is a bit ugly, should we add a dirty list for each superblock in bdi_writeback? Test in a two partition disk with attached fio script shows about 3% ~ 6% improvement. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: get rid to incorrect references to pdflush in commentsJens Axboe2009-09-251-4/+1
| | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: improve readability of the wb_writeback() continue/break logicJens Axboe2009-09-251-20/+23
| | | | | | | And throw some comments in there, too. Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: cleanup writeback_single_inode()Wu Fengguang2009-09-251-8/+7
| | | | | | | | | | | Make the if-else straight in writeback_single_inode(). No behavior change. Cc: Jan Kara <jack@suse.cz> Cc: Michael Rubin <mrubin@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: kupdate writeback shall not stop when more io is possibleWu Fengguang2009-09-251-2/+2
| | | | | | | | | | | | | | | | | Fix the kupdate case, which disregards wbc.more_io and stop writeback prematurely even when there are more inodes to be synced. wbc.more_io should always be respected. Also remove the pages_skipped check. It will set when some page(s) of some inode(s) cannot be written for now. Such inodes will be delayed for a while. This variable has nothing to do with whether there are other writeable inodes. CC: Jan Kara <jack@suse.cz> CC: Dave Chinner <david@fromorbit.com> CC: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: stop background writeback when below background thresholdWu Fengguang2009-09-251-11/+17
| | | | | | | | | | | | | | | Treat bdi_start_writeback(0) as a special request to do background write, and stop such work when we are below the background dirty threshold. Also simplify the (nr_pages <= 0) checks. Since we already pass in nr_pages=LONG_MAX for WB_SYNC_ALL and background writes, we don't need to worry about it being decreased to zero. Reported-by: Richard Kennedy <richard@rsk.demon.co.uk> CC: Jan Kara <jack@suse.cz> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* fs: Fix busyloop in wb_writeback()Jan Kara2009-09-251-1/+18
| | | | | | | | | | | | If all inodes are under writeback (e.g. in case when there's only one inode with dirty pages), wb_writeback() with WB_SYNC_NONE work basically degrades to busylooping until I_SYNC flags of the inode is cleared. Fix the problem by waiting on I_SYNC flags of an inode on b_more_io list in case we failed to write anything. Tested-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: fix possible bdi writeback refcounting problemNick Piggin2009-09-161-7/+6
| | | | | | | | | | | | | | | wb_clear_pending AFAIKS should not be called after the item has been put on the list, except by the worker threads. It could lead to the situation where the refcount is decremented below 0 and cause lots of problems. Presumably the !wb_has_dirty_io case is not a common one, so it can be discovered when the thread wakes up to check? Also add a comment in bdi_work_clear. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: Fix bdi use after free in wb_work_complete()Nick Piggin2009-09-161-2/+3
| | | | | | | | | | By the time bdi_work_on_stack gets evaluated again in bdi_work_free, it can already have been deallocated and used for something else in the !on stack case, giving a false positive in this test and causing corruption. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: improve scalability of bdi writeback work queuesNick Piggin2009-09-161-1/+2
| | | | | | | | | If you're going to do an atomic RMW on each list entry, there's not much point in all the RCU complexities of the list walking. This is only going to help the multi-thread case I guess, but it doesn't hurt to do now. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* writeback: remove smp_mb(), it's not needed with list_add_tail_rcu()Nick Piggin2009-09-161-3/+3
| | | | | | | list_add_tail_rcu contains required barriers. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>