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2021-07-20writeback: fix obtain a reference to a freeing memcg cssMuchun Song1-2/+7
[ Upstream commit 8b0ed8443ae6458786580d36b7d5f8125535c5d4 ] The caller of wb_get_create() should pin the memcg, because wb_get_create() relies on this guarantee. The rcu read lock only can guarantee that the memcg css returned by css_from_id() cannot be released, but the reference of the memcg can be zero. rcu_read_lock() memcg_css = css_from_id() wb_get_create(memcg_css) cgwb_create(memcg_css) // css_get can change the ref counter from 0 back to 1 css_get(memcg_css) rcu_read_unlock() Fix it by holding a reference to the css before calling wb_get_create(). This is not a problem I encountered in the real world. Just the result of a code review. Fixes: 682aa8e1a6a1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates") Link: https://lore.kernel.org/r/20210402091145.80635-1-songmuchun@bytedance.com Signed-off-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20block_dump: remove block_dump feature in mark_inode_dirty()zhangyi (F)1-25/+0
[ Upstream commit 12e0613715e1cf305fffafaf0e89d810d9a85cc0 ] block_dump is an old debugging interface, one of it's functions is used to print the information about who write which file on disk. If we enable block_dump through /proc/sys/vm/block_dump and turn on debug log level, we can gather information about write process name, target file name and disk from kernel message. This feature is realized in block_dump___mark_inode_dirty(), it print above information into kernel message directly when marking inode dirty, so it is noisy and can easily trigger log storm. At the same time, get the dentry refcount is also not safe, we found it will lead to deadlock on ext4 file system with data=journal mode. After tracepoints has been introduced into the kernel, we got a tracepoint in __mark_inode_dirty(), which is a better replacement of block_dump___mark_inode_dirty(). The only downside is that it only trace the inode number and not a file name, but it probably doesn't matter because the original printed file name in block_dump is not accurate in some cases, and we can still find it through the inode number and device id. So this patch delete the dirting inode part of block_dump feature. Signed-off-by: zhangyi (F) <yi.zhang@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210313030146.2882027-2-yi.zhang@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-02-13memcg: fix a crash in wb_workfn when a device disappearsTheodore Ts'o1-1/+1
[ Upstream commit 68f23b89067fdf187763e75a56087550624fdbee ] Without memcg, there is a one-to-one mapping between the bdi and bdi_writeback structures. In this world, things are fairly straightforward; the first thing bdi_unregister() does is to shutdown the bdi_writeback structure (or wb), and part of that writeback ensures that no other work queued against the wb, and that the wb is fully drained. With memcg, however, there is a one-to-many relationship between the bdi and bdi_writeback structures; that is, there are multiple wb objects which can all point to a single bdi. There is a refcount which prevents the bdi object from being released (and hence, unregistered). So in theory, the bdi_unregister() *should* only get called once its refcount goes to zero (bdi_put will drop the refcount, and when it is zero, release_bdi gets called, which calls bdi_unregister). Unfortunately, del_gendisk() in block/gen_hd.c never got the memo about the Brave New memcg World, and calls bdi_unregister directly. It does this without informing the file system, or the memcg code, or anything else. This causes the root wb associated with the bdi to be unregistered, but none of the memcg-specific wb's are shutdown. So when one of these wb's are woken up to do delayed work, they try to dereference their wb->bdi->dev to fetch the device name, but unfortunately bdi->dev is now NULL, thanks to the bdi_unregister() called by del_gendisk(). As a result, *boom*. Fortunately, it looks like the rest of the writeback path is perfectly happy with bdi->dev and bdi->owner being NULL, so the simplest fix is to create a bdi_dev_name() function which can handle bdi->dev being NULL. This also allows us to bulletproof the writeback tracepoints to prevent them from dereferencing a NULL pointer and crashing the kernel if one is tracing with memcg's enabled, and an iSCSI device dies or a USB storage stick is pulled. The most common way of triggering this will be hotremoval of a device while writeback with memcg enabled is going on. It was triggering several times a day in a heavily loaded production environment. Google Bug Id: 145475544 Link: https://lore.kernel.org/r/20191227194829.150110-1-tytso@mit.edu Link: http://lkml.kernel.org/r/20191228005211.163952-1-tytso@mit.edu Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <clm@fb.com> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-01-30fs: fix lazytime expiration handling in __writeback_single_inode()Eric Biggers1-11/+13
commit 1e249cb5b7fc09ff216aa5a12f6c302e434e88f9 upstream. When lazytime is enabled and an inode is being written due to its in-memory updated timestamps having expired, either due to a sync() or syncfs() system call or due to dirtytime_expire_interval having elapsed, the VFS needs to inform the filesystem so that the filesystem can copy the inode's timestamps out to the on-disk data structures. This is done by __writeback_single_inode() calling mark_inode_dirty_sync(), which then calls ->dirty_inode(I_DIRTY_SYNC). However, this occurs after __writeback_single_inode() has already cleared the dirty flags from ->i_state. This causes two bugs: - mark_inode_dirty_sync() redirties the inode, causing it to remain dirty. This wastefully causes the inode to be written twice. But more importantly, it breaks cases where sync_filesystem() is expected to clean dirty inodes. This includes the FS_IOC_REMOVE_ENCRYPTION_KEY ioctl (as reported at https://lore.kernel.org/r/20200306004555.GB225345@gmail.com), as well as possibly filesystem freezing (freeze_super()). - Since ->i_state doesn't contain I_DIRTY_TIME when ->dirty_inode() is called from __writeback_single_inode() for lazytime expiration, xfs_fs_dirty_inode() ignores the notification. (XFS only cares about lazytime expirations, and it assumes that i_state will contain I_DIRTY_TIME during those.) Therefore, lazy timestamps aren't persisted by sync(), syncfs(), or dirtytime_expire_interval on XFS. Fix this by moving the call to mark_inode_dirty_sync() to earlier in __writeback_single_inode(), before the dirty flags are cleared from i_state. This makes filesystems be properly notified of the timestamp expiration, and it avoids incorrectly redirtying the inode. This fixes xfstest generic/580 (which tests FS_IOC_REMOVE_ENCRYPTION_KEY) when run on ext4 or f2fs with lazytime enabled. It also fixes the new lazytime xfstest I've proposed, which reproduces the above-mentioned XFS bug (https://lore.kernel.org/r/20210105005818.92978-1-ebiggers@kernel.org). Alternatively, we could call ->dirty_inode(I_DIRTY_SYNC) directly. But due to the introduction of I_SYNC_QUEUED, mark_inode_dirty_sync() is the right thing to do because mark_inode_dirty_sync() now knows not to move the inode to a writeback list if it is currently queued for sync. Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") Cc: stable@vger.kernel.org Depends-on: 5afced3bf281 ("writeback: Avoid skipping inode writeback") Link: https://lore.kernel.org/r/20210112190253.64307-2-ebiggers@kernel.org Suggested-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-30writeback: Drop I_DIRTY_TIME_EXPIREJan Kara1-17/+11
commit 5fcd57505c002efc5823a7355e21f48dd02d5a51 upstream. The only use of I_DIRTY_TIME_EXPIRE is to detect in __writeback_single_inode() that inode got there because flush worker decided it's time to writeback the dirty inode time stamps (either because we are syncing or because of age). However we can detect this directly in __writeback_single_inode() and there's no need for the strange propagation with I_DIRTY_TIME_EXPIRE flag. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03writeback: Fix sync livelock due to b_dirty_time processingJan Kara1-27/+17
commit f9cae926f35e8230330f28c7b743ad088611a8de upstream. When we are processing writeback for sync(2), move_expired_inodes() didn't set any inode expiry value (older_than_this). This can result in writeback never completing if there's steady stream of inodes added to b_dirty_time list as writeback rechecks dirty lists after each writeback round whether there's more work to be done. Fix the problem by using sync(2) start time is inode expiry value when processing b_dirty_time list similarly as for ordinarily dirtied inodes. This requires some refactoring of older_than_this handling which simplifies the code noticeably as a bonus. Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") CC: stable@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03writeback: Avoid skipping inode writebackJan Kara1-5/+12
commit 5afced3bf28100d81fb2fe7e98918632a08feaf5 upstream. Inode's i_io_list list head is used to attach inode to several different lists - wb->{b_dirty, b_dirty_time, b_io, b_more_io}. When flush worker prepares a list of inodes to writeback e.g. for sync(2), it moves inodes to b_io list. Thus it is critical for sync(2) data integrity guarantees that inode is not requeued to any other writeback list when inode is queued for processing by flush worker. That's the reason why writeback_single_inode() does not touch i_io_list (unless the inode is completely clean) and why __mark_inode_dirty() does not touch i_io_list if I_SYNC flag is set. However there are two flaws in the current logic: 1) When inode has only I_DIRTY_TIME set but it is already queued in b_io list due to sync(2), concurrent __mark_inode_dirty(inode, I_DIRTY_SYNC) can still move inode back to b_dirty list resulting in skipping writeback of inode time stamps during sync(2). 2) When inode is on b_dirty_time list and writeback_single_inode() races with __mark_inode_dirty() like: writeback_single_inode() __mark_inode_dirty(inode, I_DIRTY_PAGES) inode->i_state |= I_SYNC __writeback_single_inode() inode->i_state |= I_DIRTY_PAGES; if (inode->i_state & I_SYNC) bail if (!(inode->i_state & I_DIRTY_ALL)) - not true so nothing done We end up with I_DIRTY_PAGES inode on b_dirty_time list and thus standard background writeback will not writeback this inode leading to possible dirty throttling stalls etc. (thanks to Martijn Coenen for this analysis). Fix these problems by tracking whether inode is queued in b_io or b_more_io lists in a new I_SYNC_QUEUED flag. When this flag is set, we know flush worker has queued inode and we should not touch i_io_list. On the other hand we also know that once flush worker is done with the inode it will requeue the inode to appropriate dirty list. When I_SYNC_QUEUED is not set, __mark_inode_dirty() can (and must) move inode to appropriate dirty list. Reported-by: Martijn Coenen <maco@android.com> Reviewed-by: Martijn Coenen <maco@android.com> Tested-by: Martijn Coenen <maco@android.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Fixes: 0ae45f63d4ef ("vfs: add support for a lazytime mount option") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-09-03writeback: Protect inode->i_io_list with inode->i_lockJan Kara1-5/+17
commit b35250c0816c7cf7d0a8de92f5fafb6a7508a708 upstream. Currently, operations on inode->i_io_list are protected by wb->list_lock. In the following patches we'll need to maintain consistency between inode->i_state and inode->i_io_list so change the code so that inode->i_lock protects also all inode's i_io_list handling. Reviewed-by: Martijn Coenen <maco@android.com> Reviewed-by: Christoph Hellwig <hch@lst.de> CC: stable@vger.kernel.org # Prerequisite for "writeback: Avoid skipping inode writeback" Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-22cgroup, blkcg: Prepare some symbols for module and !CONFIG_CGROUP usagesTejun Heo1-0/+1
commit 9b0eb69b75bccada2d341d7e7ca342f0cb1c9a6a upstream. btrfs is going to use css_put() and wbc helpers to improve cgroup writeback support. Add dummy css_get() definition and export wbc helpers to prepare for module and !CONFIG_CGROUP builds. [only backport the export of __inode_attach_wb for stable kernels - gregkh] Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-11-12cgroup,writeback: don't switch wbs immediately on dead wbs if the memcg is deadTejun Heo1-3/+6
commit 65de03e251382306a4575b1779c57c87889eee49 upstream. cgroup writeback tries to refresh the associated wb immediately if the current wb is dead. This is to avoid keeping issuing IOs on the stale wb after memcg - blkcg association has changed (ie. when blkcg got disabled / enabled higher up in the hierarchy). Unfortunately, the logic gets triggered spuriously on inodes which are associated with dead cgroups. When the logic is triggered on dead cgroups, the attempt fails only after doing quite a bit of work allocating and initializing a new wb. While c3aab9a0bd91 ("mm/filemap.c: don't initiate writeback if mapping has no dirty pages") alleviated the issue significantly as it now only triggers when the inode has dirty pages. However, the condition can still be triggered before the inode is switched to a different cgroup and the logic simply doesn't make sense. Skip the immediate switching if the associated memcg is dying. This is a simplified version of the following two patches: * https://lore.kernel.org/linux-mm/20190513183053.GA73423@dennisz-mbp/ * http://lkml.kernel.org/r/156355839560.2063.5265687291430814589.stgit@buzz Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Fixes: e8a7abf5a5bd ("writeback: disassociate inodes from dying bdi_writebacks") Acked-by: Dennis Zhou <dennis@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-07-26blkcg, writeback: dead memcgs shouldn't contribute to writeback ownership ↵Tejun Heo1-1/+7
arbitration [ Upstream commit 6631142229005e1b1c311a09efe9fb3cfdac8559 ] wbc_account_io() collects information on cgroup ownership of writeback pages to determine which cgroup should own the inode. Pages can stay associated with dead memcgs but we want to avoid attributing IOs to dead blkcgs as much as possible as the association is likely to be stale. However, currently, pages associated with dead memcgs contribute to the accounting delaying and/or confusing the arbitration. Fix it by ignoring pages associated with dead memcgs. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-22fs/writeback.c: use rcu_barrier() to wait for inflight wb switches going ↵Jiufei Xue1-3/+8
into workqueue when umount commit ec084de929e419e51bcdafaafe567d9e7d0273b7 upstream. synchronize_rcu() didn't wait for call_rcu() callbacks, so inode wb switch may not go to the workqueue after synchronize_rcu(). Thus previous scheduled switches was not finished even flushing the workqueue, which will cause a NULL pointer dereferenced followed below. VFS: Busy inodes after unmount of vdd. Self-destruct in 5 seconds. Have a nice day... BUG: unable to handle kernel NULL pointer dereference at 0000000000000278 evict+0xb3/0x180 iput+0x1b0/0x230 inode_switch_wbs_work_fn+0x3c0/0x6a0 worker_thread+0x4e/0x490 ? process_one_work+0x410/0x410 kthread+0xe6/0x100 ret_from_fork+0x39/0x50 Replace the synchronize_rcu() call with a rcu_barrier() to wait for all pending callbacks to finish. And inc isw_nr_in_flight after call_rcu() in inode_switch_wbs() to make more sense. Link: http://lkml.kernel.org/r/20190429024108.54150-1-jiufei.xue@linux.alibaba.com Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com> Acked-by: Tejun Heo <tj@kernel.org> Suggested-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-05writeback: synchronize sync(2) against cgroup writeback membership switchesTejun Heo1-2/+38
[ Upstream commit 7fc5854f8c6efae9e7624970ab49a1eac2faefb1 ] sync_inodes_sb() can race against cgwb (cgroup writeback) membership switches and fail to writeback some inodes. For example, if an inode switches to another wb while sync_inodes_sb() is in progress, the new wb might not be visible to bdi_split_work_to_wbs() at all or the inode might jump from a wb which hasn't issued writebacks yet to one which already has. This patch adds backing_dev_info->wb_switch_rwsem to synchronize cgwb switch path against sync_inodes_sb() so that sync_inodes_sb() is guaranteed to see all the target wbs and inodes can't jump wbs to escape syncing. v2: Fixed misplaced rwsem init. Spotted by Jiufei. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jiufei Xue <xuejiufei@gmail.com> Link: http://lkml.kernel.org/r/dc694ae2-f07f-61e1-7097-7c8411cee12d@gmail.com Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-05-04bdi: Fix oops in wb_workfn()Jan Kara1-1/+1
Syzbot has reported that it can hit a NULL pointer dereference in wb_workfn() due to wb->bdi->dev being NULL. This indicates that wb_workfn() was called for an already unregistered bdi which should not happen as wb_shutdown() called from bdi_unregister() should make sure all pending writeback works are completed before bdi is unregistered. Except that wb_workfn() itself can requeue the work with: mod_delayed_work(bdi_wq, &wb->dwork, 0); and if this happens while wb_shutdown() is waiting in: flush_delayed_work(&wb->dwork); the dwork can get executed after wb_shutdown() has finished and bdi_unregister() has cleared wb->bdi->dev. Make wb_workfn() use wakeup_wb() for requeueing the work which takes all the necessary precautions against racing with bdi unregistration. CC: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> CC: Tejun Heo <tj@kernel.org> Fixes: 839a8e8660b6777e7fe4e80af1a048aebe2b5977 Reported-by: syzbot <syzbot+9873874c735f2892e7e9@syzkaller.appspotmail.com> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-21writeback: safer lock nestingGreg Thelen1-3/+4
lock_page_memcg()/unlock_page_memcg() use spin_lock_irqsave/restore() if the page's memcg is undergoing move accounting, which occurs when a process leaves its memcg for a new one that has memory.move_charge_at_immigrate set. unlocked_inode_to_wb_begin,end() use spin_lock_irq/spin_unlock_irq() if the given inode is switching writeback domains. Switches occur when enough writes are issued from a new domain. This existing pattern is thus suspicious: lock_page_memcg(page); unlocked_inode_to_wb_begin(inode, &locked); ... unlocked_inode_to_wb_end(inode, locked); unlock_page_memcg(page); If both inode switch and process memcg migration are both in-flight then unlocked_inode_to_wb_end() will unconditionally enable interrupts while still holding the lock_page_memcg() irq spinlock. This suggests the possibility of deadlock if an interrupt occurs before unlock_page_memcg(). truncate __cancel_dirty_page lock_page_memcg unlocked_inode_to_wb_begin unlocked_inode_to_wb_end <interrupts mistakenly enabled> <interrupt> end_page_writeback test_clear_page_writeback lock_page_memcg <deadlock> unlock_page_memcg Due to configuration limitations this deadlock is not currently possible because we don't mix cgroup writeback (a cgroupv2 feature) and memory.move_charge_at_immigrate (a cgroupv1 feature). If the kernel is hacked to always claim inode switching and memcg moving_account, then this script triggers lockup in less than a minute: cd /mnt/cgroup/memory mkdir a b echo 1 > a/memory.move_charge_at_immigrate echo 1 > b/memory.move_charge_at_immigrate ( echo $BASHPID > a/cgroup.procs while true; do dd if=/dev/zero of=/mnt/big bs=1M count=256 done ) & while true; do sync done & sleep 1h & SLEEP=$! while true; do echo $SLEEP > a/cgroup.procs echo $SLEEP > b/cgroup.procs done The deadlock does not seem possible, so it's debatable if there's any reason to modify the kernel. I suggest we should to prevent future surprises. And Wang Long said "this deadlock occurs three times in our environment", so there's more reason to apply this, even to stable. Stable 4.4 has minor conflicts applying this patch. For a clean 4.4 patch see "[PATCH for-4.4] writeback: safer lock nesting" https://lkml.org/lkml/2018/4/11/146 Wang Long said "this deadlock occurs three times in our environment" [gthelen@google.com: v4] Link: http://lkml.kernel.org/r/20180411084653.254724-1-gthelen@google.com [akpm@linux-foundation.org: comment tweaks, struct initialization simplification] Change-Id: Ibb773e8045852978f6207074491d262f1b3fb613 Link: http://lkml.kernel.org/r/20180410005908.167976-1-gthelen@google.com Fixes: 682aa8e1a6a1 ("writeback: implement unlocked_inode_to_wb transaction and use it for stat updates") Signed-off-by: Greg Thelen <gthelen@google.com> Reported-by: Wang Long <wanglong19@meituan.com> Acked-by: Wang Long <wanglong19@meituan.com> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <tj@kernel.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: <stable@vger.kernel.org> [v4.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-04-11page cache: use xa_lockMatthew Wilcox1-11/+11
Remove the address_space ->tree_lock and use the xa_lock newly added to the radix_tree_root. Rename the address_space ->page_tree to ->i_pages, since we don't really care that it's a tree. [willy@infradead.org: fix nds32, fs/dax.c] Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Jeff Layton <jlayton@redhat.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-28fs: move I_DIRTY_INODE to fs.hChristoph Hellwig1-6/+3
And use it in a few more places rather than opencoding the values. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2018-01-06writeback: update comment in inode_io_list_move_lockedWang Long1-1/+1
The @head can be wb->b_dirty_time, so update the comment. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Wang Long <wanglong19@meituan.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-11-28Rename superblock flags (MS_xyz -> SB_xyz)Linus Torvalds1-1/+1
This is a pure automated search-and-replace of the internal kernel superblock flags. The s_flags are now called SB_*, with the names and the values for the moment mirroring the MS_* flags that they're equivalent to. Note how the MS_xyz flags are the ones passed to the mount system call, while the SB_xyz flags are what we then use in sb->s_flags. The script to do this was: # places to look in; re security/*: it generally should *not* be # touched (that stuff parses mount(2) arguments directly), but # there are two places where we really deal with superblock flags. FILES="drivers/mtd drivers/staging/lustre fs ipc mm \ include/linux/fs.h include/uapi/linux/bfs_fs.h \ security/apparmor/apparmorfs.c security/apparmor/include/lib.h" # the list of MS_... constants SYMS="RDONLY NOSUID NODEV NOEXEC SYNCHRONOUS REMOUNT MANDLOCK \ DIRSYNC NOATIME NODIRATIME BIND MOVE REC VERBOSE SILENT \ POSIXACL UNBINDABLE PRIVATE SLAVE SHARED RELATIME KERNMOUNT \ I_VERSION STRICTATIME LAZYTIME SUBMOUNT NOREMOTELOCK NOSEC BORN \ ACTIVE NOUSER" SED_PROG= for i in $SYMS; do SED_PROG="$SED_PROG -e s/MS_$i/SB_$i/g"; done # we want files that contain at least one of MS_..., # with fs/namespace.c and fs/pnode.c excluded. L=$(for i in $SYMS; do git grep -w -l MS_$i $FILES; done| sort|uniq|grep -v '^fs/namespace.c'|grep -v '^fs/pnode.c') for f in $L; do sed -i $f $SED_PROG; done Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-10writeback: merge try_to_writeback_inodes_sb_nr() into callerRakesh Pandit1-24/+6
Since commit 925a6efb8ff0c ("Btrfs: stop using try_to_writeback_inodes_sb_nr to flush delalloc") this function hasn't been used outside so stop exporting it. In addition we merge it into try_to_writeback_inodes_sb() which is the only caller. Also change return type of try_to_writeback_inodes_sb to void as the only user ext4 doesn't care. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Rakesh Pandit <rakesh@tuxera.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-04writeback: eliminate work item allocation in bd_start_writeback()Jens Axboe1-37/+34
Handle start-all writeback like we do periodic or kupdate style writeback - by marking the bdi_writeback as needing a full flush, and simply waking the thread. This eliminates the need to allocate and queue a specific work item just for this purpose. After this change, we truly only ever have one of them running at any point in time. We mark the need to start all flushes, and the writeback thread will clear it once it has processed the request. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: only allow one inflight and pending full flushJens Axboe1-0/+25
When someone calls wakeup_flusher_threads() or wakeup_flusher_threads_bdi(), they schedule writeback of all dirty pages in the system (or on that bdi). If we are tight on memory, we can get tons of these queued from kswapd/vmscan. This causes (at least) two problems: 1) We consume a ton of memory just allocating writeback work items. We've seen as much as 600 million of these writeback work items pending. That's a lot of memory to pointlessly hold hostage, while the box is under memory pressure. 2) We spend so much time processing these work items, that we introduce a softlockup in writeback processing. This is because each of the writeback work items don't end up doing any work (it's hard when you have millions of identical ones coming in to the flush machinery), so we just sit in a tight loop pulling work items and deleting/freeing them. Fix this by adding a 'start_all' bit to the writeback structure, and set that when someone attempts to flush all dirty pages. The bit is cleared when we start writeback on that work item. If the bit is already set when we attempt to queue !nr_pages writeback, then we simply ignore it. This provides us one full flush in flight, with one pending as well, and makes for more efficient handling of this type of writeback. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Chris Mason <clm@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: move nr_pages == 0 logic to one locationJens Axboe1-24/+17
Now that we have no external callers of wb_start_writeback(), we can shuffle the passing in of 'nr_pages'. Everybody passes in 0 at this point, so just kill the argument and move the dirty count retrieval to that function. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Chris Mason <clm@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: make wb_start_writeback() staticJens Axboe1-2/+2
We don't have any callers outside of fs-writeback.c anymore, make it private. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Chris Mason <clm@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: provide a wakeup_flusher_threads_bdi()Jens Axboe1-10/+29
Similar to wakeup_flusher_threads(), except that we only wake up the flusher threads on the specified backing device. No functional changes in this patch. Acked-by: Johannes Weiner <hannes@cmpxchg.org> Tested-by: Chris Mason <clm@fb.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: remove 'range_cyclic' argument for wb_start_writeback()Jens Axboe1-3/+3
All the callers pass in 'true' for range_cyclic, so kill the argument. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03writeback: switch wakeup_flusher_threads() to cyclic writebackJens Axboe1-1/+1
We're writing back the full range of dirty pages on the devices, there's no point in making this special and not do normal range cyclic writeback. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-03fs: kill 'nr_pages' argument from wakeup_flusher_threads()Jens Axboe1-5/+4
Everybody is passing in 0 now, let's get rid of the argument. Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-07-13writeback: rework wb_[dec|inc]_stat family of functionsNikolay Borisov1-4/+4
Currently the writeback statistics code uses a percpu counters to hold various statistics. Furthermore we have 2 families of functions - those which disable local irq and those which doesn't and whose names begin with double underscore. However, they both end up calling __add_wb_stats which in turn calls percpu_counter_add_batch which is already irq-safe. Exploiting this fact allows to eliminated the __wb_* functions since they don't add any further protection than we already have. Furthermore, refactor the wb_* function to call __add_wb_stat directly without the irq-disabling dance. This will likely result in better runtime of code which deals with modifying the stat counters. While at it also document why percpu_counter_add_batch is in fact preempt and irq-safe since at least 3 people got confused. Link: http://lkml.kernel.org/r/1498029937-27293-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Josef Bacik <jbacik@fb.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jeff Layton <jlayton@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-16fs: add a blank lines on some kernel-doc commentsMauro Carvalho Chehab1-5/+7
Sphinx gets confused when it finds identation without a good reason for it and without a preceding blank line: ./fs/mpage.c:347: ERROR: Unexpected indentation. ./fs/namei.c:4303: ERROR: Unexpected indentation. ./fs/fs-writeback.c:2060: ERROR: Unexpected indentation. No functional changes. Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2017-03-13writeback: fix memory leak in wb_queue_work()Tahsin Erdogan1-14/+21
When WB_registered flag is not set, wb_queue_work() skips queuing the work, but does not perform the necessary clean up. In particular, if work->auto_free is true, it should free the memory. The leak condition can be reprouced by following these steps: mount /dev/sdb /mnt/sdb /* In qemu console: device_del sdb */ umount /dev/sdb Above will result in a wb_queue_work() call on an unregistered wb and thus leak memory. Reported-by: John Sperbeck <jsperbeck@google.com> Signed-off-by: Tahsin Erdogan <tahsin@google.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-13fs/fs-writeback.c: remove redundant if checkTahsin Erdogan1-9/+7
b_more_io non-empty check is already preceded by an opposite check. Link: http://lkml.kernel.org/r/1478591249-30641-1-git-send-email-tahsin@google.com Signed-off-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-10mm, writeback: flush plugged IO in wakeup_flusher_threads()Konstantin Khlebnikov1-0/+6
I've found funny live-lock between raid10 barriers during resync and memory controller hard limits. Inside mpage_readpages() task holds on to its plug bio which blocks the barrier in raid10. Its memory cgroup have no free memory thus the task goes into reclaimer but all reclaimable pages are dirty and cannot be written because raid10 is rebuilding and stuck on the barrier. Common flush of such IO in schedule() never happens, because the caller doesn't go to sleep. Lock is 'live' because changing memory limit or killing tasks which holds that stuck bio unblock whole progress. That was what happened in 3.18.x but I see no difference in upstream logic. Theoretically this might happen even without memory cgroup. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-04writeback: Write dirty times for WB_SYNC_ALL writebackJan Kara1-0/+1
Currently we take care to handle I_DIRTY_TIME in vfs_fsync() and queue_io() so that inodes which have only dirty timestamps are properly written on fsync(2) and sync(2). However there are other call sites - most notably going through write_inode_now() - which expect inode to be clean after WB_SYNC_ALL writeback. This is not currently true as we do not clear I_DIRTY_TIME in __writeback_single_inode() even for WB_SYNC_ALL writeback in all the cases. This then resulted in the following oops because bdev_write_inode() did not clean the inode and writeback code later stumbled over a dirty inode with detached wb. general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN Modules linked in: CPU: 3 PID: 32 Comm: kworker/u10:1 Not tainted 4.6.0-rc3+ #349 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: writeback wb_workfn (flush-11:0) task: ffff88006ccf1840 ti: ffff88006cda8000 task.ti: ffff88006cda8000 RIP: 0010:[<ffffffff818884d2>] [<ffffffff818884d2>] locked_inode_to_wb_and_lock_list+0xa2/0x750 RSP: 0018:ffff88006cdaf7d0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88006ccf2050 RDX: 0000000000000000 RSI: 000000114c8a8484 RDI: 0000000000000286 RBP: ffff88006cdaf820 R08: ffff88006ccf1840 R09: 0000000000000000 R10: 000229915090805f R11: 0000000000000001 R12: ffff88006a72f5e0 R13: dffffc0000000000 R14: ffffed000d4e5eed R15: ffffffff8830cf40 FS: 0000000000000000(0000) GS:ffff88006d500000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000003301bf8 CR3: 000000006368f000 CR4: 00000000000006e0 DR0: 0000000000001ec9 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Stack: ffff88006a72f680 ffff88006a72f768 ffff8800671230d8 03ff88006cdaf948 ffff88006a72f668 ffff88006a72f5e0 ffff8800671230d8 ffff88006cdaf948 ffff880065b90cc8 ffff880067123100 ffff88006cdaf970 ffffffff8188e12e Call Trace: [< inline >] inode_to_wb_and_lock_list fs/fs-writeback.c:309 [<ffffffff8188e12e>] writeback_sb_inodes+0x4de/0x1250 fs/fs-writeback.c:1554 [<ffffffff8188efa4>] __writeback_inodes_wb+0x104/0x1e0 fs/fs-writeback.c:1600 [<ffffffff8188f9ae>] wb_writeback+0x7ce/0xc90 fs/fs-writeback.c:1709 [< inline >] wb_do_writeback fs/fs-writeback.c:1844 [<ffffffff81891079>] wb_workfn+0x2f9/0x1000 fs/fs-writeback.c:1884 [<ffffffff813bcd1e>] process_one_work+0x78e/0x15c0 kernel/workqueue.c:2094 [<ffffffff813bdc2b>] worker_thread+0xdb/0xfc0 kernel/workqueue.c:2228 [<ffffffff813cdeef>] kthread+0x23f/0x2d0 drivers/block/aoe/aoecmd.c:1303 [<ffffffff867bc5d2>] ret_from_fork+0x22/0x50 arch/x86/entry/entry_64.S:392 Code: 05 94 4a a8 06 85 c0 0f 85 03 03 00 00 e8 07 15 d0 ff 41 80 3e 00 0f 85 64 06 00 00 49 8b 9c 24 88 01 00 00 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 0f 85 17 06 00 00 48 8b 03 48 83 c0 50 48 39 c3 RIP [< inline >] wb_get include/linux/backing-dev-defs.h:212 RIP [<ffffffff818884d2>] locked_inode_to_wb_and_lock_list+0xa2/0x750 fs/fs-writeback.c:281 RSP <ffff88006cdaf7d0> ---[ end trace 986a4d314dcb2694 ]--- Fix the problem by making sure __writeback_single_inode() writes inode only with dirty times in WB_SYNC_ALL mode. Reported-by: Dmitry Vyukov <dvyukov@google.com> Tested-by: Laurent Dufour <ldufour@linux.vnet.ibm.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-07-29mm: move most file-based accounting to the nodeMel Gorman1-2/+2
There are now a number of accounting oddities such as mapped file pages being accounted for on the node while the total number of file pages are accounted on the zone. This can be coped with to some extent but it's confusing so this patch moves the relevant file-based accounted. Due to throttling logic in the page allocator for reliable OOM detection, it is still necessary to track dirty and writeback pages on a per-zone basis. [mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting] Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27fs/fs-writeback.c: inode writeback list tracking tracepointsBrian Foster1-2/+7
The per-sb inode writeback list tracks inodes currently under writeback to facilitate efficient sync processing. In particular, it ensures that sync only needs to walk through a list of inodes that were cleaned by the sync. Add a couple tracepoints to help identify when inodes are added/removed to and from the writeback lists. Piggyback off of the writeback lazytime tracepoint template as it already tracks the relevant inode information. Link: http://lkml.kernel.org/r/1466594593-6757-3-git-send-email-bfoster@redhat.com Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Dave Chinner <dchinner@redhat.com> cc: Josef Bacik <jbacik@fb.com> Cc: Holger Hoffstätte <holger.hoffstaette@applied-asynchrony.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-27fs/fs-writeback.c: add a new writeback list for syncDave Chinner1-25/+81
wait_sb_inodes() currently does a walk of all inodes in the filesystem to find dirty one to wait on during sync. This is highly inefficient and wastes a lot of CPU when there are lots of clean cached inodes that we don't need to wait on. To avoid this "all inode" walk, we need to track inodes that are currently under writeback that we need to wait for. We do this by adding inodes to a writeback list on the sb when the mapping is first tagged as having pages under writeback. wait_sb_inodes() can then walk this list of "inodes under IO" and wait specifically just for the inodes that the current sync(2) needs to wait for. Define a couple helpers to add/remove an inode from the writeback list and call them when the overall mapping is tagged for or cleared from writeback. Update wait_sb_inodes() to walk only the inodes under writeback due to the sync. With this change, filesystem sync times are significantly reduced for fs' with largely populated inode caches and otherwise no other work to do. For example, on a 16xcpu 2GHz x86-64 server, 10TB XFS filesystem with a ~10m entry inode cache, sync times are reduced from ~7.3s to less than 0.1s when the filesystem is fully clean. Link: http://lkml.kernel.org/r/1466594593-6757-2-git-send-email-bfoster@redhat.com Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Holger Hoffstätte <holger.hoffstaette@applied-asynchrony.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-30writeback: inode cgroup wb switch should not call ihold()Tahsin Erdogan1-1/+1
Asynchronous wb switching of inodes takes an additional ref count on an inode to make sure inode remains valid until switchover is completed. However, anyone calling ihold() must already have a ref count on inode, but in this case inode->i_count may already be zero: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 917 at fs/inode.c:397 ihold+0x2b/0x30 CPU: 1 PID: 917 Comm: kworker/u4:5 Not tainted 4.7.0-rc2+ #49 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Workqueue: writeback wb_workfn (flush-8:16) 0000000000000000 ffff88007ca0fb58 ffffffff805990af 0000000000000000 0000000000000000 ffff88007ca0fb98 ffffffff80268702 0000018d000004e2 ffff88007cef40e8 ffff88007c9b89a8 ffff880079e3a740 0000000000000003 Call Trace: [<ffffffff805990af>] dump_stack+0x4d/0x6e [<ffffffff80268702>] __warn+0xc2/0xe0 [<ffffffff802687d8>] warn_slowpath_null+0x18/0x20 [<ffffffff8035b4ab>] ihold+0x2b/0x30 [<ffffffff80367ecc>] inode_switch_wbs+0x11c/0x180 [<ffffffff80369110>] wbc_detach_inode+0x170/0x1a0 [<ffffffff80369abc>] writeback_sb_inodes+0x21c/0x530 [<ffffffff80369f7e>] wb_writeback+0xee/0x1e0 [<ffffffff8036a147>] wb_workfn+0xd7/0x280 [<ffffffff80287531>] ? try_to_wake_up+0x1b1/0x2b0 [<ffffffff8027bb09>] process_one_work+0x129/0x300 [<ffffffff8027be06>] worker_thread+0x126/0x480 [<ffffffff8098cde7>] ? __schedule+0x1c7/0x561 [<ffffffff8027bce0>] ? process_one_work+0x300/0x300 [<ffffffff80280ff4>] kthread+0xc4/0xe0 [<ffffffff80335578>] ? kfree+0xc8/0x100 [<ffffffff809903cf>] ret_from_fork+0x1f/0x40 [<ffffffff80280f30>] ? __kthread_parkme+0x70/0x70 ---[ end trace aaefd2fd9f306bc4 ]--- Signed-off-by: Tahsin Erdogan <tahsin@google.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-05-21mm,writeback: don't use memory reserves for wb_start_writebackTetsuo Handa1-1/+2
When writeback operation cannot make forward progress because memory allocation requests needed for doing I/O cannot be satisfied (e.g. under OOM-livelock situation), we can observe flood of order-0 page allocation failure messages caused by complete depletion of memory reserves. This is caused by unconditionally allocating "struct wb_writeback_work" objects using GFP_ATOMIC from PF_MEMALLOC context. __alloc_pages_nodemask() { __alloc_pages_slowpath() { __alloc_pages_direct_reclaim() { __perform_reclaim() { current->flags |= PF_MEMALLOC; try_to_free_pages() { do_try_to_free_pages() { wakeup_flusher_threads() { wb_start_writeback() { kzalloc(sizeof(*work), GFP_ATOMIC) { /* ALLOC_NO_WATERMARKS via PF_MEMALLOC */ } } } } } current->flags &= ~PF_MEMALLOC; } } } } Since I/O is stalling, allocating writeback requests forever shall deplete memory reserves. Fortunately, since wb_start_writeback() can fall back to wb_wakeup() when allocating "struct wb_writeback_work" failed, we don't need to allow wb_start_writeback() to use memory reserves. Mem-Info: active_anon:289393 inactive_anon:2093 isolated_anon:29 active_file:10838 inactive_file:113013 isolated_file:859 unevictable:0 dirty:108531 writeback:5308 unstable:0 slab_reclaimable:5526 slab_unreclaimable:7077 mapped:9970 shmem:2159 pagetables:2387 bounce:0 free:3042 free_pcp:0 free_cma:0 Node 0 DMA free:6968kB min:44kB low:52kB high:64kB active_anon:6056kB inactive_anon:176kB active_file:712kB inactive_file:744kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15988kB managed:15904kB mlocked:0kB dirty:756kB writeback:0kB mapped:736kB shmem:184kB slab_reclaimable:48kB slab_unreclaimable:208kB kernel_stack:160kB pagetables:144kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:9708 all_unreclaimable? yes lowmem_reserve[]: 0 1732 1732 1732 Node 0 DMA32 free:5200kB min:5200kB low:6500kB high:7800kB active_anon:1151516kB inactive_anon:8196kB active_file:42640kB inactive_file:451076kB unevictable:0kB isolated(anon):116kB isolated(file):3564kB present:2080640kB managed:1775332kB mlocked:0kB dirty:433368kB writeback:21232kB mapped:39144kB shmem:8452kB slab_reclaimable:22056kB slab_unreclaimable:28100kB kernel_stack:20976kB pagetables:9404kB unstable:0kB bounce:0kB free_pcp:120kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:2701604 all_unreclaimable? no lowmem_reserve[]: 0 0 0 0 Node 0 DMA: 25*4kB (UME) 16*8kB (UME) 3*16kB (UE) 5*32kB (UME) 2*64kB (UM) 2*128kB (ME) 2*256kB (ME) 1*512kB (E) 1*1024kB (E) 2*2048kB (ME) 0*4096kB = 6964kB Node 0 DMA32: 925*4kB (UME) 140*8kB (UME) 5*16kB (ME) 5*32kB (M) 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 5060kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 126847 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 524157 pages RAM 0 pages HighMem/MovableOnly 76348 pages reserved 0 pages hwpoisoned Out of memory: Kill process 4450 (file_io.00) score 998 or sacrifice child Killed process 4450 (file_io.00) total-vm:4308kB, anon-rss:100kB, file-rss:1184kB, shmem-rss:0kB kthreadd: page allocation failure: order:0, mode:0x2200020 file_io.00: page allocation failure: order:0, mode:0x2200020 CPU: 0 PID: 4457 Comm: file_io.00 Not tainted 4.5.0-rc7+ #45 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 Call Trace: warn_alloc_failed+0xf7/0x150 __alloc_pages_nodemask+0x23f/0xa60 alloc_pages_current+0x87/0x110 new_slab+0x3a1/0x440 ___slab_alloc+0x3cf/0x590 __slab_alloc.isra.64+0x18/0x1d kmem_cache_alloc+0x11c/0x150 wb_start_writeback+0x39/0x90 wakeup_flusher_threads+0x7f/0xf0 do_try_to_free_pages+0x1f9/0x410 try_to_free_pages+0x94/0xc0 __alloc_pages_nodemask+0x566/0xa60 alloc_pages_current+0x87/0x110 __page_cache_alloc+0xaf/0xc0 pagecache_get_page+0x88/0x260 grab_cache_page_write_begin+0x21/0x40 xfs_vm_write_begin+0x2f/0xf0 generic_perform_write+0xca/0x1c0 xfs_file_buffered_aio_write+0xcc/0x1f0 xfs_file_write_iter+0x84/0x140 __vfs_write+0xc7/0x100 vfs_write+0x9d/0x190 SyS_write+0x50/0xc0 entry_SYSCALL_64_fastpath+0x12/0x6a Mem-Info: active_anon:293335 inactive_anon:2093 isolated_anon:0 active_file:10829 inactive_file:110045 isolated_file:32 unevictable:0 dirty:109275 writeback:822 unstable:0 slab_reclaimable:5489 slab_unreclaimable:10070 mapped:9999 shmem:2159 pagetables:2420 bounce:0 free:3 free_pcp:0 free_cma:0 Node 0 DMA free:12kB min:44kB low:52kB high:64kB active_anon:6060kB inactive_anon:176kB active_file:708kB inactive_file:756kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15988kB managed:15904kB mlocked:0kB dirty:756kB writeback:0kB mapped:736kB shmem:184kB slab_reclaimable:48kB slab_unreclaimable:7160kB kernel_stack:160kB pagetables:144kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:9844 all_unreclaimable? yes lowmem_reserve[]: 0 1732 1732 1732 Node 0 DMA32 free:0kB min:5200kB low:6500kB high:7800kB active_anon:1167280kB inactive_anon:8196kB active_file:42608kB inactive_file:439424kB unevictable:0kB isolated(anon):0kB isolated(file):128kB present:2080640kB managed:1775332kB mlocked:0kB dirty:436344kB writeback:3288kB mapped:39260kB shmem:8452kB slab_reclaimable:21908kB slab_unreclaimable:33120kB kernel_stack:20976kB pagetables:9536kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:11073180 all_unreclaimable? yes lowmem_reserve[]: 0 0 0 0 Node 0 DMA: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB Node 0 DMA32: 0*4kB 0*8kB 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 0kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 123086 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 524157 pages RAM 0 pages HighMem/MovableOnly 76348 pages reserved 0 pages hwpoisoned SLUB: Unable to allocate memory on node -1 (gfp=0x2088020) cache: kmalloc-64, object size: 64, buffer size: 64, default order: 0, min order: 0 node 0: slabs: 3218, objs: 205952, free: 0 file_io.00: page allocation failure: order:0, mode:0x2200020 CPU: 0 PID: 4457 Comm: file_io.00 Not tainted 4.5.0-rc7+ #45 Assuming that somebody will find a better solution, let's apply this patch for now to stop bleeding, for this problem frequently prevents me from testing OOM livelock condition. Link: http://lkml.kernel.org/r/20160318131136.GE7152@quack.suse.cz Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov1-1/+1
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-20writeback, cgroup: fix use of the wrong bdi_writeback which mismatches the inodeTejun Heo1-10/+19
When cgroup writeback is in use, there can be multiple wb's (bdi_writeback's) per bdi and an inode may switch among them dynamically. In a couple places, the wrong wb was used leading to performing operations on the wrong list under the wrong lock corrupting the io lists. * writeback_single_inode() was taking @wb parameter and used it to remove the inode from io lists if it becomes clean after writeback. The callers of this function were always passing in the root wb regardless of the actual wb that the inode was associated with, which could also change while writeback is in progress. Fix it by dropping the @wb parameter and using inode_to_wb_and_lock_list() to determine and lock the associated wb. * After writeback_sb_inodes() writes out an inode, it re-locks @wb and inode to remove it from or move it to the right io list. It assumes that the inode is still associated with @wb; however, the inode may have switched to another wb while writeback was in progress. Fix it by using inode_to_wb_and_lock_list() to determine and lock the associated wb after writeback is complete. As the function requires the original @wb->list_lock locked for the next iteration, in the unlikely case where the inode has changed association, switch the locks. Kudos to Tahsin for pinpointing these subtle breakages. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching") Link: http://lkml.kernel.org/g/CAAeU0aMYeM_39Y2+PaRvyB1nqAPYZSNngJ1eBRmrxn7gKAt2Mg@mail.gmail.com Reported-and-diagnosed-by: Tahsin Erdogan <tahsin@google.com> Tested-by: Tahsin Erdogan <tahsin@google.com> Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Jens Axboe <axboe@fb.com>
2016-03-20writeback, cgroup: fix premature wb_put() in locked_inode_to_wb_and_lock_list()Tejun Heo1-3/+5
locked_inode_to_wb_and_lock_list() wb_get()'s the wb associated with the target inode, unlocks inode, locks the wb's list_lock and verifies that the inode is still associated with the wb. To prevent the wb going away between dropping inode lock and acquiring list_lock, the wb is pinned while inode lock is held. The wb reference is put right after acquiring list_lock citing that the wb won't be dereferenced anymore. This isn't true. If the inode is still associated with the wb, the inode has reference and it's safe to return the wb; however, if inode has been switched, the wb still needs to be unlocked which is a dereference and can lead to use-after-free if it it races with wb destruction. Fix it by putting the reference after releasing list_lock. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 87e1d789bf55 ("writeback: implement [locked_]inode_to_wb_and_lock_list()") Cc: stable@vger.kernel.org # v4.2+ Tested-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-03-04writeback: flush inode cgroup wb switches instead of pinning super_blockTejun Heo1-13/+41
If cgroup writeback is in use, inodes can be scheduled for asynchronous wb switching. Before 5ff8eaac1636 ("writeback: keep superblock pinned during cgroup writeback association switches"), this could race with umount leading to super_block being destroyed while inodes are pinned for wb switching. 5ff8eaac1636 fixed it by bumping s_active while wb switches are in flight; however, this allowed in-flight wb switches to make umounts asynchronous when the userland expected synchronosity - e.g. fsck immediately following umount may fail because the device is still busy. This patch removes the problematic super_block pinning and instead makes generic_shutdown_super() flush in-flight wb switches. wb switches are now executed on a dedicated isw_wq so that they can be flushed and isw_nr_in_flight keeps track of the number of in-flight wb switches so that flushing can be avoided in most cases. v2: Move cgroup_writeback_umount() further below and add MS_ACTIVE check in inode_switch_wbs() as Jan an Al suggested. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Tahsin Erdogan <tahsin@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Al Viro <viro@ZenIV.linux.org.uk> Link: http://lkml.kernel.org/g/CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com Fixes: 5ff8eaac1636 ("writeback: keep superblock pinned during cgroup writeback association switches") Cc: stable@vger.kernel.org #v4.5 Reviewed-by: Jan Kara <jack@suse.cz> Tested-by: Tahsin Erdogan <tahsin@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-02-16writeback: keep superblock pinned during cgroup writeback association switchesTejun Heo1-4/+11
If cgroup writeback is in use, an inode is associated with a cgroup for writeback. If the inode's main dirtier changes to another cgroup, the association gets updated asynchronously. Nothing was pinning the superblock while such switches are in progress and superblock could go away while async switching is pending or in progress leading to crashes like the following. kernel BUG at fs/jbd2/transaction.c:319! invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC CPU: 1 PID: 29158 Comm: kworker/1:10 Not tainted 4.5.0-rc3 #51 Hardware name: Google Google, BIOS Google 01/01/2011 Workqueue: events inode_switch_wbs_work_fn task: ffff880213dbbd40 ti: ffff880209264000 task.ti: ffff880209264000 RIP: 0010:[<ffffffff803e6922>] [<ffffffff803e6922>] start_this_handle+0x382/0x3e0 RSP: 0018:ffff880209267c30 EFLAGS: 00010202 ... Call Trace: [<ffffffff803e6be4>] jbd2__journal_start+0xf4/0x190 [<ffffffff803cfc7e>] __ext4_journal_start_sb+0x4e/0x70 [<ffffffff803b31ec>] ext4_evict_inode+0x12c/0x3d0 [<ffffffff8035338b>] evict+0xbb/0x190 [<ffffffff80354190>] iput+0x130/0x190 [<ffffffff80360223>] inode_switch_wbs_work_fn+0x343/0x4c0 [<ffffffff80279819>] process_one_work+0x129/0x300 [<ffffffff80279b16>] worker_thread+0x126/0x480 [<ffffffff8027ed14>] kthread+0xc4/0xe0 [<ffffffff809771df>] ret_from_fork+0x3f/0x70 Fix it by bumping s_active while cgroup association switching is in flight. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Tahsin Erdogan <tahsin@google.com> Link: http://lkml.kernel.org/g/CAAeU0aNCq7LGODvVGRU-oU_o-6enii5ey0p1c26D1ZzYwkDc5A@mail.gmail.com Fixes: d10c80955265 ("writeback: implement foreign cgroup inode bdi_writeback switching") Cc: stable@vger.kernel.org #v4.5+ Signed-off-by: Jens Axboe <axboe@fb.com>
2016-01-16cgroup, memcg, writeback: drop spurious rcu locking around ↵Tejun Heo1-2/+0
mem_cgroup_css_from_page() In earlier versions, mem_cgroup_css_from_page() could return non-root css on a legacy hierarchy which can go away and required rcu locking; however, the eventual version simply returns the root cgroup if memcg is on a legacy hierarchy and thus doesn't need rcu locking around or in it. Remove spurious rcu lockings. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-10fs/writeback.c: fix kernel-doc warningsRandy Dunlap1-1/+2
Fix kernel-doc warnings in fs/fs-writeback.c by moving a #define macro to after the function's opening brace. Also #undef this macro at the end of the function. ../fs/fs-writeback.c:1984: warning: Excess function parameter 'inode' description in 'I_DIRTY_INODE' ../fs/fs-writeback.c:1984: warning: Excess function parameter 'flags' description in 'I_DIRTY_INODE' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06mm/filemap.c: make global sync not clear error status of individual inodesJunichi Nomura1-1/+6
filemap_fdatawait() is a function to wait for on-going writeback to complete but also consume and clear error status of the mapping set during writeback. The latter functionality is critical for applications to detect writeback error with system calls like fsync(2)/fdatasync(2). However filemap_fdatawait() is also used by sync(2) or FIFREEZE ioctl, which don't check error status of individual mappings. As a result, fsync() may not be able to detect writeback error if events happen in the following order: Application System admin ---------------------------------------------------------- write data on page cache Run sync command writeback completes with error filemap_fdatawait() clears error fsync returns success (but the data is not on disk) This patch adds filemap_fdatawait_keep_errors() for call sites where writeback error is not handled so that they don't clear error status. Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Andi Kleen <ak@linux.intel.com> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Fengguang Wu <fengguang.wu@gmail.com> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-28fs/writeback, rcu: Don't use list_entry_rcu() for pointer offsetting in ↵Tejun Heo1-2/+2
bdi_split_work_to_wbs() bdi_split_work_to_wbs() uses list_for_each_entry_rcu_continue() to walk @bdi->wb_list. To set up the initial iteration condition, it uses list_entry_rcu() to calculate the entry pointer corresponding to the list head; however, this isn't an actual RCU dereference and using list_entry_rcu() for it ended up breaking a proposed list_entry_rcu() change because it was feeding an non-lvalue pointer into the macro. Don't use the RCU variant for simple pointer offsetting. Use list_entry() instead. Reported-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Darren Hart <dvhart@linux.intel.com> Cc: David Howells <dhowells@redhat.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Josh Triplett <josh@joshtriplett.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Patrick Marlier <patrick.marlier@gmail.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: pranith kumar <bobby.prani@gmail.com> Link: http://lkml.kernel.org/r/20151027051939.GA19355@mtj.duckdns.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-12writeback: bdi_writeback iteration must not skip dying onesTejun Heo1-9/+22
bdi_for_each_wb() is used in several places to wake up or issue writeback work items to all wb's (bdi_writeback's) on a given bdi. The iteration is performed by walking bdi->cgwb_tree; however, the tree only indexes wb's which are currently active. For example, when a memcg gets associated with a different blkcg, the old wb is removed from the tree so that the new one can be indexed. The old wb starts dying from then on but will linger till all its inodes are drained. As these dying wb's may still host dirty inodes, writeback operations which affect all wb's must include them. bdi_for_each_wb() skipping dying wb's led to sync(2) missing and failing to sync the inodes belonging to those wb's. This patch adds a RCU protected @bdi->wb_list which lists all wb's beloinging to that bdi. wb's are added on creation and removed on release rather than on the start of destruction. bdi_for_each_wb() usages are replaced with list_for_each[_continue]_rcu() iterations over @bdi->wb_list and bdi_for_each_wb() and its helpers are removed. v2: Updated as per Jan. last_wb ref leak in bdi_split_work_to_wbs() fixed and unnecessary list head severing in cgwb_bdi_destroy() removed. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Artem Bityutskiy <dedekind1@gmail.com> Fixes: ebe41ab0c79d ("writeback: implement bdi_for_each_wb()") Link: http://lkml.kernel.org/g/1443012552.19983.209.camel@gmail.com Cc: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-10-12writeback: fix bdi_writeback iteration in wakeup_dirtytime_writeback()Tejun Heo1-2/+2
wakeup_dirtytime_writeback() walks and wakes up all wb's of all bdi's; unfortunately, it was always waking up bdi->wb instead of the wb being walked. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 001fe6f617b1 ("writeback: make wakeup_dirtytime_writeback() handle multiple bdi_writeback's") Reviewed-by: Jan Kara <jack@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
generated by cgit v1.2.3 (git 2.39.0) at 2025-02-15 04:45:02 +0300