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path: root/drivers/block/loop.c
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2019-12-31loop: fix no-unmap write-zeroes request behaviorDarrick J. Wong
[ Upstream commit efcfec579f6139528c9e6925eca2bc4a36da65c6 ] Currently, if the loop device receives a WRITE_ZEROES request, it asks the underlying filesystem to punch out the range. This behavior is correct if unmapping is allowed. However, a NOUNMAP request means that the caller doesn't want us to free the storage backing the range, so punching out the range is incorrect behavior. To satisfy a NOUNMAP | WRITE_ZEROES request, loop should ask the underlying filesystem to FALLOC_FL_ZERO_RANGE, which is (according to the fallocate documentation) required to ensure that the entire range is backed by real storage, which suffices for our purposes. Fixes: 19372e2769179dd ("loop: implement REQ_OP_WRITE_ZEROES") Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-10-29loop: Add LOOP_SET_DIRECT_IO to compat ioctlAlessio Balsini
[ Upstream commit fdbe4eeeb1aac219b14f10c0ed31ae5d1123e9b8 ] Enabling Direct I/O with loop devices helps reducing memory usage by avoiding double caching. 32 bit applications running on 64 bits systems are currently not able to request direct I/O because is missing from the lo_compat_ioctl. This patch fixes the compatibility issue mentioned above by exporting LOOP_SET_DIRECT_IO as additional lo_compat_ioctl() entry. The input argument for this ioctl is a single long converted to a 1-bit boolean, so compatibility is preserved. Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Alessio Balsini <balsini@android.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-08-16loop: set PF_MEMALLOC_NOIO for the worker threadMikulas Patocka
commit d0a255e795ab976481565f6ac178314b34fbf891 upstream. A deadlock with this stacktrace was observed. The loop thread does a GFP_KERNEL allocation, it calls into dm-bufio shrinker and the shrinker depends on I/O completion in the dm-bufio subsystem. In order to fix the deadlock (and other similar ones), we set the flag PF_MEMALLOC_NOIO at loop thread entry. PID: 474 TASK: ffff8813e11f4600 CPU: 10 COMMAND: "kswapd0" #0 [ffff8813dedfb938] __schedule at ffffffff8173f405 #1 [ffff8813dedfb990] schedule at ffffffff8173fa27 #2 [ffff8813dedfb9b0] schedule_timeout at ffffffff81742fec #3 [ffff8813dedfba60] io_schedule_timeout at ffffffff8173f186 #4 [ffff8813dedfbaa0] bit_wait_io at ffffffff8174034f #5 [ffff8813dedfbac0] __wait_on_bit at ffffffff8173fec8 #6 [ffff8813dedfbb10] out_of_line_wait_on_bit at ffffffff8173ff81 #7 [ffff8813dedfbb90] __make_buffer_clean at ffffffffa038736f [dm_bufio] #8 [ffff8813dedfbbb0] __try_evict_buffer at ffffffffa0387bb8 [dm_bufio] #9 [ffff8813dedfbbd0] dm_bufio_shrink_scan at ffffffffa0387cc3 [dm_bufio] #10 [ffff8813dedfbc40] shrink_slab at ffffffff811a87ce #11 [ffff8813dedfbd30] shrink_zone at ffffffff811ad778 #12 [ffff8813dedfbdc0] kswapd at ffffffff811ae92f #13 [ffff8813dedfbec0] kthread at ffffffff810a8428 #14 [ffff8813dedfbf50] ret_from_fork at ffffffff81745242 PID: 14127 TASK: ffff881455749c00 CPU: 11 COMMAND: "loop1" #0 [ffff88272f5af228] __schedule at ffffffff8173f405 #1 [ffff88272f5af280] schedule at ffffffff8173fa27 #2 [ffff88272f5af2a0] schedule_preempt_disabled at ffffffff8173fd5e #3 [ffff88272f5af2b0] __mutex_lock_slowpath at ffffffff81741fb5 #4 [ffff88272f5af330] mutex_lock at ffffffff81742133 #5 [ffff88272f5af350] dm_bufio_shrink_count at ffffffffa03865f9 [dm_bufio] #6 [ffff88272f5af380] shrink_slab at ffffffff811a86bd #7 [ffff88272f5af470] shrink_zone at ffffffff811ad778 #8 [ffff88272f5af500] do_try_to_free_pages at ffffffff811adb34 #9 [ffff88272f5af590] try_to_free_pages at ffffffff811adef8 #10 [ffff88272f5af610] __alloc_pages_nodemask at ffffffff811a09c3 #11 [ffff88272f5af710] alloc_pages_current at ffffffff811e8b71 #12 [ffff88272f5af760] new_slab at ffffffff811f4523 #13 [ffff88272f5af7b0] __slab_alloc at ffffffff8173a1b5 #14 [ffff88272f5af880] kmem_cache_alloc at ffffffff811f484b #15 [ffff88272f5af8d0] do_blockdev_direct_IO at ffffffff812535b3 #16 [ffff88272f5afb00] __blockdev_direct_IO at ffffffff81255dc3 #17 [ffff88272f5afb30] xfs_vm_direct_IO at ffffffffa01fe3fc [xfs] #18 [ffff88272f5afb90] generic_file_read_iter at ffffffff81198994 #19 [ffff88272f5afc50] __dta_xfs_file_read_iter_2398 at ffffffffa020c970 [xfs] #20 [ffff88272f5afcc0] lo_rw_aio at ffffffffa0377042 [loop] #21 [ffff88272f5afd70] loop_queue_work at ffffffffa0377c3b [loop] #22 [ffff88272f5afe60] kthread_worker_fn at ffffffff810a8a0c #23 [ffff88272f5afec0] kthread at ffffffff810a8428 #24 [ffff88272f5aff50] ret_from_fork at ffffffff81745242 Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-02Revert "block/loop: Use global lock for ioctl() operation."Greg Kroah-Hartman
This reverts commit 57da9a9742200f391d1cf93fea389f7ddc25ec9a which is commit 310ca162d779efee8a2dc3731439680f3e9c1e86 upstream. Jan Kara has reported seeing problems with this patch applied, as has Salvatore Bonaccorso, so let's drop it for now. Reported-by: Salvatore Bonaccorso <carnil@debian.org> Reported-by: Jan Kara <jack@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-05Revert "loop: Fold __loop_release into loop_release"Greg Kroah-Hartman
This reverts commit f1e81ba8a3fa56dcc48828869b392b29559a0ac3 which is commit 967d1dc144b50ad005e5eecdfadfbcfb399ffff6 upstream. It does not work properly in the 4.14.y tree and causes more problems than it fixes, so revert it. Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com> Reported-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-05Revert "loop: Get rid of loop_index_mutex"Greg Kroah-Hartman
This reverts commit c1e63df4f30c3918476ac9bc594355b0e9629893 which is commit 0a42e99b58a208839626465af194cfe640ef9493 upstream. It does not work properly in the 4.14.y tree and causes more problems than it fixes, so revert it. Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com> Reported-by: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-05Revert "loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()"Greg Kroah-Hartman
This reverts commit d2762edcb6af99fc9322bab0b1d4e71a427760e8 which is commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream. It does not work properly in the 4.14.y tree and causes more problems than it fixes, so revert it. Reported-by: Thomas Lindroth <thomas.lindroth@gmail.com> Reported-by: Jan Kara <jack@suse.cz> Cc: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com> Cc: Ming Lei <ming.lei@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23loop: drop caches if offset or block_size are changedJaegeuk Kim
commit 5db470e229e22b7eda6e23b5566e532c96fb5bc3 upstream. If we don't drop caches used in old offset or block_size, we can get old data from new offset/block_size, which gives unexpected data to user. For example, Martijn found a loopback bug in the below scenario. 1) LOOP_SET_FD loads first two pages on loop file 2) LOOP_SET_STATUS64 changes the offset on the loop file 3) mount is failed due to the cached pages having wrong superblock Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-block@vger.kernel.org Reported-by: Martijn Coenen <maco@google.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl()Tetsuo Handa
commit 628bd85947091830a8c4872adfd5ed1d515a9cf2 upstream. Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when replacing loop_index_mutex with loop_ctl_mutex. Fixes: 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") Reported-by: syzbot <syzbot+c0138741c2290fc5e63f@syzkaller.appspotmail.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23loop: Get rid of loop_index_mutexJan Kara
commit 0a42e99b58a208839626465af194cfe640ef9493 upstream. Now that loop_ctl_mutex is global, just get rid of loop_index_mutex as there is no good reason to keep these two separate and it just complicates the locking. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23loop: Fold __loop_release into loop_releaseJan Kara
commit 967d1dc144b50ad005e5eecdfadfbcfb399ffff6 upstream. __loop_release() has a single call site. Fold it there. This is currently not a huge win but it will make following replacement of loop_index_mutex more obvious. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23block/loop: Use global lock for ioctl() operation.Tetsuo Handa
commit 310ca162d779efee8a2dc3731439680f3e9c1e86 upstream. syzbot is reporting NULL pointer dereference [1] which is caused by race condition between ioctl(loop_fd, LOOP_CLR_FD, 0) versus ioctl(other_loop_fd, LOOP_SET_FD, loop_fd) due to traversing other loop devices at loop_validate_file() without holding corresponding lo->lo_ctl_mutex locks. Since ioctl() request on loop devices is not frequent operation, we don't need fine grained locking. Let's use global lock in order to allow safe traversal at loop_validate_file(). Note that syzbot is also reporting circular locking dependency between bdev->bd_mutex and lo->lo_ctl_mutex [2] which is caused by calling blkdev_reread_part() with lock held. This patch does not address it. [1] https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3 [2] https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+bf89c128e05dd6c62523@syzkaller.appspotmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-23block/loop: Don't grab "struct file" for vfs_getattr() operation.Tetsuo Handa
commit b1ab5fa309e6c49e4e06270ec67dd7b3e9971d04 upstream. vfs_getattr() needs "struct path" rather than "struct file". Let's use path_get()/path_put() rather than get_file()/fput(). Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-17loop: remember whether sysfs_create_group() was doneTetsuo Handa
commit d3349b6b3c373ac1fbfb040b810fcee5e2adc7e0 upstream. syzbot is hitting WARN() triggered by memory allocation fault injection [1] because loop module is calling sysfs_remove_group() when sysfs_create_group() failed. Fix this by remembering whether sysfs_create_group() succeeded. [1] https://syzkaller.appspot.com/bug?id=3f86c0edf75c86d2633aeb9dd69eccc70bc7e90b Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <syzbot+9f03168400f56df89dbc6f1751f4458fe739ff29@syzkaller.appspotmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Renamed sysfs_ready -> sysfs_inited. Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-17loop: add recursion validation to LOOP_CHANGE_FDTheodore Ts'o
commit d2ac838e4cd7e5e9891ecc094d626734b0245c99 upstream. Refactor the validation code used in LOOP_SET_FD so it is also used in LOOP_CHANGE_FD. Otherwise it is possible to construct a set of loop devices that all refer to each other. This can lead to a infinite loop in starting with "while (is_loop_device(f)) .." in loop_set_fd(). Fix this by refactoring out the validation code and using it for LOOP_CHANGE_FD as well as LOOP_SET_FD. Reported-by: syzbot+4349872271ece473a7c91190b68b4bac7c5dbc87@syzkaller.appspotmail.com Reported-by: syzbot+40bd32c4d9a3cc12a339@syzkaller.appspotmail.com Reported-by: syzbot+769c54e66f994b041be7@syzkaller.appspotmail.com Reported-by: syzbot+0a89a9ce473936c57065@syzkaller.appspotmail.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25loop: fix LOOP_GET_STATUS lock imbalanceOmar Sandoval
commit bdac616db9bbadb90b7d6a406144571015e138f7 upstream. Commit 2d1d4c1e591f made loop_get_status() drop lo_ctx_mutex before returning, but the loop_get_status_old(), loop_get_status64(), and loop_get_status_compat() wrappers don't call loop_get_status() if the passed argument is NULL. The callers expect that the lock is dropped, so make sure we drop it in that case, too. Reported-by: syzbot+31e8daa8b3fc129e75f2@syzkaller.appspotmail.com Fixes: 2d1d4c1e591f ("loop: don't call into filesystem while holding lo_ctl_mutex") Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-05-25loop: don't call into filesystem while holding lo_ctl_mutexOmar Sandoval
commit 2d1d4c1e591fd40bd7dafd868a249d7d00e215d5 upstream. We hit an issue where a loop device on NFS was stuck in loop_get_status() doing vfs_getattr() after the NFS server died, which caused a pile-up of uninterruptible processes waiting on lo_ctl_mutex. There's no reason to hold this lock while we wait on the filesystem; let's drop it so that other processes can do their thing. We need to grab a reference on lo_backing_file while we use it, and we can get rid of the check on lo_device, which has been unnecessary since commit a34c0ae9ebd6 ("[PATCH] loop: remove the bio remapping capability") in the linux-history tree. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-04-19block/loop: fix deadlock after loop_set_statusTetsuo Handa
commit 1e047eaab3bb5564f25b41e9cd3a053009f4e789 upstream. syzbot is reporting deadlocks at __blkdev_get() [1]. ---------------------------------------- [ 92.493919] systemd-udevd D12696 525 1 0x00000000 [ 92.495891] Call Trace: [ 92.501560] schedule+0x23/0x80 [ 92.502923] schedule_preempt_disabled+0x5/0x10 [ 92.504645] __mutex_lock+0x416/0x9e0 [ 92.510760] __blkdev_get+0x73/0x4f0 [ 92.512220] blkdev_get+0x12e/0x390 [ 92.518151] do_dentry_open+0x1c3/0x2f0 [ 92.519815] path_openat+0x5d9/0xdc0 [ 92.521437] do_filp_open+0x7d/0xf0 [ 92.527365] do_sys_open+0x1b8/0x250 [ 92.528831] do_syscall_64+0x6e/0x270 [ 92.530341] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 92.931922] 1 lock held by systemd-udevd/525: [ 92.933642] #0: 00000000a2849e25 (&bdev->bd_mutex){+.+.}, at: __blkdev_get+0x73/0x4f0 ---------------------------------------- The reason of deadlock turned out that wait_event_interruptible() in blk_queue_enter() got stuck with bdev->bd_mutex held at __blkdev_put() due to q->mq_freeze_depth == 1. ---------------------------------------- [ 92.787172] a.out S12584 634 633 0x80000002 [ 92.789120] Call Trace: [ 92.796693] schedule+0x23/0x80 [ 92.797994] blk_queue_enter+0x3cb/0x540 [ 92.803272] generic_make_request+0xf0/0x3d0 [ 92.807970] submit_bio+0x67/0x130 [ 92.810928] submit_bh_wbc+0x15e/0x190 [ 92.812461] __block_write_full_page+0x218/0x460 [ 92.815792] __writepage+0x11/0x50 [ 92.817209] write_cache_pages+0x1ae/0x3d0 [ 92.825585] generic_writepages+0x5a/0x90 [ 92.831865] do_writepages+0x43/0xd0 [ 92.836972] __filemap_fdatawrite_range+0xc1/0x100 [ 92.838788] filemap_write_and_wait+0x24/0x70 [ 92.840491] __blkdev_put+0x69/0x1e0 [ 92.841949] blkdev_close+0x16/0x20 [ 92.843418] __fput+0xda/0x1f0 [ 92.844740] task_work_run+0x87/0xb0 [ 92.846215] do_exit+0x2f5/0xba0 [ 92.850528] do_group_exit+0x34/0xb0 [ 92.852018] SyS_exit_group+0xb/0x10 [ 92.853449] do_syscall_64+0x6e/0x270 [ 92.854944] entry_SYSCALL_64_after_hwframe+0x42/0xb7 [ 92.943530] 1 lock held by a.out/634: [ 92.945105] #0: 00000000a2849e25 (&bdev->bd_mutex){+.+.}, at: __blkdev_put+0x3c/0x1e0 ---------------------------------------- The reason of q->mq_freeze_depth == 1 turned out that loop_set_status() forgot to call blk_mq_unfreeze_queue() at error paths for info->lo_encrypt_type != NULL case. ---------------------------------------- [ 37.509497] CPU: 2 PID: 634 Comm: a.out Tainted: G W 4.16.0+ #457 [ 37.513608] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017 [ 37.518832] RIP: 0010:blk_freeze_queue_start+0x17/0x40 [ 37.521778] RSP: 0018:ffffb0c2013e7c60 EFLAGS: 00010246 [ 37.524078] RAX: 0000000000000000 RBX: ffff8b07b1519798 RCX: 0000000000000000 [ 37.527015] RDX: 0000000000000002 RSI: ffffb0c2013e7cc0 RDI: ffff8b07b1519798 [ 37.529934] RBP: ffffb0c2013e7cc0 R08: 0000000000000008 R09: 47a189966239b898 [ 37.532684] R10: dad78b99b278552f R11: 9332dca72259d5ef R12: ffff8b07acd73678 [ 37.535452] R13: 0000000000004c04 R14: 0000000000000000 R15: ffff8b07b841e940 [ 37.538186] FS: 00007fede33b9740(0000) GS:ffff8b07b8e80000(0000) knlGS:0000000000000000 [ 37.541168] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 37.543590] CR2: 00000000206fdf18 CR3: 0000000130b30006 CR4: 00000000000606e0 [ 37.546410] Call Trace: [ 37.547902] blk_freeze_queue+0x9/0x30 [ 37.549968] loop_set_status+0x67/0x3c0 [loop] [ 37.549975] loop_set_status64+0x3b/0x70 [loop] [ 37.549986] lo_ioctl+0x223/0x810 [loop] [ 37.549995] blkdev_ioctl+0x572/0x980 [ 37.550003] block_ioctl+0x34/0x40 [ 37.550006] do_vfs_ioctl+0xa7/0x6d0 [ 37.550017] ksys_ioctl+0x6b/0x80 [ 37.573076] SyS_ioctl+0x5/0x10 [ 37.574831] do_syscall_64+0x6e/0x270 [ 37.576769] entry_SYSCALL_64_after_hwframe+0x42/0xb7 ---------------------------------------- [1] https://syzkaller.appspot.com/bug?id=cd662bc3f6022c0979d01a262c318fab2ee9b56f Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by: syzbot <bot+48594378e9851eab70bcd6f99327c7db58c5a28a@syzkaller.appspotmail.com> Fixes: ecdd09597a572513 ("block/loop: fix race between I/O and set_status") Cc: Ming Lei <tom.leiming@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: stable <stable@vger.kernel.org> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-15loop: Fix lost writes caused by missing flagRoss Zwisler
commit 1d037577c323e5090ce281e96bc313ab2eee5be2 upstream. The following commit: commit aa4d86163e4e ("block: loop: switch to VFS ITER_BVEC") replaced __do_lo_send_write(), which used ITER_KVEC iterators, with lo_write_bvec() which uses ITER_BVEC iterators. In this change, though, the WRITE flag was lost: - iov_iter_kvec(&from, ITER_KVEC | WRITE, &kvec, 1, len); + iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len); This flag is necessary for the DAX case because we make decisions based on whether or not the iterator is a READ or a WRITE in dax_iomap_actor() and in dax_iomap_rw(). We end up going through this path in configurations where we combine a PMEM device with 4k sectors, a loopback device and DAX. The consequence of this missed flag is that what we intend as a write actually turns into a read in the DAX code, so no data is ever written. The very simplest test case is to create a loopback device and try and write a small string to it, then hexdump a few bytes of the device to see if the write took. Without this patch you read back all zeros, with this you read back the string you wrote. For XFS this causes us to fail or panic during the following xfstests: xfs/074 xfs/078 xfs/216 xfs/217 xfs/250 For ext4 we have a similar issue where writes never happen, but we don't currently have any xfstests that use loopback and show this issue. Fix this by restoring the WRITE flag argument to iov_iter_bvec(). This causes the xfstests to all pass. Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: stable@vger.kernel.org Fixes: commit aa4d86163e4e ("block: loop: switch to VFS ITER_BVEC") Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-02-03loop: fix concurrent lo_open/lo_releaseLinus Torvalds
commit ae6650163c66a7eff1acd6eb8b0f752dcfa8eba5 upstream. 范龙飞 reports that KASAN can report a use-after-free in __lock_acquire. The reason is due to insufficient serialization in lo_release(), which will continue to use the loop device even after it has decremented the lo_refcnt to zero. In the meantime, another process can come in, open the loop device again as it is being shut down. Confusion ensues. Reported-by: 范龙飞 <long7573@126.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-09-06loop: set physical block size to logical block sizeOmar Sandoval
Commit 6c6b6f28b333 ("loop: set physical block size to PAGE_SIZE") caused mkfs.xfs to barf on ppc64 [1]. Always using PAGE_SIZE as the physical block size still makes the most sense semantically, but let's just lie and always set it to the same value as the logical block size (same goes for io_min). In the future we might want to at least bump up io_min to PAGE_SIZE but I'm sick of these stupid changes so let's play it safe. 1: https://marc.info/?l=linux-xfs&m=150459024723753&w=2 Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01block/loop: fix use after freeShaohua Li
lo_rw_aio->call_read_iter-> 1 aops->direct_IO 2 iov_iter_revert lo_rw_aio_complete could happen between 1 and 2, the bio and bvec could be freed before 2, which accesses bvec. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01block/loop: allow request merge for directio modeShaohua Li
Currently loop disables merge. While it makes sense for buffer IO mode, directio mode can benefit from request merge. Without merge, loop could send small size IO to underlayer disk and harm performance. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-09-01block/loop: set hw_sectorsShaohua Li
Loop can handle any size of request. Limiting it to 255 sectors just burns the CPU for bio split and request merge for underlayer disk and also cause bad fs block allocation in directio mode. Reviewed-by: Omar Sandoval <osandov@fb.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31loop: fold loop_switch() into callersOmar Sandoval
The comments here are really outdated, and blk-mq made flushing much simpler, so just fold the two cases into the callers. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31loop: add ioctl for changing logical block sizeOmar Sandoval
This is a different approach from the first attempt in f2c6df7dbf9a ("loop: support 4k physical blocksize"). Rather than extending LOOP_{GET,SET}_STATUS, add a separate ioctl just for setting the block size. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31loop: set physical block size to PAGE_SIZEOmar Sandoval
The physical block size is "the lowest possible sector size that the hardware can operate on without reverting to read-modify-write operations" (from the comment on blk_queue_physical_block_size()). Since loop does buffered I/O on the backing file by default, the RMW unit is a page. This isn't the case for direct I/O mode, but let's keep it simple. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-31loop: get rid of lo_blocksizeOmar Sandoval
This is only used for setting the soft block size on the struct block_device once and then never used again. Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-28Merge tag 'v4.13-rc7' into for-4.14/block-postmergeJens Axboe
Linux 4.13-rc7 Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-23Revert "loop: support 4k physical blocksize"Omar Sandoval
There's some stuff still up in the air, let's not get stuck with a subpar ABI. I'll follow up with something better for 4.14. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-08-15loop: fix to a race condition due to the early registration of deviceAnton Volkov
The early device registration made possible a race leading to allocations of disks with wrong minors. This patch moves the device registration further down the loop_init function to make the race infeasible. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Anton Volkov <avolkov@ispras.ru> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-07-05Merge branch 'work.read_write' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull read/write updates from Al Viro: "Christoph's fs/read_write.c series - consolidation and cleanups" * 'work.read_write' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: nfsd: remove nfsd_vfs_read nfsd: use vfs_iter_read/write fs: implement vfs_iter_write using do_iter_write fs: implement vfs_iter_read using do_iter_read fs: move more code into do_iter_read/do_iter_write fs: remove __do_readv_writev fs: remove do_compat_readv_writev fs: remove do_readv_writev
2017-06-29fs: implement vfs_iter_write using do_iter_writeChristoph Hellwig
De-dupliate some code and allow for passing the flags argument to vfs_iter_write. Additionally it now properly updates timestamps. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-29fs: implement vfs_iter_read using do_iter_readChristoph Hellwig
De-dupliate some code and allow for passing the flags argument to vfs_iter_read. Additional it properly updates atime now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-18loop: Add PF_LESS_THROTTLE to block/loop device thread.NeilBrown
When a filesystem is mounted from a loop device, writes are throttled by balance_dirty_pages() twice: once when writing to the filesystem and once when the loop_handle_cmd() writes to the backing file. This double-throttling can trigger positive feedback loops that create significant delays. The throttling at the lower level is seen by the upper level as a slow device, so it throttles extra hard. The PF_LESS_THROTTLE flag was created to handle exactly this circumstance, though with an NFS filesystem mounted from a local NFS server. It reduces the throttling on the lower layer so that it can proceed largely unthrottled. To demonstrate this, create a filesystem on a loop device and write (e.g. with dd) several large files which combine to consume significantly more than the limit set by /proc/sys/vm/dirty_ratio or dirty_bytes. Measure the total time taken. When I do this directly on a device (no loop device) the total time for several runs (mkfs, mount, write 200 files, umount) is fairly stable: 28-35 seconds. When I do this over a loop device the times are much worse and less stable. 52-460 seconds. Half below 100seconds, half above. When I apply this patch, the times become stable again, though not as fast as the no-loop-back case: 53-72 seconds. There may be room for further improvement as the total overhead still seems too high, but this is a big improvement. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Suggested-by: Michal Hocko <mhocko@suse.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-12Merge tag 'v4.12-rc5' into for-4.13/blockJens Axboe
We've already got a few conflicts and upcoming work depends on some of the changes that have gone into mainline as regression fixes for this series. Pull in 4.12-rc5 to resolve these conflicts and make it easier on down stream trees to continue working on 4.13 changes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-09blk-mq: switch ->queue_rq return value to blk_status_tChristoph Hellwig
Use the same values for use for request completion errors as the return value from ->queue_rq. BLK_STS_RESOURCE is special cased to cause a requeue, and all the others are completed as-is. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09block: introduce new block status code typeChristoph Hellwig
Currently we use nornal Linux errno values in the block layer, and while we accept any error a few have overloaded magic meanings. This patch instead introduces a new blk_status_t value that holds block layer specific status codes and explicitly explains their meaning. Helpers to convert from and to the previous special meanings are provided for now, but I suspect we want to get rid of them in the long run - those drivers that have a errno input (e.g. networking) usually get errnos that don't know about the special block layer overloads, and similarly returning them to userspace will usually return somethings that strictly speaking isn't correct for file system operations, but that's left as an exercise for later. For now the set of errors is a very limited set that closely corresponds to the previous overloaded errno values, but there is some low hanging fruite to improve it. blk_status_t (ab)uses the sparse __bitwise annotations to allow for sparse typechecking, so that we can easily catch places passing the wrong values. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-09loop: fix error handling regressionArnd Bergmann
gcc points out an unusual indentation: drivers/block/loop.c: In function 'loop_set_status': drivers/block/loop.c:1149:3: error: this 'if' clause does not guard... [-Werror=misleading-indentation] if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit, ^~ drivers/block/loop.c:1152:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if' goto exit; This was introduced by a new feature that accidentally moved the opening braces from one condition to another. Adding a second pair of braces makes it work correctly again and also more readable. Fixes: f2c6df7dbf9a ("loop: support 4k physical blocksize") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-08loop: support 4k physical blocksizeHannes Reinecke
When generating bootable VM images certain systems (most notably s390x) require devices with 4k blocksize. This patch implements a new flag 'LO_FLAGS_BLOCKSIZE' which will set the physical blocksize to that of the underlying device, and allow to change the logical blocksize for up to the physical blocksize. Signed-off-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-08loop: Remove unused 'bdev' argument from loop_set_capacityHannes Reinecke
Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-06-08Fix loop device flush before configure v3James Wang
While installing SLES-12 (based on v4.4), I found that the installer will stall for 60+ seconds during LVM disk scan. The root cause was determined to be the removal of a bound device check in loop_flush() by commit b5dd2f6047ca ("block: loop: improve performance via blk-mq"). Restoring this check, examining ->lo_state as set by loop_set_fd() eliminates the bad behavior. Test method: modprobe loop max_loop=64 dd if=/dev/zero of=disk bs=512 count=200K for((i=0;i<4;i++))do losetup -f disk; done mkfs.ext4 -F /dev/loop0 for((i=0;i<4;i++))do mkdir t$i; mount /dev/loop$i t$i;done for f in `ls /dev/loop[0-9]*|sort`; do \ echo $f; dd if=$f of=/dev/null bs=512 count=1; \ done Test output: stock patched /dev/loop0 18.1217e-05 8.3842e-05 /dev/loop1 6.1114e-05 0.000147979 /dev/loop10 0.414701 0.000116564 /dev/loop11 0.7474 6.7942e-05 /dev/loop12 0.747986 8.9082e-05 /dev/loop13 0.746532 7.4799e-05 /dev/loop14 0.480041 9.3926e-05 /dev/loop15 1.26453 7.2522e-05 Note that from loop10 onward, the device is not mounted, yet the stock kernel consumes several orders of magnitude more wall time than it does for a mounted device. (Thanks for Mike Galbraith <efault@gmx.de>, give a changelog review.) Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: James Wang <jnwang@suse.com> Fixes: b5dd2f6047ca ("block: loop: improve performance via blk-mq") Signed-off-by: Jens Axboe <axboe@fb.com>
2017-05-02blk-mq: update ->init_request and ->exit_request prototypesChristoph Hellwig
Remove the request_idx parameter, which can't be used safely now that we support I/O schedulers with blk-mq. Except for a superflous check in mtip32xx it was unused anyway. Also pass the tag_set instead of just the driver data - this allows drivers to avoid some code duplication in a follow on cleanup. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-20blk-mq: remove the error argument to blk_mq_complete_requestChristoph Hellwig
Now that all drivers that call blk_mq_complete_requests have a ->complete callback we can remove the direct call to blk_mq_end_request, as well as the error argument to blk_mq_complete_request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Bart Van Assche <Bart.VanAssche@sandisk.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-20loop: zero-fill bio on the submitting cpuChristoph Hellwig
In thruth I've just audited which blk-mq drivers don't currently have a complete callback, but I think this change is at least borderline useful. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08block: remove the discard_zeroes_data flagChristoph Hellwig
Now that we use the proper REQ_OP_WRITE_ZEROES operation everywhere we can kill this hack. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08loop: implement REQ_OP_WRITE_ZEROESChristoph Hellwig
It's identical to discard as hole punches will always leave us with zeroes on reads. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-31blk-mq: constify struct blk_mq_opsEric Biggers
Constify all instances of blk_mq_ops, as they are never modified. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-03Merge branch 'rebased-statx' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
2017-03-03Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block layer fixes from Jens Axboe: "A collection of fixes for this merge window, either fixes for existing issues, or parts that were waiting for acks to come in. This pull request contains: - Allocation of nvme queues on the right node from Shaohua. This was ready long before the merge window, but waiting on an ack from Bjorn on the PCI bit. Now that we have that, the three patches can go in. - Two fixes for blk-mq-sched with nvmeof, which uses hctx specific request allocations. This caused an oops. One part from Sagi, one part from Omar. - A loop partition scan deadlock fix from Omar, fixing a regression in this merge window. - A three-patch series from Keith, closing up a hole on clearing out requests on shutdown/resume. - A stable fix for nbd from Josef, fixing a leak of sockets. - Two fixes for a regression in this window from Jan, fixing a problem with one of his earlier patches dealing with queue vs bdi life times. - A fix for a regression with virtio-blk, causing an IO stall if scheduling is used. From me. - A fix for an io context lock ordering problem. From me" * 'for-linus' of git://git.kernel.dk/linux-block: block: Move bdi_unregister() to del_gendisk() blk-mq: ensure that bd->last is always set correctly block: don't call ioc_exit_icq() with the queue lock held for blk-mq block: Initialize bd_bdi on inode initialization loop: fix LO_FLAGS_PARTSCAN hang nvme: Complete all stuck requests blk-mq: Provide freeze queue timeout blk-mq: Export blk_mq_freeze_queue_wait nbd: stop leaking sockets blk-mq: move update of tags->rqs to __blk_mq_alloc_request() blk-mq: kill blk_mq_set_alloc_data() blk-mq: make blk_mq_alloc_request_hctx() allocate a scheduler request blk-mq-sched: Allocate sched reserved tags as specified in the original queue tagset nvme: allocate nvme_queue in correct node PCI: add an API to get node from vector blk-mq: allocate blk_mq_tags and requests in correct node
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