user/sven/linux.git/fs/buffer.c, branch v4.9.266

fs: Don't invalidate page buffers in block_write_full_page()

2020-11-10T09:23:56Z

commit 6dbf7bb555981fb5faf7b691e8f6169fc2b2e63b upstream. If block_write_full_page() is called for a page that is beyond current inode size, it will truncate page buffers for the page and return 0. This logic has been added in 2.5.62 in commit 81eb69062588 ("fix ext3 BUG due to race with truncate") in history.git tree to fix a problem with ext3 in data=ordered mode. This particular problem doesn't exist anymore because ext3 is long gone and ext4 handles ordered data differently. Also normally buffers are invalidated by truncate code and there's no need to specially handle this in ->writepage() code. This invalidation of page buffers in block_write_full_page() is causing issues to filesystems (e.g. ext4 or ocfs2) when block device is shrunk under filesystem's hands and metadata buffers get discarded while being tracked by the journalling layer. Although it is obviously "not supported" it can cause kernel crashes like: [ 7986.689400] BUG: unable to handle kernel NULL pointer dereference at +0000000000000008 [ 7986.697197] PGD 0 P4D 0 [ 7986.699724] Oops: 0002 [#1] SMP PTI [ 7986.703200] CPU: 4 PID: 203778 Comm: jbd2/dm-3-8 Kdump: loaded Tainted: G +O --------- - - 4.18.0-147.5.0.5.h126.eulerosv2r9.x86_64 #1 [ 7986.716438] Hardware name: Huawei RH2288H V3/BC11HGSA0, BIOS 1.57 08/11/2015 [ 7986.723462] RIP: 0010:jbd2_journal_grab_journal_head+0x1b/0x40 [jbd2] ... [ 7986.810150] Call Trace: [ 7986.812595] __jbd2_journal_insert_checkpoint+0x23/0x70 [jbd2] [ 7986.818408] jbd2_journal_commit_transaction+0x155f/0x1b60 [jbd2] [ 7986.836467] kjournald2+0xbd/0x270 [jbd2] which is not great. The crash happens because bh->b_private is suddently NULL although BH_JBD flag is still set (this is because block_invalidatepage() cleared BH_Mapped flag and subsequent bh lookup found buffer without BH_Mapped set, called init_page_buffers() which has rewritten bh->b_private). So just remove the invalidation in block_write_full_page(). Note that the buffer cache invalidation when block device changes size is already careful to avoid similar problems by using invalidate_mapping_pages() which skips busy buffers so it was only this odd block_write_full_page() behavior that could tear down bdev buffers under filesystem's hands. Reported-by: Ye Bin Signed-off-by: Jan Kara Reviewed-by: Christoph Hellwig CC: stable@vger.kernel.org Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

fs: prevent BUG_ON in submit_bh_wbc()

2020-09-03T09:21:19Z

[ Upstream commit 377254b2cd2252c7c3151b113cbdf93a7736c2e9 ] If a device is hot-removed --- for example, when a physical device is unplugged from pcie slot or a nbd device's network is shutdown --- this can result in a BUG_ON() crash in submit_bh_wbc(). This is because the when the block device dies, the buffer heads will have their Buffer_Mapped flag get cleared, leading to the crash in submit_bh_wbc. We had attempted to work around this problem in commit a17712c8 ("ext4: check superblock mapped prior to committing"). Unfortunately, it's still possible to hit the BUG_ON(!buffer_mapped(bh)) if the device dies between when the work-around check in ext4_commit_super() and when submit_bh_wbh() is finally called: Code path: ext4_commit_super judge if 'buffer_mapped(sbh)' is false, return <== commit a17712c8 lock_buffer(sbh) ... unlock_buffer(sbh) __sync_dirty_buffer(sbh,... lock_buffer(sbh) judge if 'buffer_mapped(sbh))' is false, return <== added by this patch submit_bh(...,sbh) submit_bh_wbc(...,sbh,...) [100722.966497] kernel BUG at fs/buffer.c:3095! <== BUG_ON(!buffer_mapped(bh))' in submit_bh_wbc() [100722.966503] invalid opcode: 0000 [#1] SMP [100722.966566] task: ffff8817e15a9e40 task.stack: ffffc90024744000 [100722.966574] RIP: 0010:submit_bh_wbc+0x180/0x190 [100722.966575] RSP: 0018:ffffc90024747a90 EFLAGS: 00010246 [100722.966576] RAX: 0000000000620005 RBX: ffff8818a80603a8 RCX: 0000000000000000 [100722.966576] RDX: ffff8818a80603a8 RSI: 0000000000020800 RDI: 0000000000000001 [100722.966577] RBP: ffffc90024747ac0 R08: 0000000000000000 R09: ffff88207f94170d [100722.966578] R10: 00000000000437c8 R11: 0000000000000001 R12: 0000000000020800 [100722.966578] R13: 0000000000000001 R14: 000000000bf9a438 R15: ffff88195f333000 [100722.966580] FS: 00007fa2eee27700(0000) GS:ffff88203d840000(0000) knlGS:0000000000000000 [100722.966580] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [100722.966581] CR2: 0000000000f0b008 CR3: 000000201a622003 CR4: 00000000007606e0 [100722.966582] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [100722.966583] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [100722.966583] PKRU: 55555554 [100722.966583] Call Trace: [100722.966588] __sync_dirty_buffer+0x6e/0xd0 [100722.966614] ext4_commit_super+0x1d8/0x290 [ext4] [100722.966626] __ext4_std_error+0x78/0x100 [ext4] [100722.966635] ? __ext4_journal_get_write_access+0xca/0x120 [ext4] [100722.966646] ext4_reserve_inode_write+0x58/0xb0 [ext4] [100722.966655] ? ext4_dirty_inode+0x48/0x70 [ext4] [100722.966663] ext4_mark_inode_dirty+0x53/0x1e0 [ext4] [100722.966671] ? __ext4_journal_start_sb+0x6d/0xf0 [ext4] [100722.966679] ext4_dirty_inode+0x48/0x70 [ext4] [100722.966682] __mark_inode_dirty+0x17f/0x350 [100722.966686] generic_update_time+0x87/0xd0 [100722.966687] touch_atime+0xa9/0xd0 [100722.966690] generic_file_read_iter+0xa09/0xcd0 [100722.966694] ? page_cache_tree_insert+0xb0/0xb0 [100722.966704] ext4_file_read_iter+0x4a/0x100 [ext4] [100722.966707] ? __inode_security_revalidate+0x4f/0x60 [100722.966709] __vfs_read+0xec/0x160 [100722.966711] vfs_read+0x8c/0x130 [100722.966712] SyS_pread64+0x87/0xb0 [100722.966716] do_syscall_64+0x67/0x1b0 [100722.966719] entry_SYSCALL64_slow_path+0x25/0x25 To address this, add the check of 'buffer_mapped(bh)' to __sync_dirty_buffer(). This also has the benefit of fixing this for other file systems. With this addition, we can drop the workaround in ext4_commit_supper(). [ Commit description rewritten by tytso. ] Signed-off-by: Xianting Tian Link: https://lore.kernel.org/r/1596211825-8750-1-git-send-email-xianting_tian@126.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin

fs: fix guard_bio_eod to check for real EOD errors

2019-04-05T20:29:08Z

[ Upstream commit dce30ca9e3b676fb288c33c1f4725a0621361185 ] guard_bio_eod() can truncate a segment in bio to allow it to do IO on odd last sectors of a device. It already checks if the IO starts past EOD, but it does not consider the possibility of an IO request starting within device boundaries can contain more than one segment past EOD. In such cases, truncated_bytes can be bigger than PAGE_SIZE, and will underflow bvec->bv_len. Fix this by checking if truncated_bytes is lower than PAGE_SIZE. This situation has been found on filesystems such as isofs and vfat, which doesn't check the device size before mount, if the device is smaller than the filesystem itself, a readahead on such filesystem, which spans EOD, can trigger this situation, leading a call to zero_user() with a wrong size possibly corrupting memory. I didn't see any crash, or didn't let the system run long enough to check if memory corruption will be hit somewhere, but adding instrumentation to guard_bio_end() to check truncated_bytes size, was enough to see the error. The following script can trigger the error. MNT=/mnt IMG=./DISK.img DEV=/dev/loop0 mkfs.vfat $IMG mount $IMG $MNT cp -R /etc $MNT &> /dev/null umount $MNT losetup -D losetup --find --show --sizelimit 16247280 $IMG mount $DEV $MNT find $MNT -type f -exec cat {} + >/dev/null Kudos to Eric Sandeen for coming up with the reproducer above Reviewed-by: Ming Lei Signed-off-by: Carlos Maiolino Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

fs: ratelimit __find_get_block_slow() failure message.

2019-03-13T21:05:01Z

[ Upstream commit 43636c804df0126da669c261fc820fb22f62bfc2 ] When something let __find_get_block_slow() hit all_mapped path, it calls printk() for 100+ times per a second. But there is no need to print same message with such high frequency; it is just asking for stall warning, or at least bloating log files. [ 399.866302][T15342] __find_get_block_slow() failed. block=1, b_blocknr=8 [ 399.873324][T15342] b_state=0x00000029, b_size=512 [ 399.878403][T15342] device loop0 blocksize: 4096 [ 399.883296][T15342] __find_get_block_slow() failed. block=1, b_blocknr=8 [ 399.890400][T15342] b_state=0x00000029, b_size=512 [ 399.895595][T15342] device loop0 blocksize: 4096 [ 399.900556][T15342] __find_get_block_slow() failed. block=1, b_blocknr=8 [ 399.907471][T15342] b_state=0x00000029, b_size=512 [ 399.912506][T15342] device loop0 blocksize: 4096 This patch reduces frequency to up to once per a second, in addition to concatenating three lines into one. [ 399.866302][T15342] __find_get_block_slow() failed. block=1, b_blocknr=8, b_state=0x00000029, b_size=512, device loop0 blocksize: 4096 Signed-off-by: Tetsuo Handa Reviewed-by: Jan Kara Cc: Dmitry Vyukov Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

fs: add i_blocksize()

2017-06-14T13:06:00Z

commit 93407472a21b82f39c955ea7787e5bc7da100642 upstream. Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs branch. This patch also fixes multiple checkpatch warnings: WARNING: Prefer 'unsigned int' to bare use of 'unsigned' Thanks to Andrew Morton for suggesting more appropriate function instead of macro. [geliangtang@gmail.com: truncate: use i_blocksize()] Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be Signed-off-by: Fabian Frederick Signed-off-by: Geliang Tang Cc: Alexander Viro Cc: Ross Zwisler Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

fs: use mapping_set_error instead of opencoded set_bit

2016-10-11T22:06:33Z

The mapping_set_error() helper sets the correct AS_ flag for the mapping so there is no reason to open code it. Use the helper directly. [akpm@linux-foundation.org: be honest about conversion from -ENXIO to -EIO] Link: http://lkml.kernel.org/r/20160912111608.2588-2-mhocko@kernel.org Signed-off-by: Michal Hocko Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fs/buffer.c: make __getblk_slow() static

2016-09-27T22:47:38Z

__getblk_slow() was exported to modules in commit 3b5e6454aaf6 ("fs/buffer.c: support buffer cache allocations with gfp modifiers"). This seems to have been a mistake, as no users were introduced nor was the function declared in a header. Change it back to 'static'. Signed-off-by: Eric Biggers Signed-off-by: Al Viro

Merge tag 'xfs-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

2016-07-27T16:53:35Z

Pull xfs updates from Dave Chinner: "The major addition is the new iomap based block mapping infrastructure. We've been kicking this about locally for years, but there are other filesystems want to use it too (e.g. gfs2). Now it is fully working, reviewed and ready for merge and be used by other filesystems. There are a lot of other fixes and cleanups in the tree, but those are XFS internal things and none are of the scale or visibility of the iomap changes. See below for details. I am likely to send another pull request next week - we're just about ready to merge some new functionality (on disk block->owner reverse mapping infrastructure), but that's a huge chunk of code (74 files changed, 7283 insertions(+), 1114 deletions(-)) so I'm keeping that separate to all the "normal" pull request changes so they don't get lost in the noise. Summary of changes in this update: - generic iomap based IO path infrastructure - generic iomap based fiemap implementation - xfs iomap based Io path implementation - buffer error handling fixes - tracking of in flight buffer IO for unmount serialisation - direct IO and DAX io path separation and simplification - shortform directory format definition changes for wider platform compatibility - various buffer cache fixes - cleanups in preparation for rmap merge - error injection cleanups and fixes - log item format buffer memory allocation restructuring to prevent rare OOM reclaim deadlocks - sparse inode chunks are now fully supported" * tag 'xfs-for-linus-4.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (53 commits) xfs: remove EXPERIMENTAL tag from sparse inode feature xfs: bufferhead chains are invalid after end_page_writeback xfs: allocate log vector buffers outside CIL context lock libxfs: directory node splitting does not have an extra block xfs: remove dax code from object file when disabled xfs: skip dirty pages in ->releasepage() xfs: remove __arch_pack xfs: kill xfs_dir2_inou_t xfs: kill xfs_dir2_sf_off_t xfs: split direct I/O and DAX path xfs: direct calls in the direct I/O path xfs: stop using generic_file_read_iter for direct I/O xfs: split xfs_file_read_iter into buffered and direct I/O helpers xfs: remove s_maxbytes enforcement in xfs_file_read_iter xfs: kill ioflags xfs: don't pass ioflags around in the ioctl path xfs: track and serialize in-flight async buffers against unmount xfs: exclude never-released buffers from buftarg I/O accounting xfs: don't reset b_retries to 0 on every failure xfs: remove extraneous buffer flag changes ...

Merge branch 'for-4.8/drivers' of git://git.kernel.dk/linux-block

2016-07-26T22:37:51Z

Pull block driver updates from Jens Axboe: "This branch also contains core changes. I've come to the conclusion that from 4.9 and forward, I'll be doing just a single branch. We often have dependencies between core and drivers, and it's hard to always split them up appropriately without pulling core into drivers when that happens. That said, this contains: - separate secure erase type for the core block layer, from Christoph. - set of discard fixes, from Christoph. - bio shrinking fixes from Christoph, as a followup up to the op/flags change in the core branch. - map and append request fixes from Christoph. - NVMeF (NVMe over Fabrics) code from Christoph. This is pretty exciting! - nvme-loop fixes from Arnd. - removal of ->driverfs_dev from Dan, after providing a device_add_disk() helper. - bcache fixes from Bhaktipriya and Yijing. - cdrom subchannel read fix from Vchannaiah. - set of lightnvm updates from Wenwei, Matias, Johannes, and Javier. - set of drbd updates and fixes from Fabian, Lars, and Philipp. - mg_disk error path fix from Bart. - user notification for failed device add for loop, from Minfei. - NVMe in general: + NVMe delay quirk from Guilherme. + SR-IOV support and command retry limits from Keith. + fix for memory-less NUMA node from Masayoshi. + use UINT_MAX for discard sectors, from Minfei. + cancel IO fixes from Ming. + don't allocate unused major, from Neil. + error code fixup from Dan. + use constants for PSDT/FUSE from James. + variable init fix from Jay. + fabrics fixes from Ming, Sagi, and Wei. + various fixes" * 'for-4.8/drivers' of git://git.kernel.dk/linux-block: (115 commits) nvme/pci: Provide SR-IOV support nvme: initialize variable before logical OR'ing it block: unexport various bio mapping helpers scsi/osd: open code blk_make_request target: stop using blk_make_request block: simplify and export blk_rq_append_bio block: ensure bios return from blk_get_request are properly initialized virtio_blk: use blk_rq_map_kern memstick: don't allow REQ_TYPE_BLOCK_PC requests block: shrink bio size again block: simplify and cleanup bvec pool handling block: get rid of bio_rw and READA block: don't ignore -EOPNOTSUPP blkdev_issue_write_same block: introduce BLKDEV_DISCARD_ZERO to fix zeroout NVMe: don't allocate unused nvme_major nvme: avoid crashes when node 0 is memoryless node. nvme: Limit command retries loop: Make user notify for adding loop device failed nvme-loop: fix nvme-loop Kconfig dependencies nvmet: fix return value check in nvmet_subsys_alloc() ...

Merge branch 'for-4.8/core' of git://git.kernel.dk/linux-block

2016-07-26T22:03:07Z

Pull core block updates from Jens Axboe: - the big change is the cleanup from Mike Christie, cleaning up our uses of command types and modified flags. This is what will throw some merge conflicts - regression fix for the above for btrfs, from Vincent - following up to the above, better packing of struct request from Christoph - a 2038 fix for blktrace from Arnd - a few trivial/spelling fixes from Bart Van Assche - a front merge check fix from Damien, which could cause issues on SMR drives - Atari partition fix from Gabriel - convert cfq to highres timers, since jiffies isn't granular enough for some devices these days. From Jan and Jeff - CFQ priority boost fix idle classes, from me - cleanup series from Ming, improving our bio/bvec iteration - a direct issue fix for blk-mq from Omar - fix for plug merging not involving the IO scheduler, like we do for other types of merges. From Tahsin - expose DAX type internally and through sysfs. From Toshi and Yigal * 'for-4.8/core' of git://git.kernel.dk/linux-block: (76 commits) block: Fix front merge check block: do not merge requests without consulting with io scheduler block: Fix spelling in a source code comment block: expose QUEUE_FLAG_DAX in sysfs block: add QUEUE_FLAG_DAX for devices to advertise their DAX support Btrfs: fix comparison in __btrfs_map_block() block: atari: Return early for unsupported sector size Doc: block: Fix a typo in queue-sysfs.txt cfq-iosched: Charge at least 1 jiffie instead of 1 ns cfq-iosched: Fix regression in bonnie++ rewrite performance cfq-iosched: Convert slice_resid from u64 to s64 block: Convert fifo_time from ulong to u64 blktrace: avoid using timespec block/blk-cgroup.c: Declare local symbols static block/bio-integrity.c: Add #include "blk.h" block/partition-generic.c: Remove a set-but-not-used variable block: bio: kill BIO_MAX_SIZE cfq-iosched: temporarily boost queue priority for idle classes block: drbd: avoid to use BIO_MAX_SIZE block: bio: remove BIO_MAX_SECTORS ...