forked from TencentOS/TencentOS-kernel
4 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Jan Kara
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dba9712ee0 |
fs: Don't invalidate page buffers in block_write_full_page()
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 <yebin10@huawei.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
CC: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Xianting Tian
|
4e9fecce64 |
fs: prevent BUG_ON in submit_bh_wbc()
[ 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 <xianting_tian@126.com>
Link: https://lore.kernel.org/r/1596211825-8750-1-git-send-email-xianting_tian@126.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Roman Gushchin
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f33b142683 |
ext4: use non-movable memory for superblock readahead
commit d87f639258a6a5980183f11876c884931ad93da2 upstream.
Since commit a8ac900b8163 ("ext4: use non-movable memory for the
superblock") buffers for ext4 superblock were allocated using
the sb_bread_unmovable() helper which allocated buffer heads
out of non-movable memory blocks. It was necessarily to not block
page migrations and do not cause cma allocation failures.
However commit 85c8f176a611 ("ext4: preload block group descriptors")
broke this by introducing pre-reading of the ext4 superblock.
The problem is that __breadahead() is using __getblk() underneath,
which allocates buffer heads out of movable memory.
It resulted in page migration failures I've seen on a machine
with an ext4 partition and a preallocated cma area.
Fix this by introducing sb_breadahead_unmovable() and
__breadahead_gfp() helpers which use non-movable memory for buffer
head allocations and use them for the ext4 superblock readahead.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Fixes: 85c8f176a611 ("ext4: preload block group descriptors")
Signed-off-by: Roman Gushchin <guro@fb.com>
Link: https://lore.kernel.org/r/20200229001411.128010-1-guro@fb.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Kaixu Xia
|
590eaf1fec |
Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces.
Signed-off-by: Kaixu Xia <kaixuxia@tencent.com> |