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e897be17a4
Patch series "nilfs2 lockdep warning fixes".
The first two are to resolve the lockdep warning issue, and the last one
is the accompanying cleanup and low priority.
Based on your comment, this series solves the issue by separating inode
object as needed. Since I was worried about the impact of the object
composition changes, I tested the series carefully not to cause
regressions especially for delicate functions such like disk space
reclamation and snapshots.
This patch (of 3):
If CONFIG_LOCKDEP is enabled, nilfs2 hits lockdep warnings at
inode_to_wb() during page/folio operations for btree nodes:
WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 inode_to_wb include/linux/backing-dev.h:269 [inline]
WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 folio_account_dirtied mm/page-writeback.c:2460 [inline]
WARNING: CPU: 0 PID: 6575 at include/linux/backing-dev.h:269 __folio_mark_dirty+0xa7c/0xe30 mm/page-writeback.c:2509
Modules linked in:
...
RIP: 0010:inode_to_wb include/linux/backing-dev.h:269 [inline]
RIP: 0010:folio_account_dirtied mm/page-writeback.c:2460 [inline]
RIP: 0010:__folio_mark_dirty+0xa7c/0xe30 mm/page-writeback.c:2509
...
Call Trace:
__set_page_dirty include/linux/pagemap.h:834 [inline]
mark_buffer_dirty+0x4e6/0x650 fs/buffer.c:1145
nilfs_btree_propagate_p fs/nilfs2/btree.c:1889 [inline]
nilfs_btree_propagate+0x4ae/0xea0 fs/nilfs2/btree.c:2085
nilfs_bmap_propagate+0x73/0x170 fs/nilfs2/bmap.c:337
nilfs_collect_dat_data+0x45/0xd0 fs/nilfs2/segment.c:625
nilfs_segctor_apply_buffers+0x14a/0x470 fs/nilfs2/segment.c:1009
nilfs_segctor_scan_file+0x47a/0x700 fs/nilfs2/segment.c:1048
nilfs_segctor_collect_blocks fs/nilfs2/segment.c:1224 [inline]
nilfs_segctor_collect fs/nilfs2/segment.c:1494 [inline]
nilfs_segctor_do_construct+0x14f3/0x6c60 fs/nilfs2/segment.c:2036
nilfs_segctor_construct+0x7a7/0xb30 fs/nilfs2/segment.c:2372
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2480 [inline]
nilfs_segctor_thread+0x3c3/0xf90 fs/nilfs2/segment.c:2563
kthread+0x405/0x4f0 kernel/kthread.c:327
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
This is because nilfs2 uses two page caches for each inode and
inode->i_mapping never points to one of them, the btree node cache.
This causes inode_to_wb(inode) to refer to a different page cache than
the caller page/folio operations such like __folio_start_writeback(),
__folio_end_writeback(), or __folio_mark_dirty() acquired the lock.
This patch resolves the issue by allocating and using an additional
inode to hold the page cache of btree nodes. The inode is attached
one-to-one to the traditional nilfs2 inode if it requires a block
mapping with b-tree. This setup change is in memory only and does not
affect the disk format.
Link: https://lkml.kernel.org/r/1647867427-30498-1-git-send-email-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/1647867427-30498-2-git-send-email-konishi.ryusuke@gmail.com
Link: https://lore.kernel.org/r/YXrYvIo8YRnAOJCj@casper.infradead.org
Link: https://lore.kernel.org/r/9a20b33d-b38f-b4a2-4742-c1eb5b8e4d6c@redhat.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reported-by: syzbot+0d5b462a6f07447991b3@syzkaller.appspotmail.com
Reported-by: syzbot+34ef28bb2aeb28724aa0@syzkaller.appspotmail.com
Reported-by: Hao Sun <sunhao.th@gmail.com>
Reported-by: David Hildenbrand <david@redhat.com>
Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* NILFS B-tree node cache
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* Written by Seiji Kihara.
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* Revised by Ryusuke Konishi.
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*/
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#ifndef _NILFS_BTNODE_H
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#define _NILFS_BTNODE_H
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#include <linux/types.h>
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#include <linux/buffer_head.h>
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#include <linux/fs.h>
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#include <linux/backing-dev.h>
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/**
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* struct nilfs_btnode_chkey_ctxt - change key context
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* @oldkey: old key of block's moving content
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* @newkey: new key for block's content
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* @bh: buffer head of old buffer
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* @newbh: buffer head of new buffer
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*/
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struct nilfs_btnode_chkey_ctxt {
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__u64 oldkey;
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__u64 newkey;
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struct buffer_head *bh;
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struct buffer_head *newbh;
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};
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void nilfs_init_btnc_inode(struct inode *btnc_inode);
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void nilfs_btnode_cache_clear(struct address_space *);
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struct buffer_head *nilfs_btnode_create_block(struct address_space *btnc,
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__u64 blocknr);
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int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t, int,
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int, struct buffer_head **, sector_t *);
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void nilfs_btnode_delete(struct buffer_head *);
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int nilfs_btnode_prepare_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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void nilfs_btnode_commit_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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void nilfs_btnode_abort_change_key(struct address_space *,
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struct nilfs_btnode_chkey_ctxt *);
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#endif /* _NILFS_BTNODE_H */
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