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Date: Mon, 16 May 2022 09:09:08 +0800 From: yebin <yebin10@...wei.com> To: Jan Kara <jack@...e.cz> CC: <tytso@....edu>, <adilger.kernel@...ger.ca>, <linux-ext4@...r.kernel.org>, <linux-kernel@...r.kernel.org> Subject: Re: [PATCH -next v2] ext4: fix bug_on in ext4_writepages On 2022/5/14 17:28, yebin wrote: > > > On 2022/5/11 21:47, Jan Kara wrote: >> On Tue 10-05-22 18:02:28, Ye Bin wrote: >>> we got issue as follows: >>> EXT4-fs error (device loop0): ext4_mb_generate_buddy:1141: group 0, >>> block bitmap and bg descriptor inconsistent: 25 vs 31513 free cls >>> ------------[ cut here ]------------ >>> kernel BUG at fs/ext4/inode.c:2708! >>> invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI >>> CPU: 2 PID: 2147 Comm: rep Not tainted 5.18.0-rc2-next-20220413+ #155 >>> RIP: 0010:ext4_writepages+0x1977/0x1c10 >>> RSP: 0018:ffff88811d3e7880 EFLAGS: 00010246 >>> RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffff88811c098000 >>> RDX: 0000000000000000 RSI: ffff88811c098000 RDI: 0000000000000002 >>> RBP: ffff888128140f50 R08: ffffffffb1ff6387 R09: 0000000000000000 >>> R10: 0000000000000007 R11: ffffed10250281ea R12: 0000000000000001 >>> R13: 00000000000000a4 R14: ffff88811d3e7bb8 R15: ffff888128141028 >>> FS: 00007f443aed9740(0000) GS:ffff8883aef00000(0000) >>> knlGS:0000000000000000 >>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>> CR2: 0000000020007200 CR3: 000000011c2a4000 CR4: 00000000000006e0 >>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >>> Call Trace: >>> <TASK> >>> do_writepages+0x130/0x3a0 >>> filemap_fdatawrite_wbc+0x83/0xa0 >>> filemap_flush+0xab/0xe0 >>> ext4_alloc_da_blocks+0x51/0x120 >>> __ext4_ioctl+0x1534/0x3210 >>> __x64_sys_ioctl+0x12c/0x170 >>> do_syscall_64+0x3b/0x90 >>> >>> It may happen as follows: >>> 1. write inline_data inode >>> vfs_write >>> new_sync_write >>> ext4_file_write_iter >>> ext4_buffered_write_iter >>> generic_perform_write >>> ext4_da_write_begin >>> ext4_da_write_inline_data_begin -> If inline data size too >>> small will allocate block to write, then mapping will has >>> dirty page >>> ext4_da_convert_inline_data_to_extent ->clear >>> EXT4_STATE_MAY_INLINE_DATA >>> 2. fallocate >>> do_vfs_ioctl >>> ioctl_preallocate >>> vfs_fallocate >>> ext4_fallocate >>> ext4_convert_inline_data >>> ext4_convert_inline_data_nolock >>> ext4_map_blocks -> fail will goto restore data >>> ext4_restore_inline_data >>> ext4_create_inline_data >>> ext4_write_inline_data >>> ext4_set_inode_state -> set inode >>> EXT4_STATE_MAY_INLINE_DATA >>> 3. writepages >>> __ext4_ioctl >>> ext4_alloc_da_blocks >>> filemap_flush >>> filemap_fdatawrite_wbc >>> do_writepages >>> ext4_writepages >>> if (ext4_has_inline_data(inode)) >>> BUG_ON(ext4_test_inode_state(inode, >>> EXT4_STATE_MAY_INLINE_DATA)) >>> >>> The root cause of this issue is we destory inline data until call >>> ext4_writepages >>> under delay allocation mode. But there maybe already covert from >>> inline to extent. >>> To solved this issue, we call filemap_flush firstly. >>> >>> Signed-off-by: Ye Bin <yebin10@...wei.com> >>> --- >>> fs/ext4/inline.c | 8 ++++++++ >>> 1 file changed, 8 insertions(+) >>> >>> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c >>> index 6d253edebf9f..130ed5d83734 100644 >>> --- a/fs/ext4/inline.c >>> +++ b/fs/ext4/inline.c >>> @@ -2002,6 +2002,14 @@ int ext4_convert_inline_data(struct inode >>> *inode) >>> if (!ext4_has_inline_data(inode)) { >>> ext4_clear_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA); >>> return 0; >>> + } else if (test_opt(inode->i_sb, DELALLOC) && >>> !S_ISDIR(inode->i_mode)) { >>> + error = filemap_flush(inode->i_mapping); >> This is actually an interesting option and I kind of like it but >> shouldn't >> we restrict this to the situation when EXT4_STATE_MAY_INLINE_DATA is >> clear? >> Otherwise we would be writing out inline data to the inode unnecessarily >> for each ext4_convert_inline_data() call. >> >> Honza > Acctually, this issue only exist in delay allocate mode. Do we need > to restrict this to > “test_opt(inode->i_sb, DELALLOC)” as follows ? I've looked again. There's no need to add this constraint. I'll send v2 patch. > @@ -2002,6 +2002,13 @@ int ext4_convert_inline_data(struct inode *inode) > if (!ext4_has_inline_data(inode)) { > ext4_clear_inode_state(inode, > EXT4_STATE_MAY_INLINE_DATA); > return 0; > + } else if (test_opt(inode->i_sb, DELALLOC) && > + !ext4_test_inode_state(inode, > EXT4_STATE_MAY_INLINE_DATA)) { > + error = filemap_flush(inode->i_mapping); > + if (error) > + return error; > + if (!ext4_has_inline_data(inode)) > + return 0; > } > > > . >
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