Messages in this thread | | | Subject | Re: [PATCH -next] ext4: fix warning in ext4_handle_inode_extension | From | yebin <> | Date | Wed, 30 Mar 2022 20:08:13 +0800 |
| |
On 2022/3/29 17:28, Jan Kara wrote: > On Sat 26-03-22 14:53:51, Ye Bin wrote: >> We got issue as follows: >> EXT4-fs error (device loop0) in ext4_reserve_inode_write:5741: Out of memory >> EXT4-fs error (device loop0): ext4_setattr:5462: inode #13: comm syz-executor.0: mark_inode_dirty error >> EXT4-fs error (device loop0) in ext4_setattr:5519: Out of memory >> EXT4-fs error (device loop0): ext4_ind_map_blocks:595: inode #13: comm syz-executor.0: Can't allocate blocks for non-extent mapped inodes with bigalloc >> ------------[ cut here ]------------ >> WARNING: CPU: 1 PID: 4361 at fs/ext4/file.c:301 ext4_file_write_iter+0x11c9/0x1220 >> Modules linked in: >> CPU: 1 PID: 4361 Comm: syz-executor.0 Not tainted 5.10.0+ #1 >> RIP: 0010:ext4_file_write_iter+0x11c9/0x1220 >> RSP: 0018:ffff924d80b27c00 EFLAGS: 00010282 >> RAX: ffffffff815a3379 RBX: 0000000000000000 RCX: 000000003b000000 >> RDX: ffff924d81601000 RSI: 00000000000009cc RDI: 00000000000009cd >> RBP: 000000000000000d R08: ffffffffbc5a2c6b R09: 0000902e0e52a96f >> R10: ffff902e2b7c1b40 R11: ffff902e2b7c1b40 R12: 000000000000000a >> R13: 0000000000000001 R14: ffff902e0e52aa10 R15: ffffffffffffff8b >> FS: 00007f81a7f65700(0000) GS:ffff902e3bc80000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: ffffffffff600400 CR3: 000000012db88001 CR4: 00000000003706e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> do_iter_readv_writev+0x2e5/0x360 >> do_iter_write+0x112/0x4c0 >> do_pwritev+0x1e5/0x390 >> __x64_sys_pwritev2+0x7e/0xa0 >> do_syscall_64+0x37/0x50 >> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> >> Above issue may happen as follows: >> Assume >> inode.i_size=4096 >> EXT4_I(inode)->i_disksize=4096 >> >> step 1: set inode->i_isize = 8192 >> ext4_setattr >> if (attr->ia_size != inode->i_size) >> EXT4_I(inode)->i_disksize = attr->ia_size; >> rc = ext4_mark_inode_dirty >> ext4_reserve_inode_write >> ext4_get_inode_loc >> __ext4_get_inode_loc >> sb_getblk --> return -ENOMEM >> ... >> if (!error) ->will not update i_size >> i_size_write(inode, attr->ia_size); >> Now: >> inode.i_size=4096 >> EXT4_I(inode)->i_disksize=8192 >> >> step 2: Direct write 4096 bytes >> ext4_file_write_iter >> ext4_dio_write_iter >> iomap_dio_rw ->return error >> if (extend) >> ext4_handle_inode_extension >> WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize); >> ->Then trigger warning. >> >> To solve above issue, if mark inode dirty failed in ext4_setattr just >> set 'EXT4_I(inode)->i_disksize' with old value. >> >> Signed-off-by: Ye Bin <yebin10@huawei.com> > Thanks for the fix! So I think this deserves a further debate. I have two > points here: > > 1) If ext4_mark_inode_dirty() fails (or basically any metadata writeback) > we must abort the journal because metadata is not guaranteed to be > consistent anymore. In this particular callsite of ext4_mark_inode_dirty() > you were able to undo the changes but there are many more where it is not > sanely possible AFAICT. Hence I think that ext4_reserve_inode_write() needs > to call ext4_journal_abort_handle() (as already happens inside > __ext4_journal_get_write_access()) and not just ext4_std_error(). > > 2) The assertion in ext4_handle_inode_extension() should be conditioned on > !is_journal_aborted() to avoid useless warnings for filesystems we know are > inconsistent anyway. > > Thoughts? > > Honza Do you mean call jbd2_abort in ext4_reserve_inode_write() ? If we abort journal when metadata is not guaranteed to be consistent. The mode of ‘errors=continue’ is unnecessary. >> --- >> fs/ext4/inode.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c >> index 90fd6f7b6209..8adf1f802f6c 100644 >> --- a/fs/ext4/inode.c >> +++ b/fs/ext4/inode.c >> @@ -5384,6 +5384,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, >> if (attr->ia_valid & ATTR_SIZE) { >> handle_t *handle; >> loff_t oldsize = inode->i_size; >> + loff_t old_disksize; >> int shrink = (attr->ia_size < inode->i_size); >> >> if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { >> @@ -5455,6 +5456,7 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, >> inode->i_sb->s_blocksize_bits); >> >> down_write(&EXT4_I(inode)->i_data_sem); >> + old_disksize = EXT4_I(inode)->i_disksize; >> EXT4_I(inode)->i_disksize = attr->ia_size; >> rc = ext4_mark_inode_dirty(handle, inode); >> if (!error) >> @@ -5466,6 +5468,8 @@ int ext4_setattr(struct user_namespace *mnt_userns, struct dentry *dentry, >> */ >> if (!error) >> i_size_write(inode, attr->ia_size); >> + else >> + EXT4_I(inode)->i_disksize = old_disksize; >> up_write(&EXT4_I(inode)->i_data_sem); >> ext4_journal_stop(handle); >> if (error) >> -- >> 2.31.1 >>
| |