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| author | Zhihao Cheng <chengzhihao1@huawei.com> | 2023-03-21 09:37:21 +0800 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-04-28 11:07:19 -0400 |
| commit | 1dedde690303c05ef732b7c5c8356fdf60a4ade3 (patch) | |
| tree | 471e7534557f3fb5f42467841648b002b26095b5 | |
| parent | 519fe1bae7e20fc4e7f179d50b6102b49980e85d (diff) | |
| download | linux-1dedde690303c05ef732b7c5c8356fdf60a4ade3.tar.gz | |
ext4: fix i_disksize exceeding i_size problem in paritally written case
It is possible for i_disksize can exceed i_size, triggering a warning.
generic_perform_write
copied = iov_iter_copy_from_user_atomic(len) // copied < len
ext4_da_write_end
| ext4_update_i_disksize
| new_i_size = pos + copied;
| WRITE_ONCE(EXT4_I(inode)->i_disksize, newsize) // update i_disksize
| generic_write_end
| copied = block_write_end(copied, len) // copied = 0
| if (unlikely(copied < len))
| if (!PageUptodate(page))
| copied = 0;
| if (pos + copied > inode->i_size) // return false
if (unlikely(copied == 0))
goto again;
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}
We get i_disksize greater than i_size here, which could trigger WARNING
check 'i_size_read(inode) < EXT4_I(inode)->i_disksize' while doing dio:
ext4_dio_write_iter
iomap_dio_rw
__iomap_dio_rw // return err, length is not aligned to 512
ext4_handle_inode_extension
WARN_ON_ONCE(i_size_read(inode) < EXT4_I(inode)->i_disksize) // Oops
WARNING: CPU: 2 PID: 2609 at fs/ext4/file.c:319
CPU: 2 PID: 2609 Comm: aa Not tainted 6.3.0-rc2
RIP: 0010:ext4_file_write_iter+0xbc7
Call Trace:
vfs_write+0x3b1
ksys_write+0x77
do_syscall_64+0x39
Fix it by updating 'copied' value before updating i_disksize just like
ext4_write_inline_data_end() does.
A reproducer can be found in the buganizer link below.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217209
Fixes: 64769240bd07 ("ext4: Add delayed allocation support in data=writeback mode")
Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20230321013721.89818-1-chengzhihao1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/inode.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 8dbd352e3986..1cfbb929c694 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2982,6 +2982,9 @@ static int ext4_da_write_end(struct file *file, ext4_has_inline_data(inode)) return ext4_write_inline_data_end(inode, pos, len, copied, page); + if (unlikely(copied < len) && !PageUptodate(page)) + copied = 0; + start = pos & (PAGE_SIZE - 1); end = start + copied - 1; |