| Message ID | 20230321013721.89818-1-chengzhihao1@huawei.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | [v2] ext4: Fix i_disksize exceeding i_size problem in paritally written case | expand |
On Tue 21-03-23 09:37:21, Zhihao Cheng wrote: > Following process makes i_disksize exceed i_size: > > 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. > > Fetch a reproducer in [Link]. > > 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> Looks good to me. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > v1->v2: Check and update 'copied' value before updating i_disksize rather > than opencoding generic_write_end(). > fs/ext4/inode.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c > index bf0b7dea4900..41ba1c432844 100644 > --- a/fs/ext4/inode.c > +++ b/fs/ext4/inode.c > @@ -3148,6 +3148,9 @@ 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; > > -- > 2.31.1 >
On Tue, 21 Mar 2023 09:37:21 +0800, Zhihao Cheng wrote: > Following process makes i_disksize exceed i_size: > > 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; > } > > [...] Applied, thanks! [1/1] ext4: Fix i_disksize exceeding i_size problem in paritally written case commit: 1dedde690303c05ef732b7c5c8356fdf60a4ade3 Best regards,
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index bf0b7dea4900..41ba1c432844 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3148,6 +3148,9 @@ 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;
Following process makes i_disksize exceed i_size: 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. Fetch a reproducer in [Link]. 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> --- v1->v2: Check and update 'copied' value before updating i_disksize rather than opencoding generic_write_end(). fs/ext4/inode.c | 3 +++ 1 file changed, 3 insertions(+)