Re: [PATCH v5 05/17] ext2: return -EIO on ext2_iomap_end() failure
From: Jan Kara <jack@suse.cz>
Date: 2016-10-11 06:48:01
Also in:
linux-fsdevel, linux-mm, linux-xfs, lkml, nvdimm
On Fri 07-10-16 15:08:52, Ross Zwisler wrote:
quoted hunk ↗ jump to hunk
Right now we just return 0 for success, but we really want to let callers know about this failure. Signed-off-by: Ross Zwisler <redacted> --- fs/ext2/inode.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index c7dbb46..368913c 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c@@ -830,8 +830,10 @@ ext2_iomap_end(struct inode *inode, loff_t offset, loff_t length, { if (iomap->type == IOMAP_MAPPED && written < length && - (flags & IOMAP_WRITE)) + (flags & IOMAP_WRITE)) { ext2_write_failed(inode->i_mapping, offset + length); + return -EIO; + }
So this is wrong. This (written < length) happens when we fail to copy data to / from userspace buffer into pagecache pages / DAX blocks. It may be because the passed buffer pointer is just wrong, or just because the page got swapped out and we have to swap it back in. It is a role of upper layers to decide what went wrong and proceed accordingly but from filesystem point of view we just have to cancel the operation we have prepared and return to upper layers. So returning 0 in this case is correct. Honza -- Jan Kara [off-list ref] SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>