6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jan Kara jack@suse.cz
commit 963845748fe67125006859229487b45485564db7 upstream.
Commit bc264fea0f6f ("iomap: support incremental iomap_iter advances") changed the error handling logic in iomap_iter(). Previously any error from iomap_dio_bio_iter() got propagated to userspace, after this commit if ->iomap_end returns error, it gets propagated to userspace instead of an error from iomap_dio_bio_iter(). This results in unaligned writes to ext4 to silently fallback to buffered IO instead of erroring out.
Now returning ENOTBLK for DIO writes from ext4_iomap_end() seems unnecessary these days. It is enough to return ENOTBLK from ext4_iomap_begin() when we don't support DIO write for that particular file offset (due to hole).
Fixes: bc264fea0f6f ("iomap: support incremental iomap_iter advances") Cc: stable@kernel.org Signed-off-by: Jan Kara jack@suse.cz Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Message-ID: 20250901112739.32484-2-jack@suse.cz Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/inode.c | 35 ----------------------------------- 1 file changed, 35 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 5b7a15db4953..c3b23c90fd11 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3872,47 +3872,12 @@ static int ext4_iomap_overwrite_begin(struct inode *inode, loff_t offset, return ret; }
-static inline bool ext4_want_directio_fallback(unsigned flags, ssize_t written) -{ - /* must be a directio to fall back to buffered */ - if ((flags & (IOMAP_WRITE | IOMAP_DIRECT)) != - (IOMAP_WRITE | IOMAP_DIRECT)) - return false; - - /* atomic writes are all-or-nothing */ - if (flags & IOMAP_ATOMIC) - return false; - - /* can only try again if we wrote nothing */ - return written == 0; -} - -static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, - ssize_t written, unsigned flags, struct iomap *iomap) -{ - /* - * Check to see whether an error occurred while writing out the data to - * the allocated blocks. If so, return the magic error code for - * non-atomic write so that we fallback to buffered I/O and attempt to - * complete the remainder of the I/O. - * For non-atomic writes, any blocks that may have been - * allocated in preparation for the direct I/O will be reused during - * buffered I/O. For atomic write, we never fallback to buffered-io. - */ - if (ext4_want_directio_fallback(flags, written)) - return -ENOTBLK; - - return 0; -} - const struct iomap_ops ext4_iomap_ops = { .iomap_begin = ext4_iomap_begin, - .iomap_end = ext4_iomap_end, };
const struct iomap_ops ext4_iomap_overwrite_ops = { .iomap_begin = ext4_iomap_overwrite_begin, - .iomap_end = ext4_iomap_end, };
static int ext4_iomap_begin_report(struct inode *inode, loff_t offset,