[PATCH] fuse: remove page alignment check for writeback len

[Joanne Koong <joannelkoong@gmail.com>]

Remove incorrect page alignment check for the writeback len arg in
fuse_iomap_writeback_range(). len will always be block-aligned as passed
in by iomap. On regular fuse filesystems, i_blkbits is set to PAGE_SHIFT
so this is not a problem but for fuseblk filesystems, the block size is
set to a default of 512 bytes or a block size passed in at mount time.

Please note that non-page-aligned lens are fine for the logic in
fuse_iomap_writeback_range(). The check was originally added as a
safeguard to detect conspicuously wrong ranges.

Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Fixes: ef7e7cbb323f ("fuse: use iomap for writeback")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

[1] report:
https://lore.kernel.org/linux-fsdevel/CA+G9fYs5AdVM-T2Tf3LciNCwLZEHetcnSkHsjZajVwwpM2HmJw@mail.gmail.com/
---
 fs/fuse/file.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index f16426fd2bf5..883dc94a0ce0 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2155,8 +2155,6 @@ static ssize_t fuse_iomap_writeback_range(struct iomap_writepage_ctx *wpc,
 	loff_t offset = offset_in_folio(folio, pos);
 
 	WARN_ON_ONCE(!data);
-	/* len will always be page aligned */
-	WARN_ON_ONCE(len & (PAGE_SIZE - 1));
 
 	if (!data->ff) {
 		data->ff = fuse_write_file_get(fi);
-- 
2.47.3