From 8e6cfe6c30bf573d2aa5449e22520a67ff0dcfe8 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 25 Sep 2023 00:16:56 -0600 Subject: [PATCH] ovl: disable IOCB_DIO_CALLER_COMP overlayfs copies the kiocb flags when it sets up a new kiocb to handle a write, but it doesn't properly support dealing with the deferred caller completions of the kiocb. This means it doesn't get the final write completion value, and hence will complete the write with '0' as the result. We could support the caller completions in overlayfs, but for now let's just disable them in the generated write kiocb. Reported-by: Zorro Lang Link: https://lore.kernel.org/io-uring/20230924142754.ejwsjen5pvyc32l4@dell-per750-06-vm-08.rhts.eng.pek2.redhat.com/ Fixes: 8c052fb3002e ("iomap: support IOCB_DIO_CALLER_COMP") Acked-by: Amir Goldstein Signed-off-by: Jens Axboe --- fs/overlayfs/file.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c index 4193633c4c7a..693971d20280 100644 --- a/fs/overlayfs/file.c +++ b/fs/overlayfs/file.c @@ -391,6 +391,12 @@ static ssize_t ovl_write_iter(struct kiocb *iocb, struct iov_iter *iter) if (!ovl_should_sync(OVL_FS(inode->i_sb))) ifl &= ~(IOCB_DSYNC | IOCB_SYNC); + /* + * Overlayfs doesn't support deferred completions, don't copy + * this property in case it is set by the issuer. + */ + ifl &= ~IOCB_DIO_CALLER_COMP; + old_cred = ovl_override_creds(file_inode(file)->i_sb); if (is_sync_kiocb(iocb)) { file_start_write(real.file); -- 2.25.1