From 1da29f2c39b67b846b74205c81bf0ccd96d34727 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 22 Aug 2024 23:06:49 +0100 Subject: netfs, cifs: Fix handling of short DIO read Short DIO reads, particularly in relation to cifs, are not being handled correctly by cifs and netfslib. This can be tested by doing a DIO read of a file where the size of read is larger than the size of the file. When it crosses the EOF, it gets a short read and this gets retried, and in the case of cifs, the retry read fails, with the failure being translated to ENODATA. Fix this by the following means: (1) Add a flag, NETFS_SREQ_HIT_EOF, for the filesystem to set when it detects that the read did hit the EOF. (2) Make the netfslib read assessment stop processing subrequests when it encounters one with that flag set. (3) Return rreq->transferred, the accumulated contiguous amount read to that point, to userspace for a DIO read. (4) Make cifs set the flag and clear the error if the read RPC returned ENODATA. (5) Make cifs set the flag and clear the error if a short read occurred without error and the read-to file position is now at the remote inode size. Fixes: 69c3c023af25 ("cifs: Implement netfslib hooks") Signed-off-by: David Howells cc: Steve French cc: Paulo Alcantara cc: Jeff Layton cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French --- include/linux/netfs.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/netfs.h b/include/linux/netfs.h index 983816608f15..c47443e7a97e 100644 --- a/include/linux/netfs.h +++ b/include/linux/netfs.h @@ -198,6 +198,7 @@ struct netfs_io_subrequest { #define NETFS_SREQ_NEED_RETRY 9 /* Set if the filesystem requests a retry */ #define NETFS_SREQ_RETRYING 10 /* Set if we're retrying */ #define NETFS_SREQ_FAILED 11 /* Set if the subreq failed unretryably */ +#define NETFS_SREQ_HIT_EOF 12 /* Set if we hit the EOF */ }; enum netfs_io_origin { -- cgit v1.2.3