From dfb07e990a0d019d7ae9b78dd4260620ce32e79a Mon Sep 17 00:00:00 2001 From: Dan Aloni Date: Wed, 24 Jul 2024 14:07:12 +0300 Subject: nfs: add 'noalignwrite' option for lock-less 'lost writes' prevention There are some applications that write to predefined non-overlapping file offsets from multiple clients and therefore don't need to rely on file locking. However, if these applications want non-aligned offsets and sizes they need to either use locks or risk data corruption, as the NFS client defaults to extending writes to whole pages. This commit adds a new mount option `noalignwrite`, which allows to turn that off and avoid the need of locking, as long as these applications don't overlap on offsets. Signed-off-by: Dan Aloni Reviewed-by: Jeff Layton Reviewed-by: Sagi Grimberg Reviewed-by: Christoph Hellwig Signed-off-by: Anna Schumaker --- include/linux/nfs_fs_sb.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h index e1e47ebd83ef..c49bfdded5c1 100644 --- a/include/linux/nfs_fs_sb.h +++ b/include/linux/nfs_fs_sb.h @@ -158,6 +158,7 @@ struct nfs_server { #define NFS_MOUNT_WRITE_WAIT 0x02000000 #define NFS_MOUNT_TRUNK_DISCOVERY 0x04000000 #define NFS_MOUNT_SHUTDOWN 0x08000000 +#define NFS_MOUNT_NO_ALIGNWRITE 0x10000000 unsigned int fattr_valid; /* Valid attributes */ unsigned int caps; /* server capabilities */ -- cgit v1.2.3