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| author | Dan Aloni <dan.aloni@vastdata.com> | 2024-07-24 14:07:12 +0300 |
|---|---|---|
| committer | Anna Schumaker <anna.schumaker@oracle.com> | 2024-09-23 15:03:13 -0400 |
| commit | dfb07e990a0d019d7ae9b78dd4260620ce32e79a (patch) | |
| tree | 8463cc6c4b39ca3a466e55fd8cc051cec41d9304 /fs/nfs/super.c | |
| parent | 6d26c5e4d83cd39006bfd2ecbc97fbfac34aaefa (diff) | |
| download | lwn-dfb07e990a0d019d7ae9b78dd4260620ce32e79a.tar.gz lwn-dfb07e990a0d019d7ae9b78dd4260620ce32e79a.zip | |
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 <dan.aloni@vastdata.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anna Schumaker <anna.schumaker@oracle.com>
Diffstat (limited to 'fs/nfs/super.c')
| -rw-r--r-- | fs/nfs/super.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 97b386032b71..9723b6c53397 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -551,6 +551,9 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss, else seq_puts(m, ",local_lock=posix"); + if (nfss->flags & NFS_MOUNT_NO_ALIGNWRITE) + seq_puts(m, ",noalignwrite"); + if (nfss->flags & NFS_MOUNT_WRITE_EAGER) { if (nfss->flags & NFS_MOUNT_WRITE_WAIT) seq_puts(m, ",write=wait"); |