diff options
| author | George Wilson <[email protected]> | 2019-03-22 16:09:11 -0400 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2019-03-22 13:09:11 -0700 |
| commit | 2efea7c82c5741a50b476bb1dcbc9a74b8f73ad1 (patch) | |
| tree | a7f5e66611882cd43d729d23591248a1208ed692 /module/zfs | |
| parent | 060f0226e6396a3c7104fedc8d2af7063a27c1f9 (diff) | |
ZFS Reads may result in unneccesary calls to zil_commit
ZFS supports O_RSYNC for read operations and when specified will ensure
the same level of data integrity that O_DSYNC and O_SYNC provides for
writes. O_RSYNC by itself has no effect so it must be combined with
either O_DSYNC or O_SYNC. However, many platforms don't support O_RSYNC
and have mapped O_SYNC to mean O_RSYNC within ZFS. This is incorrect
and causes unnecessary calls to zil_commit. Only platforms which
support O_RSYNC should implement the zil_commit functionality in the
read code path.
Reviewed-by: Matt Ahrens <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: George Wilson <[email protected]>
Closes #8523
Diffstat (limited to 'module/zfs')
| -rw-r--r-- | module/zfs/zfs_vnops.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index bbc171bd2..c77101485 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -439,6 +439,7 @@ int zfs_read(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr) { int error = 0; + boolean_t frsync = B_FALSE; znode_t *zp = ITOZ(ip); zfsvfs_t *zfsvfs = ITOZSB(ip); @@ -466,12 +467,19 @@ zfs_read(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr) return (0); } +#ifdef FRSYNC /* * If we're in FRSYNC mode, sync out this znode before reading it. * Only do this for non-snapshots. + * + * Some platforms do not support FRSYNC and instead map it + * to FSYNC, which results in unnecessary calls to zil_commit. We + * only honor FRSYNC requests on platforms which support it. */ + frsync = !!(ioflag & FRSYNC); +#endif if (zfsvfs->z_log && - (ioflag & FRSYNC || zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)) + (frsync || zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)) zil_commit(zfsvfs->z_log, zp->z_id); /* |