diff options
author | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-11-02 14:59:00 (GMT) |
---|---|---|
committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-11-02 18:50:37 (GMT) |
commit | 260074cd8413489903d4484058e61649d6e08580 (patch) | |
tree | aa4b89ce7367791def57c172ddeb5dcf5bbdec2b /fs/nfs/flexfilelayout/flexfilelayout.h | |
parent | 135444126a1175912b43366f6109cb297018f034 (diff) | |
download | linux-260074cd8413489903d4484058e61649d6e08580.tar.xz |
pNFS/flexfiles: Add support for FF_FLAGS_NO_IO_THRU_MDS
For loosely coupled pNFS/flexfiles systems, there is often no advantage
at all in going through the MDS for I/O, since the MDS is subject to
the same limitations as all other clients when talking to DSes. If a
DS is unresponsive, I/O through the MDS will fail.
For such systems, the only scalable solution is to have the pNFS clients
retry doing pNFS, and so the protocol now provides a flag that allows
the pNFS server to signal this.
If LAYOUTGET returns FF_FLAGS_NO_IO_THRU_MDS, then we should assume that
the MDS wants the client to retry using these devices, even if they were
previously marked as being unavailable. To do so, we add a helper,
ff_layout_mark_devices_valid() that will be called from layoutget.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/flexfilelayout/flexfilelayout.h')
-rw-r--r-- | fs/nfs/flexfilelayout/flexfilelayout.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/nfs/flexfilelayout/flexfilelayout.h b/fs/nfs/flexfilelayout/flexfilelayout.h index 68cc0d9..2bb08bc 100644 --- a/fs/nfs/flexfilelayout/flexfilelayout.h +++ b/fs/nfs/flexfilelayout/flexfilelayout.h @@ -10,6 +10,7 @@ #define FS_NFS_NFS4FLEXFILELAYOUT_H #define FF_FLAGS_NO_LAYOUTCOMMIT 1 +#define FF_FLAGS_NO_IO_THRU_MDS 2 #include "../pnfs.h" @@ -146,6 +147,12 @@ FF_LAYOUT_MIRROR_COUNT(struct pnfs_layout_segment *lseg) } static inline bool +ff_layout_no_fallback_to_mds(struct pnfs_layout_segment *lseg) +{ + return FF_LAYOUT_LSEG(lseg)->flags & FF_FLAGS_NO_IO_THRU_MDS; +} + +static inline bool ff_layout_test_devid_unavailable(struct nfs4_deviceid_node *node) { return nfs4_test_deviceid_unavailable(node); |