diff options
| author | Peng Tao | 2014-08-22 17:37:41 +0800 |
|---|---|---|
| committer | Tom Haynes | 2015-02-03 11:06:39 -0800 |
| commit | 9bf87482ddc6f8db884177a2a16b1a1dc12f8777 (patch) | |
| tree | 380c0cc9a14dc4b5492f35473e88aee787b224ff /fs/nfs | |
| parent | abb9a0079c7f06360b83a5dd27ce74b8dc6d01b6 (diff) | |
nfs41: serialize first layoutget of a file
Per RFC 5661 Errata 3208:
| A client MAY always forget its layout state and associated
| layout stateid at any time (See also section 12.5.5.1).
| In such case, the client MUST use a non-layout stateid for the next
| LAYOUTGET operation. This will signal the server that the client has
| no more layouts on the file and its respective layout state can be
| released before issuing a new layout in response to LAYOUTGET.
In order to make such a signal unique to server, client needs to serialize
all layoutgets using non-layout stateid. We implement this by serializing
layoutgets when client has no layout segments at hand.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
Diffstat (limited to 'fs/nfs')
| -rw-r--r-- | fs/nfs/pnfs.c | 35 | ||||
| -rw-r--r-- | fs/nfs/pnfs.h | 1 |
2 files changed, 32 insertions, 4 deletions
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index fa00b56f176a..7e1bac189d1c 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c @@ -1288,6 +1288,7 @@ pnfs_update_layout(struct inode *ino, struct nfs_client *clp = server->nfs_client; struct pnfs_layout_hdr *lo; struct pnfs_layout_segment *lseg = NULL; + bool first; if (!pnfs_enabled_sb(NFS_SERVER(ino))) goto out; @@ -1295,6 +1296,8 @@ pnfs_update_layout(struct inode *ino, if (pnfs_within_mdsthreshold(ctx, ino, iomode)) goto out; +lookup_again: + first = false; spin_lock(&ino->i_lock); lo = pnfs_find_alloc_layout(ino, ctx, gfp_flags); if (lo == NULL) { @@ -1312,10 +1315,27 @@ pnfs_update_layout(struct inode *ino, if (pnfs_layout_io_test_failed(lo, iomode)) goto out_unlock; - /* Check to see if the layout for the given range already exists */ - lseg = pnfs_find_lseg(lo, &arg); - if (lseg) - goto out_unlock; + first = list_empty(&lo->plh_segs); + if (first) { + /* The first layoutget for the file. Need to serialize per + * RFC 5661 Errata 3208. + */ + if (test_and_set_bit(NFS_LAYOUT_FIRST_LAYOUTGET, + &lo->plh_flags)) { + spin_unlock(&ino->i_lock); + wait_on_bit(&lo->plh_flags, NFS_LAYOUT_FIRST_LAYOUTGET, + TASK_UNINTERRUPTIBLE); + pnfs_put_layout_hdr(lo); + goto lookup_again; + } + } else { + /* Check to see if the layout for the given range + * already exists + */ + lseg = pnfs_find_lseg(lo, &arg); + if (lseg) + goto out_unlock; + } if (pnfs_layoutgets_blocked(lo, 0)) goto out_unlock; @@ -1343,6 +1363,13 @@ pnfs_update_layout(struct inode *ino, lseg = send_layoutget(lo, ctx, &arg, gfp_flags); atomic_dec(&lo->plh_outstanding); out_put_layout_hdr: + if (first) { + unsigned long *bitlock = &lo->plh_flags; + + clear_bit_unlock(NFS_LAYOUT_FIRST_LAYOUTGET, bitlock); + smp_mb__after_atomic(); + wake_up_bit(bitlock, NFS_LAYOUT_FIRST_LAYOUTGET); + } pnfs_put_layout_hdr(lo); out: dprintk("%s: inode %s/%llu pNFS layout segment %s for " diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h index c39882191651..4cf0d54e14c3 100644 --- a/fs/nfs/pnfs.h +++ b/fs/nfs/pnfs.h @@ -95,6 +95,7 @@ enum { NFS_LAYOUT_ROC, /* some lseg had roc bit set */ NFS_LAYOUT_RETURN, /* Return this layout ASAP */ NFS_LAYOUT_INVALID_STID, /* layout stateid id is invalid */ + NFS_LAYOUT_FIRST_LAYOUTGET, /* Serialize first layoutget */ }; enum layoutdriver_policy_flags { |