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authorFred Isaman <iisaman@netapp.com>2011-01-06 14:36:22 +0300
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-01-06 22:46:31 +0300
commitfd6002e9b8a93220d5f53b93d9624caf73cdc8a2 (patch)
treef45c22c9ec855949b1ec0488162229df4eb3f5ed /fs/nfs/pnfs.h
parentb7edfaa1983362842351e425adeb8e297b4c11fb (diff)
downloadlinux-fd6002e9b8a93220d5f53b93d9624caf73cdc8a2.tar.xz
pnfs: change layout state seqlock to a spinlock
This prepares for future changes, where the layout state needs to change atomically with several other variables. In particular, it will need to know if lo->segs is empty, as we test that instead of manipulating the NFS_LAYOUT_STATEID_SET bit. Moreover, the layoutstateid is not really a read-mostly structure, as it is written almost as often as it is read. The behavior of pnfs_get_layout_stateid is also slightly changed, so that it no longer changes the stateid. Its name is changed to +pnfs_choose_layoutget_stateid. Signed-off-by: Fred Isaman <iisaman@netapp.com> Signed-off-by: Benny Halevy <bhalevy@panasas.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'fs/nfs/pnfs.h')
-rw-r--r--fs/nfs/pnfs.h7
1 files changed, 3 insertions, 4 deletions
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index c2f108640fc4..10937203d236 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -44,7 +44,6 @@ struct pnfs_layout_segment {
enum {
NFS_LAYOUT_RO_FAILED = 0, /* get ro layout failed stop trying */
NFS_LAYOUT_RW_FAILED, /* get rw layout failed stop trying */
- NFS_LAYOUT_STATEID_SET, /* have a valid layout stateid */
};
/* Per-layout driver specific registration structure */
@@ -63,7 +62,6 @@ struct pnfs_layout_hdr {
unsigned long plh_refcount;
struct list_head plh_layouts; /* other client layouts */
struct list_head plh_segs; /* layout segments list */
- seqlock_t plh_seqlock; /* Protects the stateid */
nfs4_stateid plh_stateid;
unsigned long plh_flags;
struct inode *plh_inode;
@@ -143,8 +141,9 @@ int pnfs_layout_process(struct nfs4_layoutget *lgp);
void pnfs_destroy_layout(struct nfs_inode *);
void pnfs_destroy_all_layouts(struct nfs_client *);
void put_layout_hdr(struct inode *inode);
-void pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
- struct nfs4_state *open_state);
+int pnfs_choose_layoutget_stateid(nfs4_stateid *dst,
+ struct pnfs_layout_hdr *lo,
+ struct nfs4_state *open_state);
static inline int lo_fail_bit(u32 iomode)