diff options
author | Fred Isaman <iisaman@netapp.com> | 2011-01-06 06:36:22 -0500 |
---|---|---|
committer | Trond Myklebust <Trond.Myklebust@netapp.com> | 2011-01-06 14:46:31 -0500 |
commit | fd6002e9b8a93220d5f53b93d9624caf73cdc8a2 (patch) | |
tree | f45c22c9ec855949b1ec0488162229df4eb3f5ed /fs | |
parent | b7edfaa1983362842351e425adeb8e297b4c11fb (diff) |
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')
-rw-r--r-- | fs/nfs/nfs4xdr.c | 2 | ||||
-rw-r--r-- | fs/nfs/pnfs.c | 79 | ||||
-rw-r--r-- | fs/nfs/pnfs.h | 7 |
3 files changed, 27 insertions, 61 deletions
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c index f3f99156bfcb..4e28242360d6 100644 --- a/fs/nfs/nfs4xdr.c +++ b/fs/nfs/nfs4xdr.c | |||
@@ -1798,7 +1798,7 @@ encode_layoutget(struct xdr_stream *xdr, | |||
1798 | p = xdr_encode_hyper(p, args->range.offset); | 1798 | p = xdr_encode_hyper(p, args->range.offset); |
1799 | p = xdr_encode_hyper(p, args->range.length); | 1799 | p = xdr_encode_hyper(p, args->range.length); |
1800 | p = xdr_encode_hyper(p, args->minlength); | 1800 | p = xdr_encode_hyper(p, args->minlength); |
1801 | pnfs_get_layout_stateid(&stateid, NFS_I(args->inode)->layout, | 1801 | pnfs_choose_layoutget_stateid(&stateid, NFS_I(args->inode)->layout, |
1802 | args->ctx->state); | 1802 | args->ctx->state); |
1803 | p = xdr_encode_opaque_fixed(p, &stateid.data, NFS4_STATEID_SIZE); | 1803 | p = xdr_encode_opaque_fixed(p, &stateid.data, NFS4_STATEID_SIZE); |
1804 | *p = cpu_to_be32(args->maxcount); | 1804 | *p = cpu_to_be32(args->maxcount); |
diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c index 6736f9e4f2e1..08313f536b45 100644 --- a/fs/nfs/pnfs.c +++ b/fs/nfs/pnfs.c | |||
@@ -258,9 +258,6 @@ pnfs_clear_lseg_list(struct pnfs_layout_hdr *lo, struct list_head *tmp_list) | |||
258 | /* List does not take a reference, so no need for put here */ | 258 | /* List does not take a reference, so no need for put here */ |
259 | list_del_init(&lo->plh_layouts); | 259 | list_del_init(&lo->plh_layouts); |
260 | spin_unlock(&clp->cl_lock); | 260 | spin_unlock(&clp->cl_lock); |
261 | write_seqlock(&lo->plh_seqlock); | ||
262 | clear_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags); | ||
263 | write_sequnlock(&lo->plh_seqlock); | ||
264 | 261 | ||
265 | dprintk("%s:Return\n", __func__); | 262 | dprintk("%s:Return\n", __func__); |
266 | } | 263 | } |
@@ -319,69 +316,40 @@ pnfs_destroy_all_layouts(struct nfs_client *clp) | |||
319 | } | 316 | } |
320 | } | 317 | } |
321 | 318 | ||
322 | /* update lo->plh_stateid with new if is more recent | 319 | /* update lo->plh_stateid with new if is more recent */ |
323 | * | ||
324 | * lo->plh_stateid could be the open stateid, in which case we just use what given. | ||
325 | */ | ||
326 | static void | 320 | static void |
327 | pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, | 321 | pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo, |
328 | const nfs4_stateid *new) | 322 | const nfs4_stateid *new) |
329 | { | 323 | { |
330 | nfs4_stateid *old = &lo->plh_stateid; | 324 | u32 oldseq, newseq; |
331 | bool overwrite = false; | ||
332 | |||
333 | write_seqlock(&lo->plh_seqlock); | ||
334 | if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags) || | ||
335 | memcmp(old->stateid.other, new->stateid.other, sizeof(new->stateid.other))) | ||
336 | overwrite = true; | ||
337 | else { | ||
338 | u32 oldseq, newseq; | ||
339 | |||
340 | oldseq = be32_to_cpu(old->stateid.seqid); | ||
341 | newseq = be32_to_cpu(new->stateid.seqid); | ||
342 | if ((int)(newseq - oldseq) > 0) | ||
343 | overwrite = true; | ||
344 | } | ||
345 | if (overwrite) | ||
346 | memcpy(&old->stateid, &new->stateid, sizeof(new->stateid)); | ||
347 | write_sequnlock(&lo->plh_seqlock); | ||
348 | } | ||
349 | |||
350 | static void | ||
351 | pnfs_layout_from_open_stateid(struct pnfs_layout_hdr *lo, | ||
352 | struct nfs4_state *state) | ||
353 | { | ||
354 | int seq; | ||
355 | 325 | ||
356 | dprintk("--> %s\n", __func__); | 326 | oldseq = be32_to_cpu(lo->plh_stateid.stateid.seqid); |
357 | write_seqlock(&lo->plh_seqlock); | 327 | newseq = be32_to_cpu(new->stateid.seqid); |
358 | do { | 328 | if ((int)(newseq - oldseq) > 0) |
359 | seq = read_seqbegin(&state->seqlock); | 329 | memcpy(&lo->plh_stateid, &new->stateid, sizeof(new->stateid)); |
360 | memcpy(lo->plh_stateid.data, state->stateid.data, | ||
361 | sizeof(state->stateid.data)); | ||
362 | } while (read_seqretry(&state->seqlock, seq)); | ||
363 | set_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags); | ||
364 | write_sequnlock(&lo->plh_seqlock); | ||
365 | dprintk("<-- %s\n", __func__); | ||
366 | } | 330 | } |
367 | 331 | ||
368 | void | 332 | int |
369 | pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo, | 333 | pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo, |
370 | struct nfs4_state *open_state) | 334 | struct nfs4_state *open_state) |
371 | { | 335 | { |
372 | int seq; | 336 | int status = 0; |
373 | 337 | ||
374 | dprintk("--> %s\n", __func__); | 338 | dprintk("--> %s\n", __func__); |
375 | do { | 339 | spin_lock(&lo->plh_inode->i_lock); |
376 | seq = read_seqbegin(&lo->plh_seqlock); | 340 | if (list_empty(&lo->plh_segs)) { |
377 | if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags)) { | 341 | int seq; |
378 | /* This will trigger retry of the read */ | 342 | |
379 | pnfs_layout_from_open_stateid(lo, open_state); | 343 | do { |
380 | } else | 344 | seq = read_seqbegin(&open_state->seqlock); |
381 | memcpy(dst->data, lo->plh_stateid.data, | 345 | memcpy(dst->data, open_state->stateid.data, |
382 | sizeof(lo->plh_stateid.data)); | 346 | sizeof(open_state->stateid.data)); |
383 | } while (read_seqretry(&lo->plh_seqlock, seq)); | 347 | } while (read_seqretry(&open_state->seqlock, seq)); |
348 | } else | ||
349 | memcpy(dst->data, lo->plh_stateid.data, sizeof(lo->plh_stateid.data)); | ||
350 | spin_unlock(&lo->plh_inode->i_lock); | ||
384 | dprintk("<-- %s\n", __func__); | 351 | dprintk("<-- %s\n", __func__); |
352 | return status; | ||
385 | } | 353 | } |
386 | 354 | ||
387 | /* | 355 | /* |
@@ -496,7 +464,6 @@ alloc_init_layout_hdr(struct inode *ino) | |||
496 | lo->plh_refcount = 1; | 464 | lo->plh_refcount = 1; |
497 | INIT_LIST_HEAD(&lo->plh_layouts); | 465 | INIT_LIST_HEAD(&lo->plh_layouts); |
498 | INIT_LIST_HEAD(&lo->plh_segs); | 466 | INIT_LIST_HEAD(&lo->plh_segs); |
499 | seqlock_init(&lo->plh_seqlock); | ||
500 | lo->plh_inode = ino; | 467 | lo->plh_inode = ino; |
501 | return lo; | 468 | return lo; |
502 | } | 469 | } |
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 { | |||
44 | enum { | 44 | enum { |
45 | NFS_LAYOUT_RO_FAILED = 0, /* get ro layout failed stop trying */ | 45 | NFS_LAYOUT_RO_FAILED = 0, /* get ro layout failed stop trying */ |
46 | NFS_LAYOUT_RW_FAILED, /* get rw layout failed stop trying */ | 46 | NFS_LAYOUT_RW_FAILED, /* get rw layout failed stop trying */ |
47 | NFS_LAYOUT_STATEID_SET, /* have a valid layout stateid */ | ||
48 | }; | 47 | }; |
49 | 48 | ||
50 | /* Per-layout driver specific registration structure */ | 49 | /* Per-layout driver specific registration structure */ |
@@ -63,7 +62,6 @@ struct pnfs_layout_hdr { | |||
63 | unsigned long plh_refcount; | 62 | unsigned long plh_refcount; |
64 | struct list_head plh_layouts; /* other client layouts */ | 63 | struct list_head plh_layouts; /* other client layouts */ |
65 | struct list_head plh_segs; /* layout segments list */ | 64 | struct list_head plh_segs; /* layout segments list */ |
66 | seqlock_t plh_seqlock; /* Protects the stateid */ | ||
67 | nfs4_stateid plh_stateid; | 65 | nfs4_stateid plh_stateid; |
68 | unsigned long plh_flags; | 66 | unsigned long plh_flags; |
69 | struct inode *plh_inode; | 67 | struct inode *plh_inode; |
@@ -143,8 +141,9 @@ int pnfs_layout_process(struct nfs4_layoutget *lgp); | |||
143 | void pnfs_destroy_layout(struct nfs_inode *); | 141 | void pnfs_destroy_layout(struct nfs_inode *); |
144 | void pnfs_destroy_all_layouts(struct nfs_client *); | 142 | void pnfs_destroy_all_layouts(struct nfs_client *); |
145 | void put_layout_hdr(struct inode *inode); | 143 | void put_layout_hdr(struct inode *inode); |
146 | void pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo, | 144 | int pnfs_choose_layoutget_stateid(nfs4_stateid *dst, |
147 | struct nfs4_state *open_state); | 145 | struct pnfs_layout_hdr *lo, |
146 | struct nfs4_state *open_state); | ||
148 | 147 | ||
149 | 148 | ||
150 | static inline int lo_fail_bit(u32 iomode) | 149 | static inline int lo_fail_bit(u32 iomode) |