forked from luck/tmp_suning_uos_patched
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>
This commit is contained in:
parent
b7edfaa198
commit
fd6002e9b8
@ -1798,7 +1798,7 @@ encode_layoutget(struct xdr_stream *xdr,
|
||||
p = xdr_encode_hyper(p, args->range.offset);
|
||||
p = xdr_encode_hyper(p, args->range.length);
|
||||
p = xdr_encode_hyper(p, args->minlength);
|
||||
pnfs_get_layout_stateid(&stateid, NFS_I(args->inode)->layout,
|
||||
pnfs_choose_layoutget_stateid(&stateid, NFS_I(args->inode)->layout,
|
||||
args->ctx->state);
|
||||
p = xdr_encode_opaque_fixed(p, &stateid.data, NFS4_STATEID_SIZE);
|
||||
*p = cpu_to_be32(args->maxcount);
|
||||
|
@ -258,9 +258,6 @@ pnfs_clear_lseg_list(struct pnfs_layout_hdr *lo, struct list_head *tmp_list)
|
||||
/* List does not take a reference, so no need for put here */
|
||||
list_del_init(&lo->plh_layouts);
|
||||
spin_unlock(&clp->cl_lock);
|
||||
write_seqlock(&lo->plh_seqlock);
|
||||
clear_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags);
|
||||
write_sequnlock(&lo->plh_seqlock);
|
||||
|
||||
dprintk("%s:Return\n", __func__);
|
||||
}
|
||||
@ -319,69 +316,40 @@ pnfs_destroy_all_layouts(struct nfs_client *clp)
|
||||
}
|
||||
}
|
||||
|
||||
/* update lo->plh_stateid with new if is more recent
|
||||
*
|
||||
* lo->plh_stateid could be the open stateid, in which case we just use what given.
|
||||
*/
|
||||
/* update lo->plh_stateid with new if is more recent */
|
||||
static void
|
||||
pnfs_set_layout_stateid(struct pnfs_layout_hdr *lo,
|
||||
const nfs4_stateid *new)
|
||||
{
|
||||
nfs4_stateid *old = &lo->plh_stateid;
|
||||
bool overwrite = false;
|
||||
u32 oldseq, newseq;
|
||||
|
||||
write_seqlock(&lo->plh_seqlock);
|
||||
if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags) ||
|
||||
memcmp(old->stateid.other, new->stateid.other, sizeof(new->stateid.other)))
|
||||
overwrite = true;
|
||||
else {
|
||||
u32 oldseq, newseq;
|
||||
|
||||
oldseq = be32_to_cpu(old->stateid.seqid);
|
||||
newseq = be32_to_cpu(new->stateid.seqid);
|
||||
if ((int)(newseq - oldseq) > 0)
|
||||
overwrite = true;
|
||||
}
|
||||
if (overwrite)
|
||||
memcpy(&old->stateid, &new->stateid, sizeof(new->stateid));
|
||||
write_sequnlock(&lo->plh_seqlock);
|
||||
oldseq = be32_to_cpu(lo->plh_stateid.stateid.seqid);
|
||||
newseq = be32_to_cpu(new->stateid.seqid);
|
||||
if ((int)(newseq - oldseq) > 0)
|
||||
memcpy(&lo->plh_stateid, &new->stateid, sizeof(new->stateid));
|
||||
}
|
||||
|
||||
static void
|
||||
pnfs_layout_from_open_stateid(struct pnfs_layout_hdr *lo,
|
||||
struct nfs4_state *state)
|
||||
int
|
||||
pnfs_choose_layoutget_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
|
||||
struct nfs4_state *open_state)
|
||||
{
|
||||
int seq;
|
||||
int status = 0;
|
||||
|
||||
dprintk("--> %s\n", __func__);
|
||||
write_seqlock(&lo->plh_seqlock);
|
||||
do {
|
||||
seq = read_seqbegin(&state->seqlock);
|
||||
memcpy(lo->plh_stateid.data, state->stateid.data,
|
||||
sizeof(state->stateid.data));
|
||||
} while (read_seqretry(&state->seqlock, seq));
|
||||
set_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags);
|
||||
write_sequnlock(&lo->plh_seqlock);
|
||||
dprintk("<-- %s\n", __func__);
|
||||
}
|
||||
spin_lock(&lo->plh_inode->i_lock);
|
||||
if (list_empty(&lo->plh_segs)) {
|
||||
int seq;
|
||||
|
||||
void
|
||||
pnfs_get_layout_stateid(nfs4_stateid *dst, struct pnfs_layout_hdr *lo,
|
||||
struct nfs4_state *open_state)
|
||||
{
|
||||
int seq;
|
||||
|
||||
dprintk("--> %s\n", __func__);
|
||||
do {
|
||||
seq = read_seqbegin(&lo->plh_seqlock);
|
||||
if (!test_bit(NFS_LAYOUT_STATEID_SET, &lo->plh_flags)) {
|
||||
/* This will trigger retry of the read */
|
||||
pnfs_layout_from_open_stateid(lo, open_state);
|
||||
} else
|
||||
memcpy(dst->data, lo->plh_stateid.data,
|
||||
sizeof(lo->plh_stateid.data));
|
||||
} while (read_seqretry(&lo->plh_seqlock, seq));
|
||||
do {
|
||||
seq = read_seqbegin(&open_state->seqlock);
|
||||
memcpy(dst->data, open_state->stateid.data,
|
||||
sizeof(open_state->stateid.data));
|
||||
} while (read_seqretry(&open_state->seqlock, seq));
|
||||
} else
|
||||
memcpy(dst->data, lo->plh_stateid.data, sizeof(lo->plh_stateid.data));
|
||||
spin_unlock(&lo->plh_inode->i_lock);
|
||||
dprintk("<-- %s\n", __func__);
|
||||
return status;
|
||||
}
|
||||
|
||||
/*
|
||||
@ -496,7 +464,6 @@ alloc_init_layout_hdr(struct inode *ino)
|
||||
lo->plh_refcount = 1;
|
||||
INIT_LIST_HEAD(&lo->plh_layouts);
|
||||
INIT_LIST_HEAD(&lo->plh_segs);
|
||||
seqlock_init(&lo->plh_seqlock);
|
||||
lo->plh_inode = ino;
|
||||
return lo;
|
||||
}
|
||||
|
@ -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)
|
||||
|
Loading…
Reference in New Issue
Block a user