NFS: Add functionality to allow waiting on all outstanding reads to complete

This will later allow NFS locking code to wait for readahead to complete
before releasing byte range locks.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2013-04-08 21:38:12 -04:00
parent bc7a05ca51
commit 577b42327d
4 changed files with 66 additions and 0 deletions

View file

@ -561,6 +561,7 @@ static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
l_ctx->lockowner.l_owner = current->files;
l_ctx->lockowner.l_pid = current->tgid;
INIT_LIST_HEAD(&l_ctx->list);
nfs_iocounter_init(&l_ctx->io_count);
}
static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)

View file

@ -229,6 +229,13 @@ extern void nfs_pgheader_init(struct nfs_pageio_descriptor *desc,
struct nfs_pgio_header *hdr,
void (*release)(struct nfs_pgio_header *hdr));
void nfs_set_pgio_error(struct nfs_pgio_header *hdr, int error, loff_t pos);
int nfs_iocounter_wait(struct nfs_io_counter *c);
static inline void nfs_iocounter_init(struct nfs_io_counter *c)
{
c->flags = 0;
atomic_set(&c->io_count, 0);
}
/* nfs2xdr.c */
extern struct rpc_procinfo nfs_procedures[];

View file

@ -84,6 +84,55 @@ nfs_page_free(struct nfs_page *p)
kmem_cache_free(nfs_page_cachep, p);
}
static void
nfs_iocounter_inc(struct nfs_io_counter *c)
{
atomic_inc(&c->io_count);
}
static void
nfs_iocounter_dec(struct nfs_io_counter *c)
{
if (atomic_dec_and_test(&c->io_count)) {
clear_bit(NFS_IO_INPROGRESS, &c->flags);
smp_mb__after_clear_bit();
wake_up_bit(&c->flags, NFS_IO_INPROGRESS);
}
}
static int
__nfs_iocounter_wait(struct nfs_io_counter *c)
{
wait_queue_head_t *wq = bit_waitqueue(&c->flags, NFS_IO_INPROGRESS);
DEFINE_WAIT_BIT(q, &c->flags, NFS_IO_INPROGRESS);
int ret = 0;
do {
prepare_to_wait(wq, &q.wait, TASK_KILLABLE);
set_bit(NFS_IO_INPROGRESS, &c->flags);
if (atomic_read(&c->io_count) == 0)
break;
ret = nfs_wait_bit_killable(&c->flags);
} while (atomic_read(&c->io_count) != 0);
finish_wait(wq, &q.wait);
return ret;
}
/**
* nfs_iocounter_wait - wait for i/o to complete
* @c: nfs_io_counter to use
*
* returns -ERESTARTSYS if interrupted by a fatal signal.
* Otherwise returns 0 once the io_count hits 0.
*/
int
nfs_iocounter_wait(struct nfs_io_counter *c)
{
if (atomic_read(&c->io_count) == 0)
return 0;
return __nfs_iocounter_wait(c);
}
/**
* nfs_create_request - Create an NFS read/write request.
* @ctx: open context to use
@ -118,6 +167,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
return ERR_CAST(l_ctx);
}
req->wb_lock_context = l_ctx;
nfs_iocounter_inc(&l_ctx->io_count);
/* Initialize the request struct. Initially, we assume a
* long write-back delay. This will be adjusted in
@ -177,6 +227,7 @@ static void nfs_clear_request(struct nfs_page *req)
req->wb_page = NULL;
}
if (l_ctx != NULL) {
nfs_iocounter_dec(&l_ctx->io_count);
nfs_put_lock_context(l_ctx);
req->wb_lock_context = NULL;
}

View file

@ -59,11 +59,18 @@ struct nfs_lockowner {
pid_t l_pid;
};
#define NFS_IO_INPROGRESS 0
struct nfs_io_counter {
unsigned long flags;
atomic_t io_count;
};
struct nfs_lock_context {
atomic_t count;
struct list_head list;
struct nfs_open_context *open_context;
struct nfs_lockowner lockowner;
struct nfs_io_counter io_count;
};
struct nfs4_state;