Commit 210c7c17 authored by Benjamin Coddington's avatar Benjamin Coddington Committed by Trond Myklebust
Browse files

NFS: Use wait_on_atomic_t() for unlock after readahead 



The use of wait_on_atomic_t() for waiting on I/O to complete before
unlocking allows us to git rid of the NFS_IO_INPROGRESS flag, and thus the
nfs_iocounter's flags member, and finally the nfs_iocounter altogether.
The count of I/O is moved to the lock context, and the counter
increment/decrement functions become simple enough to open-code.

Signed-off-by: default avatarBenjamin Coddington <bcodding@redhat.com>
[Trond: Fix up conflict with existing function nfs_wait_atomic_killable()]
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 942e3d72

fs/nfs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -756,7 +756,7 @@ do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local) 


	l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));

	if (!IS_ERR(l_ctx)) {

		status = nfs_iocounter_wait(&l_ctx->io_count);

		status = nfs_iocounter_wait(l_ctx);

		nfs_put_lock_context(l_ctx);

		if (status < 0)

			return status;

fs/nfs/inode.c

+12 −6
Original line number Diff line number Diff line
@@ -71,19 +71,25 @@ nfs_fattr_to_ino_t(struct nfs_fattr *fattr) 
	return nfs_fileid_to_ino_t(fattr->fileid);

}



/**

 * nfs_wait_bit_killable - helper for functions that are sleeping on bit locks

 * @word: long word containing the bit lock

 */

int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)

static int nfs_wait_killable(int mode)

{

	freezable_schedule_unsafe();

	if (signal_pending_state(mode, current))

		return -ERESTARTSYS;

	return 0;

}



int nfs_wait_bit_killable(struct wait_bit_key *key, int mode)

{

	return nfs_wait_killable(mode);

}

EXPORT_SYMBOL_GPL(nfs_wait_bit_killable);



int nfs_wait_atomic_killable(atomic_t *p)

{

	return nfs_wait_killable(TASK_KILLABLE);

}



/**

 * nfs_compat_user_ino64 - returns the user-visible inode number

 * @fileid: 64-bit fileid
@@ -699,7 +705,7 @@ 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);

	atomic_set(&l_ctx->io_count, 0);

}



static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)

fs/nfs/internal.h

+2 −7
Original line number Diff line number Diff line
@@ -238,7 +238,7 @@ 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);

int nfs_iocounter_wait(struct nfs_lock_context *l_ctx);



extern const struct nfs_pageio_ops nfs_pgio_rw_ops;

struct nfs_pgio_header *nfs_pgio_header_alloc(const struct nfs_rw_ops *);
@@ -252,12 +252,6 @@ void nfs_free_request(struct nfs_page *req); 
struct nfs_pgio_mirror *

nfs_pgio_current_mirror(struct nfs_pageio_descriptor *desc);



static inline void nfs_iocounter_init(struct nfs_io_counter *c)

{

	c->flags = 0;

	atomic_set(&c->io_count, 0);

}



static inline bool nfs_pgio_has_mirroring(struct nfs_pageio_descriptor *desc)

{

	WARN_ON_ONCE(desc->pg_mirror_count < 1);
@@ -386,6 +380,7 @@ extern void nfs_clear_inode(struct inode *); 
extern void nfs_evict_inode(struct inode *);

void nfs_zap_acl_cache(struct inode *inode);

extern int nfs_wait_bit_killable(struct wait_bit_key *key, int mode);

extern int nfs_wait_atomic_killable(atomic_t *p);



/* super.c */

extern const struct super_operations nfs_sops;

fs/nfs/pagelist.c

+7 −41
Original line number Diff line number Diff line
@@ -101,53 +101,18 @@ 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_atomic();

		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(&q.key, TASK_KILLABLE);

	} while (atomic_read(&c->io_count) != 0 && !ret);

	finish_wait(wq, &q.wait);

	return ret;

}



/**

 * nfs_iocounter_wait - wait for i/o to complete

 * @c: nfs_io_counter to use

 * @l_ctx: nfs_lock_context with 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)

nfs_iocounter_wait(struct nfs_lock_context *l_ctx)

{

	if (atomic_read(&c->io_count) == 0)

		return 0;

	return __nfs_iocounter_wait(c);

	return wait_on_atomic_t(&l_ctx->io_count, nfs_wait_atomic_killable,

			TASK_KILLABLE);

}



/*
@@ -370,7 +335,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct page *page, 
		return ERR_CAST(l_ctx);

	}

	req->wb_lock_context = l_ctx;

	nfs_iocounter_inc(&l_ctx->io_count);

	atomic_inc(&l_ctx->io_count);



	/* Initialize the request struct. Initially, we assume a

	 * long write-back delay. This will be adjusted in
@@ -431,7 +396,8 @@ static void nfs_clear_request(struct nfs_page *req) 
		req->wb_page = NULL;

	}

	if (l_ctx != NULL) {

		nfs_iocounter_dec(&l_ctx->io_count);

		if (atomic_dec_and_test(&l_ctx->io_count))

			wake_up_atomic_t(&l_ctx->io_count);

		nfs_put_lock_context(l_ctx);

		req->wb_lock_context = NULL;

	}

fs/nfs/write.c

+0 −8
Original line number Diff line number Diff line
@@ -1565,14 +1565,6 @@ static void nfs_writeback_result(struct rpc_task *task, 
	}

}



static int nfs_wait_atomic_killable(atomic_t *key)

{

	if (fatal_signal_pending(current))

		return -ERESTARTSYS;

	freezable_schedule_unsafe();

	return 0;

}



static int wait_on_commit(struct nfs_mds_commit_info *cinfo)

{

	return wait_on_atomic_t(&cinfo->rpcs_out,

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