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Commit 2ce209c4 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Wait for requests that are locked on the commit list 



If a request is on the commit list, but is locked, we will currently skip
it, which can lead to livelocking when the commit count doesn't reduce
to zero.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 8205b9ce

fs/nfs/pagelist.c

+2 −0
Original line number Diff line number Diff line
@@ -434,6 +434,7 @@ void nfs_release_request(struct nfs_page *req) 
{

	kref_put(&req->wb_kref, nfs_page_group_destroy);

}

EXPORT_SYMBOL_GPL(nfs_release_request);



/**

 * nfs_wait_on_request - Wait for a request to complete.
@@ -452,6 +453,7 @@ nfs_wait_on_request(struct nfs_page *req) 
	return wait_on_bit_io(&req->wb_flags, PG_BUSY,

			      TASK_UNINTERRUPTIBLE);

}

EXPORT_SYMBOL_GPL(nfs_wait_on_request);



/*

 * nfs_generic_pg_test - determine if requests can be coalesced

fs/nfs/pnfs_nfs.c

+14 −4
Original line number Diff line number Diff line
@@ -91,13 +91,23 @@ static int 
pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst,

				  struct nfs_commit_info *cinfo, int max)

{

	struct nfs_page *req, *tmp;

	struct nfs_page *req;

	int ret = 0;



	list_for_each_entry_safe(req, tmp, src, wb_list) {

		if (!nfs_lock_request(req))

			continue;

	while(!list_empty(src)) {

		req = list_first_entry(src, struct nfs_page, wb_list);



		kref_get(&req->wb_kref);

		if (!nfs_lock_request(req)) {

			int status;

			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);

			status = nfs_wait_on_request(req);

			nfs_release_request(req);

			mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);

			if (status < 0)

				break;

			continue;

		}

		nfs_request_remove_commit_list(req, cinfo);

		clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);

		nfs_list_add_request(req, dst);

fs/nfs/write.c

+13 −4
Original line number Diff line number Diff line
@@ -1030,13 +1030,22 @@ int 
nfs_scan_commit_list(struct list_head *src, struct list_head *dst,

		     struct nfs_commit_info *cinfo, int max)

{

	struct nfs_page *req, *tmp;

	struct nfs_page *req;

	int ret = 0;



	list_for_each_entry_safe(req, tmp, src, wb_list) {

		if (!nfs_lock_request(req))

			continue;

	while(!list_empty(src)) {

		req = list_first_entry(src, struct nfs_page, wb_list);

		kref_get(&req->wb_kref);

		if (!nfs_lock_request(req)) {

			int status;

			mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex);

			status = nfs_wait_on_request(req);

			nfs_release_request(req);

			mutex_lock(&NFS_I(cinfo->inode)->commit_mutex);

			if (status < 0)

				break;

			continue;

		}

		nfs_request_remove_commit_list(req, cinfo);

		nfs_list_add_request(req, dst);

		ret++;