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: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index ec97c30..548ebc7 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -434,6 +434,7 @@
{
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 @@
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
diff --git a/fs/nfs/pnfs_nfs.c b/fs/nfs/pnfs_nfs.c
index 4b0a809..303ff17 100644
--- a/fs/nfs/pnfs_nfs.c
+++ b/fs/nfs/pnfs_nfs.c
@@ -91,13 +91,23 @@
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);
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 8667028..5dd3b21 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1030,13 +1030,22 @@
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++;