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

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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>
This commit is contained in:
Trond Myklebust 2017-08-01 17:29:29 -04:00
parent 8205b9ce03
commit 2ce209c42c
3 changed files with 29 additions and 8 deletions
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2
fs/nfs/pagelist.c
View file

@ -434,6 +434,7 @@ void nfs_release_request(struct nfs_page *req)
{ {
kref_put(&req->wb_kref, nfs_page_group_destroy); 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. * 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, return wait_on_bit_io(&req->wb_flags, PG_BUSY,
TASK_UNINTERRUPTIBLE); TASK_UNINTERRUPTIBLE);
} }
EXPORT_SYMBOL_GPL(nfs_wait_on_request);
/* /*
* nfs_generic_pg_test - determine if requests can be coalesced * nfs_generic_pg_test - determine if requests can be coalesced

18
fs/nfs/pnfs_nfs.c
View file

@ -91,13 +91,23 @@ static int
pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst, pnfs_generic_transfer_commit_list(struct list_head *src, struct list_head *dst,
struct nfs_commit_info *cinfo, int max) struct nfs_commit_info *cinfo, int max)
{ {
struct nfs_page *req, *tmp; struct nfs_page *req;
int ret = 0; int ret = 0;
list_for_each_entry_safe(req, tmp, src, wb_list) { while(!list_empty(src)) {
if (!nfs_lock_request(req)) req = list_first_entry(src, struct nfs_page, wb_list);
continue;
kref_get(&req->wb_kref); 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_request_remove_commit_list(req, cinfo);
clear_bit(PG_COMMIT_TO_DS, &req->wb_flags); clear_bit(PG_COMMIT_TO_DS, &req->wb_flags);
nfs_list_add_request(req, dst); nfs_list_add_request(req, dst);

17
fs/nfs/write.c
View file

@ -1030,13 +1030,22 @@ int
nfs_scan_commit_list(struct list_head *src, struct list_head *dst, nfs_scan_commit_list(struct list_head *src, struct list_head *dst,
struct nfs_commit_info *cinfo, int max) struct nfs_commit_info *cinfo, int max)
{ {
struct nfs_page *req, *tmp; struct nfs_page *req;
int ret = 0; int ret = 0;
list_for_each_entry_safe(req, tmp, src, wb_list) { while(!list_empty(src)) {
if (!nfs_lock_request(req)) req = list_first_entry(src, struct nfs_page, wb_list);
continue;
kref_get(&req->wb_kref); 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_request_remove_commit_list(req, cinfo);
nfs_list_add_request(req, dst); nfs_list_add_request(req, dst);
ret++; ret++;