NFS: Fix up nfs_page_group_covers_page()

Fix up the test in nfs_page_group_covers_page(). The simplest implementation
is to check that we have a set of intersecting or contiguous subrequests
that connect page offset 0 to nfs_page_length(req->wb_page).

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Trond Myklebust 2017-07-17 16:58:07 -04:00
parent 1344b7ea17
commit 7e8a30f8b4

View file

@ -243,9 +243,6 @@ nfs_page_group_search_locked(struct nfs_page *head, unsigned int page_offset)
{ {
struct nfs_page *req; struct nfs_page *req;
WARN_ON_ONCE(head != head->wb_head);
WARN_ON_ONCE(!test_bit(PG_HEADLOCK, &head->wb_head->wb_flags));
req = head; req = head;
do { do {
if (page_offset >= req->wb_pgbase && if (page_offset >= req->wb_pgbase &&
@ -273,18 +270,15 @@ static bool nfs_page_group_covers_page(struct nfs_page *req)
nfs_page_group_lock(req); nfs_page_group_lock(req);
do { for (;;) {
tmp = nfs_page_group_search_locked(req->wb_head, pos); tmp = nfs_page_group_search_locked(req->wb_head, pos);
if (tmp) { if (!tmp)
/* no way this should happen */ break;
WARN_ON_ONCE(tmp->wb_pgbase != pos); pos = tmp->wb_pgbase + tmp->wb_bytes;
pos += tmp->wb_bytes - (pos - tmp->wb_pgbase); }
}
} while (tmp && pos < len);
nfs_page_group_unlock(req); nfs_page_group_unlock(req);
WARN_ON_ONCE(pos > len); return pos >= len;
return pos == len;
} }
/* We can set the PG_uptodate flag if we see that a write request /* We can set the PG_uptodate flag if we see that a write request