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-rw-r--r--fs/nfs/write.c33
1 files changed, 24 insertions, 9 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 8e5745a4deff..53c4a9917dac 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -91,8 +91,15 @@ static void nfs_context_set_write_error(struct nfs_open_context *ctx, int error)
set_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
}
+/*
+ * nfs_page_find_head_request_locked - find head request associated with @page
+ *
+ * must be called while holding the inode lock.
+ *
+ * returns matching head request with reference held, or NULL if not found.
+ */
static struct nfs_page *
-nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
+nfs_page_find_head_request_locked(struct nfs_inode *nfsi, struct page *page)
{
struct nfs_page *req = NULL;
@@ -104,25 +111,33 @@ nfs_page_find_request_locked(struct nfs_inode *nfsi, struct page *page)
/* Linearly search the commit list for the correct req */
list_for_each_entry_safe(freq, t, &nfsi->commit_info.list, wb_list) {
if (freq->wb_page == page) {
- req = freq;
+ req = freq->wb_head;
break;
}
}
}
- if (req)
+ if (req) {
+ WARN_ON_ONCE(req->wb_head != req);
+
kref_get(&req->wb_kref);
+ }
return req;
}
-static struct nfs_page *nfs_page_find_request(struct page *page)
+/*
+ * nfs_page_find_head_request - find head request associated with @page
+ *
+ * returns matching head request with reference held, or NULL if not found.
+ */
+static struct nfs_page *nfs_page_find_head_request(struct page *page)
{
struct inode *inode = page_file_mapping(page)->host;
struct nfs_page *req = NULL;
spin_lock(&inode->i_lock);
- req = nfs_page_find_request_locked(NFS_I(inode), page);
+ req = nfs_page_find_head_request_locked(NFS_I(inode), page);
spin_unlock(&inode->i_lock);
return req;
}
@@ -282,7 +297,7 @@ static struct nfs_page *nfs_find_and_lock_request(struct page *page, bool nonblo
spin_lock(&inode->i_lock);
for (;;) {
- req = nfs_page_find_request_locked(NFS_I(inode), page);
+ req = nfs_page_find_head_request_locked(NFS_I(inode), page);
if (req == NULL)
break;
if (nfs_lock_request(req))
@@ -773,7 +788,7 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
spin_lock(&inode->i_lock);
for (;;) {
- req = nfs_page_find_request_locked(NFS_I(inode), page);
+ req = nfs_page_find_head_request_locked(NFS_I(inode), page);
if (req == NULL)
goto out_unlock;
@@ -881,7 +896,7 @@ int nfs_flush_incompatible(struct file *file, struct page *page)
* dropped page.
*/
do {
- req = nfs_page_find_request(page);
+ req = nfs_page_find_head_request(page);
if (req == NULL)
return 0;
l_ctx = req->wb_lock_context;
@@ -1575,7 +1590,7 @@ int nfs_wb_page_cancel(struct inode *inode, struct page *page)
for (;;) {
wait_on_page_writeback(page);
- req = nfs_page_find_request(page);
+ req = nfs_page_find_head_request(page);
if (req == NULL)
break;
if (nfs_lock_request(req)) {