NFS: Ensure PG_writeback is cleared when writeback fails
If the writebacks are cancelled via nfs_cancel_dirty_list, or due to the
memory allocation failing in nfs_flush_one/nfs_flush_multi, then we must
ensure that the PG_writeback flag is cleared.
Also ensure that we actually own the PG_writeback flag whenever we
schedule a new writeback by making nfs_set_page_writeback() return the
value of test_set_page_writeback().
The PG_writeback page flag ends up replacing the functionality of the
PG_FLUSHING nfs_page flag, so we rip that out too.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 2867e6b..e5d7cac 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -218,9 +218,11 @@
#define NFS_CONGESTION_OFF_THRESH \
(NFS_CONGESTION_ON_THRESH - (NFS_CONGESTION_ON_THRESH >> 2))
-static void nfs_set_page_writeback(struct page *page)
+static int nfs_set_page_writeback(struct page *page)
{
- if (!test_set_page_writeback(page)) {
+ int ret = test_set_page_writeback(page);
+
+ if (!ret) {
struct inode *inode = page->mapping->host;
struct nfs_server *nfss = NFS_SERVER(inode);
@@ -228,6 +230,7 @@
NFS_CONGESTION_ON_THRESH)
set_bdi_congested(&nfss->backing_dev_info, WRITE);
}
+ return ret;
}
static void nfs_end_page_writeback(struct page *page)
@@ -277,10 +280,8 @@
spin_lock(req_lock);
}
spin_unlock(req_lock);
- if (test_and_set_bit(PG_FLUSHING, &req->wb_flags) == 0) {
+ if (nfs_set_page_writeback(page) == 0)
nfs_mark_request_dirty(req);
- nfs_set_page_writeback(page);
- }
ret = test_bit(PG_NEED_FLUSH, &req->wb_flags);
nfs_unlock_request(req);
return ret;
@@ -424,7 +425,6 @@
static void
nfs_redirty_request(struct nfs_page *req)
{
- clear_bit(PG_FLUSHING, &req->wb_flags);
__set_page_dirty_nobuffers(req->wb_page);
}
@@ -434,7 +434,11 @@
static inline int
nfs_dirty_request(struct nfs_page *req)
{
- return test_bit(PG_FLUSHING, &req->wb_flags) == 0;
+ struct page *page = req->wb_page;
+
+ if (page == NULL)
+ return 0;
+ return !PageWriteback(req->wb_page);
}
#if defined(CONFIG_NFS_V3) || defined(CONFIG_NFS_V4)
@@ -500,6 +504,7 @@
while(!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
+ nfs_end_page_writeback(req->wb_page);
nfs_inode_remove_request(req);
nfs_clear_page_writeback(req);
}
@@ -890,6 +895,7 @@
list_del(&data->pages);
nfs_writedata_release(data);
}
+ nfs_end_page_writeback(req->wb_page);
nfs_redirty_request(req);
nfs_clear_page_writeback(req);
return -ENOMEM;
@@ -935,6 +941,7 @@
while (!list_empty(head)) {
struct nfs_page *req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
+ nfs_end_page_writeback(req->wb_page);
nfs_redirty_request(req);
nfs_clear_page_writeback(req);
}
@@ -970,6 +977,7 @@
while (!list_empty(head)) {
req = nfs_list_entry(head->next);
nfs_list_remove_request(req);
+ nfs_end_page_writeback(req->wb_page);
nfs_redirty_request(req);
nfs_clear_page_writeback(req);
}
diff --git a/include/linux/nfs_page.h b/include/linux/nfs_page.h
index 2e555d4..d111be6 100644
--- a/include/linux/nfs_page.h
+++ b/include/linux/nfs_page.h
@@ -31,7 +31,6 @@
#define PG_NEED_COMMIT 1
#define PG_NEED_RESCHED 2
#define PG_NEED_FLUSH 3
-#define PG_FLUSHING 4
struct nfs_inode;
struct nfs_page {
