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NFS: Ensure PG_writeback is cleared when writeback fails

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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>
This commit is contained in:
Trond Myklebust 2007-04-14 19:10:12 -04:00 committed by Linus Torvalds
parent 60fa3f769f
commit 5a6d41b32a
2 changed files with 15 additions and 8 deletions
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22
fs/nfs/write.c
View file

@ -218,9 +218,11 @@ int nfs_congestion_kb;
#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 @@ static void nfs_set_page_writeback(struct page *page)
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 @@ static int nfs_page_mark_flush(struct page *page)
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 @@ nfs_mark_request_dirty(struct nfs_page *req)
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 @@ nfs_redirty_request(struct nfs_page *req)
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 @@ static void nfs_cancel_dirty_list(struct list_head *head)
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 @@ out_bad:
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 @@ static int nfs_flush_one(struct inode *inode, struct list_head *head, int how)
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 @@ out_err:
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);
}

1
include/linux/nfs_page.h
View file

@ -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 {