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NFS: Fix race in nfs_set_page_dirty 

Protect nfs_set_page_dirty() against races with nfs_inode_add_request.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Trond Myklebust 2007-04-20 16:12:50 -04:00 committed by Linus Torvalds
parent 612c9384fd
commit 2b82f190c8
1 changed files with 14 additions and 3 deletions
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17
fs/nfs/write.c
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@ -388,6 +388,8 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
}
SetPagePrivate(req->wb_page);
set_page_private(req->wb_page, (unsigned long)req);
if (PageDirty(req->wb_page))
set_bit(PG_NEED_FLUSH, &req->wb_flags);
nfsi->npages++;
atomic_inc(&req->wb_count);
return 0;
@ -407,6 +409,8 @@ static void nfs_inode_remove_request(struct nfs_page *req)
set_page_private(req->wb_page, 0);
ClearPagePrivate(req->wb_page);
radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
if (test_and_clear_bit(PG_NEED_FLUSH, &req->wb_flags))
__set_page_dirty_nobuffers(req->wb_page);
nfsi->npages--;
if (!nfsi->npages) {
spin_unlock(&nfsi->req_lock);
@ -1527,15 +1531,22 @@ int nfs_wb_page(struct inode *inode, struct page* page)
int nfs_set_page_dirty(struct page *page)
{
spinlock_t *req_lock = &NFS_I(page->mapping->host)->req_lock;
struct nfs_page *req;
int ret;
req = nfs_page_find_request(page);
spin_lock(req_lock);
req = nfs_page_find_request_locked(page);
if (req != NULL) {
/* Mark any existing write requests for flushing */
set_bit(PG_NEED_FLUSH, &req->wb_flags);
ret = !test_and_set_bit(PG_NEED_FLUSH, &req->wb_flags);
spin_unlock(req_lock);
nfs_release_request(req);
return ret;
}
return __set_page_dirty_nobuffers(page);
ret = __set_page_dirty_nobuffers(page);
spin_unlock(req_lock);
return ret;
}