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authorTrond Myklebust <Trond.Myklebust@netapp.com>2006-03-20 13:44:50 -0500
committerTrond Myklebust <Trond.Myklebust@netapp.com>2006-03-20 13:44:50 -0500
commitdeb7d638262019cbac5d15ab74ffd1c29242c7cb (patch)
tree88095acd2d455b594f4cec08702aa9691faff2a0
parent1dd761e9070aa2e543df3db41bd75ed4b8f2fab9 (diff)
NFS: Fix a race with PG_private and nfs_release_page()
We don't need to set PG_private for readahead pages, since they never get unlocked while I/O is in progress. However there is a small race in nfs_readpage_release() whereby the page may be unlocked, and have PG_private set. Fix is to have PG_private set only for the case of writes... Also fix a bug in nfs_clear_page_writeback(): Don't attempt to clear the radix_tree tag if we've already deleted the radix tree entry. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
-rw-r--r--fs/nfs/pagelist.c10
-rw-r--r--fs/nfs/write.c2
2 files changed, 7 insertions, 5 deletions
diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index d6e076c9dbe1..106aca388ebc 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -88,7 +88,6 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
BUG_ON(PagePrivate(page));
BUG_ON(!PageLocked(page));
BUG_ON(page->mapping->host != inode);
- SetPagePrivate(page);
req->wb_offset = offset;
req->wb_pgbase = offset;
req->wb_bytes = count;
@@ -136,9 +135,11 @@ void nfs_clear_page_writeback(struct nfs_page *req)
{
struct nfs_inode *nfsi = NFS_I(req->wb_context->dentry->d_inode);
- spin_lock(&nfsi->req_lock);
- radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);
- spin_unlock(&nfsi->req_lock);
+ if (req->wb_page != NULL) {
+ spin_lock(&nfsi->req_lock);
+ radix_tree_tag_clear(&nfsi->nfs_page_tree, req->wb_index, NFS_PAGE_TAG_WRITEBACK);
+ spin_unlock(&nfsi->req_lock);
+ }
nfs_unlock_request(req);
}
@@ -153,7 +154,6 @@ void nfs_clear_request(struct nfs_page *req)
{
struct page *page = req->wb_page;
if (page != NULL) {
- ClearPagePrivate(page);
page_cache_release(page);
req->wb_page = NULL;
}
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 647e3217c2e1..d9e5ee594572 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -429,6 +429,7 @@ static int nfs_inode_add_request(struct inode *inode, struct nfs_page *req)
if (nfs_have_delegation(inode, FMODE_WRITE))
nfsi->change_attr++;
}
+ SetPagePrivate(req->wb_page);
nfsi->npages++;
atomic_inc(&req->wb_count);
return 0;
@@ -445,6 +446,7 @@ static void nfs_inode_remove_request(struct nfs_page *req)
BUG_ON (!NFS_WBACK_BUSY(req));
spin_lock(&nfsi->req_lock);
+ ClearPagePrivate(req->wb_page);
radix_tree_delete(&nfsi->nfs_page_tree, req->wb_index);
nfsi->npages--;
if (!nfsi->npages) {