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Message-Id: <20070124195455.21259.4066.stgit@lade.trondhjem.org>
Date: Wed, 24 Jan 2007 11:54:55 -0800
From: Trond Myklebust <Trond.Myklebust@...app.com>
To: torvalds@...l.org, akpm@...l.org
Cc: linux-kernel@...r.kernel.org, nfs@...ts.sourceforge.net,
sds@...ho.nsa.gov
Subject: [PATCH 2/3] NFS: Fix races in nfs_revalidate_mapping()
From: Trond Myklebust <Trond.Myklebust@...app.com>
Prevent the call to invalidate_inode_pages2() from racing with file writes
by taking the inode->i_mutex across the page cache flush and invalidate.
Signed-off-by: Trond Myklebust <Trond.Myklebust@...app.com>
---
fs/nfs/dir.c | 2 -
fs/nfs/inode.c | 97 +++++++++++++++++++++++++++++++++---------------
fs/nfs/symlink.c | 4 +-
include/linux/nfs_fs.h | 1
4 files changed, 72 insertions(+), 32 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index dee3d6c..d9ba8cb 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -532,7 +532,7 @@ static int nfs_readdir(struct file *filp
lock_kernel();
- res = nfs_revalidate_mapping(inode, filp->f_mapping);
+ res = nfs_revalidate_mapping_nolock(inode, filp->f_mapping);
if (res < 0) {
unlock_kernel();
return res;
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 63e4702..d834982 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -665,49 +665,86 @@ int nfs_revalidate_inode(struct nfs_serv
return __nfs_revalidate_inode(server, inode);
}
+static int nfs_invalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (mapping->nrpages != 0) {
+ int ret = invalidate_inode_pages2(mapping);
+ if (ret < 0)
+ return ret;
+ }
+ spin_lock(&inode->i_lock);
+ nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
+ if (S_ISDIR(inode->i_mode)) {
+ memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
+ /* This ensures we revalidate child dentries */
+ nfsi->cache_change_attribute = jiffies;
+ }
+ spin_unlock(&inode->i_lock);
+ nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
+ dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
+ inode->i_sb->s_id, (long long)NFS_FILEID(inode));
+ return 0;
+}
+
+static int nfs_invalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+ int ret = 0;
+
+ mutex_lock(&inode->i_mutex);
+ if (NFS_I(inode)->cache_validity & NFS_INO_INVALID_DATA) {
+ ret = nfs_sync_mapping(mapping);
+ if (ret == 0)
+ ret = nfs_invalidate_mapping_nolock(inode, mapping);
+ }
+ mutex_unlock(&inode->i_mutex);
+ return ret;
+}
+
/**
- * nfs_revalidate_mapping - Revalidate the pagecache
+ * nfs_revalidate_mapping_nolock - Revalidate the pagecache
* @inode - pointer to host inode
* @mapping - pointer to mapping
*/
-int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping)
{
struct nfs_inode *nfsi = NFS_I(inode);
int ret = 0;
- if (NFS_STALE(inode))
- ret = -ESTALE;
if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
- || nfs_attribute_timeout(inode))
+ || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
- if (ret < 0)
- goto out;
+ if (ret < 0)
+ goto out;
+ }
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+ ret = nfs_invalidate_mapping_nolock(inode, mapping);
+out:
+ return ret;
+}
- if (nfsi->cache_validity & NFS_INO_INVALID_DATA) {
- if (mapping->nrpages != 0) {
- if (S_ISREG(inode->i_mode)) {
- ret = nfs_sync_mapping(mapping);
- if (ret < 0)
- goto out;
- }
- ret = invalidate_inode_pages2(mapping);
- if (ret < 0)
- goto out;
- }
- spin_lock(&inode->i_lock);
- nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
- if (S_ISDIR(inode->i_mode)) {
- memset(nfsi->cookieverf, 0, sizeof(nfsi->cookieverf));
- /* This ensures we revalidate child dentries */
- nfsi->cache_change_attribute = jiffies;
- }
- spin_unlock(&inode->i_lock);
+/**
+ * nfs_revalidate_mapping - Revalidate the pagecache
+ * @inode - pointer to host inode
+ * @mapping - pointer to mapping
+ *
+ * This version of the function will take the inode->i_mutex and attempt to
+ * flush out all dirty data if it needs to invalidate the page cache.
+ */
+int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+ struct nfs_inode *nfsi = NFS_I(inode);
+ int ret = 0;
- nfs_inc_stats(inode, NFSIOS_DATAINVALIDATE);
- dfprintk(PAGECACHE, "NFS: (%s/%Ld) data cache invalidated\n",
- inode->i_sb->s_id,
- (long long)NFS_FILEID(inode));
+ if ((nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
+ || nfs_attribute_timeout(inode) || NFS_STALE(inode)) {
+ ret = __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+ if (ret < 0)
+ goto out;
}
+ if (nfsi->cache_validity & NFS_INO_INVALID_DATA)
+ ret = nfs_invalidate_mapping(inode, mapping);
out:
return ret;
}
diff --git a/fs/nfs/symlink.c b/fs/nfs/symlink.c
index 6c68611..525c136 100644
--- a/fs/nfs/symlink.c
+++ b/fs/nfs/symlink.c
@@ -50,7 +50,9 @@ static void *nfs_follow_link(struct dent
{
struct inode *inode = dentry->d_inode;
struct page *page;
- void *err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
+ void *err;
+
+ err = ERR_PTR(nfs_revalidate_mapping_nolock(inode, inode->i_mapping));
if (err)
goto read_failed;
page = read_cache_page(&inode->i_data, 0,
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 0496306..c5d4084 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -308,6 +308,7 @@ extern int nfs_attribute_timeout(struct
extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
+extern int nfs_revalidate_mapping_nolock(struct inode *inode, struct address_space *mapping);
extern int nfs_setattr(struct dentry *, struct iattr *);
extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
extern void nfs_begin_attr_update(struct inode *);
-
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