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authorTrond Myklebust <trond.myklebust@primarydata.com>2015-03-02 23:32:08 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-03-03 13:02:29 -0500
commit874f946376de57c8d6230b30ad71f742883fee3a (patch)
tree0fd166cc4798b50069d1120f822f094a60b7a9c2 /fs
parentec3ca4e57e00d52ff724b0ae49f4489667a9c311 (diff)
downloadop-kernel-dev-874f946376de57c8d6230b30ad71f742883fee3a.zip
op-kernel-dev-874f946376de57c8d6230b30ad71f742883fee3a.tar.gz
NFS: Fix a regression in the read() syscall
When invalidating the page cache for a regular file, we want to first sync all dirty data to disk and then call invalidate_inode_pages2(). The latter relies on nfs_launder_page() and nfs_release_page() to deal respectively with dirty pages, and unstable written pages. When commit 9590544694bec ("NFS: avoid deadlocks with loop-back mounted NFS filesystems.") changed the behaviour of nfs_release_page(), then it made it possible for invalidate_inode_pages2() to fail with an EBUSY. Unfortunately, that error is then propagated back to read(). Let's therefore work around the problem for now by protecting the call to sync the data and invalidate_inode_pages2() so that they are atomic w.r.t. the addition of new writes. Later on, we can revisit whether or not we still need nfs_launder_page() and nfs_release_page(). Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfs/file.c4
-rw-r--r--fs/nfs/inode.c37
2 files changed, 36 insertions, 5 deletions
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index c045c71..41963ff 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -178,7 +178,7 @@ nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
iocb->ki_filp,
iov_iter_count(to), (unsigned long) iocb->ki_pos);
- result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping);
+ result = nfs_revalidate_mapping_protected(inode, iocb->ki_filp->f_mapping);
if (!result) {
result = generic_file_read_iter(iocb, to);
if (result > 0)
@@ -199,7 +199,7 @@ nfs_file_splice_read(struct file *filp, loff_t *ppos,
dprintk("NFS: splice_read(%pD2, %lu@%Lu)\n",
filp, (unsigned long) count, (unsigned long long) *ppos);
- res = nfs_revalidate_mapping(inode, filp->f_mapping);
+ res = nfs_revalidate_mapping_protected(inode, filp->f_mapping);
if (!res) {
res = generic_file_splice_read(filp, ppos, pipe, count, flags);
if (res > 0)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 5026c44..8edb7d0 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1067,11 +1067,14 @@ static bool nfs_mapping_need_revalidate_inode(struct inode *inode)
}
/**
- * nfs_revalidate_mapping - Revalidate the pagecache
+ * __nfs_revalidate_mapping - Revalidate the pagecache
* @inode - pointer to host inode
* @mapping - pointer to mapping
+ * @may_lock - take inode->i_mutex?
*/
-int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+static int __nfs_revalidate_mapping(struct inode *inode,
+ struct address_space *mapping,
+ bool may_lock)
{
struct nfs_inode *nfsi = NFS_I(inode);
unsigned long *bitlock = &nfsi->flags;
@@ -1120,7 +1123,12 @@ int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
nfsi->cache_validity &= ~NFS_INO_INVALID_DATA;
spin_unlock(&inode->i_lock);
trace_nfs_invalidate_mapping_enter(inode);
- ret = nfs_invalidate_mapping(inode, mapping);
+ if (may_lock) {
+ mutex_lock(&inode->i_mutex);
+ ret = nfs_invalidate_mapping(inode, mapping);
+ mutex_unlock(&inode->i_mutex);
+ } else
+ ret = nfs_invalidate_mapping(inode, mapping);
trace_nfs_invalidate_mapping_exit(inode, ret);
clear_bit_unlock(NFS_INO_INVALIDATING, bitlock);
@@ -1130,6 +1138,29 @@ out:
return ret;
}
+/**
+ * nfs_revalidate_mapping - Revalidate the pagecache
+ * @inode - pointer to host inode
+ * @mapping - pointer to mapping
+ */
+int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping)
+{
+ return __nfs_revalidate_mapping(inode, mapping, false);
+}
+
+/**
+ * nfs_revalidate_mapping_protected - Revalidate the pagecache
+ * @inode - pointer to host inode
+ * @mapping - pointer to mapping
+ *
+ * Differs from nfs_revalidate_mapping() in that it grabs the inode->i_mutex
+ * while invalidating the mapping.
+ */
+int nfs_revalidate_mapping_protected(struct inode *inode, struct address_space *mapping)
+{
+ return __nfs_revalidate_mapping(inode, mapping, true);
+}
+
static unsigned long nfs_wcc_update_inode(struct inode *inode, struct nfs_fattr *fattr)
{
struct nfs_inode *nfsi = NFS_I(inode);
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