5 files changed, 104 insertions, 0 deletions

diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index 71cab8e..cfdc055 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -116,12 +116,16 @@ struct v9fs_session_info {
 	struct p9_fid *root_fid; /* Used for file system sync */
 };
 
+/* cache_validity flags */
+#define V9FS_INO_INVALID_ATTR 0x01
+
 struct v9fs_inode {
 #ifdef CONFIG_9P_FSCACHE
 	spinlock_t fscache_lock;
 	struct fscache_cookie *fscache;
 	struct p9_qid *fscache_key;
 #endif
+	unsigned int cache_validity;
 	struct p9_fid *writeback_fid;
 	struct inode vfs_inode;
 };
diff --git a/fs/9p/v9fs_vfs.h b/fs/9p/v9fs_vfs.h
index ed9fd00..591807f 100644
--- a/fs/9p/v9fs_vfs.h
+++ b/fs/9p/v9fs_vfs.h
@@ -70,4 +70,14 @@ int v9fs_vfs_setattr_dotl(struct dentry *, struct iattr *);
 int v9fs_file_fsync_dotl(struct file *filp, int datasync);
 ssize_t v9fs_file_write_internal(struct inode *, struct p9_fid *,
 				 const char __user *, size_t, loff_t *, int);
+int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode);
+int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode);
+static inline void v9fs_invalidate_inode_attr(struct inode *inode)
+{
+	struct v9fs_inode *v9inode;
+	v9inode = V9FS_I(inode);
+	v9inode->cache_validity |= V9FS_INO_INVALID_ATTR;
+	return;
+}
+
 #define P9_LOCK_TIMEOUT (30*HZ)
diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
index a4ae4be..b6a3b9f 100644
--- a/fs/9p/vfs_dentry.c
+++ b/fs/9p/vfs_dentry.c
@@ -100,7 +100,41 @@ static void v9fs_dentry_release(struct dentry *dentry)
 	}
 }
 
+static int v9fs_lookup_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	struct p9_fid *fid;
+	struct inode *inode;
+	struct v9fs_inode *v9inode;
+
+	if (nd->flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	inode = dentry->d_inode;
+	if (!inode)
+		goto out_valid;
+
+	v9inode = V9FS_I(inode);
+	if (v9inode->cache_validity & V9FS_INO_INVALID_ATTR) {
+		int retval;
+		struct v9fs_session_info *v9ses;
+		fid = v9fs_fid_lookup(dentry);
+		if (IS_ERR(fid))
+			return PTR_ERR(fid);
+
+		v9ses = v9fs_inode2v9ses(inode);
+		if (v9fs_proto_dotl(v9ses))
+			retval = v9fs_refresh_inode_dotl(fid, inode);
+		else
+			retval = v9fs_refresh_inode(fid, inode);
+		if (retval <= 0)
+			return retval;
+	}
+out_valid:
+	return 1;
+}
+
 const struct dentry_operations v9fs_cached_dentry_operations = {
+	.d_revalidate = v9fs_lookup_revalidate,
 	.d_delete = v9fs_cached_dentry_delete,
 	.d_release = v9fs_dentry_release,
 };
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 334ad12..a28fe9f 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -220,6 +220,7 @@ struct inode *v9fs_alloc_inode(struct super_block *sb)
 	spin_lock_init(&v9inode->fscache_lock);
 #endif
 	v9inode->writeback_fid = NULL;
+	v9inode->cache_validity = 0;
 	return &v9inode->vfs_inode;
 }
 
@@ -1010,6 +1011,7 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 	char tag_name[14];
 	unsigned int i_nlink;
 	struct v9fs_session_info *v9ses = sb->s_fs_info;
+	struct v9fs_inode *v9inode = V9FS_I(inode);
 
 	inode->i_nlink = 1;
 
@@ -1069,6 +1071,7 @@ v9fs_stat2inode(struct p9_wstat *stat, struct inode *inode,
 
 	/* not real number of blocks, but 512 byte ones ... */
 	inode->i_blocks = (i_size_read(inode) + 512 - 1) >> 9;
+	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
 }
 
 /**
@@ -1323,6 +1326,32 @@ v9fs_vfs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t rdev)
 	return retval;
 }
 
+int v9fs_refresh_inode(struct p9_fid *fid, struct inode *inode)
+{
+	loff_t i_size;
+	struct p9_wstat *st;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	st = p9_client_stat(fid);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+
+	spin_lock(&inode->i_lock);
+	/*
+	 * We don't want to refresh inode->i_size,
+	 * because we may have cached data
+	 */
+	i_size = inode->i_size;
+	v9fs_stat2inode(st, inode, inode->i_sb);
+	if (v9ses->cache)
+		inode->i_size = i_size;
+	spin_unlock(&inode->i_lock);
+	p9stat_free(st);
+	kfree(st);
+	return 0;
+}
+
 static const struct inode_operations v9fs_dir_inode_operations_dotu = {
 	.create = v9fs_vfs_create,
 	.lookup = v9fs_vfs_lookup,
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index c6d9677..5c04d66 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -484,6 +484,7 @@ int v9fs_vfs_setattr_dotl(struct dentry *dentry, struct iattr *iattr)
 void
 v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode)
 {
+	struct v9fs_inode *v9inode = V9FS_I(inode);
 
 	if ((stat->st_result_mask & P9_STATS_BASIC) == P9_STATS_BASIC) {
 		inode->i_atime.tv_sec = stat->st_atime_sec;
@@ -542,6 +543,7 @@ v9fs_stat2inode_dotl(struct p9_stat_dotl *stat, struct inode *inode)
 	/* Currently we don't support P9_STATS_BTIME and P9_STATS_DATA_VERSION
 	 * because the inode structure does not have fields for them.
 	 */
+	v9inode->cache_validity &= ~V9FS_INO_INVALID_ATTR;
 }
 
 static int
@@ -822,6 +824,31 @@ ndset:
 	return NULL;
 }
 
+int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
+{
+	loff_t i_size;
+	struct p9_stat_dotl *st;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
+	if (IS_ERR(st))
+		return PTR_ERR(st);
+
+	spin_lock(&inode->i_lock);
+	/*
+	 * We don't want to refresh inode->i_size,
+	 * because we may have cached data
+	 */
+	i_size = inode->i_size;
+	v9fs_stat2inode_dotl(st, inode);
+	if (v9ses->cache)
+		inode->i_size = i_size;
+	spin_unlock(&inode->i_lock);
+	kfree(st);
+	return 0;
+}
+
 const struct inode_operations v9fs_dir_inode_operations_dotl = {
 	.create = v9fs_vfs_create_dotl,
 	.lookup = v9fs_vfs_lookup,