diff mbox

[2/6] CIFS: Make read call work with strict cache mode

Message ID 1289403711-12965-3-git-send-email-piastryyy@gmail.com (mailing list archive)
State New, archived
Headers show

Commit Message

Pavel Shilovsky Nov. 10, 2010, 3:41 p.m. UTC
None
diff mbox

Patch

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 9c37897..bbb5294 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -568,6 +568,33 @@  cifs_do_mount(struct file_system_type *fs_type,
 	return dget(sb->s_root);
 }
 
+static ssize_t cifs_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
+				  unsigned long nr_segs, loff_t pos)
+{
+	struct inode *inode;
+	struct cifs_sb_info *cifs_sb;
+	ssize_t read;
+
+	inode = iocb->ki_filp->f_path.dentry->d_inode;
+	cifs_sb = CIFS_SB(iocb->ki_filp->f_path.dentry->d_sb);
+
+	if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) == 0 ||
+	    CIFS_I(inode)->clientCanCacheRead)
+		return generic_file_aio_read(iocb, iov, nr_segs, pos);
+
+	/* in strict cache mode we need to read from the server all the time
+	   if we don't have level II oplock because the server can delay mtime
+	   change - so we can't make a decision about inode invalidating.
+	   And we can also fail with pagereading if there are mandatory locks
+	   on pages affected by this read but not on the region from pos to
+	   pos+len-1 */
+	read = cifs_user_read(iocb->ki_filp, iov->iov_base,
+			      iov->iov_len, &pos);
+	iocb->ki_pos = pos;
+
+	return read;
+}
+
 static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
 				   unsigned long nr_segs, loff_t pos)
 {
@@ -690,7 +717,7 @@  const struct inode_operations cifs_symlink_inode_ops = {
 const struct file_operations cifs_file_ops = {
 	.read = do_sync_read,
 	.write = do_sync_write,
-	.aio_read = generic_file_aio_read,
+	.aio_read = cifs_file_aio_read,
 	.aio_write = cifs_file_aio_write,
 	.open = cifs_open,
 	.release = cifs_close,
@@ -727,7 +754,7 @@  const struct file_operations cifs_file_direct_ops = {
 const struct file_operations cifs_file_nobrl_ops = {
 	.read = do_sync_read,
 	.write = do_sync_write,
-	.aio_read = generic_file_aio_read,
+	.aio_read = cifs_file_aio_read,
 	.aio_write = cifs_file_aio_write,
 	.open = cifs_open,
 	.release = cifs_close,