---

yaml
---
r: 95030
b: refs/heads/master
c: 267e4db
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3977c965ec35ce1a7eac988ad313f0fc9aee9660
+refs/heads/master: 267e4db9ac28a09973476e7ec2cb6807e609d35a

trunk/fs/ext4/inode.c

@@ -985,6 +985,16 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
 	} else {
 		retval = ext4_get_blocks_handle(handle, inode, block,
 				max_blocks, bh, create, extend_disksize);
+
+		if (retval > 0 && buffer_new(bh)) {
+			/*
+			 * We allocated new blocks which will result in
+			 * i_data's format changing.  Force the migrate
+			 * to fail by clearing migrate flags
+			 */
+			EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
+							~EXT4_EXT_MIGRATE;
+		}
 	}
 	up_write((&EXT4_I(inode)->i_data_sem));
 	return retval;
@@ -2976,7 +2986,8 @@ static int ext4_do_update_inode(handle_t *handle,
 	if (ext4_inode_blocks_set(handle, raw_inode, ei))
 		goto out_brelse;
 	raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
-	raw_inode->i_flags = cpu_to_le32(ei->i_flags);
+	/* clear the migrate flag in the raw_inode */
+	raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE);
 	if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
 	    cpu_to_le32(EXT4_OS_HURD))
 		raw_inode->i_file_acl_high =

trunk/fs/ext4/migrate.c

@@ -327,7 +327,7 @@ static int free_ind_block(handle_t *handle, struct inode *inode, __le32 *i_data)
 }
 
 static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
-				struct inode *tmp_inode)
+						struct inode *tmp_inode)
 {
 	int retval;
 	__le32	i_data[3];
@@ -339,7 +339,7 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 	 * i_data field of the original inode
 	 */
 	retval = ext4_journal_extend(handle, 1);
-	if (retval != 0) {
+	if (retval) {
 		retval = ext4_journal_restart(handle, 1);
 		if (retval)
 			goto err_out;
@@ -350,6 +350,18 @@ static int ext4_ext_swap_inode_data(handle_t *handle, struct inode *inode,
 	i_data[2] = ei->i_data[EXT4_TIND_BLOCK];
 
 	down_write(&EXT4_I(inode)->i_data_sem);
+	/*
+	 * if EXT4_EXT_MIGRATE is cleared a block allocation
+	 * happened after we started the migrate. We need to
+	 * fail the migrate
+	 */
+	if (!(EXT4_I(inode)->i_flags & EXT4_EXT_MIGRATE)) {
+		retval = -EAGAIN;
+		up_write(&EXT4_I(inode)->i_data_sem);
+		goto err_out;
+	} else
+		EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags &
+							~EXT4_EXT_MIGRATE;
 	/*
 	 * We have the extent map build with the tmp inode.
 	 * Now copy the i_data across
@@ -508,6 +520,17 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
 	 * switch the inode format to prevent read.
 	 */
 	mutex_lock(&(inode->i_mutex));
+	/*
+	 * Even though we take i_mutex we can still cause block allocation
+	 * via mmap write to holes. If we have allocated new blocks we fail
+	 * migrate.  New block allocation will clear EXT4_EXT_MIGRATE flag.
+	 * The flag is updated with i_data_sem held to prevent racing with
+	 * block allocation.
+	 */
+	down_read((&EXT4_I(inode)->i_data_sem));
+	EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags | EXT4_EXT_MIGRATE;
+	up_read((&EXT4_I(inode)->i_data_sem));
+
 	handle = ext4_journal_start(inode, 1);
 
 	ei = EXT4_I(inode);
@@ -559,9 +582,15 @@ int ext4_ext_migrate(struct inode *inode, struct file *filp,
 		 * tmp_inode
 		 */
 		free_ext_block(handle, tmp_inode);
-	else
-		retval = ext4_ext_swap_inode_data(handle, inode,
-							tmp_inode);
+	else {
+		retval = ext4_ext_swap_inode_data(handle, inode, tmp_inode);
+		if (retval)
+			/*
+			 * if we fail to swap inode data free the extent
+			 * details of the tmp inode
+			 */
+			free_ext_block(handle, tmp_inode);
+	}
 
 	/* We mark the tmp_inode dirty via ext4_ext_tree_init. */
 	if (ext4_journal_extend(handle, 1) != 0)

trunk/include/linux/ext4_fs.h

@@ -231,6 +231,7 @@ struct ext4_group_desc
 #define EXT4_TOPDIR_FL			0x00020000 /* Top of directory hierarchies*/
 #define EXT4_HUGE_FILE_FL               0x00040000 /* Set to each huge file */
 #define EXT4_EXTENTS_FL			0x00080000 /* Inode uses extents */
+#define EXT4_EXT_MIGRATE		0x00100000 /* Inode is migrating */
 #define EXT4_RESERVED_FL		0x80000000 /* reserved for ext4 lib */
 
 #define EXT4_FL_USER_VISIBLE		0x000BDFFF /* User visible flags */