ext4: update EOFBLOCKS flag on fallocate properly

EOFBLOCK_FL should be updated if called w/o FALLOCATE_FL_KEEP_SIZE
Currently it happens only if new extent was allocated.

TESTCASE:
fallocate test_file -n -l4096
fallocate test_file -l4096
Last fallocate cmd has updated size, but keept EOFBLOCK_FL set. And
fsck will complain about that.

Also remove ping pong in ext4_fallocate() in case of new extents,
where ext4_ext_map_blocks() clear EOFBLOCKS bit, and later
ext4_falloc_update_inode() restore it again.
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

fs/ext4/ext4.h

@@ -539,6 +539,8 @@ struct ext4_new_group_data {
 #define EXT4_GET_BLOCKS_PUNCH_OUT_EXT		0x0020
 	/* Don't normalize allocation size (used for fallocate) */
 #define EXT4_GET_BLOCKS_NO_NORMALIZE		0x0040
+	/* Request will not result in inode size update (user for fallocate) */
+#define EXT4_GET_BLOCKS_KEEP_SIZE		0x0080
 
 /*
  * Flags used by ext4_free_blocks

fs/ext4/extents.c

@@ -3432,14 +3432,8 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 
 	/* buffered write, writepage time, convert*/
 	ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
-	if (ret >= 0) {
+	if (ret >= 0)
 		ext4_update_inode_fsync_trans(handle, inode, 1);
-		err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
-					 map->m_len);
-		if (err < 0)
-			goto out2;
-	}
-
 out:
 	if (ret <= 0) {
 		err = ret;
@@ -3480,6 +3474,12 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
 
 map_out:
 	map->m_flags |= EXT4_MAP_MAPPED;
+	if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0) {
+		err = check_eofblocks_fl(handle, inode, map->m_lblk, path,
+					 map->m_len);
+		if (err < 0)
+			goto out2;
+	}
 out1:
 	if (allocated > map->m_len)
 		allocated = map->m_len;
@@ -3955,7 +3955,10 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
 			map->m_flags |= EXT4_MAP_UNINIT;
 	}
 
-	err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len);
+	err = 0;
+	if ((flags & EXT4_GET_BLOCKS_KEEP_SIZE) == 0)
+		err = check_eofblocks_fl(handle, inode, map->m_lblk,
+					 path, ar.len);
 	if (!err)
 		err = ext4_ext_insert_extent(handle, inode, path,
 					     &newex, flags);
@@ -4214,6 +4217,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 	int ret = 0;
 	int ret2 = 0;
 	int retries = 0;
+	int flags;
 	struct ext4_map_blocks map;
 	unsigned int credits, blkbits = inode->i_blkbits;
 
@@ -4250,6 +4254,10 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 		trace_ext4_fallocate_exit(inode, offset, max_blocks, ret);
 		return ret;
 	}
+	flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
+		EXT4_GET_BLOCKS_NO_NORMALIZE;
+	if (mode & FALLOC_FL_KEEP_SIZE)
+		flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
 retry:
 	while (ret >= 0 && ret < max_blocks) {
 		map.m_lblk = map.m_lblk + ret;
@@ -4259,9 +4267,7 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
 			ret = PTR_ERR(handle);
 			break;
 		}
-		ret = ext4_map_blocks(handle, inode, &map,
-				      EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
-				      EXT4_GET_BLOCKS_NO_NORMALIZE);
+		ret = ext4_map_blocks(handle, inode, &map, flags);
 		if (ret <= 0) {
 #ifdef EXT4FS_DEBUG
 			WARN_ON(ret <= 0);

fs/ext4/inode.c

@@ -477,9 +477,11 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
 	 */
 	down_read((&EXT4_I(inode)->i_data_sem));
 	if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
-		retval = ext4_ext_map_blocks(handle, inode, map, 0);
+		retval = ext4_ext_map_blocks(handle, inode, map, flags &
+					     EXT4_GET_BLOCKS_KEEP_SIZE);
 	} else {
-		retval = ext4_ind_map_blocks(handle, inode, map, 0);
+		retval = ext4_ind_map_blocks(handle, inode, map, flags &
+					     EXT4_GET_BLOCKS_KEEP_SIZE);
 	}
 	up_read((&EXT4_I(inode)->i_data_sem));