ext4: avoid potential hang in mpage_submit_io() when blocksize < pagesize

[firefly-linux-kernel-4.4.55.git] / fs / ext4 / xattr.c

diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index c757adc972506d672c78b7de03e654ede7eb8b1e..19fe4e3d39ecd68950b171b404262ae7f7b162c5 100644 (file)
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -820,8 +820,14 @@ inserted:
                        if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
                                goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
 
+                       /*
+                        * take i_data_sem because we will test
+                        * i_delalloc_reserved_flag in ext4_mb_new_blocks
+                        */
+                       down_read((&EXT4_I(inode)->i_data_sem));
                        block = ext4_new_meta_blocks(handle, inode, goal, 0,
                                                     NULL, &error);
+                       up_read((&EXT4_I(inode)->i_data_sem));
                        if (error)
                                goto cleanup;