ext4: check to make make sure bd_dev is set before dereferencing it
There are some drivers which may not set bdev->bd_dev. So make sure
it is non-NULL before dereferencing it.
Google-Bug-Id: 1773557
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c1036bc..e046eba 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -2304,6 +2304,8 @@
{
struct super_block *sb = sbi->s_buddy_cache->i_sb;
+ if (!sb->s_bdev->bd_part)
+ return snprintf(buf, PAGE_SIZE, "0\n");
return snprintf(buf, PAGE_SIZE, "%lu\n",
(part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
sbi->s_sectors_written_start) >> 1);
@@ -2314,6 +2316,8 @@
{
struct super_block *sb = sbi->s_buddy_cache->i_sb;
+ if (!sb->s_bdev->bd_part)
+ return snprintf(buf, PAGE_SIZE, "0\n");
return snprintf(buf, PAGE_SIZE, "%llu\n",
(unsigned long long)(sbi->s_kbytes_written +
((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
@@ -2575,8 +2579,9 @@
sbi->s_resgid = EXT4_DEF_RESGID;
sbi->s_inode_readahead_blks = EXT4_DEF_INODE_READAHEAD_BLKS;
sbi->s_sb_block = sb_block;
- sbi->s_sectors_written_start = part_stat_read(sb->s_bdev->bd_part,
- sectors[1]);
+ if (sb->s_bdev->bd_part)
+ sbi->s_sectors_written_start =
+ part_stat_read(sb->s_bdev->bd_part, sectors[1]);
unlock_kernel();
@@ -3492,10 +3497,14 @@
*/
if (!(sb->s_flags & MS_RDONLY))
es->s_wtime = cpu_to_le32(get_seconds());
- es->s_kbytes_written =
- cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
+ if (sb->s_bdev->bd_part)
+ es->s_kbytes_written =
+ cpu_to_le64(EXT4_SB(sb)->s_kbytes_written +
((part_stat_read(sb->s_bdev->bd_part, sectors[1]) -
EXT4_SB(sb)->s_sectors_written_start) >> 1));
+ else
+ es->s_kbytes_written =
+ cpu_to_le64(EXT4_SB(sb)->s_kbytes_written);
ext4_free_blocks_count_set(es, percpu_counter_sum_positive(
&EXT4_SB(sb)->s_freeblocks_counter));
es->s_free_inodes_count = cpu_to_le32(percpu_counter_sum_positive(