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ext4: check to make make sure bd_dev is set before dereferencing it

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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>
This commit is contained in:
Theodore Ts'o 2010-07-27 11:56:08 -04:00
parent cc937db74b
commit f613dfcb33
1 changed files with 13 additions and 4 deletions
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17
fs/ext4/super.c
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@ -2304,6 +2304,8 @@ static ssize_t session_write_kbytes_show(struct ext4_attr *a,
{
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 @@ static ssize_t lifetime_write_kbytes_show(struct ext4_attr *a,
{
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 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
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 @@ static int ext4_commit_super(struct super_block *sb, int sync)
*/
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(