[PATCH 4.4 018/137] ext4: fix scheduling in atomic on group checksum failure

Greg Kroah-Hartman
2016-02-24T04:40:39Z

From: Jan Kara <jack@suse.cz>

commit 05145bd799e498ce4e3b5145894174ee881f02b0 upstream.

When block group checksum is wrong, we call ext4_error() while holding
group spinlock from ext4_init_block_bitmap() or
ext4_init_inode_bitmap() which results in scheduling while in atomic.
Fix the issue by calling ext4_error() later after dropping the spinlock.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/balloc.c | 7 ++++---
fs/ext4/ialloc.c | 6 ++++--
2 files changed, 8 insertions(+), 5 deletions(-)

--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -191,7 +191,6 @@ static int ext4_init_block_bitmap(struct
/* If checksum is bad mark all blocks used to prevent allocation
* essentially implementing a per-group read-only flag. */
if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
- ext4_error(sb, "Checksum bad for group %u", block_group);
grp = ext4_get_group_info(sb, block_group);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
@@ -442,14 +441,16 @@ ext4_read_block_bitmap_nowait(struct sup
}
ext4_lock_group(sb, block_group);
if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
-
err = ext4_init_block_bitmap(sb, bh, block_group, desc);
set_bitmap_uptodate(bh);
set_buffer_uptodate(bh);
ext4_unlock_group(sb, block_group);
unlock_buffer(bh);
- if (err)
+ if (err) {
+ ext4_error(sb, "Failed to init block bitmap for group "
+ "%u: %d", block_group, err);
goto out;
+ }
goto verify;
}
ext4_unlock_group(sb, block_group);
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -76,7 +76,6 @@ static int ext4_init_inode_bitmap(struct
/* If checksum is bad mark all blocks and inodes use to prevent
* allocation, essentially implementing a per-group read-only flag. */
if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {
- ext4_error(sb, "Checksum bad for group %u", block_group);
grp = ext4_get_group_info(sb, block_group);
if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))
percpu_counter_sub(&sbi->s_freeclusters_counter,
@@ -191,8 +190,11 @@ ext4_read_inode_bitmap(struct super_bloc
set_buffer_verified(bh);
ext4_unlock_group(sb, block_group);
unlock_buffer(bh);
- if (err)
+ if (err) {
+ ext4_error(sb, "Failed to init inode bitmap for group "
+ "%u: %d", block_group, err);
goto out;
+ }
return bh;
}
ext4_unlock_group(sb, block_group);