ext4: fix BUG when calling ext4_error with locked block group
The mballoc code likes to call ext4_error while it is holding locked
block groups. This can causes a scheduling in atomic context BUG. We
can't just unlock the block group and relock it after/if ext4_error
returns since that might result in race conditions in the case where
the filesystem is set to continue after finding errors.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 0bf4c4c..cda6963 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -457,8 +457,8 @@
blocknr += first + i;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
-
- ext4_error(sb, __func__, "double-free of inode"
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ __func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr,
first + i, e4b->bd_group);
@@ -702,7 +702,7 @@
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
- ext4_error(sb, __func__,
+ ext4_grp_locked_error(sb, group, __func__,
"EXT4-fs: group %u: %u blocks in bitmap, %u in gd",
group, free, grp->bb_free);
/*
@@ -1095,8 +1095,6 @@
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
-__releases(bitlock)
-__acquires(bitlock)
{
int block = 0;
int max = 0;
@@ -1135,12 +1133,11 @@
blocknr += block;
blocknr +=
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
- ext4_unlock_group(sb, e4b->bd_group);
- ext4_error(sb, __func__, "double-free of inode"
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ __func__, "double-free of inode"
" %lu's block %llu(bit %u in group %u)",
inode ? inode->i_ino : 0, blocknr, block,
e4b->bd_group);
- ext4_lock_group(sb, e4b->bd_group);
}
mb_clear_bit(block, EXT4_MB_BITMAP(e4b));
e4b->bd_info->bb_counters[order]++;
@@ -1623,7 +1620,8 @@
* free blocks even though group info says we
* we have free blocks
*/
- ext4_error(sb, __func__, "%d free blocks as per "
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ __func__, "%d free blocks as per "
"group info. But bitmap says 0",
free);
break;
@@ -1632,7 +1630,8 @@
mb_find_extent(e4b, 0, i, ac->ac_g_ex.fe_len, &ex);
BUG_ON(ex.fe_len <= 0);
if (free < ex.fe_len) {
- ext4_error(sb, __func__, "%d free blocks as per "
+ ext4_grp_locked_error(sb, e4b->bd_group,
+ __func__, "%d free blocks as per "
"group info. But got %d blocks",
free, ex.fe_len);
/*
@@ -3822,8 +3821,9 @@
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
(unsigned long) pa->pa_len);
- ext4_error(sb, __func__, "free %u, pa_free %u",
- free, pa->pa_free);
+ ext4_grp_locked_error(sb, group,
+ __func__, "free %u, pa_free %u",
+ free, pa->pa_free);
/*
* pa is already deleted so we use the value obtained
* from the bitmap and continue.
@@ -4633,9 +4633,9 @@
else if (block >= (entry->start_blk + entry->count))
n = &(*n)->rb_right;
else {
- ext4_error(sb, __func__,
- "Double free of blocks %d (%d %d)",
- block, entry->start_blk, entry->count);
+ ext4_grp_locked_error(sb, e4b->bd_group, __func__,
+ "Double free of blocks %d (%d %d)",
+ block, entry->start_blk, entry->count);
return 0;
}
}