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Commit 05145bd7 authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o
Browse files

ext4: fix scheduling in atomic on group checksum failure 



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.

CC: stable@vger.kernel.org
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
parent ff978b09

fs/ext4/balloc.c

+4 −3
Original line number Original line Diff line number Diff line
@@ -191,7 +191,6 @@ static int ext4_init_block_bitmap(struct super_block *sb, 
	/* If checksum is bad mark all blocks used to prevent allocation

	/* If checksum is bad mark all blocks used to prevent allocation

	 * essentially implementing a per-group read-only flag. */

	 * essentially implementing a per-group read-only flag. */

	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {

	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);

		grp = ext4_get_group_info(sb, block_group);

		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))

		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))

			percpu_counter_sub(&sbi->s_freeclusters_counter,

			percpu_counter_sub(&sbi->s_freeclusters_counter,
@@ -442,14 +441,16 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) 
	}

	}

	ext4_lock_group(sb, block_group);

	ext4_lock_group(sb, block_group);

	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {

	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {



		err = ext4_init_block_bitmap(sb, bh, block_group, desc);

		err = ext4_init_block_bitmap(sb, bh, block_group, desc);

		set_bitmap_uptodate(bh);

		set_bitmap_uptodate(bh);

		set_buffer_uptodate(bh);

		set_buffer_uptodate(bh);

		ext4_unlock_group(sb, block_group);

		ext4_unlock_group(sb, block_group);

		unlock_buffer(bh);

		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 out;

		}

		goto verify;

		goto verify;

	}

	}

	ext4_unlock_group(sb, block_group);

	ext4_unlock_group(sb, block_group);

fs/ext4/ialloc.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -76,7 +76,6 @@ static int ext4_init_inode_bitmap(struct super_block *sb, 
	/* If checksum is bad mark all blocks and inodes use to prevent

	/* If checksum is bad mark all blocks and inodes use to prevent

	 * allocation, essentially implementing a per-group read-only flag. */

	 * allocation, essentially implementing a per-group read-only flag. */

	if (!ext4_group_desc_csum_verify(sb, block_group, gdp)) {

	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);

		grp = ext4_get_group_info(sb, block_group);

		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))

		if (!EXT4_MB_GRP_BBITMAP_CORRUPT(grp))

			percpu_counter_sub(&sbi->s_freeclusters_counter,

			percpu_counter_sub(&sbi->s_freeclusters_counter,
@@ -191,8 +190,11 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) 
		set_buffer_verified(bh);

		set_buffer_verified(bh);

		ext4_unlock_group(sb, block_group);

		ext4_unlock_group(sb, block_group);

		unlock_buffer(bh);

		unlock_buffer(bh);

		if (err)

		if (err) {

			ext4_error(sb, "Failed to init inode bitmap for group "

				   "%u: %d", block_group, err);

			goto out;

			goto out;

		}

		return bh;

		return bh;

	}

	}

	ext4_unlock_group(sb, block_group);

	ext4_unlock_group(sb, block_group);