Commit d17413c0 authored by Dmitry Monakhov's avatar Dmitry Monakhov Committed by Theodore Ts'o
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ext4: clean up inode bitmaps manipulation in ext4_free_inode 



- Reorganize locking scheme to batch two atomic operation in to one.
  This also allow us to state what healthy group must obey following rule
  ext4_free_inodes_count(sb, gdp) == ext4_count_free(inode_bitmap, NUM);
- Fix possible undefined pointer dereference.
- Even if group descriptor stats aren't accessible we have to update
  inode bitmaps.
- Move non-group members update out of group_lock.

Signed-off-by: default avatarDmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 21ca087a

fs/ext4/ialloc.c

+39 −46
Original line number Diff line number Diff line
@@ -240,56 +240,49 @@ void ext4_free_inode(handle_t *handle, struct inode *inode) 
	if (fatal)

		goto error_return;



	/* Ok, now we can actually update the inode bitmaps.. */

	cleared = ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),

					bit, bitmap_bh->b_data);

	if (!cleared)

		ext4_error(sb, "bit already cleared for inode %lu", ino);

	else {

	fatal = -ESRCH;

	gdp = ext4_get_group_desc(sb, block_group, &bh2);



	if (gdp) {

		BUFFER_TRACE(bh2, "get_write_access");

		fatal = ext4_journal_get_write_access(handle, bh2);

		if (fatal) goto error_return;



		if (gdp) {

	}

	ext4_lock_group(sb, block_group);

	cleared = ext4_clear_bit(bit, bitmap_bh->b_data);

	if (fatal || !cleared) {

		ext4_unlock_group(sb, block_group);

		goto out;

	}



	count = ext4_free_inodes_count(sb, gdp) + 1;

	ext4_free_inodes_set(sb, gdp, count);

	if (is_directory) {

		count = ext4_used_dirs_count(sb, gdp) - 1;

		ext4_used_dirs_set(sb, gdp, count);

				if (sbi->s_log_groups_per_flex) {

					ext4_group_t f;



					f = ext4_flex_group(sbi, block_group);

					atomic_dec(&sbi->s_flex_groups[f].used_dirs);

				}



		percpu_counter_dec(&sbi->s_dirs_counter);

	}

			gdp->bg_checksum = ext4_group_desc_csum(sbi,

							block_group, gdp);

	gdp->bg_checksum = ext4_group_desc_csum(sbi, block_group, gdp);

	ext4_unlock_group(sb, block_group);

			percpu_counter_inc(&sbi->s_freeinodes_counter);

			if (is_directory)

				percpu_counter_dec(&sbi->s_dirs_counter);



	percpu_counter_inc(&sbi->s_freeinodes_counter);

	if (sbi->s_log_groups_per_flex) {

				ext4_group_t f;

		ext4_group_t f = ext4_flex_group(sbi, block_group);



				f = ext4_flex_group(sbi, block_group);

		atomic_inc(&sbi->s_flex_groups[f].free_inodes);

			}

		if (is_directory)

			atomic_dec(&sbi->s_flex_groups[f].used_dirs);

	}

	BUFFER_TRACE(bh2, "call ext4_handle_dirty_metadata");

		err = ext4_handle_dirty_metadata(handle, NULL, bh2);

		if (!fatal) fatal = err;

	}

	fatal = ext4_handle_dirty_metadata(handle, NULL, bh2);

out:

	if (cleared) {

		BUFFER_TRACE(bitmap_bh, "call ext4_handle_dirty_metadata");

		err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);

		if (!fatal)

			fatal = err;

		sb->s_dirt = 1;

	} else

		ext4_error(sb, "bit already cleared for inode %lu", ino);



error_return:

	brelse(bitmap_bh);

	ext4_std_error(sb, fatal);

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