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Commit 7bf72ede authored by Mark Fasheh's avatar Mark Fasheh
Browse files

ocfs2: better group descriptor consistency checks 



Try to catch corrupted group descriptors with some stronger checks placed in
a couple of strategic locations. Detect a failed resizefs and refuse to
allocate past what bitmap i_clusters allows.

Signed-off-by: default avatarMark Fasheh <mark.fasheh@oracle.com>
parent 101ebf25

fs/ocfs2/suballoc.c

+94 −20
Original line number Diff line number Diff line
@@ -85,11 +85,6 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_super *osb, 
				     u64 *bg_blkno);

static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh,

					 int nr);

static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,

					     struct buffer_head *bg_bh,

					     unsigned int bits_wanted,

					     u16 *bit_off,

					     u16 *bits_found);

static inline int ocfs2_block_group_set_bits(struct ocfs2_journal_handle *handle,

					     struct inode *alloc_inode,

					     struct ocfs2_group_desc *bg,
@@ -143,6 +138,64 @@ static u32 ocfs2_bits_per_group(struct ocfs2_chain_list *cl) 
	return (u32)le16_to_cpu(cl->cl_cpg) * (u32)le16_to_cpu(cl->cl_bpc);

}



/* somewhat more expensive than our other checks, so use sparingly. */

static int ocfs2_check_group_descriptor(struct super_block *sb,

					struct ocfs2_dinode *di,

					struct ocfs2_group_desc *gd)

{

	unsigned int max_bits;



	if (!OCFS2_IS_VALID_GROUP_DESC(gd)) {

		OCFS2_RO_ON_INVALID_GROUP_DESC(sb, gd);

		return -EIO;

	}



	if (di->i_blkno != gd->bg_parent_dinode) {

		ocfs2_error(sb, "Group descriptor # %llu has bad parent "

			    "pointer (%llu, expected %llu)",

			    (unsigned long long)le64_to_cpu(gd->bg_blkno),

			    (unsigned long long)le64_to_cpu(gd->bg_parent_dinode),

			    (unsigned long long)le64_to_cpu(di->i_blkno));

		return -EIO;

	}



	max_bits = le16_to_cpu(di->id2.i_chain.cl_cpg) * le16_to_cpu(di->id2.i_chain.cl_bpc);

	if (le16_to_cpu(gd->bg_bits) > max_bits) {

		ocfs2_error(sb, "Group descriptor # %llu has bit count of %u",

			    (unsigned long long)le64_to_cpu(gd->bg_blkno),

			    le16_to_cpu(gd->bg_bits));

		return -EIO;

	}



	if (le16_to_cpu(gd->bg_chain) >=

	    le16_to_cpu(di->id2.i_chain.cl_next_free_rec)) {

		ocfs2_error(sb, "Group descriptor # %llu has bad chain %u",

			    (unsigned long long)le64_to_cpu(gd->bg_blkno),

			    le16_to_cpu(gd->bg_chain));

		return -EIO;

	}



	if (le16_to_cpu(gd->bg_free_bits_count) > le16_to_cpu(gd->bg_bits)) {

		ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "

			    "claims that %u are free",

			    (unsigned long long)le64_to_cpu(gd->bg_blkno),

			    le16_to_cpu(gd->bg_bits),

			    le16_to_cpu(gd->bg_free_bits_count));

		return -EIO;

	}



	if (le16_to_cpu(gd->bg_bits) > (8 * le16_to_cpu(gd->bg_size))) {

		ocfs2_error(sb, "Group descriptor # %llu has bit count %u but "

			    "max bitmap bits of %u",

			    (unsigned long long)le64_to_cpu(gd->bg_blkno),

			    le16_to_cpu(gd->bg_bits),

			    8 * le16_to_cpu(gd->bg_size));

		return -EIO;

	}



	return 0;

}



static int ocfs2_block_group_fill(struct ocfs2_journal_handle *handle,

				  struct inode *alloc_inode,

				  struct buffer_head *bg_bh,
@@ -663,6 +716,7 @@ static int ocfs2_test_bg_bit_allocatable(struct buffer_head *bg_bh, 
static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb,

					     struct buffer_head *bg_bh,

					     unsigned int bits_wanted,

					     unsigned int total_bits,

					     u16 *bit_off,

					     u16 *bits_found)

{
@@ -679,10 +733,8 @@ static int ocfs2_block_group_find_clear_bits(struct ocfs2_super *osb, 
	found = start = best_offset = best_size = 0;

	bitmap = bg->bg_bitmap;



	while((offset = ocfs2_find_next_zero_bit(bitmap,

						 le16_to_cpu(bg->bg_bits),

						 start)) != -1) {

		if (offset == le16_to_cpu(bg->bg_bits))

	while((offset = ocfs2_find_next_zero_bit(bitmap, total_bits, start)) != -1) {

		if (offset == total_bits)

			break;



		if (!ocfs2_test_bg_bit_allocatable(bg_bh, offset)) {
@@ -911,14 +963,35 @@ static int ocfs2_cluster_group_search(struct inode *inode, 
{

	int search = -ENOSPC;

	int ret;

	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) group_bh->b_data;

	struct ocfs2_group_desc *gd = (struct ocfs2_group_desc *) group_bh->b_data;

	u16 tmp_off, tmp_found;

	unsigned int max_bits, gd_cluster_off;



	BUG_ON(!ocfs2_is_cluster_bitmap(inode));



	if (bg->bg_free_bits_count) {

	if (gd->bg_free_bits_count) {

		max_bits = le16_to_cpu(gd->bg_bits);



		/* Tail groups in cluster bitmaps which aren't cpg

		 * aligned are prone to partial extention by a failed

		 * fs resize. If the file system resize never got to

		 * update the dinode cluster count, then we don't want

		 * to trust any clusters past it, regardless of what

		 * the group descriptor says. */

		gd_cluster_off = ocfs2_blocks_to_clusters(inode->i_sb,

							  le64_to_cpu(gd->bg_blkno));

		if ((gd_cluster_off + max_bits) >

		    OCFS2_I(inode)->ip_clusters) {

			max_bits = OCFS2_I(inode)->ip_clusters - gd_cluster_off;

			mlog(0, "Desc %llu, bg_bits %u, clusters %u, use %u\n",

			     (unsigned long long)le64_to_cpu(gd->bg_blkno),

			     le16_to_cpu(gd->bg_bits),

			     OCFS2_I(inode)->ip_clusters, max_bits);

		}



		ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),

							group_bh, bits_wanted,

							max_bits,

							&tmp_off, &tmp_found);

		if (ret)

			return ret;
@@ -951,6 +1024,7 @@ static int ocfs2_block_group_search(struct inode *inode, 
	if (bg->bg_free_bits_count)

		ret = ocfs2_block_group_find_clear_bits(OCFS2_SB(inode->i_sb),

							group_bh, bits_wanted,

							le16_to_cpu(bg->bg_bits),

							bit_off, bits_found);



	return ret;
@@ -988,9 +1062,9 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac, 
		goto bail;

	}

	bg = (struct ocfs2_group_desc *) group_bh->b_data;

	if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {

		OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);

		status = -EIO;

	status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);

	if (status) {

		mlog_errno(status);

		goto bail;

	}
@@ -1018,9 +1092,9 @@ static int ocfs2_search_chain(struct ocfs2_alloc_context *ac, 
			goto bail;

		}

		bg = (struct ocfs2_group_desc *) group_bh->b_data;

		if (!OCFS2_IS_VALID_GROUP_DESC(bg)) {

			OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, bg);

			status = -EIO;

		status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, bg);

		if (status) {

			mlog_errno(status);

			goto bail;

		}

	}
@@ -1494,9 +1568,9 @@ static int ocfs2_free_suballoc_bits(struct ocfs2_journal_handle *handle, 
	}



	group = (struct ocfs2_group_desc *) group_bh->b_data;

	if (!OCFS2_IS_VALID_GROUP_DESC(group)) {

		OCFS2_RO_ON_INVALID_GROUP_DESC(alloc_inode->i_sb, group);

		status = -EIO;

	status = ocfs2_check_group_descriptor(alloc_inode->i_sb, fe, group);

	if (status) {

		mlog_errno(status);

		goto bail;

	}

	BUG_ON((count + start_bit) > le16_to_cpu(group->bg_bits));