Commit 2973dfdb authored by Glauber de Oliveira Costa's avatar Glauber de Oliveira Costa Committed by Linus Torvalds
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[PATCH] Test for sb_getblk return value 



This patch adds tests for the return value of sb_getblk() in the ext2/3
filesystems.  In fs/buffer.c it is stated that the getblk() function never
fails.  However, it does can return NULL in some situations due to I/O
errors, which may lead us to NULL pointer dereferences

Signed-off-by: default avatarGlauber de Oliveira Costa <glommer@br.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 7f04c26d

fs/ext2/inode.c

+4 −0
Original line number Diff line number Diff line
@@ -440,6 +440,10 @@ static int ext2_alloc_branch(struct inode *inode, 
		 * the pointer to new one, then send parent to disk.

		 */

		bh = sb_getblk(inode->i_sb, parent);

		if (!bh) {

			err = -EIO;

			break;

		}

		lock_buffer(bh);

		memset(bh->b_data, 0, blocksize);

		branch[n].bh = bh;

fs/ext3/inode.c

+8 −1
Original line number Diff line number Diff line
@@ -523,7 +523,6 @@ static int ext3_alloc_branch(handle_t *handle, struct inode *inode, 
			if (!nr)

				break;

			branch[n].key = cpu_to_le32(nr);

			keys = n+1;



			/*

			 * Get buffer_head for parent block, zero it out
@@ -531,6 +530,9 @@ static int ext3_alloc_branch(handle_t *handle, struct inode *inode, 
			 * parent to disk.  

			 */

			bh = sb_getblk(inode->i_sb, parent);

			if (!bh)

				break;

			keys = n+1;

			branch[n].bh = bh;

			lock_buffer(bh);

			BUFFER_TRACE(bh, "call get_create_access");
@@ -864,6 +866,10 @@ struct buffer_head *ext3_getblk(handle_t *handle, struct inode * inode, 
	if (!*errp && buffer_mapped(&dummy)) {

		struct buffer_head *bh;

		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);

		if (!bh) {

			*errp = -EIO;

			goto err;

		}

		if (buffer_new(&dummy)) {

			J_ASSERT(create != 0);

			J_ASSERT(handle != 0);
@@ -896,6 +902,7 @@ struct buffer_head *ext3_getblk(handle_t *handle, struct inode * inode, 
		}

		return bh;

	}

err:

	return NULL;

}

fs/ext3/resize.c

+10 −0
Original line number Diff line number Diff line
@@ -118,6 +118,8 @@ static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, 
	int err;



	bh = sb_getblk(sb, blk);

	if (!bh)

		return ERR_PTR(-EIO);

	if ((err = ext3_journal_get_write_access(handle, bh))) {

		brelse(bh);

		bh = ERR_PTR(err);
@@ -202,6 +204,10 @@ static int setup_new_group_blocks(struct super_block *sb, 
		ext3_debug("update backup group %#04lx (+%d)\n", block, bit);



		gdb = sb_getblk(sb, block);

		if (!gdb) {

			err = -EIO;

			goto exit_bh;

		}

		if ((err = ext3_journal_get_write_access(handle, gdb))) {

			brelse(gdb);

			goto exit_bh;
@@ -643,6 +649,10 @@ static void update_backups(struct super_block *sb, 
			break;



		bh = sb_getblk(sb, group * bpg + blk_off);

		if (!bh) {

			err = -EIO;

			break;

		}

		ext3_debug("update metadata backup %#04lx\n",

			  (unsigned long)bh->b_blocknr);

		if ((err = ext3_journal_get_write_access(handle, bh)))

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