e2fsck: ignore badblocks if it says badblocks inode is bad

If the badblocks list says that the badblocks inode is bad, it's quite
likely that badblocks is broken.  Worse yet, if the root inode is in
the same block as the badblocks inode (likely since they're adjacent),
the filesystem becomes unfixable because pass3 notices the bad root
inode and exits.

So... if we encounter this case, just kill the badblocks inode.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

e2fsck/pass1.c

@@ -1076,6 +1076,37 @@ void e2fsck_pass1(e2fsck_t ctx)
 		if (ctx->flags & E2F_FLAG_SIGNAL_MASK)
 			return;
 		if (pctx.errcode == EXT2_ET_BAD_BLOCK_IN_INODE_TABLE) {
+			/*
+			 * If badblocks says badblocks is bad, offer to clear
+			 * the list, update the in-core bb list, and restart
+			 * the inode scan.
+			 */
+			if (ino == EXT2_BAD_INO &&
+			    fix_problem(ctx, PR_1_BADBLOCKS_IN_BADBLOCKS,
+					&pctx)) {
+				errcode_t err;
+
+				e2fsck_clear_inode(ctx, ino, inode, 0, "pass1");
+				ext2fs_badblocks_list_free(ctx->fs->badblocks);
+				ctx->fs->badblocks = NULL;
+				err = ext2fs_read_bb_inode(ctx->fs,
+							&ctx->fs->badblocks);
+				if (err) {
+					fix_problem(ctx, PR_1_ISCAN_ERROR,
+						    &pctx);
+					ctx->flags |= E2F_FLAG_ABORT;
+					goto endit;
+				}
+				err = ext2fs_inode_scan_goto_blockgroup(scan,
+									0);
+				if (err) {
+					fix_problem(ctx, PR_1_ISCAN_ERROR,
+						    &pctx);
+					ctx->flags |= E2F_FLAG_ABORT;
+					goto endit;
+				}
+				continue;
+			}
 			if (!ctx->inode_bb_map)
 				alloc_bb_map(ctx);
 			ext2fs_mark_inode_bitmap2(ctx->inode_bb_map, ino);

e2fsck/problem.c

@@ -1086,6 +1086,11 @@ static struct e2fsck_problem problem_table[] = {
 	  N_("@i %i has inline data and @x flags set but i_block contains junk.\n"),
 	  PROMPT_CLEAR_INODE, 0 },
 
+	/* Bad block list says the bad block list inode is bad */
+	{ PR_1_BADBLOCKS_IN_BADBLOCKS,
+	  N_("Bad block list says the bad block list @i is bad.  "),
+	  PROMPT_CLEAR_INODE, 0 },
+
 	/* Pass 1b errors */
 
 	/* Pass 1B: Rescan for duplicate/bad blocks */

e2fsck/problem.h

@@ -632,6 +632,9 @@ struct problem_context {
 /* inlinedata/extent set, clear inode */
 #define PR_1_CLEAR_EXTENT_INLINE_DATA_INODE	0x01007A
 
+/* badblocks is in badblocks */
+#define PR_1_BADBLOCKS_IN_BADBLOCKS		0x01007B
+
 /*
  * Pass 1b errors
  */

tests/f_bb_in_bb/expect.1

@@ -0,0 +1,17 @@
+Pass 1: Checking inodes, blocks, and sizes
+Bad block list says the bad block list inode is bad.  Clear inode? yes
+
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+Free blocks count wrong for group #0 (493, counted=494).
+Fix? yes
+
+Free blocks count wrong (493, counted=494).
+Fix? yes
+
+
+test_filesys: ***** FILE SYSTEM WAS MODIFIED *****
+test_filesys: 11/128 files (0.0% non-contiguous), 18/512 blocks
+Exit status is 1

tests/f_bb_in_bb/expect.2

@@ -0,0 +1,7 @@
+Pass 1: Checking inodes, blocks, and sizes
+Pass 2: Checking directory structure
+Pass 3: Checking directory connectivity
+Pass 4: Checking reference counts
+Pass 5: Checking group summary information
+test_filesys: 11/128 files (0.0% non-contiguous), 18/512 blocks
+Exit status is 0

tests/f_bb_in_bb/name

@@ -0,0 +1 @@
+bad block inode table block in bad block list