e2fsck: verify block bitmap checksum

Check block bitmap checksum and write a new checksum if the
verification fails.  This is ok because e2fsck has already computed
the correct block bitmap.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/e2fsck/pass5.c b/e2fsck/pass5.c
index c684b31..0477e60 100644 (file)
--- a/e2fsck/pass5.c
+++ b/e2fsck/pass5.c
@@ -28,6 +28,7 @@ static void check_inode_bitmaps(e2fsck_t ctx);
 static void check_inode_end(e2fsck_t ctx);
 static void check_block_end(e2fsck_t ctx);
 static void check_inode_bitmap_checksum(e2fsck_t ctx);
+static void check_block_bitmap_checksum(e2fsck_t ctx);
 
 void e2fsck_pass5(e2fsck_t ctx)
 {
@@ -66,6 +67,7 @@ void e2fsck_pass5(e2fsck_t ctx)
                return;
 
        check_inode_bitmap_checksum(ctx);
+       check_block_bitmap_checksum(ctx);
 
        ext2fs_free_inode_bitmap(ctx->inode_used_map);
        ctx->inode_used_map = 0;
@@ -136,6 +138,67 @@ static void check_inode_bitmap_checksum(e2fsck_t ctx)
        ext2fs_free_mem(&buf);
 }
 
+static void check_block_bitmap_checksum(e2fsck_t ctx)
+{
+       struct problem_context  pctx;
+       struct ext4_group_desc  *gdp;
+       char            *buf;
+       dgrp_t          i;
+       int             nbytes;
+       blk64_t         blk_itr;
+       errcode_t       retval;
+
+       if (!EXT2_HAS_RO_COMPAT_FEATURE(ctx->fs->super,
+                                       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM))
+               return;
+
+       /* If bitmap is dirty from being fixed, checksum will be corrected */
+       if (ext2fs_test_bb_dirty(ctx->fs))
+               return;
+
+       nbytes = (size_t)(EXT2_CLUSTERS_PER_GROUP(ctx->fs->super) / 8);
+       retval = ext2fs_get_memalign(ctx->fs->blocksize, ctx->fs->blocksize,
+                                    &buf);
+       if (retval) {
+               com_err(ctx->program_name, 0,
+                   _("check_block_bitmap_checksum: Memory allocation error"));
+               fatal_error(ctx, 0);
+       }
+
+       clear_problem_context(&pctx);
+       for (i = 0; i < ctx->fs->group_desc_count; i++) {
+               if (ext2fs_bg_flags_test(ctx->fs, i, EXT2_BG_BLOCK_UNINIT))
+                       continue;
+
+               blk_itr = EXT2FS_B2C(ctx->fs,
+                                    ctx->fs->super->s_first_data_block) +
+                         (i * (nbytes << 3));
+               gdp = (struct ext4_group_desc *)ext2fs_group_desc(ctx->fs,
+                               ctx->fs->group_desc, i);
+               retval = ext2fs_get_block_bitmap_range2(ctx->fs->block_map,
+                                                       blk_itr, nbytes << 3,
+                                                       buf);
+               if (retval)
+                       break;
+
+               if (ext2fs_block_bitmap_csum_verify(ctx->fs, i, buf, nbytes))
+                       continue;
+               pctx.group = i;
+               if (!fix_problem(ctx, PR_5_BLOCK_BITMAP_CSUM_INVALID, &pctx))
+                       continue;
+
+               /*
+                * Fixing one checksum will rewrite all of them.  The bitmap
+                * will be checked against the one we made during pass1 for
+                * discrepancies, and fixed if need be.
+                */
+               ext2fs_mark_bb_dirty(ctx->fs);
+               break;
+       }
+
+       ext2fs_free_mem(&buf);
+}
+
 static void e2fsck_discard_blocks(e2fsck_t ctx, blk64_t start,
                                  blk64_t count)
 {

diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index aaa4e36..221d120 100644 (file)
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1699,6 +1699,11 @@ static struct e2fsck_problem problem_table[] = {
          N_("@g %g @i bitmap does not match checksum\n"),
          PROMPT_FIX, PR_LATCH_IBITMAP | PR_PREEN_OK },
 
+       /* Group N block bitmap does not match checksum */
+       { PR_5_BLOCK_BITMAP_CSUM_INVALID,
+         N_("@g %g @b bitmap does not match checksum\n"),
+         PROMPT_FIX, PR_LATCH_BBITMAP | PR_PREEN_OK },
+
        /* Post-Pass 5 errors */
 
        /* Recreate journal if E2F_FLAG_JOURNAL_INODE flag is set */

diff --git a/e2fsck/problem.h b/e2fsck/problem.h
index 86ec636..200ef3b 100644 (file)
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -1030,6 +1030,9 @@ struct problem_context {
 /* Inode bitmap checksum does not match */
 #define PR_5_INODE_BITMAP_CSUM_INVALID 0x05001A
 
+/* Block bitmap checksum does not match */
+#define PR_5_BLOCK_BITMAP_CSUM_INVALID 0x05001B
+
 /*
  * Post-Pass 5 errors
  */