e2fsck: Check the all of journal blocks for validity

The original code only checked the direct blocks to make sure the
journal inode was sane.  Unfortunately, if some or all of the indirect
or doubly indirect blocks were corrupted, this would not be caught.
Thanks to Andreas Dilger and Kalpak Shah for noticing this problem.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/e2fsck/journal.c b/e2fsck/journal.c
index 18dab0e..756bbcb 100644 (file)
--- a/e2fsck/journal.c
+++ b/e2fsck/journal.c
@@ -189,8 +189,37 @@ static void e2fsck_clear_recover(e2fsck_t ctx, int error)
        ext2fs_mark_super_dirty(ctx->fs);
 }
 
+/*
+ * This is a helper function to check the validity of the journal.
+ */
+struct process_block_struct {
+       e2_blkcnt_t     last_block;
+};
+
+static int process_journal_block(ext2_filsys fs,
+                                blk_t  *block_nr,
+                                e2_blkcnt_t blockcnt,
+                                blk_t ref_block EXT2FS_ATTR((unused)),
+                                int ref_offset EXT2FS_ATTR((unused)),
+                                void *priv_data)
+{
+       struct process_block_struct *p;
+       blk_t   blk = *block_nr;
+
+       p = (struct process_block_struct *) priv_data;
+
+       if (blk < fs->super->s_first_data_block ||
+           blk >= fs->super->s_blocks_count)
+               return BLOCK_ABORT;
+
+       if (blockcnt >= 0)
+               p->last_block = blockcnt;
+       return 0;
+}
+
 static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
 {
+       struct process_block_struct pb;
        struct ext2_super_block *sb = ctx->fs->super;
        struct ext2_super_block jsuper;
        struct problem_context  pctx;
@@ -202,10 +231,8 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
        errcode_t               retval = 0;
        io_manager              io_ptr = 0;
        unsigned long           start = 0;
-       blk_t                   blk;
        int                     ext_journal = 0;
        int                     tried_backup_jnl = 0;
-       int                     i;
 
        clear_problem_context(&pctx);
 
@@ -258,6 +285,9 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
                        j_inode->i_ext2.i_size = sb->s_jnl_blocks[16];
                        j_inode->i_ext2.i_links_count = 1;
                        j_inode->i_ext2.i_mode = LINUX_S_IFREG | 0600;
+                       e2fsck_use_inode_shortcuts(ctx, 1);
+                       ctx->stashed_ino = j_inode->i_ino;
+                       ctx->stashed_inode = &j_inode->i_ext2;
                        tried_backup_jnl++;
                }
                if (!j_inode->i_ext2.i_links_count ||
@@ -270,20 +300,14 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
                        retval = EXT2_ET_JOURNAL_TOO_SMALL;
                        goto try_backup_journal;
                }
-               for (i=0; i < EXT2_N_BLOCKS; i++) {
-                       blk = j_inode->i_ext2.i_block[i];
-                       if (!blk) {
-                               if (i < EXT2_NDIR_BLOCKS) {
-                                       retval = EXT2_ET_JOURNAL_TOO_SMALL;
-                                       goto try_backup_journal;
-                               }
-                               continue;
-                       }
-                       if (blk < sb->s_first_data_block ||
-                           blk >= sb->s_blocks_count) {
-                               retval = EXT2_ET_BAD_BLOCK_NUM;
-                               goto try_backup_journal;
-                       }
+               pb.last_block = -1;
+               retval = ext2fs_block_iterate2(ctx->fs, j_inode->i_ino,
+                                              BLOCK_FLAG_HOLE, 0, 
+                                              process_journal_block, &pb);
+               if ((pb.last_block+1) * ctx->fs->blocksize < 
+                   j_inode->i_ext2.i_size) {
+                       retval = EXT2_ET_JOURNAL_TOO_SMALL;
+                       goto try_backup_journal;
                }
                if (tried_backup_jnl && !(ctx->options & E2F_OPT_READONLY)) {
                        retval = ext2fs_write_inode(ctx->fs, sb->s_journal_inum,
@@ -397,9 +421,11 @@ static errcode_t e2fsck_get_journal(e2fsck_t ctx, journal_t **ret_journal)
 #endif
 
        *ret_journal = journal;
+       e2fsck_use_inode_shortcuts(ctx, 0);
        return 0;
 
 errout:
+       e2fsck_use_inode_shortcuts(ctx, 0);
        if (dev_fs)
                ext2fs_free_mem(&dev_fs);
        if (j_inode)