e2fsck: add fast commit replay skeleton

This function adds the skeleton for the replay path. Following patches
in the series implement the handling for individual tags.

Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/e2fsck/journal.c b/e2fsck/journal.c
index f1aa0fd..007c32c 100644 (file)
--- a/e2fsck/journal.c
+++ b/e2fsck/journal.c
@@ -390,11 +390,83 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh,
 {
        e2fsck_t ctx = journal->j_fs_dev->k_ctx;
        struct e2fsck_fc_replay_state *state = &ctx->fc_replay_state;
+       int ret = JBD2_FC_REPLAY_CONTINUE;
+       struct ext4_fc_tl *tl;
+       __u8 *start, *end;
 
        if (pass == PASS_SCAN) {
                state->fc_current_pass = PASS_SCAN;
                return ext4_fc_replay_scan(journal, bh, off, expected_tid);
        }
+
+       if (state->fc_replay_num_tags == 0)
+               goto replay_done;
+
+       if (state->fc_current_pass != pass) {
+               /* Starting replay phase */
+               state->fc_current_pass = pass;
+               /* We will reset checksums */
+               ctx->fs->flags |= EXT2_FLAG_IGNORE_CSUM_ERRORS;
+               ret = ext2fs_read_bitmaps(ctx->fs);
+               if (ret) {
+                       jbd_debug(1, "Error %d while reading bitmaps\n", ret);
+                       return ret;
+               }
+               state->fc_super_state = ctx->fs->super->s_state;
+               /*
+                * Mark the file system to indicate it contains errors. That's
+                * because the updates performed by fast commit replay code are
+                * not atomic and may result in incosistent file system if it
+                * crashes before the replay is complete.
+                */
+               ctx->fs->super->s_state |= EXT2_ERROR_FS;
+               ctx->fs->super->s_state |= EXT4_FC_REPLAY;
+               ext2fs_mark_super_dirty(ctx->fs);
+               ext2fs_flush(ctx->fs);
+       }
+
+       start = (__u8 *)bh->b_data;
+       end = (__u8 *)bh->b_data + journal->j_blocksize - 1;
+
+       fc_for_each_tl(start, end, tl) {
+               if (state->fc_replay_num_tags == 0)
+                       goto replay_done;
+               jbd_debug(3, "Replay phase processing %s tag\n",
+                               tag2str(le16_to_cpu(tl->fc_tag)));
+               state->fc_replay_num_tags--;
+               switch (le16_to_cpu(tl->fc_tag)) {
+               case EXT4_FC_TAG_CREAT:
+               case EXT4_FC_TAG_LINK:
+               case EXT4_FC_TAG_UNLINK:
+               case EXT4_FC_TAG_ADD_RANGE:
+               case EXT4_FC_TAG_DEL_RANGE:
+               case EXT4_FC_TAG_INODE:
+               case EXT4_FC_TAG_TAIL:
+               case EXT4_FC_TAG_PAD:
+               case EXT4_FC_TAG_HEAD:
+                       break;
+               default:
+                       ret = -ECANCELED;
+                       break;
+               }
+               if (ret < 0)
+                       break;
+               ret = JBD2_FC_REPLAY_CONTINUE;
+       }
+       return ret;
+replay_done:
+       jbd_debug(1, "End of fast commit replay\n");
+       if (state->fc_current_pass != pass)
+               return JBD2_FC_REPLAY_STOP;
+
+       ext2fs_calculate_summary_stats(ctx->fs, 0 /* update bg also */);
+       ext2fs_write_block_bitmap(ctx->fs);
+       ext2fs_write_inode_bitmap(ctx->fs);
+       ext2fs_mark_super_dirty(ctx->fs);
+       ext2fs_set_gdt_csum(ctx->fs);
+       ctx->fs->super->s_state = state->fc_super_state;
+       ext2fs_flush(ctx->fs);
+
        return JBD2_FC_REPLAY_STOP;
 }