jbd2: enable journal clients to enable v2 checksumming
Darrick J. Wong [Sun, 27 May 2012 11:48:56 +0000 (07:48 -0400)]
Add in the necessary code so that journal clients can enable the new
journal checksumming features.

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

fs/ext4/super.c
fs/jbd2/journal.c

index 88c2054..8dfb42e 100644 (file)
@@ -3013,6 +3013,44 @@ static void ext4_destroy_lazyinit_thread(void)
        kthread_stop(ext4_lazyinit_task);
 }
 
+static int set_journal_csum_feature_set(struct super_block *sb)
+{
+       int ret = 1;
+       int compat, incompat;
+       struct ext4_sb_info *sbi = EXT4_SB(sb);
+
+       if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
+                                      EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
+               /* journal checksum v2 */
+               compat = 0;
+               incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
+       } else {
+               /* journal checksum v1 */
+               compat = JBD2_FEATURE_COMPAT_CHECKSUM;
+               incompat = 0;
+       }
+
+       if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
+               ret = jbd2_journal_set_features(sbi->s_journal,
+                               compat, 0,
+                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
+                               incompat);
+       } else if (test_opt(sb, JOURNAL_CHECKSUM)) {
+               ret = jbd2_journal_set_features(sbi->s_journal,
+                               compat, 0,
+                               incompat);
+               jbd2_journal_clear_features(sbi->s_journal, 0, 0,
+                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
+       } else {
+               jbd2_journal_clear_features(sbi->s_journal,
+                               JBD2_FEATURE_COMPAT_CHECKSUM, 0,
+                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
+                               JBD2_FEATURE_INCOMPAT_CSUM_V2);
+       }
+
+       return ret;
+}
+
 static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 {
        char *orig_data = kstrdup(data, GFP_KERNEL);
@@ -3610,19 +3648,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                goto failed_mount_wq;
        }
 
-       if (test_opt(sb, JOURNAL_ASYNC_COMMIT)) {
-               jbd2_journal_set_features(sbi->s_journal,
-                               JBD2_FEATURE_COMPAT_CHECKSUM, 0,
-                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
-       } else if (test_opt(sb, JOURNAL_CHECKSUM)) {
-               jbd2_journal_set_features(sbi->s_journal,
-                               JBD2_FEATURE_COMPAT_CHECKSUM, 0, 0);
-               jbd2_journal_clear_features(sbi->s_journal, 0, 0,
-                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
-       } else {
-               jbd2_journal_clear_features(sbi->s_journal,
-                               JBD2_FEATURE_COMPAT_CHECKSUM, 0,
-                               JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);
+       if (!set_journal_csum_feature_set(sb)) {
+               ext4_msg(sb, KERN_ERR, "Failed to set journal checksum "
+                        "feature set");
+               goto failed_mount_wq;
        }
 
        /* We have now updated the journal if required, so we can
index 1afb701..63175f9 100644 (file)
@@ -97,6 +97,15 @@ EXPORT_SYMBOL(jbd2_inode_cache);
 static void __journal_abort_soft (journal_t *journal, int errno);
 static int jbd2_journal_create_slab(size_t slab_size);
 
+/* Checksumming functions */
+int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
+{
+       if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+               return 1;
+
+       return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
+}
+
 /*
  * Helper function used to manage commit timeouts
  */
@@ -1376,6 +1385,9 @@ static int journal_get_superblock(journal_t *journal)
                }
        }
 
+       if (buffer_verified(bh))
+               return 0;
+
        sb = journal->j_superblock;
 
        err = -EINVAL;
@@ -1413,6 +1425,21 @@ static int journal_get_superblock(journal_t *journal)
                goto out;
        }
 
+       if (JBD2_HAS_COMPAT_FEATURE(journal, JBD2_FEATURE_COMPAT_CHECKSUM) &&
+           JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
+               /* Can't have checksum v1 and v2 on at the same time! */
+               printk(KERN_ERR "JBD: Can't enable checksumming v1 and v2 "
+                      "at the same time!\n");
+               goto out;
+       }
+
+       if (!jbd2_verify_csum_type(journal, sb)) {
+               printk(KERN_ERR "JBD: Unknown checksum type\n");
+               goto out;
+       }
+
+       set_buffer_verified(bh);
+
        return 0;
 
 out:
@@ -1653,6 +1680,10 @@ int jbd2_journal_check_available_features (journal_t *journal, unsigned long com
 int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
                          unsigned long ro, unsigned long incompat)
 {
+#define INCOMPAT_FEATURE_ON(f) \
+               ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
+#define COMPAT_FEATURE_ON(f) \
+               ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
        journal_superblock_t *sb;
 
        if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
@@ -1661,16 +1692,35 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
        if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
                return 0;
 
+       /* Asking for checksumming v2 and v1?  Only give them v2. */
+       if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2 &&
+           compat & JBD2_FEATURE_COMPAT_CHECKSUM)
+               compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
+
        jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
                  compat, ro, incompat);
 
        sb = journal->j_superblock;
 
+       /* If enabling v2 checksums, update superblock */
+       if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
+               sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
+               sb->s_feature_compat &=
+                       ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
+       }
+
+       /* If enabling v1 checksums, downgrade superblock */
+       if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
+               sb->s_feature_incompat &=
+                       ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2);
+
        sb->s_feature_compat    |= cpu_to_be32(compat);
        sb->s_feature_ro_compat |= cpu_to_be32(ro);
        sb->s_feature_incompat  |= cpu_to_be32(incompat);
 
        return 1;
+#undef COMPAT_FEATURE_ON
+#undef INCOMPAT_FEATURE_ON
 }
 
 /*