[PATCH 16/23] jbd2: Enable journal clients to enable v2 checksumming

From: Darrick J. Wong
Date: Tue Dec 13 2011 - 19:48:22 EST


Add in the necessary code so that journal clients can enable the new journal
checksumming features.

Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/ext4/super.c | 55 ++++++++++++++++++++++++++++++++++++++++-------------
fs/jbd2/journal.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 92 insertions(+), 13 deletions(-)


diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 6838d01..7bcbe47 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3173,6 +3173,44 @@ 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);
@@ -3762,19 +3800,10 @@ 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
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 0fa0123..300b46f 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -100,6 +100,15 @@ static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
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
*/
@@ -1222,6 +1231,9 @@ static int journal_get_superblock(journal_t *journal)
}
}

+ if (buffer_verified(bh))
+ return 0;
+
sb = journal->j_superblock;

err = -EINVAL;
@@ -1259,6 +1271,21 @@ 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:
@@ -1502,6 +1529,10 @@ 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))
@@ -1510,16 +1541,35 @@ 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
}

/*

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