jbd2: gate checksum calculations on crc driver presence, not sb flags
Change the journal's checksum functions to gate on whether or not the
crc32c driver is loaded, and gate the loading on the superblock bits.
This prevents a journal crash if someone loads a journal in no-csum
mode and then randomizes the superblock, thus flipping on the feature
bits.
Tested-By: Nikolay Borisov <kernel@kyup.com>
Reported-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 8270fe9..00f7dbd 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -124,7 +124,7 @@
/* Checksumming functions */
static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
{
- if (!jbd2_journal_has_csum_v2or3(j))
+ if (!jbd2_journal_has_csum_v2or3_feature(j))
return 1;
return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
@@ -1531,7 +1531,7 @@
goto out;
}
- if (jbd2_journal_has_csum_v2or3(journal) &&
+ if (jbd2_journal_has_csum_v2or3_feature(journal) &&
JBD2_HAS_COMPAT_FEATURE(journal, JBD2_FEATURE_COMPAT_CHECKSUM)) {
/* Can't have checksum v1 and v2 on at the same time! */
printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
@@ -1545,7 +1545,7 @@
}
/* Load the checksum driver */
- if (jbd2_journal_has_csum_v2or3(journal)) {
+ if (jbd2_journal_has_csum_v2or3_feature(journal)) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index df07e78..6da6f89 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -1338,13 +1338,18 @@
extern int jbd2_journal_blocks_per_page(struct inode *inode);
extern size_t journal_tag_bytes(journal_t *journal);
+static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
+{
+ return JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2) ||
+ JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V3);
+}
+
static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
{
- if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2) ||
- JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V3))
- return 1;
+ WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
+ journal->j_chksum_driver == NULL);
- return 0;
+ return journal->j_chksum_driver != NULL;
}
/*