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jbd2: gate checksum calculations on crc driver presence, not sb flags

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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>
This commit is contained in:
Darrick J. Wong 2015-10-15 10:30:36 -04:00 committed by Theodore Ts'o
parent b90197b655
commit 8595798ca3
2 changed files with 12 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
fs/jbd2/journal.c
View file

@ -124,7 +124,7 @@ EXPORT_SYMBOL(__jbd2_debug);
/* 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 @@ static int journal_get_superblock(journal_t *journal)
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 @@ static int journal_get_superblock(journal_t *journal)
}
/* 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");

13
include/linux/jbd2.h
View file

@ -1338,13 +1338,18 @@ static inline int tid_geq(tid_t x, tid_t y)
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;
}
/*