From: "Darrick J. Wong" Subject: [PATCH v2] jbd2: gate checksum calculations on crc driver presence, not sb flags Date: Fri, 2 Oct 2015 20:46:12 -0700 Message-ID: <20151003034601.GN10390@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Nikolay Borisov , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, SiteGround Operations , linux-ext4 To: Jan Kara , "Theodore Ts'o" Return-path: Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 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. v2: Create a feature-test helper, use it everywhere. Tested-By: Nikolay Borisov Reported-by: Nikolay Borisov Signed-off-by: Darrick J. Wong --- fs/jbd2/journal.c | 6 +++--- include/linux/jbd2.h | 13 +++++++++---- 2 files changed, 12 insertions(+), 7 deletions(-) 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 @@ 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"); 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 @@ 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; } /*