From: Nikolay Borisov Subject: Re: [PATCH v2] jbd2: gate checksum calculations on crc driver presence, not sb flags Date: Mon, 5 Oct 2015 09:28:41 +0300 Message-ID: <56121899.6020806@kyup.com> References: <20151003034601.GN10390@birch.djwong.org> <56120E06.4040103@kyup.com> <20151005062131.GA29098@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: Jan Kara , Theodore Ts'o , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, SiteGround Operations , linux-ext4 To: "Darrick J. Wong" Return-path: In-Reply-To: <20151005062131.GA29098@birch.djwong.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On 10/05/2015 09:21 AM, Darrick J. Wong wrote: > On Mon, Oct 05, 2015 at 08:43:34AM +0300, Nikolay Borisov wrote: >> It is just me or am I not seeing this feature test helper in this patch ? >> >> On 10/03/2015 06:46 AM, Darrick J. Wong wrote: >>> 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) > > Here ^^^^^^^^^^^^^^^ > But you had this function in v1 as well? I thought you had integrated Andreas' suggestion? > --D > >>> +{ >>> + 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; >>> } >>> >>> /* >>>