From: "Darrick J. Wong" Subject: Re: [PATCH v2] jbd2: gate checksum calculations on crc driver presence, not sb flags Date: Mon, 5 Oct 2015 00:11:37 -0700 Message-ID: <20151005071137.GB29098@birch.djwong.org> References: <20151003034601.GN10390@birch.djwong.org> <56120E06.4040103@kyup.com> <20151005062131.GA29098@birch.djwong.org> <56121899.6020806@kyup.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , "Theodore Ts'o" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, SiteGround Operations , linux-ext4 To: Nikolay Borisov Return-path: Content-Disposition: inline In-Reply-To: <56121899.6020806@kyup.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Mon, Oct 05, 2015 at 09:28:41AM +0300, Nikolay Borisov wrote: > > > 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) && His suggestion was to move it to the header file and use it here too. --D > >>> + journal->j_chksum_driver == NULL); > >>> > >>> - return 0; > >>> + return journal->j_chksum_driver != NULL; > >>> } > >>> > >>> /* > >>>