From: "Darrick J. Wong" Subject: [PATCH 04/23] ext4: Only call out to crc32c if necessary Date: Tue, 13 Dec 2011 16:46:41 -0800 Message-ID: <20111214004641.28243.11910.stgit@elm3c44.beaverton.ibm.com> References: <20111214004613.28243.54122.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Martin K Petersen , Greg Freemyer , Amir Goldstein , linux-kernel , Andi Kleen , Mingming Cao , Joel Becker , linux-fsdevel , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: In-Reply-To: <20111214004613.28243.54122.stgit@elm3c44.beaverton.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Only obtain a reference to the cryptoapi and crc32c if we happen to mount a filesystem with metadata checksumming enabled. Signed-off-by: Darrick J. Wong --- fs/ext4/Kconfig | 2 ++ fs/ext4/ext4.h | 23 +++++++++++++++++++++++ fs/ext4/super.c | 16 ++++++++++++++++ 3 files changed, 41 insertions(+), 0 deletions(-) diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig index 9ed1bb1..c22f170 100644 --- a/fs/ext4/Kconfig +++ b/fs/ext4/Kconfig @@ -2,6 +2,8 @@ config EXT4_FS tristate "The Extended 4 (ext4) filesystem" select JBD2 select CRC16 + select CRYPTO + select CRYPTO_CRC32C help This is the next generation of the ext3 filesystem. diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index b8242a1..84e6f68 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -29,6 +29,7 @@ #include #include #include +#include #ifdef __KERNEL__ #include #endif @@ -1259,6 +1260,9 @@ struct ext4_sb_info { /* record the last minlen when FITRIM is called. */ atomic_t s_last_trim_minblks; + + /* Reference to checksum algorithm driver via cryptoapi */ + struct crypto_shash *s_chksum_driver; }; static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb) @@ -1614,6 +1618,25 @@ static inline __le16 ext4_rec_len_to_disk(unsigned len, unsigned blocksize) #define DX_HASH_HALF_MD4_UNSIGNED 4 #define DX_HASH_TEA_UNSIGNED 5 +static inline u32 ext4_chksum(struct ext4_sb_info *sbi, u32 crc, + const void *address, unsigned int length) +{ + struct { + struct shash_desc shash; + char ctx[crypto_shash_descsize(sbi->s_chksum_driver)]; + } desc; + int err; + + desc.shash.tfm = sbi->s_chksum_driver; + desc.shash.flags = 0; + *(u32 *)desc.ctx = crc; + + err = crypto_shash_update(&desc.shash, address, length); + BUG_ON(err); + + return *(u32 *)desc.ctx; +} + #ifdef __KERNEL__ /* hash info structure used by the directory hash */ diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a56c14e..8ff94dc 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -887,6 +887,8 @@ static void ext4_put_super(struct super_block *sb) unlock_super(sb); kobject_put(&sbi->s_kobj); wait_for_completion(&sbi->s_kobj_unregister); + if (sbi->s_chksum_driver) + crypto_free_shash(sbi->s_chksum_driver); kfree(sbi->s_blockgroup_lock); kfree(sbi); } @@ -3200,6 +3202,18 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) goto cantfind_ext4; } + /* Load the checksum driver */ + if (EXT4_HAS_RO_COMPAT_FEATURE(sb, + EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) { + sbi->s_chksum_driver = crypto_alloc_shash("crc32c", 0, 0); + if (IS_ERR(sbi->s_chksum_driver)) { + ext4_msg(sb, KERN_ERR, "Cannot load crc32c driver."); + ret = PTR_ERR(sbi->s_chksum_driver); + sbi->s_chksum_driver = NULL; + goto failed_mount; + } + } + /* Set defaults before we parse the mount options */ def_mount_opts = le32_to_cpu(es->s_default_mount_opts); set_opt(sb, INIT_INODE_TABLE); @@ -3880,6 +3894,8 @@ failed_mount2: brelse(sbi->s_group_desc[i]); ext4_kvfree(sbi->s_group_desc); failed_mount: + if (sbi->s_chksum_driver) + crypto_free_shash(sbi->s_chksum_driver); if (sbi->s_proc) { remove_proc_entry(sb->s_id, ext4_proc_root); }