On Mon, Mar 07, 2016 at 03:54:24PM -0800, Keith Mok wrote: > No, other common filesystem use this BUG_ON in this way, pls read: > fs/btrfs/hash.c > fs/ext4/ext4.h > and even the BUG_ON is used inside crc32c function that is exported by > libcrc32c.c which xfs and many other drivers are using: > lib/libcrc32c.c > fs/xfs/libxfs/xfs_cksum.h >
Thank you for the summary. I've checked out ext4 and btrfs commits in terms of the crc32 fuction. It seems that they copied crc32 library code, and indeed there-in crc32 function treats with crypto_shash_update using BUG_ON. Let me test this patch for a while. :) Thanks, > > If it should have some fallback mechanism, it should be done inside > the crypto_shash_update function, rather than scatter all over to > their users. > > Thanks. > > 2016-03-07 15:35 GMT-08:00 Jaegeuk Kim <[email protected]>: > > On Wed, Mar 02, 2016 at 12:01:02PM -0800, Keith Mok wrote: > >> Will update the first BUG_ON by using SHASH_DESC_ON_STACK. > > > > I meant, for *every* BUG_ONs, doing like: > > > > if (err) > > return original f2fs_crc32(); > > > > Thanks, > > > >> > >> > >> 2016-03-02 10:21 GMT-08:00 Jaegeuk Kim <[email protected]>: > >> > Hi Keith, > >> > > >> >> +static inline __u32 f2fs_crc32(struct f2fs_sb_info *sbi, const void > >> >> *address, > >> >> + unsigned int length) > >> >> +{ > >> >> + struct { > >> >> + struct shash_desc shash; > >> >> + char ctx[4]; > >> >> + } desc; > >> >> + int err; > >> >> + > >> >> + BUG_ON(crypto_shash_descsize(sbi->s_chksum_driver) != > >> >> sizeof(desc.ctx)); > >> > > >> > I can't accept this and the below BUG_ON, since this hits during the > >> > checkpoint > >> > procedure which is very critical for entire filesystem. > >> > How about calling back the original method for the error cases? > >> > > >> > Thanks, > >> > > >> >> + > >> >> + desc.shash.tfm = sbi->s_chksum_driver; > >> >> + desc.shash.flags = 0; > >> >> + *(u32 *)desc.ctx = F2FS_SUPER_MAGIC; > >> >> + > >> >> + err = crypto_shash_update(&desc.shash, address, length); > >> >> + BUG_ON(err); > >> >> + > >> >> + return *(__u32 *)desc.ctx; > >> >> +} > >> >> + > >> >> +static inline bool f2fs_crc_valid(struct f2fs_sb_info *sbi, __u32 > >> >> blk_crc, > >> >> + void *buf, size_t buf_size) > >> >> +{ > >> >> + return f2fs_crc32(sbi, buf, buf_size) == blk_crc; > >> >> +} > >> >> + > >> >> static inline struct f2fs_inode_info *F2FS_I(struct inode *inode) > >> >> { > >> >> return container_of(inode, struct f2fs_inode_info, vfs_inode); > >> >> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > >> >> index 6134832..9630865 100644 > >> >> --- a/fs/f2fs/super.c > >> >> +++ b/fs/f2fs/super.c > >> >> @@ -574,6 +574,8 @@ static void f2fs_put_super(struct super_block *sb) > >> >> wait_for_completion(&sbi->s_kobj_unregister); > >> >> > >> >> sb->s_fs_info = NULL; > >> >> + if (sbi->s_chksum_driver) > >> >> + crypto_free_shash(sbi->s_chksum_driver); > >> >> kfree(sbi->raw_super); > >> >> kfree(sbi); > >> >> } > >> >> @@ -1254,6 +1256,15 @@ try_onemore: > >> >> if (!sbi) > >> >> return -ENOMEM; > >> >> > >> >> + /* Load the checksum driver */ > >> >> + sbi->s_chksum_driver = crypto_alloc_shash("crc32", 0, 0); > >> >> + if (IS_ERR(sbi->s_chksum_driver)) { > >> >> + f2fs_msg(sb, KERN_ERR, "Cannot load crc32 driver."); > >> >> + err = PTR_ERR(sbi->s_chksum_driver); > >> >> + sbi->s_chksum_driver = NULL; > >> >> + goto free_sbi; > >> >> + } > >> >> + > >> >> /* set a block size */ > >> >> if (unlikely(!sb_set_blocksize(sb, F2FS_BLKSIZE))) { > >> >> f2fs_msg(sb, KERN_ERR, "unable to set blocksize"); > >> >> @@ -1506,6 +1517,8 @@ free_options: > >> >> free_sb_buf: > >> >> kfree(raw_super); > >> >> free_sbi: > >> >> + if (sbi->s_chksum_driver) > >> >> + crypto_free_shash(sbi->s_chksum_driver); > >> >> kfree(sbi); > >> >> > >> >> /* give only one another chance */ > >> >> -- > >> >> 2.5.1 ------------------------------------------------------------------------------ Transform Data into Opportunity. Accelerate data analysis in your applications with Intel Data Analytics Acceleration Library. Click to learn more. http://makebettercode.com/inteldaal-eval _______________________________________________ Linux-f2fs-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
