From: "Aneesh Kumar K.V" Subject: Re: + ext4-uninitialized-block-groups-fix.patch added to -mm tree Date: Fri, 21 Sep 2007 11:19:51 +0530 Message-ID: <46F35B7F.6070302@linux.vnet.ibm.com> References: <200709210502.l8L52HRw019656@imap1.linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mm-commits@vger.kernel.org, mathur@linux.vnet.ibm.com, adilger@clusterfs.com, cmm@us.ibm.com, linux-ext4@vger.kernel.org, mathur@us.ibm.com To: akpm@linux-foundation.org Return-path: Received: from E23SMTP03.au.ibm.com ([202.81.18.172]:35050 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750895AbXIUFu0 (ORCPT ); Fri, 21 Sep 2007 01:50:26 -0400 In-Reply-To: <200709210502.l8L52HRw019656@imap1.linux-foundation.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org akpm@linux-foundation.org wrote: > The patch titled > Ext4: Uninitialized Block Groups (fix) > has been added to the -mm tree. Its filename is > ext4-uninitialized-block-groups-fix.patch > > *** Remember to use Documentation/SubmitChecklist when testing your code *** > > See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find > out what to do about this > > ------------------------------------------------------ > Subject: Ext4: Uninitialized Block Groups (fix) > From: Avantika Mathur > > Andreas Dilger wrote: >> On Sep 18, 2007 20:03 -0700, Andrew Morton wrote: >> >>> On Tue, 18 Sep 2007 17:25:31 -0700 Avantika Mathur wrote: >>> >>> >>>> +#if !defined(CONFIG_CRC16) >>>> +/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1) */ >>>> +__u16 const crc16_table[256] = { me >>>> + 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, >>>> >>> That's rather sad. A plain old "depends on" would be better. >>> >> My bad. We wrote this patch and it had to run on older kernels that might >> not even have lib/crc16.c (it was added around 2.6.15 or so, so e.g. RHEL4 >> doesn't have it). I forgot to remove it from the upstream submission, >> and since it didn't cause problems nobody else complained... > The incremental patch below removes the local crc16 code, and also resolves an > issue with properly updating bg_itable_unused when an inode is allocated in an > unused block groups. > > Cc: Andreas Dilger > Cc: Avantika Mathur > Cc: Mingming Cao > Cc: Aneesh Kumar K.V > Cc: > Signed-off-by: Andrew Morton Signed-off-by: Aneesh Kumar K.V > --- > > fs/Kconfig | 1 > fs/ext4/ialloc.c | 8 ++++++- > fs/ext4/super.c | 51 --------------------------------------------- > 3 files changed, 9 insertions(+), 51 deletions(-) > > diff -puN fs/ext4/ialloc.c~ext4-uninitialized-block-groups-fix fs/ext4/ialloc.c > --- a/fs/ext4/ialloc.c~ext4-uninitialized-block-groups-fix > +++ a/fs/ext4/ialloc.c > @@ -632,12 +632,18 @@ got: > if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) { > if (gdp->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) { > gdp->bg_flags &= cpu_to_le16(~EXT4_BG_INODE_UNINIT); > - free = EXT4_INODES_PER_GROUP(sb); I guess a comment as below would help to explain why are we not decrementing bg_itable_unused by 1. /* When marking the block group with ~EXT4_BG_INODE_UNINIT we don't want to depend * on the value of bg_itable_unsed even though mke2fs could have initialized the * same for us. Instead we calculated the value below */ > + free = 0; > } else { > free = EXT4_INODES_PER_GROUP(sb) - > le16_to_cpu(gdp->bg_itable_unused); > } > > + /* > + * Check the relative inode number against the last used > + * relative inode number in this group. if it is greater > + * we need to update the bg_itable_unused count > + * > + */ > if (ino > free) > gdp->bg_itable_unused = > cpu_to_le16(EXT4_INODES_PER_GROUP(sb) - ino); > diff -puN fs/ext4/super.c~ext4-uninitialized-block-groups-fix fs/ext4/super.c > --- a/fs/ext4/super.c~ext4-uninitialized-block-groups-fix > +++ a/fs/ext4/super.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > > #include > > @@ -1337,56 +1338,6 @@ static int ext4_setup_super(struct super > return res; > } > > -#if !defined(CONFIG_CRC16) > -/** CRC table for the CRC-16. The poly is 0x8005 (x16 + x15 + x2 + 1) */ > -__u16 const crc16_table[256] = { > - 0x0000, 0xC0C1, 0xC181, 0x0140, 0xC301, 0x03C0, 0x0280, 0xC241, > - 0xC601, 0x06C0, 0x0780, 0xC741, 0x0500, 0xC5C1, 0xC481, 0x0440, > - 0xCC01, 0x0CC0, 0x0D80, 0xCD41, 0x0F00, 0xCFC1, 0xCE81, 0x0E40, > - 0x0A00, 0xCAC1, 0xCB81, 0x0B40, 0xC901, 0x09C0, 0x0880, 0xC841, > - 0xD801, 0x18C0, 0x1980, 0xD941, 0x1B00, 0xDBC1, 0xDA81, 0x1A40, > - 0x1E00, 0xDEC1, 0xDF81, 0x1F40, 0xDD01, 0x1DC0, 0x1C80, 0xDC41, > - 0x1400, 0xD4C1, 0xD581, 0x1540, 0xD701, 0x17C0, 0x1680, 0xD641, > - 0xD201, 0x12C0, 0x1380, 0xD341, 0x1100, 0xD1C1, 0xD081, 0x1040, > - 0xF001, 0x30C0, 0x3180, 0xF141, 0x3300, 0xF3C1, 0xF281, 0x3240, > - 0x3600, 0xF6C1, 0xF781, 0x3740, 0xF501, 0x35C0, 0x3480, 0xF441, > - 0x3C00, 0xFCC1, 0xFD81, 0x3D40, 0xFF01, 0x3FC0, 0x3E80, 0xFE41, > - 0xFA01, 0x3AC0, 0x3B80, 0xFB41, 0x3900, 0xF9C1, 0xF881, 0x3840, > - 0x2800, 0xE8C1, 0xE981, 0x2940, 0xEB01, 0x2BC0, 0x2A80, 0xEA41, > - 0xEE01, 0x2EC0, 0x2F80, 0xEF41, 0x2D00, 0xEDC1, 0xEC81, 0x2C40, > - 0xE401, 0x24C0, 0x2580, 0xE541, 0x2700, 0xE7C1, 0xE681, 0x2640, > - 0x2200, 0xE2C1, 0xE381, 0x2340, 0xE101, 0x21C0, 0x2080, 0xE041, > - 0xA001, 0x60C0, 0x6180, 0xA141, 0x6300, 0xA3C1, 0xA281, 0x6240, > - 0x6600, 0xA6C1, 0xA781, 0x6740, 0xA501, 0x65C0, 0x6480, 0xA441, > - 0x6C00, 0xACC1, 0xAD81, 0x6D40, 0xAF01, 0x6FC0, 0x6E80, 0xAE41, > - 0xAA01, 0x6AC0, 0x6B80, 0xAB41, 0x6900, 0xA9C1, 0xA881, 0x6840, > - 0x7800, 0xB8C1, 0xB981, 0x7940, 0xBB01, 0x7BC0, 0x7A80, 0xBA41, > - 0xBE01, 0x7EC0, 0x7F80, 0xBF41, 0x7D00, 0xBDC1, 0xBC81, 0x7C40, > - 0xB401, 0x74C0, 0x7580, 0xB541, 0x7700, 0xB7C1, 0xB681, 0x7640, > - 0x7200, 0xB2C1, 0xB381, 0x7340, 0xB101, 0x71C0, 0x7080, 0xB041, > - 0x5000, 0x90C1, 0x9181, 0x5140, 0x9301, 0x53C0, 0x5280, 0x9241, > - 0x9601, 0x56C0, 0x5780, 0x9741, 0x5500, 0x95C1, 0x9481, 0x5440, > - 0x9C01, 0x5CC0, 0x5D80, 0x9D41, 0x5F00, 0x9FC1, 0x9E81, 0x5E40, > - 0x5A00, 0x9AC1, 0x9B81, 0x5B40, 0x9901, 0x59C0, 0x5880, 0x9841, > - 0x8801, 0x48C0, 0x4980, 0x8941, 0x4B00, 0x8BC1, 0x8A81, 0x4A40, > - 0x4E00, 0x8EC1, 0x8F81, 0x4F40, 0x8D01, 0x4DC0, 0x4C80, 0x8C41, > - 0x4400, 0x84C1, 0x8581, 0x4540, 0x8701, 0x47C0, 0x4680, 0x8641, > - 0x8201, 0x42C0, 0x4380, 0x8341, 0x4100, 0x81C1, 0x8081, 0x4040 > -}; > - > -static inline __u16 crc16_byte(__u16 crc, const __u8 data) > -{ > - return (crc >> 8) ^ crc16_table[(crc ^ data) & 0xff]; > -} > - > -__u16 crc16(__u16 crc, __u8 const *buffer, size_t len) > -{ > - while (len--) > - crc = crc16_byte(crc, *buffer++); > - return crc; > -} > -#endif > - > __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group, > struct ext4_group_desc *gdp) > { > diff -puN fs/Kconfig~ext4-uninitialized-block-groups-fix fs/Kconfig > --- a/fs/Kconfig~ext4-uninitialized-block-groups-fix > +++ a/fs/Kconfig > @@ -140,6 +140,7 @@ config EXT4DEV_FS > tristate "Ext4dev/ext4 extended fs support development (EXPERIMENTAL)" > depends on EXPERIMENTAL > select JBD2 > + select CRC16 > help > Ext4dev is a predecessor filesystem of the next generation > extended fs ext4, based on ext3 filesystem code. It will be > _ > > Patches currently in -mm which might be from mathur@linux.vnet.ibm.com are > > ext4-uninitialized-block-groups-fix.patch > >