On Thu, May 20, 2010 at 2:10 PM, Jeff Mahoney <jeffm@xxxxxxxx> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 05/19/2010 06:00 PM, Edward Shishkin wrote: >> Leonardo Chiquitto wrote: >>> On Wed, May 19, 2010 at 4:22 PM, Jeff Mahoney <jeffm@xxxxxxxx> wrote: >>> >>>> In its early life, reiserfs had an evolving s_max_bytes. It started out >>>> at 4 GB, then was raised to MAX_LFS_FILESIZE, then dropped to 2 TiB >>>> when >>>> it was observed that struct stat only had a 32-bit st_blocks field. >>>> >>>> Since then, both the kernel and glibc have evolved as well and now both >>>> support 64-bit st_blocks. Applications that can't deal with these >>>> ranges >>>> are assumed to be "legacy" or "broken." File systems now routinely >>>> support file sizes much larger than can be represented by 2^32 * 512. >>>> >>>> But we never revisited that limitation. ReiserFS has always been >>>> able to >>>> support larger file sizes (up to 16 TiB, in fact), but the s_max_bytes >>>> limitation has prevented that. >>>> >>>> This patch adds a max_file_offset helper to set s_max_bytes to a more >>>> appropriate value. I noticed that XFS adjusts the limit based on the >>>> CPU but I'd prefer to err on the side of compatibility and place the >>>> limit at the smaller of the 32-bit MAX_LFS_FILESIZE and the maximum >>>> supported by the file system. At a 4k block size, this is conveniently >>>> also the advertised maximum file size of reiserfs. >>>> >>>> Update: This version properly extends PAGE_SIZE_CACHE so the math works >>>> on 32-bit systems. >>>> >>>> This bug is tracked at: >>>> https://bugzilla.novell.com/show_bug.cgi?id=592100 >>>> >>>> Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx> >>>> - --- >>>> fs/reiserfs/super.c | 17 +++++++++++++---- >>>> 1 file changed, 13 insertions(+), 4 deletions(-) >>>> >>>> - --- a/fs/reiserfs/super.c >>>> +++ b/fs/reiserfs/super.c >>>> @@ -1309,6 +1309,18 @@ out_err: >>>> return err; >>>> } >>>> +static inline loff_t >>>> +reiserfs_max_file_offset(struct super_block *sb) >>>> +{ >>>> + /* Limited by stat_data->sd_blocks, 2^32-1 blocks */ >>>> + loff_t fs_max = ((u64)sb->s_blocksize << 32) - sb->s_blocksize; >>>> + >>>> + /* Limited by 32-bit MAX_LFS_FILESIZE */ >>>> + loff_t page_cache_max = (((u64)PAGE_CACHE_SIZE << 31)-1); >>>> + >>>> + return min(fs_max, page_cache_max); >>>> +} >>>> + >>>> static int read_super_block(struct super_block *s, int offset) >>>> { >>>> struct buffer_head *bh; >>>> @@ -1398,10 +1410,7 @@ static int read_super_block(struct super >>>> s->dq_op = &reiserfs_quota_operations; >>>> #endif >>>> - /* new format is limited by the 32 bit wide i_blocks field, >>>> want to >>>> - - ** be one full block below that. >>>> - - */ >>>> - - s->s_maxbytes = (512LL << 32) - s->s_blocksize; >>>> + s->s_maxbytes = reiserfs_max_file_offset(s); >>>> return 0; >>>> } >>>> >>> >>> Hello ReiserFS developers, >>> >>> Any chance to have this patch submitted to 2.6.35? >> >> I wouldn't rely on this. Reiserfsprogs also should be aware >> of the new limits. It's all long.. > > I certainly hope not. Things would be broken already. The 2 TB limit is > 2048 * 2^32. > > - -Jeff > >>> We're hitting the 2TB >>> file limit here and this patch resolves the problem. >>> >>> Thanks, >>> Leonardo >>> -- >>> To unsubscribe from this list: send the line "unsubscribe >>> reiserfs-devel" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> >>> >> > > > - -- > Jeff Mahoney > SUSE Labs > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v2.0.15 (GNU/Linux) > Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org/ > > iEYEARECAAYFAkv1iTwACgkQLPWxlyuTD7I/yQCcCrGCVlu15YW7tBPbXb08SR7U > xc0AmwT5nDgG9T9apDXyQtqlpkx5vwva > =gb6N > -----END PGP SIGNATURE----- > -- > To unsubscribe from this list: send the line "unsubscribe reiserfs-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > I do not believe this patch will cause problems. As you mention, ReiserFS was intended to support a max 16TB filesize. Edward, it looks to me as though reiserfsprogs will be aware of the new limits, unless I am missing something (it does not have its own method for accessing the super block somewhere, correct?). -- To unsubscribe from this list: send the line "unsubscribe reiserfs-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
