From mboxrd@z Thu Jan 1 00:00:00 1970 From: Edward Shishkin Subject: Re: [PATCH RESUBMIT] reiserfs: Remove 2 TB file size limit Date: Tue, 15 Jun 2010 23:00:16 +0200 Message-ID: <4C17E9E0.6070105@gmail.com> References: <4BF43A65.405@suse.com> <4BF45F94.40500@gmail.com> <4BF5893C.3010802@suse.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: reiserfs-devel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Leonardo Chiquitto Cc: T.Shearouse@gmail.com, Jeff Mahoney , reiserfs-devel@vger.kernel.org Leonardo Chiquitto wrote: > On Fri, May 21, 2010 at 10:17 AM, Tim Shearouse wrote: > >> On Thu, May 20, 2010 at 2:10 PM, Jeff Mahoney 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 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 >>>>>> - --- >>>>>> 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 >>>>> >>> - -- >>> Jeff Mahoney >>> SUSE Labs >>> >> 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?). >> > > Hello, > > I apologize for insisting here but it's really important for us to get > this fixed upstream. Please, can someone submit it for 2.6.35 I guess nobody will accept this to 2.6.35.. We only can push it to -mm with the following proceeding from the akpm's side.. > or, > if the patch is not a good idea, give a little insight on what's wrong? > Jeff, did you have any chances to run and fsck this on 32 and 64-bit machines? Thanks, Edward.