Return-Path: <linux-kernel-owner+willy=40w.ods.org@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id <S317880AbSGKThx>; Thu, 11 Jul 2002 15:37:53 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org
	id <S317881AbSGKThw>; Thu, 11 Jul 2002 15:37:52 -0400
Received: from astound-64-85-224-253.ca.astound.net ([64.85.224.253]:26377
	"EHLO master.linux-ide.org") by vger.kernel.org with ESMTP
	id <S317880AbSGKThu>; Thu, 11 Jul 2002 15:37:50 -0400
Date: Thu, 11 Jul 2002 12:37:56 -0700 (PDT)
From: Andre Hedrick <andre@linux-ide.org>
To: Anton Altaparmakov <aia21@cantab.net>
cc: Linus Torvalds <torvalds@transmeta.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [BK-PATCH-2.5] NTFS: 2.0.18 - Fix race condition in reading of
 compressed files
In-Reply-To: <E17SjcG-0002of-00@storm.christs.cam.ac.uk>
Message-ID: <Pine.LNX.4.10.10207111236010.20092-100000@master.linux-ide.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Sender: linux-kernel-owner@vger.kernel.org
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 7369
Lines: 197


Hey Anton,

Not a problem!  Will keep an updated patch for people to use to fix all
the other issues that are not IDE.  To bad some people can't remember when
they had a good thing.

Cheers,

Andre Hedrick
LAD Storage Consulting Group

On Thu, 11 Jul 2002, Anton Altaparmakov wrote:

> Linus, please do a
> 
> 	bk pull http://linux-ntfs.bkbits.net/ntfs-tng-2.5
> 
> This fixes a nasty little race condition in reading compressed files. There
> was a narrow window between checking a buffer head for being uptodate and
> locking it in fs/ntfs/compress.c::ntfs_file_read_compressed_block(). We now
> lock the buffer and then check whether it is uptodate or not.
> 
> Big thanks go to Andre and Jens for bringing a stable IDE layer to 2.5.25
> which actually makes it possible to start finding bugs in other places
> other than IDE!
> 
> I am running http://www.linuxdiskcert.org/LAD-ide24-2.5.25.patch.bz2 on
> top of the current 2.5 BitKeeper tree and it's working great!!! Thanks guys!
> 
> Best regards,
> 
> 	Anton
> -- 
> Anton Altaparmakov <aia21 at cantab.net> (replace at with @)
> Linux NTFS maintainer / IRC: #ntfs on irc.openprojects.net
> WWW: http://linux-ntfs.sf.net/, http://www-stu.christs.cam.ac.uk/~aia21/
> 
> ===================================================================
> 
> This will update the following files:
> 
>  Documentation/filesystems/ntfs.txt |    2 ++
>  fs/ntfs/ChangeLog                  |    8 ++++++++
>  fs/ntfs/Makefile                   |    2 +-
>  fs/ntfs/compress.c                 |   17 +++++++++--------
>  4 files changed, 20 insertions(+), 9 deletions(-)
> 
> through these ChangeSets:
> 
> <aia21@cantab.net> (02/07/11 1.621)
>    NTFS: 2.0.18 - Fix race condition in reading of compressed files.
>    - There was a narrow window between checking a buffer head for being
>    uptodate and locking it in ntfs_file_read_compressed_block(). We now
>    lock the buffer and then check whether it is uptodate or not.
> 
> 
> diff -Nru a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt
> --- a/Documentation/filesystems/ntfs.txt	Thu Jul 11 20:19:13 2002
> +++ b/Documentation/filesystems/ntfs.txt	Thu Jul 11 20:19:13 2002
> @@ -247,6 +247,8 @@
>  
>  Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
>  
> +2.0.18:
> +	- Fix race condition in reading of compressed files.
>  2.0.17:
>  	- Cleanups and optimizations.
>  2.0.16:
> diff -Nru a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
> --- a/fs/ntfs/ChangeLog	Thu Jul 11 20:19:13 2002
> +++ b/fs/ntfs/ChangeLog	Thu Jul 11 20:19:13 2002
> @@ -13,6 +13,14 @@
>  	  with initialized_size < data_size. I don't think it can happen but
>  	  it requires more careful consideration.
>  	- Enable NFS exporting of NTFS.
> +	- Apply block resolution optimization from aops.c::ntfs_read_block() to
> +	  compress.c::ntfs_file_read_compressed_block() as well.
> +
> +2.0.18 - Fix race condition in reading of compressed files.
> +
> +	- There was a narrow window between checking a buffer head for being
> +	  uptodate and locking it in ntfs_file_read_compressed_block(). We now
> +	  lock the buffer and then check whether it is uptodate or not.
>  
>  2.0.17 - Cleanups and optimizations - shrinking the ToDo list.
>  
> diff -Nru a/fs/ntfs/Makefile b/fs/ntfs/Makefile
> --- a/fs/ntfs/Makefile	Thu Jul 11 20:19:13 2002
> +++ b/fs/ntfs/Makefile	Thu Jul 11 20:19:13 2002
> @@ -5,7 +5,7 @@
>  ntfs-objs := aops.o attrib.o compress.o debug.o dir.o file.o inode.o mft.o \
>  	     mst.o namei.o super.o sysctl.o time.o unistr.o upcase.o
>  
> -EXTRA_CFLAGS = -DNTFS_VERSION=\"2.0.17\"
> +EXTRA_CFLAGS = -DNTFS_VERSION=\"2.0.18\"
>  
>  ifeq ($(CONFIG_NTFS_DEBUG),y)
>  EXTRA_CFLAGS += -DDEBUG
> diff -Nru a/fs/ntfs/compress.c b/fs/ntfs/compress.c
> --- a/fs/ntfs/compress.c	Thu Jul 11 20:19:13 2002
> +++ b/fs/ntfs/compress.c	Thu Jul 11 20:19:13 2002
> @@ -157,7 +157,7 @@
>  
>  	/* Default error code. */
>  	int err = -EOVERFLOW;
> -	
> +
>  	ntfs_debug("Entering, cb_size = 0x%x.", cb_size);
>  do_next_sb:
>  	ntfs_debug("Beginning sub-block at offset = 0x%x in the cb.",
> @@ -193,7 +193,7 @@
>  	/* Setup offsets for the current sub-block destination. */
>  	do_sb_start = *dest_ofs;
>  	do_sb_end = do_sb_start + NTFS_SB_SIZE;
> -	
> +
>  	/* Check that we are still within allowed boundaries. */
>  	if (*dest_index == dest_max_index && do_sb_end > dest_max_ofs)
>  		goto return_overflow;
> @@ -572,11 +572,13 @@
>  	for (i = 0; i < nr_bhs; i++) {
>  		struct buffer_head *tbh = bhs[i];
>  
> -		if (buffer_uptodate(tbh))
> +		if (unlikely(test_set_buffer_locked(tbh)))
>  			continue;
> -
> -		lock_buffer(tbh);
> -		get_bh(tbh);
> +		if (unlikely(buffer_uptodate(tbh))) {
> +			unlock_buffer(tbh);
> +			continue;
> +		}
> +		atomic_inc(&tbh->b_count);
>  		tbh->b_end_io = end_buffer_io_sync;
>  		submit_bh(READ, tbh);
>  	}
> @@ -587,9 +589,8 @@
>  
>  		if (buffer_uptodate(tbh))
>  			continue;
> -
>  		wait_on_buffer(tbh);
> -		if (!buffer_uptodate(tbh))
> +		if (unlikely(!buffer_uptodate(tbh)))
>  			goto read_err;
>  	}
>  
> 
> ===================================================================
> 
> This BitKeeper patch contains the following changesets:
> +
> ## Wrapped with gzip_uu ##
> 
> 
> begin 664 bkpatch27457
> M'XL(`#':+3T``\5776_;-A1]-G_%70L,"0K+)/7MP473..F"9FV0I-L>`AB4
> M1,5";-&0Z+K9M/^^2\F)&SG>8C?=;,<$:?+PD.>>>Y67\*F41;\C,L$9>0D_
> MJU+W.['(M8BL7&H<.E<*AWKSLNB51=S3^37!T3.AXS%\ED79[S#+OA_1MS/9
> M[YP?O?MT>G!.R&``AV.17\L+J6$P(%H5G\4D*=\(/9ZHW-*%R,NIU,**U;2Z
> MGUIQ2CF^7>;;U/4JYE''KV*6,"8<)A/*G<!S2,WZS8IM&\!GE-LVY6[%F&?[
> M9`C,\C@#RGO4[S$&G/:9W[>=5Y3U*84V'KQRH$O)6WA>VH<DA@^7QQ=]X!:U
> M6`!=.,Z^0"%B";'*DTQG*H<LAT**),NO0:4X/IT5LBQE`FDVD:6%&%VX',M"
> MPD*4("`71:$6L,CR!)M(ZH64.<1C&=\8#`'1/$UE`6,$A505.`7'$68^TRH1
> M6H+($YBH9GJF#8%<I^7([#<R5$8K$J/(3-S;M^`W";E:((P9`#V6=_L8-.PN
> M*<!B++%7U,#E:D_DD2MMD?>`$G%*SE;Q0KI;O@BA@I+7\/9]E98]P[WWB[B1
> MAG_%0I]2AF^;AFY84>SX52IC%KG,94Y"[6A=_W6895@Q%J+$K+(9]Y<[#E4\
> MGTI<:<3KU1K=EEI.&P1+?]&/<*"L\EWJ29^F7'I1$MG1.HDG(+=HL8!Z_L.+
> M:&[U5%T_QL*KDM1+0\&0C$QM/W4V7\4*J+6IBQ9S'VYZ%R]6_-BN0>4QAZ6Q
> M'P@_\1W!O<V[?H74VM:Q;<>M$\V_WY/)0,\HU7K^>;I4F)AXZ/**\2`,Z\3$
> MW;6\Q#;F)?Z]\M)\5MO2)':3A$R>:)*4<6@=5A^A6RSJ#SKN[`FWOH./3[@3
> M`B?-SGW2V2E!FIA8B]IE".QHBW7%-]KB7F`W<():8$;#+10._@^%&P^W%%X[
> MXBZ",A<"H^/!;#:YA;IZH'JEFLQK+=5,9]/LCSJ(("W4%(2:H=O[_;H$U=5G
> M67+P2D@'8)41EG/^J4P!5LB%G$PL<D6^I>9>F2,\0]%%_L]2=1'GV\KNUQZY
> M*W(MBVQ50C<;I%U"\<L\DYD2ZC4)T*-;V(-!E_WG]FC*_09[W!UP!W<,`V#D
> MQ'P=_7YY?C`Z/#X]>'<!`^@.S7/BZ->C\XN3CQ\&5R\:*E<O'@BWLD)+NFWK
> M[V;UUNHO#9B/"MJ5[7BTR6^.OX5^(72#[Z+?]JY^Q-"(LZ6E-_D9D;9Q]$8[
> M(\X3GZ.;!Z(-0;K2<9<PQ6LW@=HT5]@/O;I?-]AW?=?TFZ;3R5+8F^>3[$9.
> M;O>T+/6HE'K4'&QD#BJ3/1V-]_?WS5(?;+,T!+>]=+GB[JS+-?`GSNO@)`1:
> M@M:__&2&47R=Y7-I.G_AG]!JFL6C+(_W?L1)W=<1BC#/-<X>NJ$Y#C:\)E\W
> >+08_/$YA]8]PK4TYGPY2P:(@DC[Y&^KUPD=:#P``
> `
> end
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
> 

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/