kernel.git/fs/hfsplus/bnode.c, branch linux-3.2.y

hfs,hfsplus: cache pages correctly between bnode_create and bnode_free

2015-10-13T02:46:08Z

commit 7cb74be6fd827e314f81df3c5889b87e4c87c569 upstream. Pages looked up by __hfs_bnode_create() (called by hfs_bnode_create() and hfs_bnode_find() for finding or creating pages corresponding to an inode) are immediately kmap()'ed and used (both read and write) and kunmap()'ed, and should not be page_cache_release()'ed until hfs_bnode_free(). This patch fixes a problem I first saw in July 2012: merely running "du" on a large hfsplus-mounted directory a few times on a reasonably loaded system would get the hfsplus driver all confused and complaining about B-tree inconsistencies, and generates a "BUG: Bad page state". Most recently, I can generate this problem on up-to-date Fedora 22 with shipped kernel 4.0.5, by running "du /" (="/" + "/home" + "/mnt" + other smaller mounts) and "du /mnt" simultaneously on two windows, where /mnt is a lightly-used QEMU VM image of the full Mac OS X 10.9: $ df -i / /home /mnt Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/fedora-root 3276800 551665 2725135 17% / /dev/mapper/fedora-home 52879360 716221 52163139 2% /home /dev/nbd0p2 4294967295 1387818 4293579477 1% /mnt After applying the patch, I was able to run "du /" (60+ times) and "du /mnt" (150+ times) continuously and simultaneously for 6+ hours. There are many reports of the hfsplus driver getting confused under load and generating "BUG: Bad page state" or other similar issues over the years. [1] The unpatched code [2] has always been wrong since it entered the kernel tree. The only reason why it gets away with it is that the kmap/memcpy/kunmap follow very quickly after the page_cache_release() so the kernel has not had a chance to reuse the memory for something else, most of the time. The current RW driver appears to have followed the design and development of the earlier read-only hfsplus driver [3], where-by version 0.1 (Dec 2001) had a B-tree node-centric approach to read_cache_page()/page_cache_release() per bnode_get()/bnode_put(), migrating towards version 0.2 (June 2002) of caching and releasing pages per inode extents. When the current RW code first entered the kernel [2] in 2005, there was an REF_PAGES conditional (and "//" commented out code) to switch between B-node centric paging to inode-centric paging. There was a mistake with the direction of one of the REF_PAGES conditionals in __hfs_bnode_create(). In a subsequent "remove debug code" commit [4], the read_cache_page()/page_cache_release() per bnode_get()/bnode_put() were removed, but a page_cache_release() was mistakenly left in (propagating the "REF_PAGES <-> !REF_PAGE" mistake), and the commented-out page_cache_release() in bnode_release() (which should be spanned by !REF_PAGES) was never enabled. References: [1]: Michael Fox, Apr 2013 http://www.spinics.net/lists/linux-fsdevel/msg63807.html ("hfsplus volume suddenly inaccessable after 'hfs: recoff %d too large'") Sasha Levin, Feb 2015 http://lkml.org/lkml/2015/2/20/85 ("use after free") https://bugs.launchpad.net/ubuntu/+source/linux/+bug/740814 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1027887 https://bugzilla.kernel.org/show_bug.cgi?id=42342 https://bugzilla.kernel.org/show_bug.cgi?id=63841 https://bugzilla.kernel.org/show_bug.cgi?id=78761 [2]: http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfs/bnode.c?id=d1081202f1d0ee35ab0beb490da4b65d4bc763db commit d1081202f1d0ee35ab0beb490da4b65d4bc763db Author: Andrew Morton Date: Wed Feb 25 16:17:36 2004 -0800 [PATCH] HFS rewrite http://git.kernel.org/cgit/linux/kernel/git/tglx/history.git/commit/\ fs/hfsplus/bnode.c?id=91556682e0bf004d98a529bf829d339abb98bbbd commit 91556682e0bf004d98a529bf829d339abb98bbbd Author: Andrew Morton Date: Wed Feb 25 16:17:48 2004 -0800 [PATCH] HFS+ support [3]: http://sourceforge.net/projects/linux-hfsplus/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.1/ http://sourceforge.net/projects/linux-hfsplus/files/Linux%202.4.x%20patch/hfsplus%200.2/ http://linux-hfsplus.cvs.sourceforge.net/viewvc/linux-hfsplus/linux/\ fs/hfsplus/bnode.c?r1=1.4&r2=1.5 Date: Thu Jun 6 09:45:14 2002 +0000 Use buffer cache instead of page cache in bnode.c. Cache inode extents. [4]: http://git.kernel.org/cgit/linux/kernel/git/\ stable/linux-stable.git/commit/?id=a5e3985fa014029eb6795664c704953720cc7f7d commit a5e3985fa014029eb6795664c704953720cc7f7d Author: Roman Zippel Date: Tue Sep 6 15:18:47 2005 -0700 [PATCH] hfs: remove debug code Signed-off-by: Hin-Tak Leung Signed-off-by: Sergei Antonov Reviewed-by: Anton Altaparmakov Reported-by: Sasha Levin Cc: Al Viro Cc: Christoph Hellwig Cc: Vyacheslav Dubeyko Cc: Sougata Santra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings

hfsplus: %L-to-%ll, macro correction, and remove unneeded braces

2010-12-16T17:08:46Z

Clean-up based on checkpatch.pl report against unnecessary braces (`{' and `}'), non-standard format option %Lu (%llu recommended) as well as one trailing statement in a macro definition which should have been on the next line. Signed-off-by: Anton Salikhmetov Signed-off-by: Christoph Hellwig

hfsplus: C99 comments clean-up

2010-12-16T17:08:46Z

Match coding style restriction against C99 comments where checkpatch.pl reported errors about their usage. Signed-off-by: Anton Salikhmetov Signed-off-by: Christoph Hellwig

hfsplus: over 80 character lines clean-up

2010-12-16T17:08:45Z

Match coding style line length limitation where checkpatch.pl reported over-80-character-line warnings. Signed-off-by: Anton Salikhmetov Signed-off-by: Christoph Hellwig

hfsplus: silence a few debug printks

2010-11-23T13:37:40Z

Turn a few noisy debug printks that show up during xfstests into complied out debug print statements. Signed-off-by: Christoph Hellwig

[PATCH] fs: Conversions from kmalloc+memset to k(z|c)alloc

2006-09-27T15:26:10Z

Conversions from kmalloc+memset to kzalloc. Signed-off-by: Panagiotis Issaris Jffs2-bit-acked-by: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] read_mapping_page for address space

2006-06-23T14:43:02Z

Add read_mapping_page() which is used for callers that pass mapping->a_ops->readpage as the filler for read_cache_page. This removes some duplication from filesystem code. Signed-off-by: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

BUG_ON() Conversion in fs/hfsplus/

2006-03-31T23:14:43Z

this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn Signed-off-by: Adrian Bunk

[PATCH] hfs: cleanup HFS+ prints

2006-01-19T03:20:22Z

Add the log level and a "hfs: " prefix to all kernel prints. (HFS and HFS+ will use the same prefix, as they share some code and could be merged at some point.) Signed-off-by: Roman Zippel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] changing CONFIG_LOCALVERSION rebuilds too much, for no good reason

2005-11-09T15:55:57Z

This patch removes almost all inclusions of linux/version.h. The 3 #defines are unused in most of the touched files. A few drivers use the simple KERNEL_VERSION(a,b,c) macro, which is unfortunatly in linux/version.h. There are also lots of #ifdef for long obsolete kernels, this was not touched. In a few places, the linux/version.h include was move to where the LINUX_VERSION_CODE was used. quilt vi `find * -type f -name "*.[ch]"|xargs grep -El '(UTS_RELEASE|LINUX_VERSION_CODE|KERNEL_VERSION|linux/version.h)'|grep -Ev '(/(boot|coda|drm)/|~$)'` search pattern: /UTS_RELEASE\|LINUX_VERSION_CODE\|KERNEL_VERSION\|linux\/$utsname\|version$.h Signed-off-by: Olaf Hering Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds