<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs, branch v3.2.33</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Revert "lockd: use rpc client's cl_nodename for id encoding"</title>
<updated>2012-10-30T23:27:08+00:00</updated>
<author>
<name>Ben Hutchings</name>
<email>ben@decadent.org.uk</email>
</author>
<published>2012-10-28T18:43:50+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8c812dca4d68f3c11e6f6d28cd8e92b4282909a6'/>
<id>8c812dca4d68f3c11e6f6d28cd8e92b4282909a6</id>
<content type='text'>
This reverts 5ff39e971c87ea9f4c4c7b253898abafa960e32b which was commit
303a7ce92064c285a04c870f2dc0192fdb2968cb upstream.

It is not necessary for kernel versions without per-netns RPC clients.

Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts 5ff39e971c87ea9f4c4c7b253898abafa960e32b which was commit
303a7ce92064c285a04c870f2dc0192fdb2968cb upstream.

It is not necessary for kernel versions without per-netns RPC clients.

Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>fs/compat_ioctl.c: VIDEO_SET_SPU_PALETTE missing error check</title>
<updated>2012-10-30T23:27:08+00:00</updated>
<author>
<name>Kees Cook</name>
<email>keescook@chromium.org</email>
</author>
<published>2012-10-25T20:38:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5bbeedc3110bbb1b5c6b01fc1f027ab5d2eb40d6'/>
<id>5bbeedc3110bbb1b5c6b01fc1f027ab5d2eb40d6</id>
<content type='text'>
commit 12176503366885edd542389eed3aaf94be163fdb upstream.

The compat ioctl for VIDEO_SET_SPU_PALETTE was missing an error check
while converting ioctl arguments.  This could lead to leaking kernel
stack contents into userspace.

Patch extracted from existing fix in grsecurity.

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Brad Spengler &lt;spender@grsecurity.net&gt;
Cc: PaX Team &lt;pageexec@freemail.hu&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 12176503366885edd542389eed3aaf94be163fdb upstream.

The compat ioctl for VIDEO_SET_SPU_PALETTE was missing an error check
while converting ioctl arguments.  This could lead to leaking kernel
stack contents into userspace.

Patch extracted from existing fix in grsecurity.

Signed-off-by: Kees Cook &lt;keescook@chromium.org&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: Brad Spengler &lt;spender@grsecurity.net&gt;
Cc: PaX Team &lt;pageexec@freemail.hu&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>freezer: exec should clear PF_NOFREEZE along with PF_KTHREAD</title>
<updated>2012-10-30T23:27:06+00:00</updated>
<author>
<name>Oleg Nesterov</name>
<email>oleg@redhat.com</email>
</author>
<published>2012-10-25T20:28:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d4d11f5bb26878b31b602d8b363e89f291426b47'/>
<id>d4d11f5bb26878b31b602d8b363e89f291426b47</id>
<content type='text'>
commit b40a79591ca918e7b91b0d9b6abd5d00f2e88c19 upstream.

flush_old_exec() clears PF_KTHREAD but forgets about PF_NOFREEZE.

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
[bwh: Backported to 3.2: PF_FORKNOEXEC is cleared elsewhere]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b40a79591ca918e7b91b0d9b6abd5d00f2e88c19 upstream.

flush_old_exec() clears PF_KTHREAD but forgets about PF_NOFREEZE.

Signed-off-by: Oleg Nesterov &lt;oleg@redhat.com&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
[bwh: Backported to 3.2: PF_FORKNOEXEC is cleared elsewhere]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sysfs: sysfs_pathname/sysfs_add_one: Use strlcat() instead of strcat()</title>
<updated>2012-10-30T23:26:59+00:00</updated>
<author>
<name>Geert Uytterhoeven</name>
<email>geert@linux-m68k.org</email>
</author>
<published>2012-09-29T20:23:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6a026352765b0830d1e6f1fa2a8c1c0499fc1508'/>
<id>6a026352765b0830d1e6f1fa2a8c1c0499fc1508</id>
<content type='text'>
commit 66081a72517a131430dcf986775f3268aafcb546 upstream.

The warning check for duplicate sysfs entries can cause a buffer overflow
when printing the warning, as strcat() doesn't check buffer sizes.
Use strlcat() instead.

Since strlcat() doesn't return a pointer to the passed buffer, unlike
strcat(), I had to convert the nested concatenation in sysfs_add_one() to
an admittedly more obscure comma operator construct, to avoid emitting code
for the concatenation if CONFIG_BUG is disabled.

Signed-off-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 66081a72517a131430dcf986775f3268aafcb546 upstream.

The warning check for duplicate sysfs entries can cause a buffer overflow
when printing the warning, as strcat() doesn't check buffer sizes.
Use strlcat() instead.

Since strlcat() doesn't return a pointer to the passed buffer, unlike
strcat(), I had to convert the nested concatenation in sysfs_add_one() to
an admittedly more obscure comma operator construct, to avoid emitting code
for the concatenation if CONFIG_BUG is disabled.

Signed-off-by: Geert Uytterhoeven &lt;geert@linux-m68k.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>NLM: nlm_lookup_file() may return NLMv4-specific error codes</title>
<updated>2012-10-30T23:26:49+00:00</updated>
<author>
<name>Trond Myklebust</name>
<email>Trond.Myklebust@netapp.com</email>
</author>
<published>2012-10-13T04:30:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=34fb2c5983d16fac57b1ff78b5dbfe98b12bbde0'/>
<id>34fb2c5983d16fac57b1ff78b5dbfe98b12bbde0</id>
<content type='text'>
commit cd0b16c1c3cda12dbed1f8de8f1a9b0591990724 upstream.

If the filehandle is stale, or open access is denied for some reason,
nlm_fopen() may return one of the NLMv4-specific error codes nlm4_stale_fh
or nlm4_failed. These get passed right through nlm_lookup_file(),
and so when nlmsvc_retrieve_args() calls the latter, it needs to filter
the result through the cast_status() machinery.

Failure to do so, will trigger the BUG_ON() in encode_nlm_stat...

Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Reported-by: Larry McVoy &lt;lm@bitmover.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cd0b16c1c3cda12dbed1f8de8f1a9b0591990724 upstream.

If the filehandle is stale, or open access is denied for some reason,
nlm_fopen() may return one of the NLMv4-specific error codes nlm4_stale_fh
or nlm4_failed. These get passed right through nlm_lookup_file(),
and so when nlmsvc_retrieve_args() calls the latter, it needs to filter
the result through the cast_status() machinery.

Failure to do so, will trigger the BUG_ON() in encode_nlm_stat...

Signed-off-by: Trond Myklebust &lt;Trond.Myklebust@netapp.com&gt;
Reported-by: Larry McVoy &lt;lm@bitmover.com&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nohz: Fix idle ticks in cpu summary line of /proc/stat</title>
<updated>2012-10-30T23:26:42+00:00</updated>
<author>
<name>Michal Hocko</name>
<email>mhocko@suse.cz</email>
</author>
<published>2012-10-10T06:21:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3b0622adf033c6ed9cc35adfcfc8dfad20c56445'/>
<id>3b0622adf033c6ed9cc35adfcfc8dfad20c56445</id>
<content type='text'>
commit 7386cdbf2f57ea8cff3c9fde93f206e58b9fe13f upstream.

Git commit 09a1d34f8535ecf9 "nohz: Make idle/iowait counter update
conditional" introduced a bug in regard to cpu hotplug. The effect is
that the number of idle ticks in the cpu summary line in /proc/stat is
still counting ticks for offline cpus.

Reproduction is easy, just start a workload that keeps all cpus busy,
switch off one or more cpus and then watch the idle field in top.
On a dual-core with one cpu 100% busy and one offline cpu you will get
something like this:

%Cpu(s): 48.7 us,  1.3 sy,  0.0 ni, 50.0 id,  0.0 wa,  0.0 hi,  0.0 si,
%0.0 st

The problem is that an offline cpu still has ts-&gt;idle_active == 1.
To fix this we should make sure that the cpu is online when calling
get_cpu_idle_time_us and get_cpu_iowait_time_us.

[Srivatsa: Rebased to current mainline]

Reported-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Signed-off-by: Michal Hocko &lt;mhocko@suse.cz&gt;
Reviewed-by: Srivatsa S. Bhat &lt;srivatsa.bhat@linux.vnet.ibm.com&gt;
Signed-off-by: Srivatsa S. Bhat &lt;srivatsa.bhat@linux.vnet.ibm.com&gt;
Link: http://lkml.kernel.org/r/20121010061820.8999.57245.stgit@srivatsabhat.in.ibm.com
Cc: deepthi@linux.vnet.ibm.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7386cdbf2f57ea8cff3c9fde93f206e58b9fe13f upstream.

Git commit 09a1d34f8535ecf9 "nohz: Make idle/iowait counter update
conditional" introduced a bug in regard to cpu hotplug. The effect is
that the number of idle ticks in the cpu summary line in /proc/stat is
still counting ticks for offline cpus.

Reproduction is easy, just start a workload that keeps all cpus busy,
switch off one or more cpus and then watch the idle field in top.
On a dual-core with one cpu 100% busy and one offline cpu you will get
something like this:

%Cpu(s): 48.7 us,  1.3 sy,  0.0 ni, 50.0 id,  0.0 wa,  0.0 hi,  0.0 si,
%0.0 st

The problem is that an offline cpu still has ts-&gt;idle_active == 1.
To fix this we should make sure that the cpu is online when calling
get_cpu_idle_time_us and get_cpu_iowait_time_us.

[Srivatsa: Rebased to current mainline]

Reported-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Signed-off-by: Michal Hocko &lt;mhocko@suse.cz&gt;
Reviewed-by: Srivatsa S. Bhat &lt;srivatsa.bhat@linux.vnet.ibm.com&gt;
Signed-off-by: Srivatsa S. Bhat &lt;srivatsa.bhat@linux.vnet.ibm.com&gt;
Link: http://lkml.kernel.org/r/20121010061820.8999.57245.stgit@srivatsabhat.in.ibm.com
Cc: deepthi@linux.vnet.ibm.com
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>ext4: race-condition protection for ext4_convert_unwritten_extents_endio</title>
<updated>2012-10-30T23:26:41+00:00</updated>
<author>
<name>Dmitry Monakhov</name>
<email>dmonakhov@openvz.org</email>
</author>
<published>2012-10-10T05:04:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=814a7833df19e1de7447f870ae890adb12561627'/>
<id>814a7833df19e1de7447f870ae890adb12561627</id>
<content type='text'>
commit dee1f973ca341c266229faa5a1a5bb268bed3531 upstream.

We assumed that at the time we call ext4_convert_unwritten_extents_endio()
extent in question is fully inside [map.m_lblk, map-&gt;m_len] because
it was already split during submission.  But this may not be true due to
a race between writeback vs fallocate.

If extent in question is larger than requested we will split it again.
Special precautions should being done if zeroout required because
[map.m_lblk, map-&gt;m_len] already contains valid data.

Signed-off-by: Dmitry Monakhov &lt;dmonakhov@openvz.org&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit dee1f973ca341c266229faa5a1a5bb268bed3531 upstream.

We assumed that at the time we call ext4_convert_unwritten_extents_endio()
extent in question is fully inside [map.m_lblk, map-&gt;m_len] because
it was already split during submission.  But this may not be true due to
a race between writeback vs fallocate.

If extent in question is larger than requested we will split it again.
Special precautions should being done if zeroout required because
[map.m_lblk, map-&gt;m_len] already contains valid data.

Signed-off-by: Dmitry Monakhov &lt;dmonakhov@openvz.org&gt;
Signed-off-by: "Theodore Ts'o" &lt;tytso@mit.edu&gt;
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tmpfs,ceph,gfs2,isofs,reiserfs,xfs: fix fh_len checking</title>
<updated>2012-10-30T23:26:40+00:00</updated>
<author>
<name>Hugh Dickins</name>
<email>hughd@google.com</email>
</author>
<published>2012-10-08T03:32:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ba3385bc8c513fd741f09ef75e53e0e6547b079e'/>
<id>ba3385bc8c513fd741f09ef75e53e0e6547b079e</id>
<content type='text'>
commit 35c2a7f4908d404c9124c2efc6ada4640ca4d5d5 upstream.

Fuzzing with trinity oopsed on the 1st instruction of shmem_fh_to_dentry(),
	u64 inum = fid-&gt;raw[2];
which is unhelpfully reported as at the end of shmem_alloc_inode():

BUG: unable to handle kernel paging request at ffff880061cd3000
IP: [&lt;ffffffff812190d0&gt;] shmem_alloc_inode+0x40/0x40
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Call Trace:
 [&lt;ffffffff81488649&gt;] ? exportfs_decode_fh+0x79/0x2d0
 [&lt;ffffffff812d77c3&gt;] do_handle_open+0x163/0x2c0
 [&lt;ffffffff812d792c&gt;] sys_open_by_handle_at+0xc/0x10
 [&lt;ffffffff83a5f3f8&gt;] tracesys+0xe1/0xe6

Right, tmpfs is being stupid to access fid-&gt;raw[2] before validating that
fh_len includes it: the buffer kmalloc'ed by do_sys_name_to_handle() may
fall at the end of a page, and the next page not be present.

But some other filesystems (ceph, gfs2, isofs, reiserfs, xfs) are being
careless about fh_len too, in fh_to_dentry() and/or fh_to_parent(), and
could oops in the same way: add the missing fh_len checks to those.

Reported-by: Sasha Levin &lt;levinsasha928@gmail.com&gt;
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: Sage Weil &lt;sage@inktank.com&gt;
Cc: Steven Whitehouse &lt;swhiteho@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 35c2a7f4908d404c9124c2efc6ada4640ca4d5d5 upstream.

Fuzzing with trinity oopsed on the 1st instruction of shmem_fh_to_dentry(),
	u64 inum = fid-&gt;raw[2];
which is unhelpfully reported as at the end of shmem_alloc_inode():

BUG: unable to handle kernel paging request at ffff880061cd3000
IP: [&lt;ffffffff812190d0&gt;] shmem_alloc_inode+0x40/0x40
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Call Trace:
 [&lt;ffffffff81488649&gt;] ? exportfs_decode_fh+0x79/0x2d0
 [&lt;ffffffff812d77c3&gt;] do_handle_open+0x163/0x2c0
 [&lt;ffffffff812d792c&gt;] sys_open_by_handle_at+0xc/0x10
 [&lt;ffffffff83a5f3f8&gt;] tracesys+0xe1/0xe6

Right, tmpfs is being stupid to access fid-&gt;raw[2] before validating that
fh_len includes it: the buffer kmalloc'ed by do_sys_name_to_handle() may
fall at the end of a page, and the next page not be present.

But some other filesystems (ceph, gfs2, isofs, reiserfs, xfs) are being
careless about fh_len too, in fh_to_dentry() and/or fh_to_parent(), and
could oops in the same way: add the missing fh_len checks to those.

Reported-by: Sasha Levin &lt;levinsasha928@gmail.com&gt;
Signed-off-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Cc: Sage Weil &lt;sage@inktank.com&gt;
Cc: Steven Whitehouse &lt;swhiteho@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@infradead.org&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>nfsd4: fix nfs4 stateid leak</title>
<updated>2012-10-30T23:26:36+00:00</updated>
<author>
<name>J. Bruce Fields</name>
<email>bfields@redhat.com</email>
</author>
<published>2012-08-29T22:21:58+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f42ce0ca9eaf8a71f95dd0909c3ade7ab9cd824d'/>
<id>f42ce0ca9eaf8a71f95dd0909c3ade7ab9cd824d</id>
<content type='text'>
commit cf9182e90b2af04245ac4fae497fe73fc71285b4 upstream.

Processes that open and close multiple files may end up setting this
oo_last_closed_stid without freeing what was previously pointed to.
This can result in a major leak, visible for example by watching the
nfsd4_stateids line of /proc/slabinfo.

Reported-by: Cyril B. &lt;cbay@excellency.fr&gt;
Tested-by: Cyril B. &lt;cbay@excellency.fr&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit cf9182e90b2af04245ac4fae497fe73fc71285b4 upstream.

Processes that open and close multiple files may end up setting this
oo_last_closed_stid without freeing what was previously pointed to.
This can result in a major leak, visible for example by watching the
nfsd4_stateids line of /proc/slabinfo.

Reported-by: Cyril B. &lt;cbay@excellency.fr&gt;
Tested-by: Cyril B. &lt;cbay@excellency.fr&gt;
Signed-off-by: J. Bruce Fields &lt;bfields@redhat.com&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>jbd: Fix assertion failure in commit code due to lacking transaction credits</title>
<updated>2012-10-30T23:26:27+00:00</updated>
<author>
<name>Jan Kara</name>
<email>jack@suse.cz</email>
</author>
<published>2012-07-11T21:16:25+00:00</published>
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commit 09e05d4805e6c524c1af74e524e5d0528bb3fef3 upstream.

ext3 users of data=journal mode with blocksize &lt; pagesize were occasionally
hitting assertion failure in journal_commit_transaction() checking whether the
transaction has at least as many credits reserved as buffers attached.  The
core of the problem is that when a file gets truncated, buffers that still need
checkpointing or that are attached to the committing transaction are left with
buffer_mapped set. When this happens to buffers beyond i_size attached to a
page stradding i_size, subsequent write extending the file will see these
buffers and as they are mapped (but underlying blocks were freed) things go
awry from here.

The assertion failure just coincidentally (and in this case luckily as we would
start corrupting filesystem) triggers due to journal_head not being properly
cleaned up as well.

Under some rare circumstances this bug could even hit data=ordered mode users.
There the assertion won't trigger and we would end up corrupting the
filesystem.

We fix the problem by unmapping buffers if possible (in lots of cases we just
need a buffer attached to a transaction as a place holder but it must not be
written out anyway). And in one case, we just have to bite the bullet and wait
for transaction commit to finish.

Reviewed-by: Josef Bacik &lt;jbacik@fusionio.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
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commit 09e05d4805e6c524c1af74e524e5d0528bb3fef3 upstream.

ext3 users of data=journal mode with blocksize &lt; pagesize were occasionally
hitting assertion failure in journal_commit_transaction() checking whether the
transaction has at least as many credits reserved as buffers attached.  The
core of the problem is that when a file gets truncated, buffers that still need
checkpointing or that are attached to the committing transaction are left with
buffer_mapped set. When this happens to buffers beyond i_size attached to a
page stradding i_size, subsequent write extending the file will see these
buffers and as they are mapped (but underlying blocks were freed) things go
awry from here.

The assertion failure just coincidentally (and in this case luckily as we would
start corrupting filesystem) triggers due to journal_head not being properly
cleaned up as well.

Under some rare circumstances this bug could even hit data=ordered mode users.
There the assertion won't trigger and we would end up corrupting the
filesystem.

We fix the problem by unmapping buffers if possible (in lots of cases we just
need a buffer attached to a transaction as a place holder but it must not be
written out anyway). And in one case, we just have to bite the bullet and wait
for transaction commit to finish.

Reviewed-by: Josef Bacik &lt;jbacik@fusionio.com&gt;
Signed-off-by: Jan Kara &lt;jack@suse.cz&gt;
Signed-off-by: Ben Hutchings &lt;ben@decadent.org.uk&gt;
</pre>
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