<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/fs/xfs, branch v4.4</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>Merge branch 'for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs</title>
<updated>2015-11-14T02:02:30+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-14T02:02:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5d2eb548b309be34ecf3b91f0b7300a2b9d09b8c'/>
<id>5d2eb548b309be34ecf3b91f0b7300a2b9d09b8c</id>
<content type='text'>
Pull vfs xattr cleanups from Al Viro.

* 'for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  f2fs: xattr simplifications
  squashfs: xattr simplifications
  9p: xattr simplifications
  xattr handlers: Pass handler to operations instead of flags
  jffs2: Add missing capability check for listing trusted xattrs
  hfsplus: Remove unused xattr handler list operations
  ubifs: Remove unused security xattr handler
  vfs: Fix the posix_acl_xattr_list return value
  vfs: Check attribute names in posix acl xattr handers
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull vfs xattr cleanups from Al Viro.

* 'for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  f2fs: xattr simplifications
  squashfs: xattr simplifications
  9p: xattr simplifications
  xattr handlers: Pass handler to operations instead of flags
  jffs2: Add missing capability check for listing trusted xattrs
  hfsplus: Remove unused xattr handler list operations
  ubifs: Remove unused security xattr handler
  vfs: Fix the posix_acl_xattr_list return value
  vfs: Check attribute names in posix acl xattr handers
</pre>
</div>
</content>
</entry>
<entry>
<title>xattr handlers: Pass handler to operations instead of flags</title>
<updated>2015-11-14T01:34:32+00:00</updated>
<author>
<name>Andreas Gruenbacher</name>
<email>agruenba@redhat.com</email>
</author>
<published>2015-10-04T17:18:51+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d9a82a04033f87bbd06efb29f78c0170a38154a8'/>
<id>d9a82a04033f87bbd06efb29f78c0170a38154a8</id>
<content type='text'>
The xattr_handler operations are currently all passed a file system
specific flags value which the operations can use to disambiguate between
different handlers; some file systems use that to distinguish the xattr
namespace, for example.  In some oprations, it would be useful to also have
access to the handler prefix.  To allow that, pass a pointer to the handler
to operations instead of the flags value alone.

Signed-off-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The xattr_handler operations are currently all passed a file system
specific flags value which the operations can use to disambiguate between
different handlers; some file systems use that to distinguish the xattr
namespace, for example.  In some oprations, it would be useful to also have
access to the handler prefix.  To allow that, pass a pointer to the handler
to operations instead of the flags value alone.

Signed-off-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs</title>
<updated>2015-11-12T04:18:48+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-12T04:18:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5d50ac70fe98518dbf620bfba8184254663125eb'/>
<id>5d50ac70fe98518dbf620bfba8184254663125eb</id>
<content type='text'>
Pull xfs updates from Dave Chinner:
 "There is nothing really major here - the only significant addition is
  the per-mount operation statistics infrastructure.  Otherwises there's
  various ACL, xattr, DAX, AIO and logging fixes, and a smattering of
  small cleanups and fixes elsewhere.

  Summary:

   - per-mount operational statistics in sysfs
   - fixes for concurrent aio append write submission
   - various logging fixes
   - detection of zeroed logs and invalid log sequence numbers on v5 filesystems
   - memory allocation failure message improvements
   - a bunch of xattr/ACL fixes
   - fdatasync optimisation
   - miscellaneous other fixes and cleanups"

* tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (39 commits)
  xfs: give all workqueues rescuer threads
  xfs: fix log recovery op header validation assert
  xfs: Fix error path in xfs_get_acl
  xfs: optimise away log forces on timestamp updates for fdatasync
  xfs: don't leak uuid table on rmmod
  xfs: invalidate cached acl if set via ioctl
  xfs: Plug memory leak in xfs_attrmulti_attr_set
  xfs: Validate the length of on-disk ACLs
  xfs: invalidate cached acl if set directly via xattr
  xfs: xfs_filemap_pmd_fault treats read faults as write faults
  xfs: add -&gt;pfn_mkwrite support for DAX
  xfs: DAX does not use IO completion callbacks
  xfs: Don't use unwritten extents for DAX
  xfs: introduce BMAPI_ZERO for allocating zeroed extents
  xfs: fix inode size update overflow in xfs_map_direct()
  xfs: clear PF_NOFREEZE for xfsaild kthread
  xfs: fix an error code in xfs_fs_fill_super()
  xfs: stats are no longer dependent on CONFIG_PROC_FS
  xfs: simplify /proc teardown &amp; error handling
  xfs: per-filesystem stats counter implementation
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull xfs updates from Dave Chinner:
 "There is nothing really major here - the only significant addition is
  the per-mount operation statistics infrastructure.  Otherwises there's
  various ACL, xattr, DAX, AIO and logging fixes, and a smattering of
  small cleanups and fixes elsewhere.

  Summary:

   - per-mount operational statistics in sysfs
   - fixes for concurrent aio append write submission
   - various logging fixes
   - detection of zeroed logs and invalid log sequence numbers on v5 filesystems
   - memory allocation failure message improvements
   - a bunch of xattr/ACL fixes
   - fdatasync optimisation
   - miscellaneous other fixes and cleanups"

* tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (39 commits)
  xfs: give all workqueues rescuer threads
  xfs: fix log recovery op header validation assert
  xfs: Fix error path in xfs_get_acl
  xfs: optimise away log forces on timestamp updates for fdatasync
  xfs: don't leak uuid table on rmmod
  xfs: invalidate cached acl if set via ioctl
  xfs: Plug memory leak in xfs_attrmulti_attr_set
  xfs: Validate the length of on-disk ACLs
  xfs: invalidate cached acl if set directly via xattr
  xfs: xfs_filemap_pmd_fault treats read faults as write faults
  xfs: add -&gt;pfn_mkwrite support for DAX
  xfs: DAX does not use IO completion callbacks
  xfs: Don't use unwritten extents for DAX
  xfs: introduce BMAPI_ZERO for allocating zeroed extents
  xfs: fix inode size update overflow in xfs_map_direct()
  xfs: clear PF_NOFREEZE for xfsaild kthread
  xfs: fix an error code in xfs_fs_fill_super()
  xfs: stats are no longer dependent on CONFIG_PROC_FS
  xfs: simplify /proc teardown &amp; error handling
  xfs: per-filesystem stats counter implementation
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>vfs: remove unused wrapper block_page_mkwrite()</title>
<updated>2015-11-11T07:19:33+00:00</updated>
<author>
<name>Ross Zwisler</name>
<email>ross.zwisler@linux.intel.com</email>
</author>
<published>2015-10-13T22:51:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5c50002963369c7c622b18ff751719eadbe225c5'/>
<id>5c50002963369c7c622b18ff751719eadbe225c5</id>
<content type='text'>
The function currently called "__block_page_mkwrite()" used to be called
"block_page_mkwrite()" until a wrapper for this function was added by:

commit 24da4fab5a61 ("vfs: Create __block_page_mkwrite() helper passing
	error values back")

This wrapper, the current "block_page_mkwrite()", is currently unused.
__block_page_mkwrite() is used directly by ext4, nilfs2 and xfs.

Remove the unused wrapper, rename __block_page_mkwrite() back to
block_page_mkwrite() and update the comment above block_page_mkwrite().

Signed-off-by: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.com&gt;
Cc: Jan Kara &lt;jack@suse.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The function currently called "__block_page_mkwrite()" used to be called
"block_page_mkwrite()" until a wrapper for this function was added by:

commit 24da4fab5a61 ("vfs: Create __block_page_mkwrite() helper passing
	error values back")

This wrapper, the current "block_page_mkwrite()", is currently unused.
__block_page_mkwrite() is used directly by ext4, nilfs2 and xfs.

Remove the unused wrapper, rename __block_page_mkwrite() back to
block_page_mkwrite() and update the comment above block_page_mkwrite().

Signed-off-by: Ross Zwisler &lt;ross.zwisler@linux.intel.com&gt;
Reviewed-by: Jan Kara &lt;jack@suse.com&gt;
Cc: Jan Kara &lt;jack@suse.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
Signed-off-by: Al Viro &lt;viro@zeniv.linux.org.uk&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'xfs-misc-fixes-for-4.4-3' into for-next</title>
<updated>2015-11-09T23:20:48+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>david@fromorbit.com</email>
</author>
<published>2015-11-09T23:20:48+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4e14e49a91e18098fd8ef30743972e0c3cb727c1'/>
<id>4e14e49a91e18098fd8ef30743972e0c3cb727c1</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
<entry>
<title>xfs: give all workqueues rescuer threads</title>
<updated>2015-11-09T23:10:34+00:00</updated>
<author>
<name>Chris Mason</name>
<email>clm@fb.com</email>
</author>
<published>2015-11-09T23:10:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7a29ac474a47eb8cf212b45917683ae89d6fa13b'/>
<id>7a29ac474a47eb8cf212b45917683ae89d6fa13b</id>
<content type='text'>
We're consistently hitting deadlocks here with XFS on recent kernels.
After some digging through the crash files, it looks like everyone in
the system is waiting for XFS to reclaim memory.

Something like this:

PID: 2733434  TASK: ffff8808cd242800  CPU: 19  COMMAND: "java"
 #0 [ffff880019c53588] __schedule at ffffffff818c4df2
 #1 [ffff880019c535d8] schedule at ffffffff818c5517
 #2 [ffff880019c535f8] _xfs_log_force_lsn at ffffffff81316348
 #3 [ffff880019c53688] xfs_log_force_lsn at ffffffff813164fb
 #4 [ffff880019c536b8] xfs_iunpin_wait at ffffffff8130835e
 #5 [ffff880019c53728] xfs_reclaim_inode at ffffffff812fd453
 #6 [ffff880019c53778] xfs_reclaim_inodes_ag at ffffffff812fd8c7
 #7 [ffff880019c53928] xfs_reclaim_inodes_nr at ffffffff812fe433
 #8 [ffff880019c53958] xfs_fs_free_cached_objects at ffffffff8130d3b9
 #9 [ffff880019c53968] super_cache_scan at ffffffff811a6f73
#10 [ffff880019c539c8] shrink_slab at ffffffff811460e6
#11 [ffff880019c53aa8] shrink_zone at ffffffff8114a53f
#12 [ffff880019c53b48] do_try_to_free_pages at ffffffff8114a8ba
#13 [ffff880019c53be8] try_to_free_pages at ffffffff8114ad5a
#14 [ffff880019c53c78] __alloc_pages_nodemask at ffffffff8113e1b8
#15 [ffff880019c53d88] alloc_kmem_pages_node at ffffffff8113e671
#16 [ffff880019c53dd8] copy_process at ffffffff8104f781
#17 [ffff880019c53ec8] do_fork at ffffffff8105129c
#18 [ffff880019c53f38] sys_clone at ffffffff810515b6
#19 [ffff880019c53f48] stub_clone at ffffffff818c8e4d

xfs_log_force_lsn is waiting for logs to get cleaned, which is waiting
for IO, which is waiting for workers to complete the IO which is waiting
for worker threads that don't exist yet:

PID: 2752451  TASK: ffff880bd6bdda00  CPU: 37  COMMAND: "kworker/37:1"
 #0 [ffff8808d20abbb0] __schedule at ffffffff818c4df2
 #1 [ffff8808d20abc00] schedule at ffffffff818c5517
 #2 [ffff8808d20abc20] schedule_timeout at ffffffff818c7c6c
 #3 [ffff8808d20abcc0] wait_for_completion_killable at ffffffff818c6495
 #4 [ffff8808d20abd30] kthread_create_on_node at ffffffff8106ec82
 #5 [ffff8808d20abdf0] create_worker at ffffffff8106752f
 #6 [ffff8808d20abe40] worker_thread at ffffffff810699be
 #7 [ffff8808d20abec0] kthread at ffffffff8106ef59
 #8 [ffff8808d20abf50] ret_from_fork at ffffffff818c8ac8

I think we should be using WQ_MEM_RECLAIM to make sure this thread
pool makes progress when we're not able to allocate new workers.

[dchinner: make all workqueues WQ_MEM_RECLAIM]

Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We're consistently hitting deadlocks here with XFS on recent kernels.
After some digging through the crash files, it looks like everyone in
the system is waiting for XFS to reclaim memory.

Something like this:

PID: 2733434  TASK: ffff8808cd242800  CPU: 19  COMMAND: "java"
 #0 [ffff880019c53588] __schedule at ffffffff818c4df2
 #1 [ffff880019c535d8] schedule at ffffffff818c5517
 #2 [ffff880019c535f8] _xfs_log_force_lsn at ffffffff81316348
 #3 [ffff880019c53688] xfs_log_force_lsn at ffffffff813164fb
 #4 [ffff880019c536b8] xfs_iunpin_wait at ffffffff8130835e
 #5 [ffff880019c53728] xfs_reclaim_inode at ffffffff812fd453
 #6 [ffff880019c53778] xfs_reclaim_inodes_ag at ffffffff812fd8c7
 #7 [ffff880019c53928] xfs_reclaim_inodes_nr at ffffffff812fe433
 #8 [ffff880019c53958] xfs_fs_free_cached_objects at ffffffff8130d3b9
 #9 [ffff880019c53968] super_cache_scan at ffffffff811a6f73
#10 [ffff880019c539c8] shrink_slab at ffffffff811460e6
#11 [ffff880019c53aa8] shrink_zone at ffffffff8114a53f
#12 [ffff880019c53b48] do_try_to_free_pages at ffffffff8114a8ba
#13 [ffff880019c53be8] try_to_free_pages at ffffffff8114ad5a
#14 [ffff880019c53c78] __alloc_pages_nodemask at ffffffff8113e1b8
#15 [ffff880019c53d88] alloc_kmem_pages_node at ffffffff8113e671
#16 [ffff880019c53dd8] copy_process at ffffffff8104f781
#17 [ffff880019c53ec8] do_fork at ffffffff8105129c
#18 [ffff880019c53f38] sys_clone at ffffffff810515b6
#19 [ffff880019c53f48] stub_clone at ffffffff818c8e4d

xfs_log_force_lsn is waiting for logs to get cleaned, which is waiting
for IO, which is waiting for workers to complete the IO which is waiting
for worker threads that don't exist yet:

PID: 2752451  TASK: ffff880bd6bdda00  CPU: 37  COMMAND: "kworker/37:1"
 #0 [ffff8808d20abbb0] __schedule at ffffffff818c4df2
 #1 [ffff8808d20abc00] schedule at ffffffff818c5517
 #2 [ffff8808d20abc20] schedule_timeout at ffffffff818c7c6c
 #3 [ffff8808d20abcc0] wait_for_completion_killable at ffffffff818c6495
 #4 [ffff8808d20abd30] kthread_create_on_node at ffffffff8106ec82
 #5 [ffff8808d20abdf0] create_worker at ffffffff8106752f
 #6 [ffff8808d20abe40] worker_thread at ffffffff810699be
 #7 [ffff8808d20abec0] kthread at ffffffff8106ef59
 #8 [ffff8808d20abf50] ret_from_fork at ffffffff818c8ac8

I think we should be using WQ_MEM_RECLAIM to make sure this thread
pool makes progress when we're not able to allocate new workers.

[dchinner: make all workqueues WQ_MEM_RECLAIM]

Signed-off-by: Chris Mason &lt;clm@fb.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>xfs: fix log recovery op header validation assert</title>
<updated>2015-11-09T23:10:33+00:00</updated>
<author>
<name>Brian Foster</name>
<email>bfoster@redhat.com</email>
</author>
<published>2015-11-09T23:10:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=848ccfc8fe0e8ae572ed0d8a9a2c3a0cda3bce3b'/>
<id>848ccfc8fe0e8ae572ed0d8a9a2c3a0cda3bce3b</id>
<content type='text'>
Commit 89cebc84 ("xfs: validate transaction header length on log
recovery") added additional validation of the on-disk op header length
to protect from buffer overflow during log recovery. It accounts for the
fact that the transaction header can be split across multiple op
headers. It added an assert for when this occurs that verifies the
length of the second part of a split transaction header is less than a
full transaction header. In other words, it expects that the first op
header of a split transaction header includes at least some portion of
the transaction header.

This expectation is not always valid as a zero-length op header can
exist for the first op header of a split transaction header (see
xlog_recover_add_to_trans() for details). This means that the second op
header can have a valid, full length transaction header and thus the
full header is copied in xlog_recover_add_to_cont_trans(). Fix the
assert in xlog_recover_add_to_cont_trans() to handle this case correctly
and require that the op header length is less than or equal to a full
transaction header.

Signed-off-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;


</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Commit 89cebc84 ("xfs: validate transaction header length on log
recovery") added additional validation of the on-disk op header length
to protect from buffer overflow during log recovery. It accounts for the
fact that the transaction header can be split across multiple op
headers. It added an assert for when this occurs that verifies the
length of the second part of a split transaction header is less than a
full transaction header. In other words, it expects that the first op
header of a split transaction header includes at least some portion of
the transaction header.

This expectation is not always valid as a zero-length op header can
exist for the first op header of a split transaction header (see
xlog_recover_add_to_trans() for details). This means that the second op
header can have a valid, full length transaction header and thus the
full header is copied in xlog_recover_add_to_cont_trans(). Fix the
assert in xlog_recover_add_to_cont_trans() to handle this case correctly
and require that the op header length is less than or equal to a full
transaction header.

Signed-off-by: Brian Foster &lt;bfoster@redhat.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;


</pre>
</div>
</content>
</entry>
<entry>
<title>xfs: Fix error path in xfs_get_acl</title>
<updated>2015-11-09T23:09:45+00:00</updated>
<author>
<name>Andreas Gruenbacher</name>
<email>agruenba@redhat.com</email>
</author>
<published>2015-11-09T23:09:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=edfb8ebce225a0638cf62591d4ccb502f052ffd4'/>
<id>edfb8ebce225a0638cf62591d4ccb502f052ffd4</id>
<content type='text'>
Error codes from xfs_attr_get other than -ENOATTR were not properly
reported.  Fix that.

In addition, the declaration of struct xfs_inode in xfs_acl.h isn't needed.

Signed-off-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;


</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Error codes from xfs_attr_get other than -ENOATTR were not properly
reported.  Fix that.

In addition, the declaration of struct xfs_inode in xfs_acl.h isn't needed.

Signed-off-by: Andreas Gruenbacher &lt;agruenba@redhat.com&gt;
Reviewed-by: Dave Chinner &lt;dchinner@redhat.com&gt;
Signed-off-by: Dave Chinner &lt;david@fromorbit.com&gt;


</pre>
</div>
</content>
</entry>
<entry>
<title>mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd</title>
<updated>2015-11-07T01:50:42+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2015-11-07T00:28:21+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d0164adc89f6bb374d304ffcc375c6d2652fe67d'/>
<id>d0164adc89f6bb374d304ffcc375c6d2652fe67d</id>
<content type='text'>
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Vitaly Wool &lt;vitalywool@gmail.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Vitaly Wool &lt;vitalywool@gmail.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'xfs-dax-updates' into for-next</title>
<updated>2015-11-03T02:28:41+00:00</updated>
<author>
<name>Dave Chinner</name>
<email>david@fromorbit.com</email>
</author>
<published>2015-11-03T02:28:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=264e89ad3412ce1e2977e5e807bcf7d20d3b0a59'/>
<id>264e89ad3412ce1e2977e5e807bcf7d20d3b0a59</id>
<content type='text'>
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
</pre>
</div>
</content>
</entry>
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