Commit Graph

3779 Commits

Author SHA1 Message Date
Vladimir Davydov 5d097056c9 kmemcg: account certain kmem allocations to memcg
Mark those kmem allocations that are known to be easily triggered from
userspace as __GFP_ACCOUNT/SLAB_ACCOUNT, which makes them accounted to
memcg.  For the list, see below:

 - threadinfo
 - task_struct
 - task_delay_info
 - pid
 - cred
 - mm_struct
 - vm_area_struct and vm_region (nommu)
 - anon_vma and anon_vma_chain
 - signal_struct
 - sighand_struct
 - fs_struct
 - files_struct
 - fdtable and fdtable->full_fds_bits
 - dentry and external_name
 - inode for all filesystems. This is the most tedious part, because
   most filesystems overwrite the alloc_inode method.

The list is far from complete, so feel free to add more objects.
Nevertheless, it should be close to "account everything" approach and
keep most workloads within bounds.  Malevolent users will be able to
breach the limit, but this was possible even with the former "account
everything" approach (simply because it did not account everything in
fact).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-01-14 16:00:49 -08:00
Linus Torvalds 7fdec82af6 xfs: updates for 4.5-rc1
This update contains:
 o extensive CRC validation during log recovery
 o several log recovery bug fixes
 o Various DAX support fixes
 o AGFL size calculation fix
 o various cleanups in preparation for new functionality
 o project quota ENOSPC notification via netlink
 o tracing and debug improvements
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQIcBAABAgAGBQJWlx22AAoJEK3oKUf0dfodtyYP/2vXx/ZFreyLGndUgx6AlKgf
 h2AIoHJJPoAdiNApY3hYUglPbBSH2jqQBkw/jpdrkAJ+iR//BlqF+Mh8WxiUbf5q
 DKkLBHxAMyAe52ur+GA8uxIW5HznZVkIMxnBWF9wKFcQpaXjQlnXROr6wQ/GZvG2
 PNW80dN7khRLdh9/ITFYDINRU/tWy+D9rRrEfmC8PJBxzLkOxqC/hgyrpm/OefoA
 ikVtMY5KEcC8VZXwXpta2W7GowEvMaNEomg3zMvnu0hFvm78cxBL6KB42FaVMtyu
 V3l3bQe6w2LLst07ZQoH5Zpbb6WFdgwaaQdrRBnFP/mdQRMAU7YJwnqfCvqHUpHp
 T2BbQYy8LdWWp5mwNSXXoHWdVng7FwEQV2IrIpUQywEs9wAdbnhBEk41S2fDM11P
 TCS3Nn8MXg2jsIcpc6Zfj0S575rmRDdR83YQGJZtSbCWWqyqGdc5RUZ9qrVoYRLP
 SV72dLb0bUPrDtE1yvPVc/iXfQOcelYfc6KnkDSMs+4r2wjeXTqvOSMkIaiCx+CX
 IeYZr6jnVsgsnLJH4K2GE3OXzAI4WTz5lyqgrk7XyjyN39PC5Czm+/qtdnpbOj+e
 dLUXYyCFu4vx5nzy/CjD3XdnrBccqkLHmxz312qQX3aozvpBa4Y3BqWyd9SB1uVD
 N//PFaCClwsGH2inIBVC
 =eCYp
 -----END PGP SIGNATURE-----

Merge tag 'xfs-for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

Pull xfs updates from Dave Chinner:
 "There's not a lot in this - the main addition is the CRC validation of
  the entire region of the log that the will be recovered, along with
  several log recovery fixes.  Most of the rest is small bug fixes and
  cleanups.

  I have three bug fixes still pending, all that address recently fixed
  regressions that I will send to next week after they've had some time
  in for-next.

  Summary:
   - extensive CRC validation during log recovery
   - several log recovery bug fixes
   - Various DAX support fixes
   - AGFL size calculation fix
   - various cleanups in preparation for new functionality
   - project quota ENOSPC notification via netlink
   - tracing and debug improvements"

* tag 'xfs-for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (26 commits)
  xfs: handle dquot buffer readahead in log recovery correctly
  xfs: inode recovery readahead can race with inode buffer creation
  xfs: eliminate committed arg from xfs_bmap_finish
  xfs: bmapbt checking on debug kernels too expensive
  xfs: add tracepoints to readpage calls
  xfs: debug mode log record crc error injection
  xfs: detect and trim torn writes during log recovery
  xfs: fix recursive splice read locking with DAX
  xfs: Don't use reserved blocks for data blocks with DAX
  XFS: Use a signed return type for suffix_kstrtoint()
  libxfs: refactor short btree block verification
  libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct
  libxfs: use a convenience variable instead of open-coding the fork
  xfs: fix log ticket type printing
  libxfs: make xfs_alloc_fix_freelist non-static
  xfs: make xfs_buf_ioend_async() static
  xfs: send warning of project quota to userspace via netlink
  xfs: get mp from bma->ip in xfs_bmap code
  xfs: print name of verifier if it fails
  libxfs: Optimize the loop for xfs_bitmap_empty
  ...
2016-01-13 21:15:18 -08:00
Linus Torvalds 33caf82acf Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
 "All kinds of stuff.  That probably should've been 5 or 6 separate
  branches, but by the time I'd realized how large and mixed that bag
  had become it had been too close to -final to play with rebasing.

  Some fs/namei.c cleanups there, memdup_user_nul() introduction and
  switching open-coded instances, burying long-dead code, whack-a-mole
  of various kinds, several new helpers for ->llseek(), assorted
  cleanups and fixes from various people, etc.

  One piece probably deserves special mention - Neil's
  lookup_one_len_unlocked().  Similar to lookup_one_len(), but gets
  called without ->i_mutex and tries to avoid ever taking it.  That, of
  course, means that it's not useful for any directory modifications,
  but things like getting inode attributes in nfds readdirplus are fine
  with that.  I really should've asked for moratorium on lookup-related
  changes this cycle, but since I hadn't done that early enough...  I
  *am* asking for that for the coming cycle, though - I'm going to try
  and get conversion of i_mutex to rwsem with ->lookup() done under lock
  taken shared.

  There will be a patch closer to the end of the window, along the lines
  of the one Linus had posted last May - mechanical conversion of
  ->i_mutex accesses to inode_lock()/inode_unlock()/inode_trylock()/
  inode_is_locked()/inode_lock_nested().  To quote Linus back then:

    -----
    |    This is an automated patch using
    |
    |        sed 's/mutex_lock(&\(.*\)->i_mutex)/inode_lock(\1)/'
    |        sed 's/mutex_unlock(&\(.*\)->i_mutex)/inode_unlock(\1)/'
    |        sed 's/mutex_lock_nested(&\(.*\)->i_mutex,[     ]*I_MUTEX_\([A-Z0-9_]*\))/inode_lock_nested(\1, I_MUTEX_\2)/'
    |        sed 's/mutex_is_locked(&\(.*\)->i_mutex)/inode_is_locked(\1)/'
    |        sed 's/mutex_trylock(&\(.*\)->i_mutex)/inode_trylock(\1)/'
    |
    |    with a very few manual fixups
    -----

  I'm going to send that once the ->i_mutex-affecting stuff in -next
  gets mostly merged (or when Linus says he's about to stop taking
  merges)"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
  nfsd: don't hold i_mutex over userspace upcalls
  fs:affs:Replace time_t with time64_t
  fs/9p: use fscache mutex rather than spinlock
  proc: add a reschedule point in proc_readfd_common()
  logfs: constify logfs_block_ops structures
  fcntl: allow to set O_DIRECT flag on pipe
  fs: __generic_file_splice_read retry lookup on AOP_TRUNCATED_PAGE
  fs: xattr: Use kvfree()
  [s390] page_to_phys() always returns a multiple of PAGE_SIZE
  nbd: use ->compat_ioctl()
  fs: use block_device name vsprintf helper
  lib/vsprintf: add %*pg format specifier
  fs: use gendisk->disk_name where possible
  poll: plug an unused argument to do_poll
  amdkfd: don't open-code memdup_user()
  cdrom: don't open-code memdup_user()
  rsxx: don't open-code memdup_user()
  mtip32xx: don't open-code memdup_user()
  [um] mconsole: don't open-code memdup_user_nul()
  [um] hostaudio: don't open-code memdup_user()
  ...
2016-01-12 17:11:47 -08:00
Linus Torvalds ddf1d6238d Merge branch 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs xattr updates from Al Viro:
 "Andreas' xattr cleanup series.

  It's a followup to his xattr work that went in last cycle; -0.5KLoC"

* 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xattr handlers: Simplify list operation
  ocfs2: Replace list xattr handler operations
  nfs: Move call to security_inode_listsecurity into nfs_listxattr
  xfs: Change how listxattr generates synthetic attributes
  tmpfs: listxattr should include POSIX ACL xattrs
  tmpfs: Use xattr handler infrastructure
  btrfs: Use xattr handler infrastructure
  vfs: Distinguish between full xattr names and proper prefixes
  posix acls: Remove duplicate xattr name definitions
  gfs2: Remove gfs2_xattr_acl_chmod
  vfs: Remove vfs_xattr_cmp
2016-01-11 13:32:10 -08:00
Dave Chinner dde7f55bd0 Merge branch 'xfs-misc-fixes-for-4.5-2' into for-next 2016-01-12 07:04:30 +11:00
Dave Chinner 7d6a13f023 xfs: handle dquot buffer readahead in log recovery correctly
When we do dquot readahead in log recovery, we do not use a verifier
as the underlying buffer may not have dquots in it. e.g. the
allocation operation hasn't yet been replayed. Hence we do not want
to fail recovery because we detect an operation to be replayed has
not been run yet. This problem was addressed for inodes in commit
d891400 ("xfs: inode buffers may not be valid during recovery
readahead") but the problem was not recognised to exist for dquots
and their buffers as the dquot readahead did not have a verifier.

The result of not using a verifier is that when the buffer is then
next read to replay a dquot modification, the dquot buffer verifier
will only be attached to the buffer if *readahead is not complete*.
Hence we can read the buffer, replay the dquot changes and then add
it to the delwri submission list without it having a verifier
attached to it. This then generates warnings in xfs_buf_ioapply(),
which catches and warns about this case.

Fix this and make it handle the same readahead verifier error cases
as for inode buffers by adding a new readahead verifier that has a
write operation as well as a read operation that marks the buffer as
not done if any corruption is detected.  Also make sure we don't run
readahead if the dquot buffer has been marked as cancelled by
recovery.

This will result in readahead either succeeding and the buffer
having a valid write verifier, or readahead failing and the buffer
state requiring the subsequent read to resubmit the IO with the new
verifier.  In either case, this will result in the buffer always
ending up with a valid write verifier on it.

Note: we also need to fix the inode buffer readahead error handling
to mark the buffer with EIO. Brian noticed the code I copied from
there wrong during review, so fix it at the same time. Add comments
linking the two functions that handle readahead verifier errors
together so we don't forget this behavioural link in future.

cc: <stable@vger.kernel.org> # 3.12 - current
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-12 07:04:01 +11:00
Dave Chinner b79f4a1c68 xfs: inode recovery readahead can race with inode buffer creation
When we do inode readahead in log recovery, we do can do the
readahead before we've replayed the icreate transaction that stamps
the buffer with inode cores. The inode readahead verifier catches
this and marks the buffer as !done to indicate that it doesn't yet
contain valid inodes.

In adding buffer error notification  (i.e. setting b_error = -EIO at
the same time as as we clear the done flag) to such a readahead
verifier failure, we can then get subsequent inode recovery failing
with this error:

XFS (dm-0): metadata I/O error: block 0xa00060 ("xlog_recover_do..(read#2)") error 5 numblks 32

This occurs when readahead completion races with icreate item replay
such as:

	inode readahead
		find buffer
		lock buffer
		submit RA io
	....
	icreate recovery
	    xfs_trans_get_buffer
		find buffer
		lock buffer
		<blocks on RA completion>
	.....
	<ra completion>
		fails verifier
		clear XBF_DONE
		set bp->b_error = -EIO
		release and unlock buffer
	<icreate gains lock>
	icreate initialises buffer
	marks buffer as done
	adds buffer to delayed write queue
	releases buffer

At this point, we have an initialised inode buffer that is up to
date but has an -EIO state registered against it. When we finally
get to recovering an inode in that buffer:

	inode item recovery
	    xfs_trans_read_buffer
		find buffer
		lock buffer
		sees XBF_DONE is set, returns buffer
	    sees bp->b_error is set
		fail log recovery!

Essentially, we need xfs_trans_get_buf_map() to clear the error status of
the buffer when doing a lookup. This function returns uninitialised
buffers, so the buffer returned can not be in an error state and
none of the code that uses this function expects b_error to be set
on return. Indeed, there is an ASSERT(!bp->b_error); in the
transaction case in xfs_trans_get_buf_map() that would have caught
this if log recovery used transactions....

This patch firstly changes the inode readahead failure to set -EIO
on the buffer, and secondly changes xfs_buf_get_map() to never
return a buffer with an error state set so this first change doesn't
cause unexpected log recovery failures.

cc: <stable@vger.kernel.org> # 3.12 - current
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-12 07:03:44 +11:00
Eric Sandeen f6106efae5 xfs: eliminate committed arg from xfs_bmap_finish
Calls to xfs_bmap_finish() and xfs_trans_ijoin(), and the
associated comments were replicated several times across
the attribute code, all dealing with what to do if the
transaction was or wasn't committed.

And in that replicated code, an ASSERT() test of an
uninitialized variable occurs in several locations:

	error = xfs_attr_thing(&args);
	if (!error) {
		error = xfs_bmap_finish(&args.trans, args.flist,
					&committed);
	}
	if (error) {
		ASSERT(committed);

If the first xfs_attr_thing() failed, we'd skip the xfs_bmap_finish,
never set "committed", and then test it in the ASSERT.

Fix this up by moving the committed state internal to xfs_bmap_finish,
and add a new inode argument.  If an inode is passed in, it is passed
through to __xfs_trans_roll() and joined to the transaction there if
the transaction was committed.

xfs_qm_dqalloc() was a little unique in that it called bjoin rather
than ijoin, but as Dave points out we can detect the committed state
but checking whether (*tpp != tp).

Addresses-Coverity-Id: 102360
Addresses-Coverity-Id: 102361
Addresses-Coverity-Id: 102363
Addresses-Coverity-Id: 102364
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-11 11:34:01 +11:00
Dave Chinner e35438196c xfs: bmapbt checking on debug kernels too expensive
For large sparse or fragmented files, checking every single entry in
the bmapbt on every operation is prohibitively expensive. Especially
as such checks rarely discover problems during normal operations on
high extent coutn files. Our regression tests don't tend to exercise
files with hundreds of thousands to millions of extents, so mostly
this isn't noticed.

However, trying to run things like xfs_mdrestore of large filesystem
dumps on a debug kernel quickly becomes impossible as the CPU is
completely burnt up repeatedly walking the sparse file bmapbt that
is generated for every allocation that is made.

Hence, if the file has more than 10,000 extents, just don't bother
with walking the tree to check it exhaustively. The btree code has
checks that ensure that the newly inserted/removed/modified record
is correctly ordered, so the entrie tree walk in thses cases has
limited additional value.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-08 11:28:49 +11:00
Dave Chinner 121e213eab xfs: add tracepoints to readpage calls
This allows us to see page cache driven readahead in action as it
passes through XFS. This helps to understand buffered read
throughput problems such as readahead IO IO sizes being too small
for the underlying device to reach max throughput.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-08 11:28:35 +11:00
Dmitry Monakhov a1c6f05733 fs: use block_device name vsprintf helper
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-06 13:03:18 -05:00
Dave Chinner 4922be51ef Merge branch 'xfs-dax-fixes-for-4.5' into for-next 2016-01-05 08:08:47 +11:00
Dave Chinner 7eeabbd4b6 Merge branch 'xfs-misc-fixes-for-4.5' into for-next 2016-01-05 08:08:35 +11:00
Brian Foster 609adfc2ed xfs: debug mode log record crc error injection
XFS now uses CRC verification over a limited section of the log to
detect torn writes prior to a crash. This is difficult to test directly
due to the timing and hardware requirements to cause a short write.

Add a mechanism to inject CRC errors into log records to facilitate
testing torn write detection during log recovery. This mechanism is
dangerous and can result in filesystem corruption. Thus, it is only
available in DEBUG mode for testing/development purposes. Set a non-zero
value to the following sysfs entry to enable error injection:

	/sys/fs/xfs/<dev>/log/log_badcrc_factor

Once enabled, XFS intentionally writes an invalid CRC to a log record at
some random point in the future based on the provided frequency. The
filesystem immediately shuts down once the record has been written to
the physical log to prevent metadata writeback (e.g., AIL insertion)
once the log write completes. This helps reasonably simulate a torn
write to the log as the affected record must be safe to discard. The
next mount after the intentional shutdown requires log recovery and
should detect and recover from the torn write.

Note again that this _will_ result in data loss or worse. For testing
and development purposes only!

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-05 07:41:16 +11:00
Brian Foster 7088c4136f xfs: detect and trim torn writes during log recovery
Certain types of storage, such as persistent memory, do not provide
sector atomicity for writes. This means that if a crash occurs while XFS
is writing log records, only part of those records might make it to the
storage. This is problematic because log recovery uses the cycle value
packed at the top of each log block to locate the head/tail of the log.
This can lead to CRC verification failures during log recovery and an
unmountable fs for a filesystem that is otherwise consistent.

Update log recovery to incorporate log record CRC verification as part
of the head/tail discovery process. Once the head is located via the
traditional algorithm, run a CRC-only pass over the records up to the
head of the log. If CRC verification fails, assume that the records are
torn as a matter of policy and trim the head block back to the start of
the first bad record.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-05 07:40:16 +11:00
Dave Chinner a6d7636e8d xfs: fix recursive splice read locking with DAX
Doing a splice read (generic/249) generates a lockdep splat because
we recursively lock the inode iolock in this path:

SyS_sendfile64
do_sendfile
do_splice_direct
splice_direct_to_actor
do_splice_to
xfs_file_splice_read			<<<<<< lock here
default_file_splice_read
vfs_readv
do_readv_writev
do_iter_readv_writev
xfs_file_read_iter			<<<<<< then here

The issue here is that for DAX inodes we need to avoid the page
cache path and hence simply push it into the normal read path.
Unfortunately, we can't tell down at xfs_file_read_iter() whether we
are being called from the splice path and hence we cannot avoid the
locking at this layer. Hence we simply have to drop the inode
locking at the higher splice layer for DAX.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:28:25 +11:00
Dave Chinner 3b0fe47805 xfs: Don't use reserved blocks for data blocks with DAX
Commit 1ca1915 ("xfs: Don't use unwritten extents for DAX") enabled
the DAX allocation call to dip into the reserve pool in case it was
converting unwritten extents rather than allocating blocks. This was
a direct copy of the unwritten extent conversion code, but had an
unintended side effect of allowing normal data block allocation to
use the reserve pool. Hence normal block allocation could deplete
the reserve pool and prevent unwritten extent conversion at ENOSPC,
hence violating fallocate guarantees on preallocated space.

Fix it by checking whether the incoming map from __xfs_get_blocks()
spans an unwritten extent and only use the reserve pool if the
allocation covers an unwritten extent.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Tested-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:22:45 +11:00
Markus Elfring a841b64df2 XFS: Use a signed return type for suffix_kstrtoint()
The return type "unsigned long" was used by the suffix_kstrtoint()
function even though it will eventually return a negative error code.
Improve this implementation detail by using the type "int" instead.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:13:21 +11:00
Darrick J. Wong c5ab131ba0 libxfs: refactor short btree block verification
Create xfs_btree_sblock_verify() to verify short-format btree blocks
(i.e. the per-AG btrees with 32-bit block pointers) instead of
open-coding them.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:13:21 +11:00
Darrick J. Wong 96f859d52b libxfs: pack the agfl header structure so XFS_AGFL_SIZE is correct
Because struct xfs_agfl is 36 bytes long and has a 64-bit integer
inside it, gcc will quietly round the structure size up to the nearest
64 bits -- in this case, 40 bytes.  This results in the XFS_AGFL_SIZE
macro returning incorrect results for v5 filesystems on 64-bit
machines (118 items instead of 119).  As a result, a 32-bit xfs_repair
will see garbage in AGFL item 119 and complain.

Therefore, tell gcc not to pad the structure so that the AGFL size
calculation is correct.

cc: <stable@vger.kernel.org> # 3.10 - 4.4
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:13:21 +11:00
Darrick J. Wong 6d3eb1eca0 libxfs: use a convenience variable instead of open-coding the fork
Use a convenience variable instead of open-coding the inode fork.
This isn't really needed for now, but will become important when we
add the copy-on-write fork later.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:12:42 +11:00
Darrick J. Wong 9b434a347c xfs: fix log ticket type printing
Update the log ticket reservation type printing code to reflect
all the types of log tickets, to avoid incorrect debug output and
avoid running off the end of the array.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:11:42 +11:00
Darrick J. Wong 2e9101da60 libxfs: make xfs_alloc_fix_freelist non-static
Since xfs_repair wants to use xfs_alloc_fix_freelist, remove the
static designation.  xfsprogs already has this; this simply brings
the kernel up to date.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:42 +11:00
Alexander Kuleshov 211fe1a4db xfs: make xfs_buf_ioend_async() static
There are no callers of the xfs_buf_ioend_async() function outside
of the fs/xfs/xfs_buf.c. So, let's make it static.

Signed-off-by: Alexander Kuleshov <kuleshovmail@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:42 +11:00
Masatake YAMATO ffc671f1ea xfs: send warning of project quota to userspace via netlink
Linux's quota subsystem has an ability to handle project quota. This
commit just utilizes the ability from xfs side.  dbus-monitor and
quota_nld shipped as part of quota-tools can be used for testing.
See the patch posting on the XFS list for details on testing.

Signed-off-by: Masatake YAMATO <yamato@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:42 +11:00
Eric Sandeen f1f96c4946 xfs: get mp from bma->ip in xfs_bmap code
In my earlier commit

  c29aad4 xfs: pass mp to XFS_WANT_CORRUPTED_GOTO

I added some local mp variables with code which indicates that
mp might be NULL.  Coverity doesn't like this now, because the
updated per-fs XFS_STATS macros dereference mp.

I don't think this is actually a problem; from what I can tell,
we cannot get to these functions with a null bma->tp, so my NULL
check was probably pointless.  Still, it's not super obvious.

So switch this code to get mp from the inode on the xfs_bmalloca
structure, with no conditional, because the functions are already
using bmap->ip directly.

Addresses-Coverity-Id: 1339552
Addresses-Coverity-Id: 1339553
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:42 +11:00
Eric Sandeen 233135b763 xfs: print name of verifier if it fails
This adds a name to each buf_ops structure, so that if
a verifier fails we can print the type of verifier that
failed it.  Should be a slight debugging aid, I hope.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:19 +11:00
Jia He 1d4292bfdc libxfs: Optimize the loop for xfs_bitmap_empty
If there is any non zero bit in a long bitmap, it can jump out of the
loop and finish the function as soon as possible.

Signed-off-by: Jia He <hejianet@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 16:10:19 +11:00
Brian Foster eed6b462fb xfs: refactor log record start detection into a new helper
As part of the head/tail discovery process, log recovery locates the
head block and then reverse seeks to find the start of the last active
record in the log. This is non-trivial as the record itself could have
wrapped around the end of the physical log. Log recovery torn write
detection potentially needs to walk further behind the last record in
the log, as multiple log I/Os can be in-flight at one time during a
crash event.

Therefore, refactor the reverse log record header search mechanism into
a new helper that supports the ability to seek past an arbitrary number
of log records (or until the tail is hit). Update the head/tail search
mechanism to call the new helper, but otherwise there is no change in
log recovery behavior.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Brian Foster 6528250b71 xfs: support a crc verification only log record pass
Log recovery torn write detection uses CRC verification over a range of
the active log to identify torn writes. Since the generic log recovery
pass code implements a superset of the functionality required for CRC
verification, it can be easily modified to support a CRC verification
only pass.

Create a new CRC pass type and update the log record processing helper
to skip everything beyond CRC verification when in this mode. This pass
will be invoked in subsequent patches to implement torn write detection.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Brian Foster d7f37692e3 xfs: return start block of first bad log record during recovery
Each log recovery pass walks from the tail block to the head block and
processes records appropriately based on the associated log pass type.
There are various failure conditions that can occur through this
sequence, such as I/O errors, CRC errors, etc. Log torn write detection
will perform CRC verification near the head of the log to detect torn
writes and trim torn records from the log appropriately.

As it is, xlog_do_recovery_pass() only returns an error code in the
event of CRC failure, which isn't enough information to trim the head of
the log. Update xlog_do_recovery_pass() to optionally return the start
block of the associated record when an error occurs. This patch contains
no functional changes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Brian Foster b94fb2d178 xfs: refactor and open code log record crc check
Log record CRC verification currently occurs during active log recovery,
immediately before a log record is unpacked. Therefore, the CRC
calculation code is buried within the data unpack function. CRC
verification pass support only needs to go so far as check the CRC, but
this is not easily allowed as the code is currently organized.

Since we now have a new log record processing helper, pull the record
CRC verification code out from the unpack helper and open-code it at the
top of the new process helper. This facilitates the ability to modify
how records are processed based on the type of the current pass. This
patch contains no functional changes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Brian Foster 9d94901f6e xfs: refactor log record unpack and data processing
xlog_do_recovery_pass() duplicates a couple function calls related to
processing log records because the function must handle wrapping around
the end of the log if the head is behind the tail. This is implemented
as separate loops. CRC verification pass support will modify how records
are processed in both of these loops.

Rather than continue to duplicate code, factor the calls that process a
log record into a new helper and call that helper from both loops. This
patch contains no functional changes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Brian Foster a70f9fe52d xfs: detect and handle invalid iclog size set by mkfs
XFS log records have separate fields for the record size and the iclog
size used to write the record. mkfs.xfs zeroes the log and writes an
unmount record to generate a clean log for the subsequent mount. The
userspace record logging code has a bug where the iclog size (h_size)
field of the log record is hardcoded to 32k, even if a log stripe unit
is specified. The log record length is correctly extended to the stripe
unit. Since the kernel log recovery code uses the h_size field to
determine the log buffer size, this means that the kernel can attempt to
read/process records larger than the buffer size and overrun the buffer.

This has historically not been a problem because the kernel doesn't
actually run through log recovery in the clean unmount case. Instead,
the kernel detects that a single unmount record exists between the head
and tail and pushes the tail forward such that the log is viewed as
clean (head == tail). Once CRC verification is enabled, however, all
records at the head of the log are verified for CRC errors and thus we
are susceptible to overrun problems if the iclog field is not correct.

While the core problem must be fixed in userspace, this is historical
behavior that must be detected in the kernel to avoid severe side
effects such as memory corruption and crashes. Update the log buffer
size calculation code to detect this condition, warn the user and resize
the log buffer based on the log stripe unit. Return a corruption error
in cases where this does not look like a clean filesystem (i.e., the log
record header indicates more than one operation).

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2016-01-04 15:55:10 +11:00
Al Viro fceef393a5 switch ->get_link() to delayed_call, kill ->put_link()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-30 13:01:03 -05:00
Al Viro 6b2553918d replace ->follow_link() with new method that could stay in RCU mode
new method: ->get_link(); replacement of ->follow_link().  The differences
are:
	* inode and dentry are passed separately
	* might be called both in RCU and non-RCU mode;
the former is indicated by passing it a NULL dentry.
	* when called that way it isn't allowed to block
and should return ERR_PTR(-ECHILD) if it needs to be called
in non-RCU mode.

It's a flagday change - the old method is gone, all in-tree instances
converted.  Conversion isn't hard; said that, so far very few instances
do not immediately bail out when called in RCU mode.  That'll change
in the next commits.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-08 22:41:54 -05:00
Andreas Gruenbacher 5d92b75c75 xfs: Change how listxattr generates synthetic attributes
Instead of adding the synthesized POSIX ACL attribute names after listing all
non-synthesized attributes, generate them immediately when listing the
non-synthesized attributes.

In addition, merge xfs_xattr_put_listent and xfs_xattr_put_listent_sizes to
ensure that the list size is computed correctly; the split version was
overestimating the list size for non-root users.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-06 21:34:16 -05:00
Andreas Gruenbacher 98e9cb5711 vfs: Distinguish between full xattr names and proper prefixes
Add an additional "name" field to struct xattr_handler.  When the name
is set, the handler matches attributes with exactly that name.  When the
prefix is set instead, the handler matches attributes with the given
prefix and with a non-empty suffix.

This patch should avoid bugs like the one fixed in commit c361016a in
the future.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-06 21:33:52 -05:00
Andreas Gruenbacher 97d7929922 posix acls: Remove duplicate xattr name definitions
Remove POSIX_ACL_XATTR_{ACCESS,DEFAULT} and GFS2_POSIX_ACL_{ACCESS,DEFAULT}
and replace them with the definitions in <include/uapi/linux/xattr.h>.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-12-06 21:25:17 -05:00
Linus Torvalds 5d2eb548b3 Merge branch 'for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
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
2015-11-13 18:02:30 -08:00
Andreas Gruenbacher d9a82a0403 xattr handlers: Pass handler to operations instead of flags
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 <agruenba@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-13 20:34:32 -05:00
Linus Torvalds 5d50ac70fe xfs: updates for 4.4-rc1
This update contains:
 o per-mount operational statistics in sysfs
 o fixes for concurrent aio append write submission
 o various logging fixes
 o detection of zeroed logs and invalid log sequence numbers on v5 filesystems
 o memory allocation failure message improvements
 o a bunch of xattr/ACL fixes
 o fdatasync optimisation
 o miscellaneous other fixes and cleanups
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1.4.12 (GNU/Linux)
 
 iQIcBAABAgAGBQJWQ7GzAAoJEK3oKUf0dfodJakP/3s3N5ngqRWa+PQwBQPdTO0r
 MBQppSKXWdT7YLhiFt1ZRlvXiMQOIZPNx0yBS9mzQghL9sTGvcPdxjbQnNh6LUnE
 fGC2Yzi/J8lM2M80ezk3JoFqdqAQ/U78ARA/VpZct4imrps/h+s2Klkx87xPJsiK
 /wY56FXFtoUS1ADYhL8qCeiAGOFpyIttiDNOVW3O2ZXn4iJUsa2nLCoiFwF/yFvU
 S85iUJWAsvVSW5WgfUufmodC4u+WOT+9isNRxEmBjpxYYAFrFb5+8DYY3Coh6z0V
 HqYPhpzBOG9gXbAue5v+ccsp2w60atXIFUQkR2HFBblvxsDMkvsgycJWJgDNmJiw
 RYDMBJ26epxUdTScUxijKiGfnnbZW5b+uzp6FvVsE4KPdP62ol7YNqxj8/FFIjQN
 JBl2ooiczOgvhCdvdWmWNEGWHccBcJ8UJ2RzJ0owVIIJZZYwjkZNzeSieWzYc7tr
 b9wBC4wnaYAK/V7aEGLJxMXVjkanrqAnaXf5ymICSFv8me/qAfZ2sLcY2P6SHuhO
 Fmkj6R5Thh1SYxk3thgGFZg7LGuxJW9cmypvFGpKhIvEaNGIM6ScdIwO7kCHYWv7
 3EkP42mmJLIYxKz/q2nHqt7R246YFraIRowLWptJUl32uyzO7SrdKbc8+o5WD4Wl
 2byjE9TjXOa1jGuPa3kN
 =zu+5
 -----END PGP SIGNATURE-----

Merge tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs

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 ->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 & error handling
  xfs: per-filesystem stats counter implementation
  ...
2015-11-11 20:18:48 -08:00
Ross Zwisler 5c50002963 vfs: remove unused wrapper block_page_mkwrite()
The function currently called "__block_page_mkwrite()" used to be called
"block_page_mkwrite()" until a wrapper for this function was added by:

commit 24da4fab5a ("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 <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-11 02:19:33 -05:00
Dave Chinner 4e14e49a91 Merge branch 'xfs-misc-fixes-for-4.4-3' into for-next 2015-11-10 10:20:48 +11:00
Chris Mason 7a29ac474a xfs: give all workqueues rescuer threads
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 <clm@fb.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-11-10 10:10:34 +11:00
Brian Foster 848ccfc8fe xfs: fix log recovery op header validation assert
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 <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-11-10 10:10:33 +11:00
Andreas Gruenbacher edfb8ebce2 xfs: Fix error path in xfs_get_acl
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 <agruenba@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2015-11-10 10:09:45 +11:00
Mel Gorman d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__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 <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Dave Chinner 264e89ad34 Merge branch 'xfs-dax-updates' into for-next 2015-11-03 13:28:41 +11:00
Dave Chinner 2da5c4b05a Merge branch 'xfs-misc-fixes-for-4.4-2' into for-next 2015-11-03 13:27:58 +11:00