Commit Graph

318 Commits

Author SHA1 Message Date
Linus Torvalds 9bfccec24e Lots of bugs fixes, including Zheng and Jan's extent status shrinker
fixes, which should improve CPU utilization and potential soft lockups
 under heavy memory pressure, and Eric Whitney's bigalloc fixes.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 updates from Ted Ts'o:
 "Lots of bugs fixes, including Zheng and Jan's extent status shrinker
  fixes, which should improve CPU utilization and potential soft lockups
  under heavy memory pressure, and Eric Whitney's bigalloc fixes"

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (26 commits)
  ext4: ext4_da_convert_inline_data_to_extent drop locked page after error
  ext4: fix suboptimal seek_{data,hole} extents traversial
  ext4: ext4_inline_data_fiemap should respect callers argument
  ext4: prevent fsreentrance deadlock for inline_data
  ext4: forbid journal_async_commit in data=ordered mode
  jbd2: remove unnecessary NULL check before iput()
  ext4: Remove an unnecessary check for NULL before iput()
  ext4: remove unneeded code in ext4_unlink
  ext4: don't count external journal blocks as overhead
  ext4: remove never taken branch from ext4_ext_shift_path_extents()
  ext4: create nojournal_checksum mount option
  ext4: update comments regarding ext4_delete_inode()
  ext4: cleanup GFP flags inside resize path
  ext4: introduce aging to extent status tree
  ext4: cleanup flag definitions for extent status tree
  ext4: limit number of scanned extents in status tree shrinker
  ext4: move handling of list of shrinkable inodes into extent status code
  ext4: change LRU to round-robin in extent status tree shrinker
  ext4: cache extent hole in extent status tree for ext4_da_map_blocks()
  ext4: fix block reservation for bigalloc filesystems
  ...
2014-12-12 09:28:03 -08:00
Darrick J. Wong 32f3869184 jbd2: fix regression where we fail to initialize checksum seed when loading
When we're enabling journal features, we cannot use the predicate
jbd2_journal_has_csum_v2or3() because we haven't yet set the sb
feature flag fields!  Moreover, we just finished loading the shash
driver, so the test is unnecessary; calculate the seed always.

Without this patch, we fail to initialize the checksum seed the first
time we turn on journal_checksum, which means that all journal blocks
written during that first mount are corrupt.  Transactions written
after the second mount will be fine, since the feature flag will be
set in the journal superblock.  xfstests generic/{034,321,322} are the
regression tests.

(This is important for 3.18.)

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.coM>
Reported-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-12-01 21:57:06 -05:00
Theodore Ts'o d9f39d1e44 jbd2: remove unnecessary NULL check before iput()
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-11-25 20:02:37 -05:00
Theodore Ts'o d48458d4a7 jbd2: use a better hash function for the revoke table
The old hash function didn't work well for 64-bit block numbers, and
used undefined (negative) shift right behavior.  Use the generic
64-bit hash function instead.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com>
2014-10-30 10:53:17 -04:00
Jan Kara 50849db32a jbd2: simplify calling convention around __jbd2_journal_clean_checkpoint_list
__jbd2_journal_clean_checkpoint_list() returns number of buffers it
freed but noone was using the value so just stop doing that. This
also allows for simplifying the calling convention for
journal_clean_once_cp_list().

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-18 00:58:12 -04:00
Jan Kara cc97f1a7c7 jbd2: avoid pointless scanning of checkpoint lists
Yuanhan has reported that when he is running fsync(2) heavy workload
creating new files over ramdisk, significant amount of time is spent in
__jbd2_journal_clean_checkpoint_list() trying to clean old transactions
(but they cannot be cleaned up because flusher hasn't yet checkpointed
those buffers). The workload can be generated by:
  fs_mark -d /fs/ram0/1 -D 2 -N 2560 -n 1000000 -L 1 -S 1 -s 4096

Reduce the amount of scanning by stopping to scan the transaction list
once we find a transaction that cannot be checkpointed. Note that this
way of cleaning is still enough to keep freeing space in the journal
after fully checkpointed transactions.

Reported-and-tested-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-18 00:42:16 -04:00
Dmitry Monakhov 1245799f75 jbd2: jbd2_log_wait_for_space improve error detetcion
If EIO happens after we have dropped j_state_lock, we won't notice
that the journal has been aborted.  So it is reasonable to move this
check after we have grabbed the j_checkpoint_mutex and re-grabbed the
j_state_lock.  This patch helps to prevent false positive complain
after EIO.

#DMESG:
__jbd2_log_wait_for_space: needed 8448 blocks and only had 8386 space available
__jbd2_log_wait_for_space: no way to get more journal space in ram1-8
------------[ cut here ]------------
WARNING: CPU: 15 PID: 6739 at fs/jbd2/checkpoint.c:168 __jbd2_log_wait_for_space+0x188/0x200()
Modules linked in: brd iTCO_wdt lpc_ich mfd_core igb ptp dm_mirror dm_region_hash dm_log dm_mod
CPU: 15 PID: 6739 Comm: fsstress Tainted: G        W      3.17.0-rc2-00429-g684de57 #139
Hardware name: Intel Corporation W2600CR/W2600CR, BIOS SE5C600.86B.99.99.x028.061320111235 06/13/2011
 00000000000000a8 ffff88077aaab878 ffffffff815c1a8c 00000000000000a8
 0000000000000000 ffff88077aaab8b8 ffffffff8106ce8c ffff88077aaab898
 ffff8807c57e6000 ffff8807c57e6028 0000000000002100 ffff8807c57e62f0
Call Trace:
 [<ffffffff815c1a8c>] dump_stack+0x51/0x6d
 [<ffffffff8106ce8c>] warn_slowpath_common+0x8c/0xc0
 [<ffffffff8106ceda>] warn_slowpath_null+0x1a/0x20
 [<ffffffff812419f8>] __jbd2_log_wait_for_space+0x188/0x200
 [<ffffffff8123be9a>] start_this_handle+0x4da/0x7b0
 [<ffffffff810990e5>] ? local_clock+0x25/0x30
 [<ffffffff810aba87>] ? lockdep_init_map+0xe7/0x180
 [<ffffffff8123c5bc>] jbd2__journal_start+0xdc/0x1d0
 [<ffffffff811f2414>] ? __ext4_new_inode+0x7f4/0x1330
 [<ffffffff81222a38>] __ext4_journal_start_sb+0xf8/0x110
 [<ffffffff811f2414>] __ext4_new_inode+0x7f4/0x1330
 [<ffffffff810ac359>] ? lock_release_holdtime+0x29/0x190
 [<ffffffff812025bb>] ext4_create+0x8b/0x150
 [<ffffffff8117fe3b>] vfs_create+0x7b/0xb0
 [<ffffffff8118097b>] do_last+0x7db/0xcf0
 [<ffffffff8117e31d>] ? inode_permission+0x4d/0x50
 [<ffffffff811845d2>] path_openat+0x242/0x590
 [<ffffffff81191a76>] ? __alloc_fd+0x36/0x140
 [<ffffffff81184a6a>] do_filp_open+0x4a/0xb0
 [<ffffffff81191b61>] ? __alloc_fd+0x121/0x140
 [<ffffffff81172f20>] do_sys_open+0x170/0x220
 [<ffffffff8117300e>] SyS_open+0x1e/0x20
 [<ffffffff811715d6>] SyS_creat+0x16/0x20
 [<ffffffff815c7e12>] system_call_fastpath+0x16/0x1b
---[ end trace cd71c831f82059db ]---

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-16 14:50:50 -04:00
Darrick J. Wong 064d83892e jbd2: free bh when descriptor block checksum fails
Free the buffer head if the journal descriptor block fails checksum
verification.

This is the jbd2 port of the e2fsprogs patch "e2fsck: free bh on csum
verify error in do_one_pass".

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Cc: stable@vger.kernel.org
2014-09-16 14:43:09 -04:00
Darrick J. Wong feb8c6d3dd jbd2: fix journal checksum feature flag handling
Clear all three journal checksum feature flags before turning on
whichever journal checksum options we want.  Rearrange the error
checking so that newer flags get complained about first.

Reported-by: TR Reardon <thomas_reardon@hotmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-11 11:38:21 -04:00
Gioh Kim a49058fab2 jbd/jbd2: use non-movable memory for the jbd superblock
Sicne the jbd/jbd2 superblock is not released until the file system is
unmounted, allocate the buffer cache from the non-moveable area to
allow page migration and CMA allocations to more easily succeed.

Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2014-09-04 22:36:35 -04:00
Jan Kara 0e5ecf0a76 jbd2: optimize jbd2_log_do_checkpoint() a bit
When we discover written out buffer in transaction checkpoint list we
don't have to recheck validity of a transaction. Either this is the
last buffer in a transaction - and then we are done - or this isn't
and then we can just take another buffer from the checkpoint list
without dropping j_list_lock.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-04 18:09:29 -04:00
Theodore Ts'o dc6e8d669c jbd2: don't call get_bh() before calling __jbd2_journal_remove_checkpoint()
The __jbd2_journal_remove_checkpoint() doesn't require an elevated
b_count; indeed, until the jh structure gets released by the call to
jbd2_journal_put_journal_head(), the bh's b_count is elevated by
virtue of the existence of the jh structure.

Suggested-by: Jan Kara <jack@suse.cz>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-04 18:09:22 -04:00
Theodore Ts'o 88fe1acb5b jbd2: fold __wait_cp_io into jbd2_log_do_checkpoint()
__wait_cp_io() is only called by jbd2_log_do_checkpoint().  Fold it in
to make it a bit easier to understand.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2014-09-01 21:26:09 -04:00
Theodore Ts'o be1158cc61 jbd2: fold __process_buffer() into jbd2_log_do_checkpoint()
__process_buffer() is only called by jbd2_log_do_checkpoint(), and it
had a very complex locking protocol where it would be called with the
j_list_lock, and sometimes exit with the lock held (if the return code
was 0), or release the lock.

This was confusing both to humans and to smatch (which erronously
complained that the lock was taken twice).

Folding __process_buffer() to the caller allows us to simplify the
control flow, making the resulting function easier to read and reason
about, and dropping the compiled size of fs/jbd2/checkpoint.c by 150
bytes (over 4% of the text size).

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
2014-09-01 21:19:01 -04:00
Darrick J. Wong db9ee22036 jbd2: fix descriptor block size handling errors with journal_csum
It turns out that there are some serious problems with the on-disk
format of journal checksum v2.  The foremost is that the function to
calculate descriptor tag size returns sizes that are too big.  This
causes alignment issues on some architectures and is compounded by the
fact that some parts of jbd2 use the structure size (incorrectly) to
determine the presence of a 64bit journal instead of checking the
feature flags.

Therefore, introduce journal checksum v3, which enlarges the
descriptor block tag format to allow for full 32-bit checksums of
journal blocks, fix the journal tag function to return the correct
sizes, and fix the jbd2 recovery code to use feature flags to
determine 64bitness.

Add a few function helpers so we don't have to open-code quite so
many pieces.

Switching to a 16-byte block size was found to increase journal size
overhead by a maximum of 0.1%, to convert a 32-bit journal with no
checksumming to a 32-bit journal with checksum v3 enabled.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: TR Reardon <thomas_reardon@hotmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2014-08-28 22:22:29 -04:00
Darrick J. Wong 022eaa7517 jbd2: fix infinite loop when recovering corrupt journal blocks
When recovering the journal, don't fall into an infinite loop if we
encounter a corrupt journal block.  Instead, just skip the block and
return an error, which fails the mount and thus forces the user to run
a full filesystem fsck.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2014-08-28 22:22:28 -04:00
NeilBrown 743162013d sched: Remove proliferation of wait_on_bit() action functions
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16 15:10:39 +02:00
Eric Sandeen 5dd214248f ext4: disable synchronous transaction batching if max_batch_time==0
The mount manpage says of the max_batch_time option,

	This optimization can be turned off entirely
	by setting max_batch_time to 0.

But the code doesn't do that.  So fix the code to do
that.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
2014-07-05 19:18:22 -04:00
Peter Zijlstra 4e857c58ef arch: Mass conversion of smp_mb__*()
Mostly scripted conversion of the smp_mb__* barriers.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-04-18 14:20:48 +02:00
Theodore Ts'o 66a4cb187b jbd2: improve error messages for inconsistent journal heads
Fix up error messages printed when the transaction pointers in a
journal head are inconsistent.  This improves the error messages which
are printed when running xfstests generic/068 in data=journal mode.
See the bug report at: https://bugzilla.kernel.org/show_bug.cgi?id=60786

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-12 16:38:03 -04:00
Theodore Ts'o 0bfea8118d jbd2: minimize region locked by j_list_lock in jbd2_journal_forget()
It's not needed until we start trying to modifying fields in the
journal_head which are protected by j_list_lock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-09 00:56:58 -05:00
Theodore Ts'o 6e4862a5bb jbd2: minimize region locked by j_list_lock in journal_get_create_access()
It's not needed until we start trying to modifying fields in the
journal_head which are protected by j_list_lock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-09 00:46:23 -05:00
Theodore Ts'o d2eb0b9989 jbd2: check jh->b_transaction without taking j_list_lock
jh->b_transaction is adequately protected for reading by the
jbd_lock_bh_state(bh), so we don't need to take j_list_lock in
__journal_try_to_free_buffer().

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-09 00:07:19 -05:00
Theodore Ts'o d4e839d4a9 jbd2: add transaction to checkpoint list earlier
We don't otherwise need j_list_lock during the rest of commit phase
#7, so add the transaction to the checkpoint list at the very end of
commit phase #6.  This allows us to drop j_list_lock earlier, which is
a good thing since it is a super hot lock.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-08 22:34:10 -05:00
Theodore Ts'o 42cf3452d5 jbd2: calculate statistics without holding j_state_lock and j_list_lock
The two hottest locks, and thus the biggest scalability bottlenecks,
in the jbd2 layer, are the j_list_lock and j_state_lock.  This has
inspired some people to do some truly unnatural things[1].

[1] https://www.usenix.org/system/files/conference/fast14/fast14-paper_kang.pdf

We don't need to be holding both j_state_lock and j_list_lock while
calculating the journal statistics, so move those calculations to the
very end of jbd2_journal_commit_transaction.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-08 19:51:16 -05:00
Theodore Ts'o 3469a32a1e jbd2: don't hold j_state_lock while calling wake_up()
The j_state_lock is one of the hottest locks in the jbd2 layer and
thus one of its scalability bottlenecks.

We don't need to be holding the j_state_lock while we are calling
wake_up(&journal->j_wait_commit), so release the lock a little bit
earlier.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-08 19:11:36 -05:00
Theodore Ts'o df3c1e9a05 jbd2: don't unplug after writing revoke records
During commit process, keep the block device plugged after we are done
writing the revoke records, until we are finished writing the rest of
the commit records in the journal.  This will allow most of the
journal blocks to be written in a single I/O operation, instead of
separating the the revoke blocks from the rest of the journal blocks.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2014-03-08 18:13:52 -05:00
Rashika Kheria 7747e6d028 jbd2: mark file-local functions as static
Mark functions as static in jbd2/journal.c because they are not used
outside this file.

This eliminates the following warning in jbd2/journal.c:
fs/jbd2/journal.c:125:5: warning: no previous prototype for ‘jbd2_verify_csum_type’ [-Wmissing-prototypes]
fs/jbd2/journal.c:146:5: warning: no previous prototype for ‘jbd2_superblock_csum_verify’ [-Wmissing-prototypes]
fs/jbd2/journal.c:154:6: warning: no previous prototype for ‘jbd2_superblock_csum_set’ [-Wmissing-prototypes]

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
2014-02-17 20:49:04 -05:00
Dan Carpenter 92e3b40537 jbd2: fix use after free in jbd2_journal_start_reserved()
If start_this_handle() fails then it leads to a use after free of
"handle".

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2014-02-17 20:33:01 -05:00
Dmitry Monakhov a67c848a8b jbd2: rename obsoleted msg JBD->JBD2
Rename performed via: perl -pi -e 's/JBD:/JBD2:/g' fs/jbd2/*.c

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
2013-12-08 21:14:59 -05:00
Jan Kara 75685071cd jbd2: revise KERN_EMERG error messages
Some of KERN_EMERG printk messages do not really deserve this log
level and the one in log_wait_commit() is even rather useless (the
journal has been previously aborted and *that* is where we should have
been complaining). So make some messages just KERN_ERR and remove the
useless message.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-12-08 21:13:59 -05:00
Theodore Ts'o f6c07cad08 jbd2: don't BUG but return ENOSPC if a handle runs out of space
If a handle runs out of space, we currently stop the kernel with a BUG
in jbd2_journal_dirty_metadata().  This makes it hard to figure out
what might be going on.  So return an error of ENOSPC, so we can let
the file system layer figure out what is going on, to make it more
likely we can get useful debugging information).  This should make it
easier to debug problems such as the one which was reported by:

    https://bugzilla.kernel.org/show_bug.cgi?id=44731

The only two callers of this function are ext4_handle_dirty_metadata()
and ocfs2_journal_dirty().  The ocfs2 function will trigger a
BUG_ON(), which means there will be no change in behavior.  The ext4
function will call ext4_error_inode() which will print the useful
debugging information and then handle the situation using ext4's error
handling mechanisms (i.e., which might mean halting the kernel or
remounting the file system read-only).

Also, since both file systems already call WARN_ON(), drop the WARN_ON
from jbd2_journal_dirty_metadata() to avoid two stack traces from
being displayed.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: ocfs2-devel@oss.oracle.com
Acked-by: Joel Becker <jlbec@evilplan.org>
2013-12-08 21:12:59 -05:00
Darrick J. Wong 18a6ea1e5c jbd2: Fix endian mixing problems in the checksumming code
In the jbd2 checksumming code, explicitly declare separate variables with
endianness information so that we don't get confused and screw things up again.
Also fixes sparse warnings.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 14:59:58 -04:00
Theodore Ts'o 41a5b91319 jbd2: invalidate handle if jbd2_journal_restart() fails
If jbd2_journal_restart() fails the handle will have been disconnected
from the current transaction.  In this situation, the handle must not
be used for for any jbd2 function other than jbd2_journal_stop().
Enforce this with by treating a handle which has a NULL transaction
pointer as an aborted handle, and issue a kernel warning if
jbd2_journal_extent(), jbd2_journal_get_write_access(),
jbd2_journal_dirty_metadata(), etc. is called with an invalid handle.

This commit also fixes a bug where jbd2_journal_stop() would trip over
a kernel jbd2 assertion check when trying to free an invalid handle.

Also move the responsibility of setting current->journal_info to
start_this_handle(), simplifying the three users of this function.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Younger Liu <younger.liu@huawei.com>
Cc: Jan Kara <jack@suse.cz>
2013-07-01 08:12:41 -04:00
Theodore Ts'o 39c04153fd jbd2: fix theoretical race in jbd2__journal_restart
Once we decrement transaction->t_updates, if this is the last handle
holding the transaction from closing, and once we release the
t_handle_lock spinlock, it's possible for the transaction to commit
and be released.  In practice with normal kernels, this probably won't
happen, since the commit happens in a separate kernel thread and it's
unlikely this could all happen within the space of a few CPU cycles.

On the other hand, with a real-time kernel, this could potentially
happen, so save the tid found in transaction->t_tid before we release
t_handle_lock.  It would require an insane configuration, such as one
where the jbd2 thread was set to a very high real-time priority,
perhaps because a high priority real-time thread is trying to read or
write to a file system.  But some people who use real-time kernels
have been known to do insane things, including controlling
laser-wielding industrial robots.  :-)

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
2013-07-01 08:12:40 -04:00
Theodore Ts'o fe52d17cdd jbd2: move superblock checksum calculation to jbd2_write_superblock()
Some of the functions which modify the jbd2 superblock were not
updating the checksum before calling jbd2_write_superblock().  Move
the call to jbd2_superblock_csum_set() to jbd2_write_superblock(), so
that the checksum is calculated consistently.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: stable@vger.kernel.org
2013-07-01 08:12:38 -04:00
Paul Gortmaker 75497d0607 jbd2: remove debug dependency on debug_fs and update Kconfig help text
Commit b6e96d0067 ("jbd2: use module parameters instead of debugfs
for jbd_debug") removed any need for a dependency on DEBUG_FS.  It
also moved the /sys variables out from underneath the typical debugfs
mount point.  Delete the dependency and update the /sys path to where
the debug settings are currently.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 23:07:51 -04:00
Paul Gortmaker 169f1a2a87 jbd2: use a single printk for jbd_debug()
Since the jbd_debug() is implemented with two separate printk()
calls, it can lead to corrupted and misleading debug output like
the following (see lines marked with "*"):

[  290.339362] (fs/jbd2/journal.c, 203): kjournald2: kjournald2 wakes
[  290.339365] (fs/jbd2/journal.c, 155): kjournald2: commit_sequence=42103, commit_request=42104
[  290.339369] (fs/jbd2/journal.c, 158): kjournald2: OK, requests differ
[* 290.339376] (fs/jbd2/journal.c, 648): jbd2_log_wait_commit:
[* 290.339379] (fs/jbd2/commit.c, 370): jbd2_journal_commit_transaction: JBD2: want 42104, j_commit_sequence=42103
[* 290.339382] JBD2: starting commit of transaction 42104
[  290.339410] (fs/jbd2/revoke.c, 566): jbd2_journal_write_revoke_records: Wrote 0 revoke records
[  290.376555] (fs/jbd2/commit.c, 1088): jbd2_journal_commit_transaction: JBD2: commit 42104 complete, head 42079

i.e. the debug output from log_wait_commit and journal_commit_transaction
have become interleaved.  The output should have been:

(fs/jbd2/journal.c, 648): jbd2_log_wait_commit: JBD2: want 42104, j_commit_sequence=42103
(fs/jbd2/commit.c, 370): jbd2_journal_commit_transaction: JBD2: starting commit of transaction 42104

It is expected that this is not easy to replicate -- I was only able
to cause it on preempt-rt kernels, and even then only under heavy
I/O load.

Reported-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Suggested-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 23:04:04 -04:00
Paul Gortmaker cfc7bc896f jbd2: fix duplicate debug label for phase 2
Currently we see this output:

  $git grep phase fs/jbd2
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 1\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 2\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 2\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 3\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 4\n");
  [...]

There is clearly a duplicate label for phase 2, and they are
both active (i.e. not in #if ... #else block).  Rename them to
be "2a" and "2b" so the debug output is unambiguous.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 22:56:35 -04:00
Paul Gortmaker 0ef54180e0 jbd2: drop checkpoint mutex when waiting in __jbd2_log_wait_for_space()
While trying to debug an an issue under extreme I/O loading
on preempt-rt kernels, the following backtrace was observed
via SysRQ output:

rm              D ffff8802203afbc0  4600  4878   4748 0x00000000
 ffff8802217bfb78 0000000000000082 ffff88021fc2bb80 ffff88021fc2bb80
 ffff88021fc2bb80 ffff8802217bffd8 ffff8802217bffd8 ffff8802217bffd8
 ffff88021f1d4c80 ffff88021fc2bb80 ffff8802217bfb88 ffff88022437b000
Call Trace:
 [<ffffffff8172dc34>] schedule+0x24/0x70
 [<ffffffff81225b5d>] jbd2_log_wait_commit+0xbd/0x140
 [<ffffffff81060390>] ? __init_waitqueue_head+0x50/0x50
 [<ffffffff81223635>] jbd2_log_do_checkpoint+0xf5/0x520
 [<ffffffff81223b09>] __jbd2_log_wait_for_space+0xa9/0x1f0
 [<ffffffff8121dc40>] start_this_handle.isra.10+0x2e0/0x530
 [<ffffffff81060390>] ? __init_waitqueue_head+0x50/0x50
 [<ffffffff8121e0a3>] jbd2__journal_start+0xc3/0x110
 [<ffffffff811de7ce>] ? ext4_rmdir+0x6e/0x230
 [<ffffffff8121e0fe>] jbd2_journal_start+0xe/0x10
 [<ffffffff811f308b>] ext4_journal_start_sb+0x5b/0x160
 [<ffffffff811de7ce>] ext4_rmdir+0x6e/0x230
 [<ffffffff811435c5>] vfs_rmdir+0xd5/0x140
 [<ffffffff8114370f>] do_rmdir+0xdf/0x120
 [<ffffffff8105c6b4>] ? task_work_run+0x44/0x80
 [<ffffffff81002889>] ? do_notify_resume+0x89/0x100
 [<ffffffff817361ae>] ? int_signal+0x12/0x17
 [<ffffffff81145d85>] sys_unlinkat+0x25/0x40
 [<ffffffff81735f22>] system_call_fastpath+0x16/0x1b

What is interesting here, is that we call log_wait_commit, from
within wait_for_space, but we are still holding the checkpoint_mutex
as it surrounds mostly the whole of wait_for_space.  And then, as we
are waiting, journal_commit_transaction can run, and if the JBD2_FLUSHED
bit is set, then we will also try to take the same checkpoint_mutex.

It seems that we need to drop the checkpoint_mutex while sitting in
jbd2_log_wait_commit, if we want to guarantee that progress can be made
by jbd2_journal_commit_transaction().  There does not seem to be
anything preempt-rt specific about this, other then perhaps increasing
the odds of it happening.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 22:47:35 -04:00
Paul Gortmaker 3ca841c106 jbd2: relocate assert after state lock in journal_commit_transaction()
The state lock is taken after we are doing an assert on the state
value, not before.  So we might in fact be doing an assert on a
transient value.  Ensure the state check is within the scope of
the state lock being taken.

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 22:46:35 -04:00
Dmitry Monakhov 9ff8644624 jbd2: optimize jbd2_journal_force_commit
Current implementation of jbd2_journal_force_commit() is suboptimal because
result in empty and useless commits. But callers just want to force and wait
any unfinished commits. We already have jbd2_journal_force_commit_nested()
which does exactly what we want, except we are guaranteed that we do not hold
journal transaction open.

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-12 22:24:07 -04:00
Jan Kara 8f7d89f368 jbd2: transaction reservation support
In some cases we cannot start a transaction because of locking
constraints and passing started transaction into those places is not
handy either because we could block transaction commit for too long.
Transaction reservation is designed to solve these issues.  It
reserves a handle with given number of credits in the journal and the
handle can be later attached to the running transaction without
blocking on commit or checkpointing.  Reserved handles do not block
transaction commit in any way, they only reduce maximum size of the
running transaction (because we have to always be prepared to
accomodate request for attaching reserved handle).

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:35:11 -04:00
Jan Kara f29fad7210 jbd2: remove unused waitqueues
j_wait_logspace and j_wait_checkpoint are unused.  Remove them.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:24:11 -04:00
Jan Kara fe1e8db598 jbd2: fix race in t_outstanding_credits update in jbd2_journal_extend()
jbd2_journal_extend() first checked whether transaction can accept
extending handle with more credits and then added credits to
t_outstanding_credits.  This can race with start_this_handle() adding
another handle to a transaction and thus overbooking a transaction.
Make jbd2_journal_extend() use atomic_add_return() to close the race.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:22:15 -04:00
Jan Kara 76c3990456 jbd2: cleanup needed free block estimates when starting a transaction
__jbd2_log_space_left() and jbd_space_needed() were kind of odd.
jbd_space_needed() accounted also credits needed for currently
committing transaction while it didn't account for credits needed for
control blocks.  __jbd2_log_space_left() then accounted for control
blocks as a fraction of free space.  Since results of these two
functions are always only compared against each other, this works
correct but is somewhat strange.  Move the estimates so that
jbd_space_needed() returns number of blocks needed for a transaction
including control blocks and __jbd2_log_space_left() returns free
space in the journal (with the committing transaction already
subtracted).  Rename functions to jbd2_log_space_left() and
jbd2_space_needed() while we are changing them.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:12:57 -04:00
Jan Kara 2f387f849b jbd2: remove outdated comment
The comment about credit estimates isn't true anymore. We do what the
comment describes now.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:10:11 -04:00
Jan Kara b34090e5e2 jbd2: refine waiting for shadow buffers
Currently when we add a buffer to a transaction, we wait until the
buffer is removed from BJ_Shadow list (so that we prevent any changes
to the buffer that is just written to the journal).  This can take
unnecessarily long as a lot happens between the time the buffer is
submitted to the journal and the time when we remove the buffer from
BJ_Shadow list.  (e.g.  We wait for all data buffers in the
transaction, we issue a cache flush, etc.)  Also this creates a
dependency of do_get_write_access() on transaction commit (namely
waiting for data IO to complete) which we want to avoid when
implementing transaction reservation.

So we modify commit code to set new BH_Shadow flag when temporary
shadowing buffer is created and we clear that flag once IO on that
buffer is complete.  This allows do_get_write_access() to wait only
for BH_Shadow bit and thus removes the dependency on data IO
completion.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:08:56 -04:00
Jan Kara e5a120aeb5 jbd2: remove journal_head from descriptor buffers
Similarly as for metadata buffers, also log descriptor buffers don't
really need the journal head. So strip it and remove BJ_LogCtl list.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:06:01 -04:00
Jan Kara f5113effc2 jbd2: don't create journal_head for temporary journal buffers
When writing metadata to the journal, we create temporary buffer heads
for that task.  We also attach journal heads to these buffer heads but
the only purpose of the journal heads is to keep buffers linked in
transaction's BJ_IO list.  We remove the need for journal heads by
reusing buffer_head's b_assoc_buffers list for that purpose.  Also
since BJ_IO list is just a temporary list for transaction commit, we
use a private list in jbd2_journal_commit_transaction() for that thus
removing BJ_IO list from transaction completely.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-06-04 12:01:45 -04:00