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>
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
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>
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>
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>
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>
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
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>
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>
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>
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
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>
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>
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>
__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>
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>
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>
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>
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>
invalidatepage now accepts range to invalidate and there are two file
system using jbd2 also implementing punch hole feature which can benefit
from this. We need to implement the same thing for jbd2 layer in order to
allow those file system take benefit of this functionality.
This commit adds length argument to the jbd2_journal_invalidatepage()
and updates all instances in ext4 and ocfs2.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
While investigating interactivity problems it was clear that processes
sometimes stall for long periods of times if an attempt is made to
lock a buffer which is undergoing writeback. It would stall in
a trace looking something like
[<ffffffff811a39de>] __lock_buffer+0x2e/0x30
[<ffffffff8123a60f>] do_get_write_access+0x43f/0x4b0
[<ffffffff8123a7cb>] jbd2_journal_get_write_access+0x2b/0x50
[<ffffffff81220f79>] __ext4_journal_get_write_access+0x39/0x80
[<ffffffff811f3198>] ext4_reserve_inode_write+0x78/0xa0
[<ffffffff811f3209>] ext4_mark_inode_dirty+0x49/0x220
[<ffffffff811f57d1>] ext4_dirty_inode+0x41/0x60
[<ffffffff8119ac3e>] __mark_inode_dirty+0x4e/0x2d0
[<ffffffff8118b9b9>] update_time+0x79/0xc0
[<ffffffff8118ba98>] file_update_time+0x98/0x100
[<ffffffff81110ffc>] __generic_file_aio_write+0x17c/0x3b0
[<ffffffff811112aa>] generic_file_aio_write+0x7a/0xf0
[<ffffffff811ea853>] ext4_file_write+0x83/0xd0
[<ffffffff81172b23>] do_sync_write+0xa3/0xe0
[<ffffffff811731ae>] vfs_write+0xae/0x180
[<ffffffff8117361d>] sys_write+0x4d/0x90
[<ffffffff8159d62d>] system_call_fastpath+0x1a/0x1f
[<ffffffffffffffff>] 0xffffffffffffffff
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The jbd2_alloc_handle() function is only called by new_handle(). So
this commit uses kmem_cache_zalloc() instead of
kmem_cache_alloc()/memset().
Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2_journal_dirty_metadata() didn't get a reference to journal_head it
was working with. This is OK in most of the cases since the journal head
should be attached to a transaction but in rare occasions when we are
journalling data, __ext4_journalled_writepage() can race with
jbd2_journal_invalidatepage() stripping buffers from a page and thus
journal head can be freed under hands of jbd2_journal_dirty_metadata().
Fix the problem by getting own journal head reference in
jbd2_journal_dirty_metadata() (and also in jbd2_journal_set_triggers()
which can possibly have the same issue).
Reported-by: Zheng Liu <gnehzuil.liu@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Handles which stay open a long time are problematic when it comes time
to close down a transaction so it can be committed. These tracepoints
will help us determine which ones are the problematic ones, and to
validate whether changes makes things better or worse.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Track the delay between when we first request that the commit begin
and when it actually begins, so we can see how much of a gap exists.
In theory, this should just be the remaining scheduling quantuum of
the thread which requested the commit (assuming it was not a
synchronous operation which triggered the commit request) plus
scheduling overhead; however, it's possible that real time processes
might get in the way of letting the kjournald thread from executing.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
which could cause file system corruptions when performing file punch
operations.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 bug fixes from Ted Ts'o:
"Various bug fixes for ext4. Perhaps the most serious bug fixed is one
which could cause file system corruptions when performing file punch
operations."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4:
ext4: avoid hang when mounting non-journal filesystems with orphan list
ext4: lock i_mutex when truncating orphan inodes
ext4: do not try to write superblock on ro remount w/o journal
ext4: include journal blocks in df overhead calcs
ext4: remove unaligned AIO warning printk
ext4: fix an incorrect comment about i_mutex
ext4: fix deadlock in journal_unmap_buffer()
ext4: split off ext4_journalled_invalidatepage()
jbd2: fix assertion failure in jbd2_journal_flush()
ext4: check dioread_nolock on remount
ext4: fix extent tree corruption caused by hole punch
We cannot wait for transaction commit in journal_unmap_buffer()
because we hold page lock which ranks below transaction start. We
solve the issue by bailing out of journal_unmap_buffer() and
jbd2_journal_invalidatepage() with -EBUSY. Caller is then responsible
for waiting for transaction commit to finish and try invalidation
again. Since the issue can happen only for page stradding i_size, it
is simple enough to manually call jbd2_journal_invalidatepage() for
such page from ext4_setattr(), check the return value and wait if
necessary.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The following race is possible between start_this_handle() and someone
calling jbd2_journal_flush().
Process A Process B
start_this_handle().
if (journal->j_barrier_count) # false
if (!journal->j_running_transaction) { #true
read_unlock(&journal->j_state_lock);
jbd2_journal_lock_updates()
jbd2_journal_flush()
write_lock(&journal->j_state_lock);
if (journal->j_running_transaction) {
# false
... wait for committing trans ...
write_unlock(&journal->j_state_lock);
...
write_lock(&journal->j_state_lock);
if (!journal->j_running_transaction) { # true
jbd2_get_transaction(journal, new_transaction);
write_unlock(&journal->j_state_lock);
goto repeat; # eventually blocks on j_barrier_count > 0
...
J_ASSERT(!journal->j_running_transaction);
# fails
We fix the race by rechecking j_barrier_count after reacquiring j_state_lock
in exclusive mode.
Reported-by: yjwsignal@empal.com
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
inline data, which allows small files or directories to be stored in
the in-inode extended attribute area. (This requires that the file
system use inodes which are at least 256 bytes or larger; 128 byte
inodes do not have any room for in-inode xattrs.)
The second new feature is SEEK_HOLE/SEEK_DATA support. This is
enabled by the extent status tree patches, and this infrastructure
will be used to further optimize ext4 in the future.
Beyond that, we have the usual collection of code cleanups and bug
fixes.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 update from Ted Ts'o:
"There are two major features for this merge window. The first is
inline data, which allows small files or directories to be stored in
the in-inode extended attribute area. (This requires that the file
system use inodes which are at least 256 bytes or larger; 128 byte
inodes do not have any room for in-inode xattrs.)
The second new feature is SEEK_HOLE/SEEK_DATA support. This is
enabled by the extent status tree patches, and this infrastructure
will be used to further optimize ext4 in the future.
Beyond that, we have the usual collection of code cleanups and bug
fixes."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (63 commits)
ext4: zero out inline data using memset() instead of empty_zero_page
ext4: ensure Inode flags consistency are checked at build time
ext4: Remove CONFIG_EXT4_FS_XATTR
ext4: remove unused variable from ext4_ext_in_cache()
ext4: remove redundant initialization in ext4_fill_super()
ext4: remove redundant code in ext4_alloc_inode()
ext4: use sync_inode_metadata() when syncing inode metadata
ext4: enable ext4 inline support
ext4: let fallocate handle inline data correctly
ext4: let ext4_truncate handle inline data correctly
ext4: evict inline data out if we need to strore xattr in inode
ext4: let fiemap work with inline data
ext4: let ext4_rename handle inline dir
ext4: let empty_dir handle inline dir
ext4: let ext4_delete_entry() handle inline data
ext4: make ext4_delete_entry generic
ext4: let ext4_find_entry handle inline data
ext4: create a new function search_dir
ext4: let ext4_readdir handle inline data
ext4: let add_dir_entry handle inline data properly
...
"Whether" is misspelled in various comments across the tree; this
fixes them. No code changes.
Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
ext4_handle_release_buffer() was intended to remove journal
write access from a buffer, but it doesn't actually do anything
at all other than add a BUFFER_TRACE point, but it's not reliably
used for that either. Remove all the associated dead code.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
ext4 users of data=journal mode with blocksize < pagesize were
occasionally hitting assertion failure in
jbd2_journal_commit_transaction() checking whether the transaction has
at least as many credits reserved as buffers attached. The core of the
problem is that when a file gets truncated, buffers that still need
checkpointing or that are attached to the committing transaction are
left with buffer_mapped set. When this happens to buffers beyond i_size
attached to a page stradding i_size, subsequent write extending the file
will see these buffers and as they are mapped (but underlying blocks
were freed) things go awry from here.
The assertion failure just coincidentally (and in this case luckily as
we would start corrupting filesystem) triggers due to journal_head not
being properly cleaned up as well.
We fix the problem by unmapping buffers if possible (in lots of cases we
just need a buffer attached to a transaction as a place holder but it
must not be written out anyway). And in one case, we just have to bite
the bullet and wait for transaction commit to finish.
CC: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Use kmem_cache_zalloc wrapper instead of flag __GFP_ZERO.
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
The changes to export dirty_writeback_interval are from Artem's s_dirt
cleanup patch series. The same is true of the change to remove the
s_dirt helper functions which never got used by anyone in-tree. I've
run these changes by Al Viro, and am carrying them so that Artem can
more easily fix up the rest of the file systems during the next merge
window. (Originally we had hopped to remove the use of s_dirt from
ext4 during this merge window, but his patches had some bugs, so I
ultimately ended dropping them from the ext4 tree.)
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates for 3.4 from Ted Ts'o:
"Ext4 commits for 3.3 merge window; mostly cleanups and bug fixes
The changes to export dirty_writeback_interval are from Artem's s_dirt
cleanup patch series. The same is true of the change to remove the
s_dirt helper functions which never got used by anyone in-tree. I've
run these changes by Al Viro, and am carrying them so that Artem can
more easily fix up the rest of the file systems during the next merge
window. (Originally we had hopped to remove the use of s_dirt from
ext4 during this merge window, but his patches had some bugs, so I
ultimately ended dropping them from the ext4 tree.)"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (66 commits)
vfs: remove unused superblock helpers
mm: export dirty_writeback_interval
ext4: remove useless s_dirt assignment
ext4: write superblock only once on unmount
ext4: do not mark superblock as dirty unnecessarily
ext4: correct ext4_punch_hole return codes
ext4: remove restrictive checks for EOFBLOCKS_FL
ext4: always set then trimmed blocks count into len
ext4: fix trimmed block count accunting
ext4: fix start and len arguments handling in ext4_trim_fs()
ext4: update s_free_{inodes,blocks}_count during online resize
ext4: change some printk() calls to use ext4_msg() instead
ext4: avoid output message interleaving in ext4_error_<foo>()
ext4: remove trailing newlines from ext4_msg() and ext4_error() messages
ext4: add no_printk argument validation, fix fallout
ext4: remove redundant "EXT4-fs: " from uses of ext4_msg
ext4: give more helpful error message in ext4_ext_rm_leaf()
ext4: remove unused code from ext4_ext_map_blocks()
ext4: rewrite punch hole to use ext4_ext_remove_space()
jbd2: cleanup journal tail after transaction commit
...
The check b_jlist == BJ_None in __journal_try_to_free_buffer() is
always true (__jbd2_journal_temp_unlink_buffer() also checks this in
an assertion) so just remove it.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
There is normally only a handful of these active at any one time, but
putting them in a separate slab cache makes debugging memory
corruption problems easier. Manish Katiyar also wanted this make it
easier to test memory failure scenarios in the jbd2 layer.
Cc: Manish Katiyar <mkatiyar@gmail.com>
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
journal_unmap_buffer()'s zap_buffer: code clears a lot of buffer head
state ala discard_buffer(), but does not touch _Delay or _Unwritten as
discard_buffer() does.
This can be problematic in some areas of the ext4 code which assume
that if they have found a buffer marked unwritten or delay, then it's
a live one. Perhaps those spots should check whether it is mapped
as well, but if jbd2 is going to tear down a buffer, let's really
tear it down completely.
Without this I get some fsx failures on sub-page-block filesystems
up until v3.2, at which point 4e96b2dbbf
and 189e868fa8 make the failures go
away, because buried within that large change is some more flag
clearing. I still think it's worth doing in jbd2, since
->invalidatepage leads here directly, and it's the right place
to clear away these flags.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
Toshiyuki Okajima found out that when running
for ((i=0; i < 100000; i++)); do
if ((i%2 == 0)); then
chattr +j /mnt/file
else
chattr -j /mnt/file
fi
echo "0" >> /mnt/file
done
process sometimes hangs indefinitely in jbd2_journal_lock_updates().
Toshiyuki identified that the following race happens:
jbd2_journal_lock_updates() |jbd2_journal_stop()
---------------------------------------+---------------------------------------
write_lock(&journal->j_state_lock) | .
++journal->j_barrier_count | .
spin_lock(&tran->t_handle_lock) | .
atomic_read(&tran->t_updates) //not 0 |
| atomic_dec_and_test(&tran->t_updates)
| // t_updates = 0
| wake_up(&journal->j_wait_updates)
prepare_to_wait() | // no process is woken up.
spin_unlock(&tran->t_handle_lock) |
write_unlock(&journal->j_state_lock) |
schedule() // never return |
We fix the problem by first calling prepare_to_wait() and only after that
checking t_updates in jbd2_journal_lock_updates().
Reported-and-analyzed-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Some jbd2 code prints out kernel messages with "JBD2: " prefix, at the
same time other jbd2 code prints with "JBD: " prefix. Unify the prefix
to "JBD2: ".
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Fix build error when CONFIG_BUG is not enabled:
fs/jbd2/transaction.c:1175:3: error: implicit declaration of function '__WARN'
by changing __WARN() to WARN_ON(), as suggested by
Arnaud Lacombe <lacombar@gmail.com>.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Arnaud Lacombe <lacombar@gmail.com>
This silences some Sparse warnings:
fs/jbd2/transaction.c:135:69: warning: incorrect type in argument 2 (different base types)
fs/jbd2/transaction.c:135:69: expected restricted gfp_t [usertype] flags
fs/jbd2/transaction.c:135:69: got int [signed] gfp_mask
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Add debugging information in case jbd2_journal_dirty_metadata() is
called with a buffer_head which didn't have
jbd2_journal_get_write_access() called on it, or if the journal_head
has the wrong transaction in it. In addition, return an error code.
This won't change anything for ocfs2, which will BUG_ON() the non-zero
exit code.
For ext4, the caller of this function is ext4_handle_dirty_metadata(),
and on seeing a non-zero return code, will call __ext4_journal_stop(),
which will print the function and line number of the (buggy) calling
function and abort the journal. This will allow us to recover instead
of bug halting, which is better from a robustness and reliability
point of view.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2_journal_remove_journal_head() can oops when trying to access
journal_head returned by bh2jh(). This is caused for example by the
following race:
TASK1 TASK2
jbd2_journal_commit_transaction()
...
processing t_forget list
__jbd2_journal_refile_buffer(jh);
if (!jh->b_transaction) {
jbd_unlock_bh_state(bh);
jbd2_journal_try_to_free_buffers()
jbd2_journal_grab_journal_head(bh)
jbd_lock_bh_state(bh)
__journal_try_to_free_buffer()
jbd2_journal_put_journal_head(jh)
jbd2_journal_remove_journal_head(bh);
jbd2_journal_put_journal_head() in TASK2 sees that b_jcount == 0 and
buffer is not part of any transaction and thus frees journal_head
before TASK1 gets to doing so. Note that even buffer_head can be
released by try_to_free_buffers() after
jbd2_journal_put_journal_head() which adds even larger opportunity for
oops (but I didn't see this happen in reality).
Fix the problem by making transactions hold their own journal_head
reference (in b_jcount). That way we don't have to remove journal_head
explicitely via jbd2_journal_remove_journal_head() and instead just
remove journal_head when b_jcount drops to zero. The result of this is
that [__]jbd2_journal_refile_buffer(),
[__]jbd2_journal_unfile_buffer(), and
__jdb2_journal_remove_checkpoint() can free journal_head which needs
modification of a few callers. Also we have to be careful because once
journal_head is removed, buffer_head might be freed as well. So we
have to get our own buffer_head reference where it matters.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
credits isn't a parameter for jbd2_journal_get_write_access and
jbd2_journal_get_undo_access. So remove the corresponding comments.
Acked-by: Jan Kara <jack@suse.cz>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
jbd2__journal_start() returns an ERR_PTR() value rather than NULL on
failure.
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
