linux-toradex.git/include/linux/jbd2.h, branch v3.14.3

jbd2: invalidate handle if jbd2_journal_restart() fails

2013-07-01T12:12:41+00:00

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" 
Reported-by: Younger Liu 
Cc: Jan Kara

jbd2: use a single printk for jbd_debug()

2013-06-13T03:04:04+00:00

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 
Suggested-by: "Theodore Ts'o" 
Signed-off-by: Paul Gortmaker 
Signed-off-by: "Theodore Ts'o"

jbd/jbd2: relocate bit_spinlock header to jbd_common

2013-06-13T03:02:35+00:00

The bit_spinlock functions are only used for the jbd_lock_bh_state
functions (and friends) in jbd_common.h and are not directly used
by either of jbd.h or jbd2.h content.

The jbd_common file is new as of commit 446066724c36 ("jdb/jbd2: factor
out common functions from the jbd[2] header files") but common
(and isolated) headers were not considered for factoring at that time.

Signed-off-by: Paul Gortmaker 
Signed-off-by: "Theodore Ts'o"

ext4: fix data integrity for ext4_sync_fs

2013-06-13T02:25:07+00:00

Inode's data or non journaled quota may be written w/o jounral so we
_must_ send a barrier at the end of ext4_sync_fs. But it can be
skipped if journal commit will do it for us.

Also fix data integrity for nojournal mode.

Signed-off-by: Dmitry Monakhov 
Signed-off-by: "Theodore Ts'o"

jbd2: optimize jbd2_journal_force_commit

2013-06-13T02:24:07+00:00

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 
Signed-off-by: "Theodore Ts'o"

jbd2: transaction reservation support

2013-06-04T16:35:11+00:00

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 
Signed-off-by: "Theodore Ts'o"

jbd2: remove unused waitqueues

2013-06-04T16:24:11+00:00

j_wait_logspace and j_wait_checkpoint are unused.  Remove them.

Reviewed-by: Zheng Liu 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

jbd2: cleanup needed free block estimates when starting a transaction

2013-06-04T16:12:57+00:00

__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 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

jbd2: refine waiting for shadow buffers

2013-06-04T16:08:56+00:00

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 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"

jbd2: remove journal_head from descriptor buffers

2013-06-04T16:06:01+00:00

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 
Signed-off-by: Jan Kara 
Signed-off-by: "Theodore Ts'o"