linux-toradex.git/include/linux/jbd2.h, branch v5.0-rc3

jbd2: update locking documentation for transaction_t

2018-12-04T05:30:22+00:00

The following members of struct transaction_s aka transaction_t
were turned into lock-free variables in the past:
- t_updates
- t_outstanding_credits
- t_handle_count
However, the documentation has not been updated yet.
This commit replaced the annotated lock by [none].

Found by LockDoc (Alexander Lochmann, Horst Schirmeier and Olaf Spinczyk)

Signed-off-by: Alexander Lochmann 
Signed-off-by: Horst Schirmeier 
Signed-off-by: Theodore Ts'o

jbd2: avoid long hold times of j_state_lock while committing a transaction

2018-12-04T04:16:07+00:00

We can hold j_state_lock for writing at the beginning of
jbd2_journal_commit_transaction() for a rather long time (reportedly for
30 ms) due cleaning revoke bits of all revoked buffers under it. The
handling of revoke tables as well as cleaning of t_reserved_list, and
checkpoint lists does not need j_state_lock for anything. It is only
needed to prevent new handles from joining the transaction. Generally
T_LOCKED transaction state prevents new handles from joining the
transaction - except for reserved handles which have to allowed to join
while we wait for other handles to complete.

To prevent reserved handles from joining the transaction while cleaning
up lists, add new transaction state T_SWITCH and watch for it when
starting reserved handles. With this we can just drop the lock for
operations that don't need it.

Reported-and-tested-by: Adrian Hunter 
Suggested-by: "Theodore Y. Ts'o" 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o

jbd2: fix sphinx kernel-doc build warnings

2018-01-10T05:27:29+00:00

Sphinx emits various (26) warnings when building make target 'htmldocs'.
Currently struct definitions contain duplicate documentation, some as
kernel-docs and some as standard c89 comments.  We can reduce
duplication while cleaning up the kernel docs.

Move all kernel-docs to right above each struct member.  Use the set of
all existing comments (kernel-doc and c89).  Add documentation for
missing struct members and function arguments.

Signed-off-by: Tobin C. Harding 
Signed-off-by: Theodore Ts'o 
Cc: stable@vger.kernel.org

ext4: Support for synchronous DAX faults

2017-11-03T13:26:26+00:00

We return IOMAP_F_DIRTY flag from ext4_iomap_begin() when asked to
prepare blocks for writing and the inode has some uncommitted metadata
changes. In the fault handler ext4_dax_fault() we then detect this case
(through VM_FAULT_NEEDDSYNC return value) and call helper
dax_finish_sync_fault() to flush metadata changes and insert page table
entry. Note that this will also dirty corresponding radix tree entry
which is what we want - fsync(2) will still provide data integrity
guarantees for applications not using userspace flushing. And
applications using userspace flushing can avoid calling fsync(2) and
thus avoid the performance overhead.

Reviewed-by: Ross Zwisler 
Signed-off-by: Jan Kara 
Signed-off-by: Dan Williams

jbd2: mark the transaction context with the scope GFP_NOFS context

2017-05-03T22:52:09+00:00

now that we have memalloc_nofs_{save,restore} api we can mark the whole
transaction context as implicitly GFP_NOFS.  All allocations will
automatically inherit GFP_NOFS this way.  This means that we do not have
to mark any of those requests with GFP_NOFS and moreover all the
ext4_kv[mz]alloc(GFP_NOFS) are also safe now because even the hardcoded
GFP_KERNEL allocations deep inside the vmalloc will be NOFS now.

[akpm@linux-foundation.org: tweak comments]
Link: http://lkml.kernel.org/r/20170306131408.9828-7-mhocko@kernel.org
Signed-off-by: Michal Hocko 
Reviewed-by: Jan Kara 
Cc: Dave Chinner 
Cc: Theodore Ts'o 
Cc: Chris Mason 
Cc: David Sterba 
Cc: Brian Foster 
Cc: Darrick J. Wong 
Cc: Nikolay Borisov 
Cc: Peter Zijlstra 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

jbd2: track more dependencies on transaction commit

2016-06-30T15:40:54+00:00

So far we were tracking only dependency on transaction commit due to
starting a new handle (which may require commit to start a new
transaction). Now add tracking also for other cases where we wait for
transaction commit. This way lockdep can catch deadlocks e. g. because we
call jbd2_journal_stop() for a synchronous handle with some locks held
which rank below transaction start.

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

jbd2: move lockdep tracking to journal_s

2016-06-30T15:39:38+00:00

Currently lockdep map is tracked in each journal handle. To be able to
expand lockdep support to cover also other cases where we depend on
transaction commit and where handle is not available, move lockdep map
into struct journal_s. Since this makes the lockdep map shared for all
handles, we have to use rwsem_acquire_read() for acquisitions now.

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

jbd2: remove excess descriptions for handle_s

2016-05-06T02:35:54+00:00

Commit bf6993276f74 ("jbd2: Use tracepoints for history file")
removed the members j_history, j_history_max and j_history_cur from struct
handle_s but the descriptions stayed lingering. Removing them.

Signed-off-by: Luis de Bethencourt 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara

jbd2: add support for avoiding data writes during transaction commits

2016-04-24T04:56:07+00:00

Currently when filesystem needs to make sure data is on permanent
storage before committing a transaction it adds inode to transaction's
inode list. During transaction commit, jbd2 writes back all dirty
buffers that have allocated underlying blocks and waits for the IO to
finish. However when doing writeback for delayed allocated data, we
allocate blocks and immediately submit the data. Thus asking jbd2 to
write dirty pages just unnecessarily adds more work to jbd2 possibly
writing back other redirtied blocks.

Add support to jbd2 to allow filesystem to ask jbd2 to only wait for
outstanding data writes before committing a transaction and thus avoid
unnecessary writes.

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

jbd2: unify revoke and tag block checksum handling

2016-02-23T04:19:09+00:00

Revoke and tag descriptor blocks are just different kinds of descriptor
blocks and thus have checksum in the same place. Unify computation and
checking of checksums for these.

Reviewed-by: Darrick J. Wong 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o