linux-toradex.git/include/linux/jbd2.h, branch v3.9-rc3

jbd2: use module parameters instead of debugfs for jbd_debug

2013-02-09T21:29:20+00:00

There are multiple reasons to move away from debugfs.  First of all,
we are only using it for a single parameter, and it is much more
complicated to set up (some 30 lines of code compared to 3), and one
more thing that might fail while loading the jbd2 module.

Secondly, as a module paramter it can be specified as a boot option if
jbd2 is built into the kernel, or as a parameter when the module is
loaded, and it can also be manipulated dynamically under
/sys/module/jbd2/parameters/jbd2_debug.  So it is more flexible.

Ultimately we want to move away from using jbd_debug() towards
tracepoints, but for now this is still a useful simplification of the
code base.

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

jbd2: add tracepoints which provide per-handle statistics

2013-02-08T18:00:22+00:00

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"

jbd2: revert "jbd2: add COW fields to struct jbd2_journal_handle"

2013-02-07T05:02:15+00:00

This reverts commit 93737456d68ddcb86232f669b83da673dd12e351.

The cow-snapshots effort is no longer active, so remove these extra
fields to shrink down the handle structure.

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

jbd2: track request delay statistics

2013-02-07T03:30:23+00:00

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"

ext4: fix deadlock in journal_unmap_buffer()

2012-12-25T18:29:52+00:00

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

jbd2: remove VLAIS usage from JBD2 code

2012-11-08T16:24:46+00:00

The use of variable length arrays in structs (VLAIS) in the Linux Kernel code
precludes the use of compilers which don't implement VLAIS (for instance the
Clang compiler). Since ctx is always a 32-bit CRC, hard coding a size of 4
bytes accomplishes the same thing without the use of VLAIS. This is the same
technique already employed in fs/ext4/ext4.h

Signed-off-by: Mark Charlebois 
Signed-off-by: Behan Webster 
Signed-off-by: "Theodore Ts'o"

ext4: remove ext4_handle_release_buffer()

2012-11-08T16:22:46+00:00

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 
Signed-off-by: "Theodore Ts'o" 
Reviewed-by: Carlos Maiolino

ext4: make sure the journal sb is written in ext4_clear_journal_err()

2012-08-05T23:04:57+00:00

After we transfer set the EXT4_ERROR_FS bit in the file system
superblock, it's not enough to call jbd2_journal_clear_err() to clear
the error indication from journal superblock --- we need to call
jbd2_journal_update_sb_errno() as well.  Otherwise, when the root file
system is mounted read-only, the journal is replayed, and the error
indicator is transferred to the superblock --- but the s_errno field
in the jbd2 superblock is left set (since although we cleared it in
memory, we never flushed it out to disk).

This can end up confusing e2fsck.  We should make e2fsck more robust
in this case, but the kernel shouldn't be leaving things in this
confused state, either.

Signed-off-by: "Theodore Ts'o" 
Cc: stable@kernel.org

ext4/jbd2: add metadata checksumming to the list of supported features

2012-05-27T12:12:42+00:00

Activate the metadata checksumming feature by adding it to ext4 and
jbd2's lists of supported features.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"

jbd2: checksum journal superblock

2012-05-27T12:08:22+00:00

Calculate and verify a checksum covering the journal superblock.

Signed-off-by: Darrick J. Wong 
Signed-off-by: "Theodore Ts'o"