linux.git/fs/f2fs/segment.c, branch v4.0

f2fs: use spinlock for segmap_lock instead of rwlock

2015-02-12T01:04:51+00:00

rwlock can provide better concurrency when there are much more readers than
writers because readers can hold the rwlock simultaneously.

But now, for segmap_lock rwlock in struct free_segmap_info, there is only one
reader 'mount' from below call path:
->f2fs_fill_super
  ->build_segment_manager
    ->build_dirty_segmap
      ->init_dirty_segmap
        ->find_next_inuse
          read_lock
          ...
          read_unlock

Now that our concurrency can not be improved since there is no other reader for
this lock, we do not need to use rwlock_t type for segmap_lock, let's replace it
with spinlock_t type.

Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: avoid variable length array

2015-02-12T01:04:50+00:00

Instead of using variable length array, this patch let preallocate memory for
them.

Signed-off-by: Jaegeuk Kim

f2fs: introduce macros to convert bytes and blocks in f2fs

2015-02-12T01:04:48+00:00

This patch adds two macros for transition between byte and block offsets.
Currently, f2fs only supports 4KB blocks, so use the default size for now.

Signed-off-by: Jaegeuk Kim

f2fs: introduce a batched trim

2015-02-12T01:04:44+00:00

This patch introduces a batched trimming feature, which submits split discard
commands.

This is to avoid long latency due to huge trim commands.
If fstrim was triggered ranging from 0 to the end of device, we should lock
all the checkpoint-related mutexes, resulting in very long latency.

Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: split UMOUNT and FASTBOOT flags

2015-02-12T01:04:41+00:00

This patch adds FASTBOOT flag into checkpoint as follows.

 - CP_UMOUNT_FLAG is set when system is umounted.
 - CP_FASTBOOT_FLAG is set when intermediate checkpoint having node summaries
   was done.

So, if you get CP_UMOUNT_FLAG from checkpoint, the system was umounted cleanly.
Instead, if there was sudden-power-off, you can get CP_FASTBOOT_FLAG or nothing.

Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: align direct_io'ed data to section

2015-01-10T01:02:27+00:00

This patch aligns the start block address of a file for direct io to the f2fs's
section size.

Some flash devices manage an over 4KB-sized page as a write unit, and if the
direct_io'ed data are written but not aligned to that unit, the performance can
be degraded due to the partial page copies.

Thus, since f2fs has a section that is well aligned to FTL units, we can align
the block address to the section size so that f2fs avoids this misalignment.

Signed-off-by: Jaegeuk Kim

f2fs: clean up to remove parameter

2015-01-10T01:02:26+00:00

This patch uses dn->data_blkaddr as a parameter for the destination block
address.

Signed-off-by: Jaegeuk Kim

f2fs: add block count by in-place-update in stat info

2015-01-10T01:02:25+00:00

This patch adds block count by in-place-update in stat.

Signed-off-by: Changman Lee 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim

f2fs: activate f2fs_trace_pid

2015-01-10T01:02:24+00:00

This patch activates f2fs_trace_pid.

Signed-off-by: Jaegeuk Kim

f2fs: use f2fs_io_info to clean up messy parameters during IO path

2015-01-10T01:02:23+00:00

This patch cleans up parameters on IO paths.
The key idea is to use f2fs_io_info adding a parameter, block address, and then
use this structure as parameters.

Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim