linux/fs/nilfs2
Andreas Rohner 75dc857c46 nilfs2: avoid duplicate segment construction for fsync()
This patch removes filemap_write_and_wait_range() from nilfs_sync_file(),
because it triggers a data segment construction by calling
nilfs_writepages() with WB_SYNC_ALL.  A data segment construction does not
remove the inode from the i_dirty list and it does not clear the
NILFS_I_DIRTY flag.  Therefore nilfs_inode_dirty() still returns true,
which leads to an unnecessary duplicate segment construction in
nilfs_sync_file().

A call to filemap_write_and_wait_range() is not needed, because NILFS2
does not rely on the generic writeback mechanisms.  Instead it implements
its own mechanism to collect all dirty pages and write them into segments.
 It is more efficient to initiate the segment construction directly in
nilfs_sync_file() without the detour over filemap_write_and_wait_range().

Additionally the lock of i_mutex is not needed, because all code blocks
that are protected by i_mutex are also protected by a NILFS transaction:

  Function                i_mutex     nilfs_transaction
  ------------------------------------------------------
  nilfs_ioctl_setflags:   yes         yes
  nilfs_fiemap:           yes         no
  nilfs_write_begin:      yes         yes
  nilfs_write_end:        yes         yes
  nilfs_lookup:           yes         no
  nilfs_create:           yes         yes
  nilfs_link:             yes         yes
  nilfs_mknod:            yes         yes
  nilfs_symlink:          yes         yes
  nilfs_mkdir:            yes         yes
  nilfs_unlink:           yes         yes
  nilfs_rmdir:            yes         yes
  nilfs_rename:           yes         yes
  nilfs_setattr:          yes         yes

For nilfs_lookup() i_mutex is held for the parent directory, to protect it
from modification.  The segment construction does not modify directory
inodes, so no lock is needed.

nilfs_fiemap() reads the block layout on the disk, by using
nilfs_bmap_lookup_contig(). This is already protected by bmap->b_sem.

Signed-off-by: Andreas Rohner <andreas.rohner@gmx.net>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10 17:41:16 -08:00
..
alloc.c nilfs2: implement calculation of free inodes count 2013-07-03 16:08:01 -07:00
alloc.h nilfs2: implement calculation of free inodes count 2013-07-03 16:08:01 -07:00
bmap.c
bmap.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
btnode.c nilfs2: use mark_buffer_dirty to mark btnode or meta data dirty 2011-05-10 22:21:57 +09:00
btnode.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
btree.c nilfs2: fix missing block address termination in btree node shrinking 2011-06-11 15:51:15 +09:00
btree.h
cpfile.c nilfs2: verify metadata sizes read from disk 2014-04-03 16:21:26 -07:00
cpfile.h
dat.c nilfs2: verify metadata sizes read from disk 2014-04-03 16:21:26 -07:00
dat.h
dir.c [readdir] convert nilfs2 2013-06-29 12:56:36 +04:00
direct.c
direct.h
export.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
file.c nilfs2: avoid duplicate segment construction for fsync() 2014-12-10 17:41:16 -08:00
gcinode.c nilfs2: ensure proper cache clearing for gc-inodes 2012-06-20 14:39:35 -07:00
ifile.c ] nilfs2: use atomic64_t type for inodes_count and blocks_count fields in nilfs_root struct 2013-07-03 16:08:01 -07:00
ifile.h nilfs2: implement calculation of free inodes count 2013-07-03 16:08:01 -07:00
inode.c nilfs2: improve the performance of fdatasync() 2014-10-14 02:18:20 +02:00
ioctl.c nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() 2014-10-14 02:18:20 +02:00
Kconfig fs/nilfs2: remove depends on CONFIG_EXPERIMENTAL 2013-01-11 11:39:04 -08:00
Makefile nilfs2: integrate sysfs support into driver 2014-08-08 15:57:21 -07:00
mdt.c nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
mdt.h nilfs2: add omitted comments for different structures in driver implementation 2012-07-30 17:25:19 -07:00
namei.c fs: encode_fh: return FILEID_INVALID if invalid fid_type 2013-02-26 02:46:10 -05:00
nilfs.h nilfs2: improve the performance of fdatasync() 2014-10-14 02:18:20 +02:00
page.c nilfs2: fix issue with race condition of competition between segments for dirty blocks 2013-09-30 14:31:02 -07:00
page.h nilfs2: fix issue with flush kernel thread after remount in RO mode because of driver's internal error or metadata corruption 2013-04-30 17:04:04 -07:00
recovery.c nilfs2: drop vmtruncate 2012-12-20 18:40:54 -05:00
segbuf.c block: Abstract out bvec iterator 2013-11-23 22:33:47 -08:00
segbuf.h
segment.c nilfs2: improve the performance of fdatasync() 2014-10-14 02:18:20 +02:00
segment.h
sufile.c nilfs2: verify metadata sizes read from disk 2014-04-03 16:21:26 -07:00
sufile.h nilfs2: add nilfs_sufile_trim_fs to trim clean segs 2014-04-03 16:21:25 -07:00
super.c nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() 2014-10-14 02:18:20 +02:00
sysfs.c nilfs2: integrate sysfs support into driver 2014-08-08 15:57:21 -07:00
sysfs.h nilfs2: add /sys/fs/nilfs2/<device>/mounted_snapshots/<snapshot> group 2014-08-08 15:57:21 -07:00
the_nilfs.c nilfs2: integrate sysfs support into driver 2014-08-08 15:57:21 -07:00
the_nilfs.h nilfs2: add missing blkdev_issue_flush() to nilfs_sync_fs() 2014-10-14 02:18:20 +02:00