dedekind1 at gmail
May 4, 2012, 10:27 AM
Post #1 of 5
This patch-set makes JFFS2 file-system stop using the VFS '->write_supers()'
[PATCH 0/3] do not use s_dirt in JFFS2
call-back because I plan to remove it once all users are gone.
The final goal is to get rid of the 'sync_supers()' kernel thread. This kernel
thread wakes up every 5 seconds (by default) and calls '->write_super()' for
all mounted file-systems. And the bad thing is that this is done even if all
the superblocks are clean. Moreover, some file-systems do not even need this
end they do not register the '->write_super()' method at all (e.g., btrfs).
So 'sync_supers()' most often just generates useless wake-ups and wastes power.
I am trying to make all file-systems independent of '->write_super()' and plan
to remove 'sync_supers()' and '->write_super' completely once there are no more
The '->write_supers()' method is mostly used by baroque file-systems like hfs,
udf, etc. Modern file-systems like btrfs and xfs do not use it. This justifies
removing this stuff from VFS completely and make every FS self-manage own
Note: in the past I was trying to upstream patches which optimized 'sync_super()',
but Al Viro wanted me to kill it completely instead, which I am trying to do
now, see http://lkml.org/lkml/2010/7/22/96
1. ext4: patches submitted, waiting for reply from Ted Ts'o:
Ted keeps silence so far WRT the fate of this patch-set.
2. ext2: patches are in the ext2 tree maintained by Jan Kara:
3. Version 3 of FAT FS changes were sent to Andrew and Hirofumi:
4. JFFS2 patches are sent being sent now.
TODO: affs, exofs, hfs, hfsplus, reiserfs, sysv, udf, ufs
fs/fat/fat.h | 1 +
fs/fat/fatent.c | 22 +++++++++++++-----
fs/fat/inode.c | 54 ++++++++++++++++++++-------------------------
include/linux/msdos_fs.h | 3 +-
4 files changed, 43 insertions(+), 37 deletions(-)
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