linux.git/fs/bfs/inode.c, branch v3.0.48

fs: icache RCU free inodes

2011-01-07T06:50:26+00:00

RCU free the struct inode. This will allow:

- Subsequent store-free path walking patch. The inode must be consulted for
  permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
  to take i_lock no longer need to take sb_inode_list_lock to walk the list in
  the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
  page lock to follow page->mapping.

The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.

In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.

The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.

Signed-off-by: Nick Piggin

new helper: mount_bdev()

2010-10-29T08:16:13+00:00

... and switch of the obvious get_sb_bdev() users to ->mount()

Signed-off-by: Al Viro

BKL: Remove BKL from BFS

2010-10-04T19:10:35+00:00

The BKL is only used in put_super and fill_super that are both protected by
the superblocks s_umount rw_semaphore. Therefore it is safe to remove the BKL
entirely.

Signed-off-by: Jan Blunck 
Signed-off-by: Arnd Bergmann

BKL: Explicitly add BKL around get_sb/fill_super

2010-10-04T19:10:10+00:00

This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]

Signed-off-by: Jan Blunck 
Signed-off-by: Arnd Bergmann 
Cc: Matthew Wilcox 
Cc: Christoph Hellwig

BFS: clean up the superblock usage

2010-08-09T20:48:53+00:00

BFS is a very simple FS and its superblocks contains only static
information and is never changed. However, the BFS code for some
misterious reasons marked its buffer head as dirty from time to
time, but nothing in that buffer was ever changed.

This patch removes all the BFS superblock manipulation, simply
because it is not needed. It removes:

1. The si_sbh filed from 'struct bfs_sb_info' because it is not
   needed. We only need to read the SB once on mount to get the
   start of data blocks and the FS size. After this, we can forget
   about the SB.
2. All instances of 'mark_buffer_dirty(sbh)' for BFS SB because
   it is never changed.
3. The '->sync_fs()' method because there is nothing to sync
   (inodes are synched by VFS).
4. The '->write_super()' method, again, because the SB is never
   changed.

Tested-by: Artem Bityutskiy 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: Al Viro

switch bfs to ->evict_inode(), clean up

2010-08-09T20:48:04+00:00

Signed-off-by: Al Viro

pass writeback_control to ->write_inode

2010-03-05T18:25:52+00:00

This gives the filesystem more information about the writeback that
is happening.  Trond requested this for the NFS unstable write handling,
and other filesystems might benefit from this too by beeing able to
distinguish between the different callers in more detail.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

Fix failure exits in bfs_fill_super()

2010-01-27T03:22:25+00:00

double iput(), leaks...

Signed-off-by: Al Viro

bfs: add ->sync_fs

2009-06-12T01:36:14+00:00

Add a ->sync_fs method for data integrity syncs, and reimplement
->write_super ontop of it.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Al Viro

repair bfs_write_inode(), switch bfs to simple_fsync()

2009-06-12T01:36:14+00:00

Signed-off-by: Al Viro