linux-stable.git/fs/sysv/inode.c, branch v3.2.78

fix sysvfs symlinks

2015-12-30T02:25:57+00:00

commit 0ebf7f10d67a70e120f365018f1c5fce9ddc567d upstream.

The thing got broken back in 2002 - sysvfs does *not* have inline
symlinks; even short ones have bodies stored in the first block
of file.  sysv_symlink() handles that correctly; unfortunately,
attempting to look an existing symlink up will end up confusing
them for inline symlinks, and interpret the block number containing
the body as the body itself.

Nobody has noticed until now, which says something about the level
of testing sysvfs gets ;-/

Signed-off-by: Al Viro 
[bwh: Backported to 3.2:
 - Adjust context
 - Also delete unused sysv_fast_symlink_inode_operations]
Signed-off-by: Ben Hutchings

filesystems: add set_nlink()

2011-11-02T11:53:43+00:00

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.

Signed-off-by: Miklos Szeredi 
Tested-by: Toshiyuki Okajima 
Signed-off-by: Christoph Hellwig

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

sysv: do not mark superblock dirty on remount

2010-08-09T20:48:58+00:00

No need to mark the superblock as dirty in sysv_remount, synchronize
it instead (only if mounting R/O).

I did not find any docs about this file-system, and I have no possibility
to test my changes. Thus, this is untested. I see other issues in sysv,
e.g., why sysv_sync_fs writes only in the FSTYPE_SYSV4 case? However,
it marks its SB bh's dirty for all types, and does not wait for them
ever. With zero docs I'm unable to fix this.

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

switch sysv to ->evict_inode()

2010-08-09T20:47:59+00:00

Signed-off-by: Al Viro

fix fs/sysv s_dirt handling

2010-05-28T02:16:05+00:00

got broken on ->sync_fs() conversion a year ago, nobody noticed...

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

get rid of BKL in fs/sysv

2009-06-17T04:36:37+00:00

Signed-off-by: Al Viro

sysv: add ->sync_fs

2009-06-12T01:36:16+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 sysv_write_inode(), switch sysv to simple_fsync()

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

Signed-off-by: Al Viro