linux-toradex.git/fs/proc/inode.c, branch v3.2-rc5

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

procfs: return ENOENT on opening a being-removed proc entry

2011-07-26T23:49:43+00:00

Change the return value to ENOENT.  This return value is then returned
when opening the proc entry that have been removed.  For example,
open("/proc/bus/pci/XX/YY") when the corresponding device is being
hot-removed.

Signed-off-by: Daisuke Ogino 
Cc: Jesse Barnes 
Acked-by: Alexey Dobriyan 
Cc: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ns: proc files for namespace naming policy.

2011-05-10T21:31:44+00:00

Create files under /proc//ns/ to allow controlling the
namespaces of a process.

This addresses three specific problems that can make namespaces hard to
work with.
- Namespaces require a dedicated process to pin them in memory.
- It is not possible to use a namespace unless you are the child
  of the original creator.
- Namespaces don't have names that userspace can use to talk about
  them.

The namespace files under /proc//ns/ can be opened and the
file descriptor can be used to talk about a specific namespace, and
to keep the specified namespace alive.

A namespace can be kept alive by either holding the file descriptor
open or bind mounting the file someplace else.  aka:
mount --bind /proc/self/ns/net /some/filesystem/path
mount --bind /proc/self/fd/ /some/filesystem/path

This allows namespaces to be named with userspace policy.

It requires additional support to make use of these filedescriptors
and that will be comming in the following patches.

Acked-by: Daniel Lezcano 
Signed-off-by: Eric W. Biederman

procfs: kill the global proc_mnt variable

2011-03-24T02:46:58+00:00

After the previous cleanup in proc_get_sb() the global proc_mnt has no
reasons to exists, kill it.

Signed-off-by: Oleg Nesterov 
Signed-off-by: Eric W. Biederman 
Signed-off-by: Daniel Lezcano 
Cc: Alexey Dobriyan 
Acked-by: Serge E. Hallyn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

unfuck proc_sysctl ->d_compare()

2011-03-08T07:22:27+00:00

a) struct inode is not going to be freed under ->d_compare();
however, the thing PROC_I(inode)->sysctl points to just might.
Fortunately, it's enough to make freeing that sucker delayed,
provided that we don't step on its ->unregistering, clear
the pointer to it in PROC_I(inode) before dropping the reference
and check if it's NULL in ->d_compare().

b) I'm not sure that we *can* walk into NULL inode here (we recheck
dentry->seq between verifying that it's still hashed / fetching
dentry->d_inode and passing it to ->d_compare() and there's no
negative hashed dentries in /proc/sys/*), but if we can walk into
that, we really should not have ->d_compare() return 0 on it!
Said that, I really suspect that this check can be simply killed.
Nick?

Signed-off-by: Al Viro

proc: ->low_ino cleanup

2011-01-13T16:03:16+00:00

- ->low_ino is write-once field -- reading it under locks is unnecessary.

- /proc/$PID stuff never reaches pde_put()/free_proc_entry() --
   PROC_DYNAMIC_FIRST check never triggers.

- in proc_get_inode(), inode number always matches proc dir entry, so
  save one parameter.

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

BKL: remove extraneous #include

2010-11-17T16:59:32+00:00

The big kernel lock has been removed from all these files at some point,
leaving only the #include.

Remove this too as a cleanup.

Signed-off-by: Arnd Bergmann 
Signed-off-by: Linus Torvalds

bkl: Remove locked .ioctl file operation

2010-08-13T22:24:24+00:00

The last user is gone, so we can safely remove this

Signed-off-by: Arnd Bergmann 
Cc: John Kacur 
Cc: Al Viro 
Cc: Thomas Gleixner 
Signed-off-by: Frederic Weisbecker

switch procfs to ->evict_inode()

2010-08-09T20:47:52+00:00

Signed-off-by: Al Viro