linux-toradex.git/include/linux/fs_struct.h, branch v2.6.36-rc7

fs: fs_struct rwlock to spinlock

2010-08-18T12:35:46+00:00

fs: fs_struct rwlock to spinlock

struct fs_struct.lock is an rwlock with the read-side used to protect root and
pwd members while taking references to them. Taking a reference to a path
typically requires just 2 atomic ops, so the critical section is very small.
Parallel read-side operations would have cacheline contention on the lock, the
dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
real parallelism increase.

Replace it with a spinlock to avoid one or two atomic operations in typical
path lookup fastpath.

Signed-off-by: Nick Piggin 
Signed-off-by: Al Viro

vfs: add helpers to get root and pwd

2010-08-11T04:28:20+00:00

Add three helpers that retrieve a refcounted copy of the root and cwd
from the supplied fs_struct.

 get_fs_root()
 get_fs_pwd()
 get_fs_root_and_pwd()

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro

New locking/refcounting for fs_struct

2009-04-01T03:00:26+00:00

* all changes of current->fs are done under task_lock and write_lock of
  old fs->lock
* refcount is not atomic anymore (same protection)
* its decrements are done when removing reference from current; at the
  same time we decide whether to free it.
* put_fs_struct() is gone
* new field - ->in_exec.  Set by check_unsafe_exec() if we are trying to do
  execve() and only subthreads share fs_struct.  Cleared when finishing exec
  (success and failure alike).  Makes CLONE_FS fail with -EAGAIN if set.
* check_unsafe_exec() may fail with -EAGAIN if another execve() from subthread
  is in progress.

Signed-off-by: Al Viro

Take fs_struct handling to new file (fs/fs_struct.c)

2009-04-01T03:00:26+00:00

Pure code move; two new helper functions for nfsd and daemonize
(unshare_fs_struct() and daemonize_fs_struct() resp.; for now -
the same code as used to be in callers).  unshare_fs_struct()
exported (for nfsd, as copy_fs_struct()/exit_fs() used to be),
copy_fs_struct() and exit_fs() don't need exports anymore.

Signed-off-by: Al Viro

Annotate struct fs_struct's usage count restriction

2009-03-29T00:30:00+00:00

Annotate struct fs_struct's usage count to indicate the restrictions upon it.
It may not be incremented, except by clone(CLONE_FS), as this affects the
check in check_unsafe_exec() in fs/exec.c.

Signed-off-by: David Howells 
Signed-off-by: Hugh Dickins 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds

take init_fs to saner place

2008-12-31T23:07:42+00:00

Signed-off-by: Al Viro

[PATCH] kill altroot

2008-07-27T00:53:20+00:00

long overdue...

Signed-off-by: Al Viro

Make set_fs_{root,pwd} take a struct path

2008-02-15T05:13:33+00:00

In nearly all cases the set_fs_{root,pwd}() calls work on a struct
path. Change the function to reflect this and use path_get() here.

Signed-off-by: Jan Blunck 
Signed-off-by: Andreas Gruenbacher 
Acked-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Use struct path in fs_struct

2008-02-15T05:13:33+00:00

* Use struct path in fs_struct.

Signed-off-by: Andreas Gruenbacher 
Signed-off-by: Jan Blunck 
Acked-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Move fs_cachep to linux/fs_struct.h

2006-12-07T16:39:23+00:00

fs_cachep is only used in kernel/exit.c and in kernel/fork.c.

It is used to store fs_struct items so it should be placed in linux/fs_struct.h

Signed-off-by: Christoph Lameter 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds