linux-toradex.git/fs/stat.c, branch v3.1-rc2

vfs: optimize inode cache access patterns

2011-08-07T05:53:23+00:00

The inode structure layout is largely random, and some of the vfs paths
really do care.  The path lookup in particular is already quite D$
intensive, and profiles show that accessing the 'inode->i_op->xyz'
fields is quite costly.

We already optimized the dcache to not unnecessarily load the d_op
structure for members that are often NULL using the DCACHE_OP_xyz bits
in dentry->d_flags, and this does something very similar for the inode
ops that are used during pathname lookup.

It also re-orders the fields so that the fields accessed by 'stat' are
together at the beginning of the inode structure, and roughly in the
order accessed.

The effect of this seems to be in the 1-2% range for an empty kernel
"make -j" run (which is fairly kernel-intensive, mostly in filename
lookup), so it's visible.  The numbers are fairly noisy, though, and
likely depend a lot on exact microarchitecture.  So there's more tuning
to be done.

Signed-off-by: Linus Torvalds

readlinkat(), fchownat() and fstatat() with empty relative pathnames

2011-03-15T06:21:45+00:00

For readlinkat() we simply allow empty pathname; it will fail unless
we have dfd equal to O_PATH-opened symlink, so we are outside of
POSIX scope here.  For fchownat() and fstatat() we allow AT_EMPTY_PATH;
let the caller explicitly ask for such behaviour.

Signed-off-by: Al Viro

Add an AT_NO_AUTOMOUNT flag to suppress terminal automount

2011-01-16T01:07:33+00:00

Add an AT_NO_AUTOMOUNT flag to suppress terminal automounting of automount
point directories.  This can be used by fstatat() users to permit the
gathering of attributes on an automount point and also prevent
mass-automounting of a directory of automount points by ls.

Signed-off-by: David Howells 
Acked-by: Ian Kent 
Signed-off-by: Al Viro

Mark arguments to certain syscalls as being const

2010-08-13T23:53:13+00:00

Mark arguments to certain system calls as being const where they should be but
aren't.  The list includes:

 (*) The filename arguments of various stat syscalls, execve(), various utimes
     syscalls and some mount syscalls.

 (*) The filename arguments of some syscall helpers relating to the above.

 (*) The buffer argument of various write syscalls.

Signed-off-by: David Howells 
Acked-by: David S. Miller 
Signed-off-by: Linus Torvalds

Add unlocked version of inode_add_bytes() function

2009-12-23T12:33:54+00:00

Quota code requires unlocked version of this function. Off course
we can just copy-paste the code, but copy-pasting is always an evil.

Signed-off-by: Dmitry Monakhov 
Signed-off-by: Jan Kara

kill vfs_stat_fd / vfs_lstat_fd

2009-04-21T03:02:52+00:00

There's really no reason to keep vfs_stat_fd and vfs_lstat_fd with
Oleg's vfs_fstatat.  Use vfs_fstatat for the few cases having the
directory fd, and switch all others to vfs_stat / vfs_lstat.

Reviewed-by: Christoph Hellwig 

Signed-off-by: Al Viro

Separate out common fstatat code into vfs_fstatat

2009-04-21T03:02:51+00:00

This is a version incorporating Christoph's suggestion.

Separate out common *fstatat functionality into a single function
instead of duplicating it all over the code.

Signed-off-by: Oleg Drokin 
Signed-off-by: Al Viro

[CVE-2009-0029] System call wrappers part 30

2009-01-14T13:15:30+00:00

Signed-off-by: Heiko Carstens

[CVE-2009-0029] System call wrappers part 16

2009-01-14T13:15:25+00:00

Signed-off-by: Heiko Carstens

[CVE-2009-0029] System call wrappers part 11

2009-01-14T13:15:23+00:00

Signed-off-by: Heiko Carstens