linux.git/fs/open.c, branch v2.6.16

[PATCH] vfs: *at functions: core

2006-01-19T03:20:29+00:00

Here is a series of patches which introduce in total 13 new system calls
which take a file descriptor/filename pair instead of a single file
name.  These functions, openat etc, have been discussed on numerous
occasions.  They are needed to implement race-free filesystem traversal,
they are necessary to implement a virtual per-thread current working
directory (think multi-threaded backup software), etc.

We have in glibc today implementations of the interfaces which use the
/proc/self/fd magic.  But this code is rather expensive.  Here are some
results (similar to what Jim Meyering posted before).

The test creates a deep directory hierarchy on a tmpfs filesystem.  Then
rm -fr is used to remove all directories.  Without syscall support I get
this:

real    0m31.921s
user    0m0.688s
sys     0m31.234s

With syscall support the results are much better:

real    0m20.699s
user    0m0.536s
sys     0m20.149s

The interfaces are for obvious reasons currently not much used.  But they'll
be used.  coreutils (and Jeff's posixutils) are already using them.
Furthermore, code like ftw/fts in libc (maybe even glob) will also start using
them.  I expect a patch to make follow soon.  Every program which is walking
the filesystem tree will benefit.

Signed-off-by: Ulrich Drepper 
Signed-off-by: Alexey Dobriyan 
Cc: Christoph Hellwig 
Cc: Al Viro 
Acked-by: Ingo Molnar 
Cc: Michael Kerrisk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] capable/capability.h (fs/)

2006-01-12T02:42:13+00:00

fs: Use  where capable() is used.

Signed-off-by: Randy Dunlap 
Acked-by: Tim Schmielau 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem

2006-01-09T23:59:24+00:00

This patch converts the inode semaphore to a mutex. I have tested it on
XFS and compiled as much as one can consider on an ia64. Anyway your
luck with it might be different.

Modified-by: Ingo Molnar 

(finished the conversion)

Signed-off-by: Jes Sorensen 
Signed-off-by: Ingo Molnar

[PATCH] tiny: Uninline some open.c functions

2006-01-09T04:14:10+00:00

uninline some open.c functions

add/remove: 3/0 grow/shrink: 0/6 up/down: 679/-1166 (-487)
function                                     old     new   delta
do_sys_truncate                                -     336    +336
do_sys_ftruncate                               -     317    +317
__put_unused_fd                                -      26     +26
put_unused_fd                                 57      49      -8
sys_close                                    150     119     -31
sys_ftruncate64                              260      26    -234
sys_ftruncate                                272      24    -248
sys_truncate                                 339      25    -314
sys_truncate64                               336       5    -331

Signed-off-by: Matt Mackall 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] Fix some problems with truncate and mtime semantics.

2006-01-09T04:13:52+00:00

SUS requires that when truncating a file to the size that it currently
is:
  truncate and ftruncate should NOT modify ctime or mtime
  O_TRUNC SHOULD modify ctime and mtime.

Currently mtime and ctime are always modified on most local
filesystems (side effect of ->truncate) or never modified (on NFS).

With this patch:
  ATTR_CTIME|ATTR_MTIME are sent with ATTR_SIZE precisely when
    an update of these times is required whether size changes or not
    (via a new argument to do_truncate).  This allows NFS to do
    the right thing for O_TRUNC.
  inode_setattr nolonger forces ATTR_MTIME|ATTR_CTIME when the ATTR_SIZE
    sets the size to it's current value.  This allows local filesystems
    to do the right thing for f?truncate.

Also, the logic in inode_setattr is changed a bit so there are two return
points.  One returns the error from vmtruncate if it failed, the other
returns 0 (there can be no other failure).

Finally, if vmtruncate succeeds, and ATTR_SIZE is the only change
requested, we now fall-through and mark_inode_dirty.  If a filesystem did
not have a ->truncate function, then vmtruncate will have changed i_size,
without marking the inode as 'dirty', and I think this is wrong.

Signed-off-by: Neil Brown 
Cc: Christoph Hellwig 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] add a file_permission helper

2005-11-09T15:55:59+00:00

A few more callers of permission() just want to check for a different access
pattern on an already open file.  This patch adds a wrapper for permission()
that takes a file in preparation of per-mount read-only support and to clean
up the callers a little.  The helper is not intended for new code, everything
without the interface set in stone should use vfs_permission()

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

[PATCH] add a vfs_permission helper

2005-11-09T15:55:58+00:00

Most permission() calls have a struct nameidata * available.  This helper
takes that as an argument and thus makes sure we pass it down for lookup
intents and prepares for per-mount read-only support where we need a struct
vfsmount for checking whether a file is writeable.

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

[PATCH] VFS: pass file pointer to filesystem from ftruncate()

2005-11-07T15:53:42+00:00

This patch extends the iattr structure with a file pointer memeber, and adds
an ATTR_FILE validity flag for this member.

This is set if do_truncate() is invoked from ftruncate() or from
do_coredump().

The change is source and binary compatible.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] memory leak in dentry_open()

2005-11-07T15:53:39+00:00

There is a memory leak possible in dentry_open().  If get_empty_filp()
fails, then the references to dentry and mnt need to be released.  The
attached patch adds the calls to dput() and mntput() to release these two
references.

Signed-off-by: Peter Staubach 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

VFS: Allow the filesystem to return a full file pointer on open intent

2005-10-18T21:20:16+00:00

 This is needed by NFSv4 for atomicity reasons: our open command is in
 fact a lookup+open, so we need to be able to propagate open context
 information from lookup() into the resulting struct file's
 private_data field.

 Signed-off-by: Trond Myklebust