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Ulrich Drepper 5590ff0d55 [PATCH] vfs: *at functions: core 
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 <drepper@redhat.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
 		2006-01-18 19:20:29 -08:00
..
9p [PATCH] v9fs: add readpage support 2006-01-18 19:20:22 -08:00
adfs
…
affs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
afs add loglevel to printk in fs/afs/cmservice.c 2006-01-11 01:52:40 +01:00
autofs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
autofs4 [PATCH] autofs4 oops fix 2006-01-14 18:25:19 -08:00
befs
…
bfs
…
cifs [PATCH] turn "const static" into "static const" 2006-01-10 08:01:55 -08:00
coda [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
configfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
cramfs
…
debugfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
devfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
devpts [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
efs return statement cleanup - kill pointless parentheses 2006-01-15 02:37:08 +01:00
exportfs [PATCH] exportfs: add find_acceptable_alias helper 2006-01-18 19:20:28 -08:00
ext2 [PATCH] ext2: remove d_splice_alias NULL check from ext2_lookup 2006-01-14 18:27:10 -08:00
ext3 [PATCH] ext3: remove d_splice_alias NULL check from ext3_lookup 2006-01-14 18:27:10 -08:00
fat [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
freevxfs [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
fuse [PATCH] fuse: fix bitfield race 2006-01-16 23:15:31 -08:00
hfs [PATCH] hfs: cleanup HFS prints 2006-01-18 19:20:23 -08:00
hfsplus [PATCH] hfs: set type/creator for symlinks 2006-01-18 19:20:23 -08:00
hostfs [PATCH] uml: hostfs - fix possible PAGE_CACHE_SHIFT overflows 2005-12-29 09:48:15 -08:00
hpfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
hppfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
hugetlbfs [PATCH] Add tmpfs options for memory placement policies 2006-01-14 18:27:07 -08:00
isofs [PATCH] isofs: remove d_splice_alias NULL check from isofs_lookup 2006-01-14 18:27:12 -08:00
jbd [PATCH] jbd: remove_transaction fix 2006-01-18 19:20:16 -08:00
jffs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
jffs2 [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
jfs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
lockd [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
minix
…
msdos
…
ncpfs [PATCH] ncpfs: remove kmalloc wrapper 2006-01-14 18:27:12 -08:00
nfs [PATCH] per-mountpoint noatime/nodiratime 2006-01-10 08:01:34 -08:00
nfs_common
…
nfsd [PATCH] knfsd: Provide missing NFSv2 part of patch for checking vfs_getattr. 2006-01-18 19:20:28 -08:00
nls
…
ntfs [PATCH] ntfs: remove superflous MS_NOATIME/MS_NODIRATIME assignments 2006-01-10 08:01:33 -08:00
ocfs2 [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
openpromfs
…
partitions [PATCH] partitions: Read Rio Karma partition table 2006-01-16 23:15:29 -08:00
proc [PATCH] convert /proc/devices to use seq_file interface 2006-01-14 18:25:19 -08:00
qnx4 fs/qnx4/bitmap.c: #if 0 qnx4_new_block() 2006-01-03 13:21:37 +01:00
ramfs [PATCH] NOMMU: Provide shared-writable mmap support on ramfs 2006-01-06 08:33:32 -08:00
reiserfs [PATCH] reiserfs: remove d_splice_alias NULL check from reiserfs_lookup 2006-01-14 18:27:12 -08:00
relayfs [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
romfs [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
smbfs [PATCH] smbfs: remove kmalloc wrapper 2006-01-14 18:27:13 -08:00
sysfs [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
sysv correct email address of Manfred Spraul 2006-01-15 02:43:54 +01:00
udf [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
ufs [PATCH] ufs cleanup 2006-01-14 10:27:32 -08:00
vfat
…
xfs [XFS] Fix a race in xfs_submit_ioend() where we can be completing I/O for 2006-01-18 13:38:12 +11:00
Kconfig [PATCH] kexec: change CONFIG_PHYSICAL_START dependency 2006-01-10 08:01:29 -08:00
Kconfig.binfmt [PATCH] frv: suppress configuration of certain features for FRV 2006-01-08 20:13:36 -08:00
Makefile [PATCH] sanitize building of fs/compat_ioctl.c 2006-01-10 08:01:33 -08:00
aio.c [PATCH] rcu file: use atomic primitives 2006-01-08 20:13:48 -08:00
attr.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
bad_inode.c
…
binfmt_aout.c [PATCH] dump_thread() cleanup 2006-01-10 08:01:25 -08:00
binfmt_elf.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
binfmt_elf_fdpic.c [PATCH] fs/binfmt_elf: Remove unneeded kmalloc() return value casts 2006-01-10 08:02:01 -08:00
binfmt_em86.c
…
binfmt_flat.c [PATCH] uclinux: delay binfmt_flat trace 2006-01-10 09:31:27 -08:00
binfmt_misc.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
binfmt_script.c
…
binfmt_som.c
…
bio.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
block_dev.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
buffer.c Make alloc_page_buffers() initialise buffer_heads using init_buffer(), 2006-01-17 09:02:07 +11:00
char_dev.c [PATCH] convert /proc/devices to use seq_file interface 2006-01-14 18:25:19 -08:00
compat.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
compat_ioctl.c [PATCH] Implement ioctl emulation for the parport character device 2006-01-12 09:08:49 -08:00
dcache.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
dcookies.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
direct-io.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
dnotify.c
…
dquot.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
drop_caches.c [PATCH] drop-pagecache 2006-01-08 20:12:40 -08:00
eventpoll.c
…
exec.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
fcntl.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
fifo.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
file.c
…
file_table.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
filesystems.c
…
fs-writeback.c
…
inode.c [PATCH] per-mountpoint noatime/nodiratime 2006-01-10 08:01:34 -08:00
inotify.c [PATCH] add missing syscall declarations 2006-01-18 19:20:22 -08:00
ioctl.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
ioprio.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
libfs.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
locks.c [PATCH] tiny: Uninline some fslocks.c functions 2006-01-08 20:14:10 -08:00
mbcache.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
mpage.c [PATCH] fix possible PAGE_CACHE_SHIFT overflows 2006-01-08 20:13:54 -08:00
namei.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
namespace.c [PATCH] add /sys/fs 2006-01-16 23:15:29 -08:00
nfsctl.c
…
open.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
pipe.c [PATCH] Unlinline a bunch of other functions 2006-01-14 18:27:06 -08:00
pnode.c [PATCH] shared mounts: cleanup 2006-01-08 20:13:56 -08:00
pnode.h
…
posix_acl.c
…
quota.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
quota_v1.c
…
quota_v2.c [PATCH] quota: make useless quota error message informative 2006-01-14 18:27:12 -08:00
read_write.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
readdir.c [PATCH] mutex subsystem, semaphore to mutex: VFS, ->i_sem 2006-01-09 15:59:24 -08:00
select.c
…
seq_file.c
…
stat.c [PATCH] vfs: *at functions: core 2006-01-18 19:20:29 -08:00
super.c [PATCH] mutex subsystem, semaphore to mutex: VFS, sb->s_lock 2006-01-09 15:59:25 -08:00
xattr.c [PATCH] move xattr permission checks into the VFS 2006-01-10 08:01:29 -08:00
xattr_acl.c
…