5590ff0d55
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>
62 lines
1.9 KiB
C
62 lines
1.9 KiB
C
#ifndef _LINUX_FCNTL_H
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#define _LINUX_FCNTL_H
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#include <asm/fcntl.h>
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#define F_SETLEASE (F_LINUX_SPECIFIC_BASE+0)
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#define F_GETLEASE (F_LINUX_SPECIFIC_BASE+1)
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/*
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* Request nofications on a directory.
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* See below for events that may be notified.
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*/
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#define F_NOTIFY (F_LINUX_SPECIFIC_BASE+2)
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/*
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* Types of directory notifications that may be requested.
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*/
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#define DN_ACCESS 0x00000001 /* File accessed */
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#define DN_MODIFY 0x00000002 /* File modified */
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#define DN_CREATE 0x00000004 /* File created */
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#define DN_DELETE 0x00000008 /* File removed */
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#define DN_RENAME 0x00000010 /* File renamed */
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#define DN_ATTRIB 0x00000020 /* File changed attibutes */
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#define DN_MULTISHOT 0x80000000 /* Don't remove notifier */
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#define AT_FDCWD -100 /* Special value used to indicate
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openat should use the current
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working directory. */
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#define AT_SYMLINK_NOFOLLOW 0x100 /* Do not follow symbolic links. */
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#define AT_REMOVEDIR 0x200 /* Remove directory instead of
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unlinking file. */
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#ifdef __KERNEL__
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#ifndef force_o_largefile
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#define force_o_largefile() (BITS_PER_LONG != 32)
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#endif
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#if BITS_PER_LONG == 32
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#define IS_GETLK32(cmd) ((cmd) == F_GETLK)
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#define IS_SETLK32(cmd) ((cmd) == F_SETLK)
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#define IS_SETLKW32(cmd) ((cmd) == F_SETLKW)
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#define IS_GETLK64(cmd) ((cmd) == F_GETLK64)
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#define IS_SETLK64(cmd) ((cmd) == F_SETLK64)
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#define IS_SETLKW64(cmd) ((cmd) == F_SETLKW64)
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#else
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#define IS_GETLK32(cmd) (0)
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#define IS_SETLK32(cmd) (0)
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#define IS_SETLKW32(cmd) (0)
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#define IS_GETLK64(cmd) ((cmd) == F_GETLK)
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#define IS_SETLK64(cmd) ((cmd) == F_SETLK)
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#define IS_SETLKW64(cmd) ((cmd) == F_SETLKW)
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#endif /* BITS_PER_LONG == 32 */
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#define IS_GETLK(cmd) (IS_GETLK32(cmd) || IS_GETLK64(cmd))
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#define IS_SETLK(cmd) (IS_SETLK32(cmd) || IS_SETLK64(cmd))
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#define IS_SETLKW(cmd) (IS_SETLKW32(cmd) || IS_SETLKW64(cmd))
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#endif /* __KERNEL__ */
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#endif
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