From f79e2abb9bd452d97295f34376dedbec9686b986 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 31 Mar 2006 02:30:42 -0800 Subject: [PATCH] sys_sync_file_range() Remove the recently-added LINUX_FADV_ASYNC_WRITE and LINUX_FADV_WRITE_WAIT fadvise() additions, do it in a new sys_sync_file_range() syscall instead. Reasons: - It's more flexible. Things which would require two or three syscalls with fadvise() can be done in a single syscall. - Using fadvise() in this manner is something not covered by POSIX. The patch wires up the syscall for x86. The sycall is implemented in the new fs/sync.c. The intention is that we can move sys_fsync(), sys_fdatasync() and perhaps sys_sync() into there later. Documentation for the syscall is in fs/sync.c. A test app (sync_file_range.c) is in http://www.zip.com.au/~akpm/linux/patches/stuff/ext3-tools.tar.gz. The available-to-GPL-modules do_sync_file_range() is for knfsd: "A COMMIT can say NFS_DATA_SYNC or NFS_FILE_SYNC. I can skip the ->fsync call for NFS_DATA_SYNC which is hopefully the more common." Note: the `async' writeout mode SYNC_FILE_RANGE_WRITE will turn synchronous if the queue is congested. This is trivial to fix: add a new flag bit, set wbc->nonblocking. But I'm not sure that we want to expose implementation details down to that level. Note: it's notable that we can sync an fd which wasn't opened for writing. Same with fsync() and fdatasync()). Note: the code takes some care to handle attempts to sync file contents outside the 16TB offset on 32-bit machines. It makes such attempts appear to succeed, for best 32-bit/64-bit compatibility. Perhaps it should make such requests fail... Cc: Nick Piggin Cc: Michael Kerrisk Cc: Ulrich Drepper Cc: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/asm-i386/unistd.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/asm-i386/unistd.h') diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h index 789e9bdd0a4..2e7f3e257fd 100644 --- a/include/asm-i386/unistd.h +++ b/include/asm-i386/unistd.h @@ -319,8 +319,9 @@ #define __NR_set_robust_list 311 #define __NR_get_robust_list 312 #define __NR_sys_splice 313 +#define __NR_sys_sync_file_range 314 -#define NR_syscalls 314 +#define NR_syscalls 315 /* * user-visible error numbers are in the range -1 - -128: see -- cgit v1.2.3