diff options
author | Andrew Morton <akpm@osdl.org> | 2006-03-31 02:30:42 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-31 12:18:54 -0800 |
commit | f79e2abb9bd452d97295f34376dedbec9686b986 (patch) | |
tree | 56b9998caa11983556e842fb9a8143d86d765fa3 /include/linux/syscalls.h | |
parent | d6dfd1310d3562698fd7c3c086f6c239f96394ac (diff) | |
download | op-kernel-dev-f79e2abb9bd452d97295f34376dedbec9686b986.zip op-kernel-dev-f79e2abb9bd452d97295f34376dedbec9686b986.tar.gz |
[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 <nickpiggin@yahoo.com.au>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/syscalls.h')
-rw-r--r-- | include/linux/syscalls.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index e78ffc7..5717147 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -571,5 +571,7 @@ asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename, asmlinkage long sys_unshare(unsigned long unshare_flags); asmlinkage long sys_splice(int fdin, int fdout, size_t len, unsigned int flags); +asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes, + int flags); #endif |