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authorAndrew Morton <akpm@osdl.org>2006-03-31 02:30:42 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-31 12:18:54 -0800
commitf79e2abb9bd452d97295f34376dedbec9686b986 (patch)
tree56b9998caa11983556e842fb9a8143d86d765fa3 /include/linux
parentd6dfd1310d3562698fd7c3c086f6c239f96394ac (diff)
[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')
-rw-r--r--include/linux/fadvise.h6
-rw-r--r--include/linux/fs.h7
-rw-r--r--include/linux/syscalls.h2
3 files changed, 9 insertions, 6 deletions
diff --git a/include/linux/fadvise.h b/include/linux/fadvise.h
index b2913bba35d..e8e747139b9 100644
--- a/include/linux/fadvise.h
+++ b/include/linux/fadvise.h
@@ -18,10 +18,4 @@
#define POSIX_FADV_NOREUSE 5 /* Data will be accessed once. */
#endif
-/*
- * Linux-specific fadvise() extensions:
- */
-#define LINUX_FADV_ASYNC_WRITE 32 /* Start writeout on range */
-#define LINUX_FADV_WRITE_WAIT 33 /* Wait upon writeout to range */
-
#endif /* FADVISE_H_INCLUDED */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 20a7afd4590..4ed7e602d70 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -757,6 +757,13 @@ extern void send_sigio(struct fown_struct *fown, int fd, int band);
extern int fcntl_setlease(unsigned int fd, struct file *filp, long arg);
extern int fcntl_getlease(struct file *filp);
+/* fs/sync.c */
+#define SYNC_FILE_RANGE_WAIT_BEFORE 1
+#define SYNC_FILE_RANGE_WRITE 2
+#define SYNC_FILE_RANGE_WAIT_AFTER 4
+extern int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
+ int flags);
+
/* fs/locks.c */
extern void locks_init_lock(struct file_lock *);
extern void locks_copy_lock(struct file_lock *, struct file_lock *);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index e78ffc7d5b5..5717147596b 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