From: Andrew Morton <[email protected]>
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.
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 appears to
succeed, for best 32-bit/64-bit compatibility. Perhaps it should make such
requests fail...
Cc: Nick Piggin <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Cc: Ulrich Drepper <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---
arch/i386/kernel/syscall_table.S | 1
fs/Makefile | 2
fs/sync.c | 147 +++++++++++++++++++++++++++++
include/asm-i386/unistd.h | 3
include/linux/fadvise.h | 6 -
include/linux/fs.h | 5
include/linux/syscalls.h | 2
mm/fadvise.c | 20 ---
8 files changed, 158 insertions(+), 28 deletions(-)
diff -puN mm/fadvise.c~sys_sync_file_range mm/fadvise.c
--- devel/mm/fadvise.c~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/mm/fadvise.c 2006-03-29 23:26:42.000000000 -0800
@@ -35,17 +35,6 @@
*
* LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
*
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently
- * dirty pages at the disk.
- *
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE, LINUX_FADV_WRITE_WAIT: push
- * all of the currently dirty pages at the disk, wait until they have been
- * written.
- *
- * It should be noted that none of these operations write out the file's
- * metadata. So unless the application is strictly performing overwrites of
- * already-instantiated disk blocks, there are no guarantees here that the data
- * will be available after a crash.
*/
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
@@ -129,15 +118,6 @@ asmlinkage long sys_fadvise64_64(int fd,
invalidate_mapping_pages(mapping, start_index,
end_index);
break;
- case LINUX_FADV_ASYNC_WRITE:
- ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
- WB_SYNC_NONE);
- break;
- case LINUX_FADV_WRITE_WAIT:
- ret = wait_on_page_writeback_range(mapping,
- offset >> PAGE_CACHE_SHIFT,
- endbyte >> PAGE_CACHE_SHIFT);
- break;
default:
ret = -EINVAL;
}
diff -puN include/linux/fadvise.h~sys_sync_file_range include/linux/fadvise.h
--- devel/include/linux/fadvise.h~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/include/linux/fadvise.h 2006-03-29 23:26:42.000000000 -0800
@@ -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 -puN /dev/null fs/sync.c
--- /dev/null 2003-09-15 06:40:47.000000000 -0700
+++ devel-akpm/fs/sync.c 2006-03-29 23:26:42.000000000 -0800
@@ -0,0 +1,147 @@
+/*
+ * High-level sync()-related operations
+ */
+
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/writeback.h>
+#include <linux/syscalls.h>
+#include <linux/linkage.h>
+#include <linux/pagemap.h>
+
+#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
+ SYNC_FILE_RANGE_WAIT_AFTER)
+
+/*
+ * sys_sync_file_range() permits finely controlled syncing over a segment of
+ * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
+ * zero then sys_sync_file_range() will operate from offset out to EOF.
+ *
+ * The flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
+ * before performing the write.
+ *
+ * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
+ * range which are not presently under writeback.
+ *
+ * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
+ * after performing the write.
+ *
+ * Useful combinations of the flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
+ * in the range which were dirty on entry to sys_sync_file_range() are placed
+ * under writeout. This is a start-write-for-data-integrity operation.
+ *
+ * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
+ * are not presently under writeout. This is an asynchronous flush-to-disk
+ * operation. Not suitable for data integrity operations.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
+ * completion of writeout of all pages in the range. This will be used after an
+ * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
+ * for that operation to complete and to return the result.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
+ * a traditional sync() operation. This is a write-for-data-integrity operation
+ * which will ensure that all pages in the range which were dirty on entry to
+ * sys_sync_file_range() are committed to disk.
+ *
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
+ * I/O errors or ENOSPC conditions and will return those to the caller, after
+ * clearing the EIO and ENOSPC flags in the address_space.
+ *
+ * It should be noted that none of these operations write out the file's
+ * metadata. So unless the application is strictly performing overwrites of
+ * already-instantiated disk blocks, there are no guarantees here that the data
+ * will be available after a crash.
+ */
+asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+ int flags)
+{
+ int ret;
+ struct file *file;
+ struct address_space *mapping;
+ loff_t endbyte; /* inclusive */
+
+ ret = -EINVAL;
+ if (flags & ~VALID_FLAGS)
+ goto out;
+
+ endbyte = offset + nbytes;
+
+ if ((s64)offset < 0)
+ goto out;
+ if ((s64)endbyte < 0)
+ goto out;
+ if (endbyte < offset)
+ goto out;
+
+ if (sizeof(pgoff_t) == 4) {
+ if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+ /*
+ * The range starts outside a 32 bit machine's
+ * pagecache addressing capabilities. Let it "succeed"
+ */
+ ret = 0;
+ goto out;
+ }
+ if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+ /*
+ * Out to EOF
+ */
+ nbytes = 0;
+ }
+ }
+
+ if (nbytes == 0)
+ endbyte = -1;
+ else
+ endbyte--; /* inclusive */
+
+ file = fget(fd);
+ if (!file) {
+ ret = -EBADF;
+ goto out;
+ }
+
+ if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
+ ret = -ESPIPE;
+ goto out_put;
+ }
+
+ mapping = file->f_mapping;
+ if (!mapping) {
+ ret = -EINVAL;
+ goto out_put;
+ }
+
+ ret = 0;
+ if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
+ ret = wait_on_page_writeback_range(mapping,
+ offset >> PAGE_CACHE_SHIFT,
+ endbyte >> PAGE_CACHE_SHIFT);
+ if (ret < 0)
+ goto out_put;
+ }
+
+ if (flags & SYNC_FILE_RANGE_WRITE) {
+ ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
+ WB_SYNC_NONE);
+ if (ret < 0)
+ goto out_put;
+ }
+
+ if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
+ ret = wait_on_page_writeback_range(mapping,
+ offset >> PAGE_CACHE_SHIFT,
+ endbyte >> PAGE_CACHE_SHIFT);
+ }
+out_put:
+ fput(file);
+out:
+ return ret;
+}
diff -puN include/linux/syscalls.h~sys_sync_file_range include/linux/syscalls.h
--- devel/include/linux/syscalls.h~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/include/linux/syscalls.h 2006-03-29 23:40:57.000000000 -0800
@@ -569,5 +569,7 @@ asmlinkage long compat_sys_newfstatat(un
asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename,
int flags, int mode);
asmlinkage long sys_unshare(unsigned long unshare_flags);
+asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+ int flags);
#endif
diff -puN include/linux/fs.h~sys_sync_file_range include/linux/fs.h
--- devel/include/linux/fs.h~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/include/linux/fs.h 2006-03-29 23:40:55.000000000 -0800
@@ -757,6 +757,11 @@ extern void send_sigio(struct fown_struc
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
+
/* fs/locks.c */
extern void locks_init_lock(struct file_lock *);
extern void locks_copy_lock(struct file_lock *, struct file_lock *);
diff -puN fs/Makefile~sys_sync_file_range fs/Makefile
--- devel/fs/Makefile~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/fs/Makefile 2006-03-29 23:40:54.000000000 -0800
@@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.
ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
- ioprio.o pnode.o drop_caches.o
+ ioprio.o pnode.o drop_caches.o sync.o
obj-$(CONFIG_INOTIFY) += inotify.o
obj-$(CONFIG_EPOLL) += eventpoll.o
diff -puN include/asm-i386/unistd.h~sys_sync_file_range include/asm-i386/unistd.h
--- devel/include/asm-i386/unistd.h~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/include/asm-i386/unistd.h 2006-03-29 23:26:42.000000000 -0800
@@ -318,8 +318,9 @@
#define __NR_unshare 310
#define __NR_set_robust_list 311
#define __NR_get_robust_list 312
+#define __NR_sys_sync_file_range 313
-#define NR_syscalls 313
+#define NR_syscalls 314
/*
* user-visible error numbers are in the range -1 - -128: see
diff -puN arch/i386/kernel/syscall_table.S~sys_sync_file_range arch/i386/kernel/syscall_table.S
--- devel/arch/i386/kernel/syscall_table.S~sys_sync_file_range 2006-03-29 23:26:42.000000000 -0800
+++ devel-akpm/arch/i386/kernel/syscall_table.S 2006-03-29 23:26:42.000000000 -0800
@@ -312,3 +312,4 @@ ENTRY(sys_call_table)
.long sys_unshare /* 310 */
.long sys_set_robust_list
.long sys_get_robust_list
+ .long sys_sync_file_range
_
On Wednesday March 29, [email protected] wrote:
>
> From: Andrew Morton <[email protected]>
>
> 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.
Hmmm... any chance this could be split into a sys_sync_file_range and
a vfs_sync_file_range which takes a 'struct file*' and does less (or
no) sanity checking, so I can call it from nfsd?
Currently I implement COMMIT (which has a range) with a by messing
around with filemap_fdatawrite and filemap_fdatawait (ignoring the
range) and I'd rather than a vfs helper.
And in nfsd I call filp->f_op->fsync between the two. Doesn't
sys_sync_file_range need to call into the filesystem at all?
NeilBrown
Neil Brown <[email protected]> wrote:
>
> On Wednesday March 29, [email protected] wrote:
> >
> > From: Andrew Morton <[email protected]>
> >
> > 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.
>
> Hmmm... any chance this could be split into a sys_sync_file_range and
> a vfs_sync_file_range which takes a 'struct file*' and does less (or
> no) sanity checking, so I can call it from nfsd?
Coming right up. (Will switch it to fget_light() too)
> Currently I implement COMMIT (which has a range) with a by messing
> around with filemap_fdatawrite and filemap_fdatawait (ignoring the
> range) and I'd rather than a vfs helper.
>
> And in nfsd I call filp->f_op->fsync between the two. Doesn't
> sys_sync_file_range need to call into the filesystem at all?
Interesting question. sync_file_range() is purely a pagecache (ie: file
contents) operation. It doesn't touch metadata at all.
So if it's being used for data-integrity purposes then it really only makes
sense when it's doing file overwrites.
It does call into the filesystem of course - a_ops.writepages() and perhaps
a_ops.writepage().
Neil Brown <[email protected]> wrote:
>
> Hmmm... any chance this could be split into a sys_sync_file_range and
> a vfs_sync_file_range which takes a 'struct file*' and does less (or
> no) sanity checking, so I can call it from nfsd?
Problem is, we don't appear to have a way of syncing the file's metadata
without also syncing all of its pagecache.
For example, ext3_sync_file() will run a commit, which will sync all data
and metadata.
ext2_sync_file() will also sync all pagecache as well as metadata. Even
though do_fsync() already synced the file data (!).
Is the below still useful?
diff -puN mm/fadvise.c~sys_sync_file_range mm/fadvise.c
--- devel/mm/fadvise.c~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/mm/fadvise.c 2006-03-29 23:48:28.000000000 -0800
@@ -35,17 +35,6 @@
*
* LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
*
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE: push all of the currently
- * dirty pages at the disk.
- *
- * LINUX_FADV_WRITE_WAIT, LINUX_FADV_ASYNC_WRITE, LINUX_FADV_WRITE_WAIT: push
- * all of the currently dirty pages at the disk, wait until they have been
- * written.
- *
- * It should be noted that none of these operations write out the file's
- * metadata. So unless the application is strictly performing overwrites of
- * already-instantiated disk blocks, there are no guarantees here that the data
- * will be available after a crash.
*/
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
{
@@ -129,15 +118,6 @@ asmlinkage long sys_fadvise64_64(int fd,
invalidate_mapping_pages(mapping, start_index,
end_index);
break;
- case LINUX_FADV_ASYNC_WRITE:
- ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
- WB_SYNC_NONE);
- break;
- case LINUX_FADV_WRITE_WAIT:
- ret = wait_on_page_writeback_range(mapping,
- offset >> PAGE_CACHE_SHIFT,
- endbyte >> PAGE_CACHE_SHIFT);
- break;
default:
ret = -EINVAL;
}
diff -puN include/linux/fadvise.h~sys_sync_file_range include/linux/fadvise.h
--- devel/include/linux/fadvise.h~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/include/linux/fadvise.h 2006-03-29 23:48:28.000000000 -0800
@@ -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 -puN /dev/null fs/sync.c
--- /dev/null 2003-09-15 06:40:47.000000000 -0700
+++ devel-akpm/fs/sync.c 2006-03-30 00:16:37.000000000 -0800
@@ -0,0 +1,163 @@
+/*
+ * High-level sync()-related operations
+ */
+
+#include <linux/kernel.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/syscalls.h>
+#include <linux/linkage.h>
+#include <linux/pagemap.h>
+
+#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
+ SYNC_FILE_RANGE_WAIT_AFTER)
+
+/*
+ * sys_sync_file_range() permits finely controlled syncing over a segment of
+ * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
+ * zero then sys_sync_file_range() will operate from offset out to EOF.
+ *
+ * The flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
+ * before performing the write.
+ *
+ * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
+ * range which are not presently under writeback.
+ *
+ * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
+ * after performing the write.
+ *
+ * Useful combinations of the flag bits are:
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
+ * in the range which were dirty on entry to sys_sync_file_range() are placed
+ * under writeout. This is a start-write-for-data-integrity operation.
+ *
+ * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
+ * are not presently under writeout. This is an asynchronous flush-to-disk
+ * operation. Not suitable for data integrity operations.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
+ * completion of writeout of all pages in the range. This will be used after an
+ * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
+ * for that operation to complete and to return the result.
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
+ * a traditional sync() operation. This is a write-for-data-integrity operation
+ * which will ensure that all pages in the range which were dirty on entry to
+ * sys_sync_file_range() are committed to disk.
+ *
+ *
+ * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
+ * I/O errors or ENOSPC conditions and will return those to the caller, after
+ * clearing the EIO and ENOSPC flags in the address_space.
+ *
+ * It should be noted that none of these operations write out the file's
+ * metadata. So unless the application is strictly performing overwrites of
+ * already-instantiated disk blocks, there are no guarantees here that the data
+ * will be available after a crash.
+ */
+asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+ int flags)
+{
+ int ret;
+ struct file *file;
+ loff_t endbyte; /* inclusive */
+ int fput_needed;
+
+ ret = -EINVAL;
+ if (flags & ~VALID_FLAGS)
+ goto out;
+
+ endbyte = offset + nbytes;
+
+ if ((s64)offset < 0)
+ goto out;
+ if ((s64)endbyte < 0)
+ goto out;
+ if (endbyte < offset)
+ goto out;
+
+ if (sizeof(pgoff_t) == 4) {
+ if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+ /*
+ * The range starts outside a 32 bit machine's
+ * pagecache addressing capabilities. Let it "succeed"
+ */
+ ret = 0;
+ goto out;
+ }
+ if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
+ /*
+ * Out to EOF
+ */
+ nbytes = 0;
+ }
+ }
+
+ if (nbytes == 0)
+ endbyte = -1;
+ else
+ endbyte--; /* inclusive */
+
+ file = fget_light(fd, &fput_needed);
+ if (!file) {
+ ret = -EBADF;
+ goto out;
+ }
+
+ if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
+ ret = -ESPIPE;
+ goto out_put;
+ }
+
+ ret = do_sync_file_range(file, offset, endbyte, flags);
+out_put:
+ fput_light(file, fput_needed);
+out:
+ return ret;
+}
+
+/*
+ * `endbyte' is inclusive
+ */
+int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
+ int flags)
+{
+ int ret;
+ struct address_space *mapping;
+
+ mapping = file->f_mapping;
+ if (!mapping) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ret = 0;
+ if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
+ ret = wait_on_page_writeback_range(mapping,
+ offset >> PAGE_CACHE_SHIFT,
+ endbyte >> PAGE_CACHE_SHIFT);
+ if (ret < 0)
+ goto out;
+ }
+
+ if (flags & SYNC_FILE_RANGE_WRITE) {
+ ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
+ WB_SYNC_NONE);
+ if (ret < 0)
+ goto out;
+ }
+
+ if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
+ ret = wait_on_page_writeback_range(mapping,
+ offset >> PAGE_CACHE_SHIFT,
+ endbyte >> PAGE_CACHE_SHIFT);
+ }
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(do_sync_file_range);
diff -puN include/linux/syscalls.h~sys_sync_file_range include/linux/syscalls.h
--- devel/include/linux/syscalls.h~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/include/linux/syscalls.h 2006-03-30 00:11:50.000000000 -0800
@@ -569,5 +569,7 @@ asmlinkage long compat_sys_newfstatat(un
asmlinkage long compat_sys_openat(unsigned int dfd, const char __user *filename,
int flags, int mode);
asmlinkage long sys_unshare(unsigned long unshare_flags);
+asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
+ int flags);
#endif
diff -puN include/linux/fs.h~sys_sync_file_range include/linux/fs.h
--- devel/include/linux/fs.h~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/include/linux/fs.h 2006-03-30 00:15:44.000000000 -0800
@@ -757,6 +757,13 @@ extern void send_sigio(struct fown_struc
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 -puN fs/Makefile~sys_sync_file_range fs/Makefile
--- devel/fs/Makefile~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/fs/Makefile 2006-03-30 00:11:47.000000000 -0800
@@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.
ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
- ioprio.o pnode.o drop_caches.o
+ ioprio.o pnode.o drop_caches.o sync.o
obj-$(CONFIG_INOTIFY) += inotify.o
obj-$(CONFIG_EPOLL) += eventpoll.o
diff -puN include/asm-i386/unistd.h~sys_sync_file_range include/asm-i386/unistd.h
--- devel/include/asm-i386/unistd.h~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/include/asm-i386/unistd.h 2006-03-29 23:48:28.000000000 -0800
@@ -318,8 +318,9 @@
#define __NR_unshare 310
#define __NR_set_robust_list 311
#define __NR_get_robust_list 312
+#define __NR_sys_sync_file_range 313
-#define NR_syscalls 313
+#define NR_syscalls 314
/*
* user-visible error numbers are in the range -1 - -128: see
diff -puN arch/i386/kernel/syscall_table.S~sys_sync_file_range arch/i386/kernel/syscall_table.S
--- devel/arch/i386/kernel/syscall_table.S~sys_sync_file_range 2006-03-29 23:48:28.000000000 -0800
+++ devel-akpm/arch/i386/kernel/syscall_table.S 2006-03-29 23:48:28.000000000 -0800
@@ -312,3 +312,4 @@ ENTRY(sys_call_table)
.long sys_unshare /* 310 */
.long sys_set_robust_list
.long sys_get_robust_list
+ .long sys_sync_file_range
_
On Thursday March 30, [email protected] wrote:
> Neil Brown <[email protected]> wrote:
> >
> > Hmmm... any chance this could be split into a sys_sync_file_range and
> > a vfs_sync_file_range which takes a 'struct file*' and does less (or
> > no) sanity checking, so I can call it from nfsd?
>
> Problem is, we don't appear to have a way of syncing the file's metadata
> without also syncing all of its pagecache.
>
> For example, ext3_sync_file() will run a commit, which will sync all data
> and metadata.
>
> ext2_sync_file() will also sync all pagecache as well as metadata. Even
> though do_fsync() already synced the file data (!).
>
>
> Is the below still useful?
Yes. 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.
I didn't before because when I was righting that (2.4 days) there were
a lot fewer options on how to sync things.
So yes, that will be perfect, thanks.
NeilBrown
Andrew Morton <[email protected]> writes:
> + if ((s64)offset < 0)
> + goto out;
> + if ((s64)endbyte < 0)
> + goto out;
loff_t is long long on all arch. This is not need?
> + if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
> + ret = -ESPIPE;
> + goto out_put;
> + }
How about to check "if (!file->f_op || !file->f_op->fsync)" or something?
For chrdev is also strange, and in the case of fsync(), it returns -EINVAL.
IMHO it seems there is consistency.
Thanks.
--
OGAWA Hirofumi <[email protected]>
OGAWA Hirofumi <[email protected]> wrote:
>
> Andrew Morton <[email protected]> writes:
>
> > + if ((s64)offset < 0)
> > + goto out;
> > + if ((s64)endbyte < 0)
> > + goto out;
>
> loff_t is long long on all arch. This is not need?
True, the casts happen to be unneeded. But they do set the reader's mind
at ease.
> > + if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
> > + ret = -ESPIPE;
> > + goto out_put;
> > + }
>
> How about to check "if (!file->f_op || !file->f_op->fsync)" or something?
This syscall won't call ->fsync.
> For chrdev is also strange, and in the case of fsync(), it returns -EINVAL.
> IMHO it seems there is consistency.
>
I guess so. Perhaps it should be S_ISREG|S_ISBLK|S_ISDIR|S_ISLNK.
On Thu, Mar 30, 2006 at 06:58:46PM +1100, Neil Brown wrote:
> On Wednesday March 29, [email protected] wrote:
> > 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.
>
> Hmmm... any chance this could be split into a sys_sync_file_range and
> a vfs_sync_file_range which takes a 'struct file*' and does less (or
> no) sanity checking, so I can call it from nfsd?
>
> Currently I implement COMMIT (which has a range) with a by messing
> around with filemap_fdatawrite and filemap_fdatawait (ignoring the
> range) and I'd rather than a vfs helper.
I'm not 100% sure, but it looks like the PF_SYNCWRITE process flag
should be set on the nfsd's while they're doing that, which doesn't
seem to be happening atm. Looks like a couple of the IO schedulers
will make use of that knowledge now. All the more reason for a VFS
helper here I guess. ;)
cheers.
--
Nathan
Index: 2.6.x-xfs/fs/nfsd/vfs.c
===================================================================
--- 2.6.x-xfs.orig/fs/nfsd/vfs.c
+++ 2.6.x-xfs/fs/nfsd/vfs.c
@@ -712,11 +712,13 @@ static inline int nfsd_dosync(struct fil
int (*fsync) (struct file *, struct dentry *, int);
int err;
+ current->flags |= PF_SYNCWRITE;
err = filemap_fdatawrite(inode->i_mapping);
if (err == 0 && fop && (fsync = fop->fsync))
err = fsync(filp, dp, 0);
if (err == 0)
err = filemap_fdatawait(inode->i_mapping);
+ current->flags &= ~PF_SYNCWRITE;
return err;
}