mirror of
https://github.com/adulau/aha.git
synced 2024-12-29 12:16:20 +00:00
f79e2abb9b
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>
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
|
|
* mm/fadvise.c
|
|
*
|
|
* Copyright (C) 2002, Linus Torvalds
|
|
*
|
|
* 11Jan2003 akpm@digeo.com
|
|
* Initial version.
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/file.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/pagevec.h>
|
|
#include <linux/fadvise.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/syscalls.h>
|
|
|
|
#include <asm/unistd.h>
|
|
|
|
/*
|
|
* POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
|
|
* deactivate the pages and clear PG_Referenced.
|
|
*
|
|
* LINUX_FADV_ASYNC_WRITE: start async writeout of any dirty pages between file
|
|
* offsets `offset' and `offset+len' inclusive. Any pages which are currently
|
|
* under writeout are skipped, whether or not they are dirty.
|
|
*
|
|
* LINUX_FADV_WRITE_WAIT: wait upon writeout of any dirty pages between file
|
|
* offsets `offset' and `offset+len'.
|
|
*
|
|
* By combining these two operations the application may do several things:
|
|
*
|
|
* LINUX_FADV_ASYNC_WRITE: push some or all of the dirty pages at the disk.
|
|
*
|
|
*/
|
|
asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
|
|
{
|
|
struct file *file = fget(fd);
|
|
struct address_space *mapping;
|
|
struct backing_dev_info *bdi;
|
|
loff_t endbyte; /* inclusive */
|
|
pgoff_t start_index;
|
|
pgoff_t end_index;
|
|
unsigned long nrpages;
|
|
int ret = 0;
|
|
|
|
if (!file)
|
|
return -EBADF;
|
|
|
|
if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
|
|
ret = -ESPIPE;
|
|
goto out;
|
|
}
|
|
|
|
mapping = file->f_mapping;
|
|
if (!mapping || len < 0) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (mapping->a_ops->get_xip_page)
|
|
/* no bad return value, but ignore advice */
|
|
goto out;
|
|
|
|
/* Careful about overflows. Len == 0 means "as much as possible" */
|
|
endbyte = offset + len;
|
|
if (!len || endbyte < len)
|
|
endbyte = -1;
|
|
else
|
|
endbyte--; /* inclusive */
|
|
|
|
bdi = mapping->backing_dev_info;
|
|
|
|
switch (advice) {
|
|
case POSIX_FADV_NORMAL:
|
|
file->f_ra.ra_pages = bdi->ra_pages;
|
|
break;
|
|
case POSIX_FADV_RANDOM:
|
|
file->f_ra.ra_pages = 0;
|
|
break;
|
|
case POSIX_FADV_SEQUENTIAL:
|
|
file->f_ra.ra_pages = bdi->ra_pages * 2;
|
|
break;
|
|
case POSIX_FADV_WILLNEED:
|
|
case POSIX_FADV_NOREUSE:
|
|
if (!mapping->a_ops->readpage) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* First and last PARTIAL page! */
|
|
start_index = offset >> PAGE_CACHE_SHIFT;
|
|
end_index = endbyte >> PAGE_CACHE_SHIFT;
|
|
|
|
/* Careful about overflow on the "+1" */
|
|
nrpages = end_index - start_index + 1;
|
|
if (!nrpages)
|
|
nrpages = ~0UL;
|
|
|
|
ret = force_page_cache_readahead(mapping, file,
|
|
start_index,
|
|
max_sane_readahead(nrpages));
|
|
if (ret > 0)
|
|
ret = 0;
|
|
break;
|
|
case POSIX_FADV_DONTNEED:
|
|
if (!bdi_write_congested(mapping->backing_dev_info))
|
|
filemap_flush(mapping);
|
|
|
|
/* First and last FULL page! */
|
|
start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
|
|
end_index = (endbyte >> PAGE_CACHE_SHIFT);
|
|
|
|
if (end_index >= start_index)
|
|
invalidate_mapping_pages(mapping, start_index,
|
|
end_index);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
}
|
|
out:
|
|
fput(file);
|
|
return ret;
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_FADVISE64
|
|
|
|
asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
|
|
{
|
|
return sys_fadvise64_64(fd, offset, len, advice);
|
|
}
|
|
|
|
#endif
|