Commit 22f96b38 authored by Jens Axboe's avatar Jens Axboe
Browse files

fs: add sync_file_range() helper 



This just pulls out the ksys_sync_file_range() code to work on a struct
file instead of an fd, so we can use it elsewhere.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent de0617e4

fs/sync.c

+71 −64
Original line number Diff line number Diff line
@@ -234,58 +234,10 @@ SYSCALL_DEFINE1(fdatasync, unsigned int, fd) 
	return do_fsync(fd, 1);

}



/*

 * 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. Note that this may block for

 * significant periods due to exhaustion of disk request structures.

 *

 * 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.

 */

int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,

int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,

		    unsigned int flags)

{

	int ret;

	struct fd f;

	struct address_space *mapping;

	loff_t endbyte;			/* inclusive */

	umode_t i_mode;
@@ -325,41 +277,96 @@ int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes, 
	else

		endbyte--;		/* inclusive */



	ret = -EBADF;

	f = fdget(fd);

	if (!f.file)

		goto out;



	i_mode = file_inode(f.file)->i_mode;

	i_mode = file_inode(file)->i_mode;

	ret = -ESPIPE;

	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&

			!S_ISLNK(i_mode))

		goto out_put;

		goto out;



	mapping = f.file->f_mapping;

	mapping = file->f_mapping;

	ret = 0;

	if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {

		ret = file_fdatawait_range(f.file, offset, endbyte);

		ret = file_fdatawait_range(file, offset, endbyte);

		if (ret < 0)

			goto out_put;

			goto out;

	}



	if (flags & SYNC_FILE_RANGE_WRITE) {

		ret = __filemap_fdatawrite_range(mapping, offset, endbyte,

						 WB_SYNC_NONE);

		if (ret < 0)

			goto out_put;

			goto out;

	}



	if (flags & SYNC_FILE_RANGE_WAIT_AFTER)

		ret = file_fdatawait_range(f.file, offset, endbyte);

		ret = file_fdatawait_range(file, offset, endbyte);



out_put:

	fdput(f);

out:

	return ret;

}



/*

 * 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. Note that this may block for

 * significant periods due to exhaustion of disk request structures.

 *

 * 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.

 */

int ksys_sync_file_range(int fd, loff_t offset, loff_t nbytes,

			 unsigned int flags)

{

	int ret;

	struct fd f;



	ret = -EBADF;

	f = fdget(fd);

	if (f.file)

		ret = sync_file_range(f.file, offset, nbytes, flags);



	fdput(f);

	return ret;

}



SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,

				unsigned int, flags)

{

include/linux/fs.h

+3 −0
Original line number Diff line number Diff line
@@ -2785,6 +2785,9 @@ extern int vfs_fsync_range(struct file *file, loff_t start, loff_t end, 
			   int datasync);

extern int vfs_fsync(struct file *file, int datasync);



extern int sync_file_range(struct file *file, loff_t offset, loff_t nbytes,

				unsigned int flags);



/*

 * Sync the bytes written if this was a synchronous write.  Expect ki_pos

 * to already be updated for the write, and will return either the amount