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Commit 8aa7d37e authored by Eric Sandeen's avatar Eric Sandeen Committed by Dave Chinner
Browse files

xfs: Factor xfs_seek_hole_data into helper 



Factor xfs_seek_hole_data into an unlocked helper which takes
an xfs inode rather than a file for internal use.

Also allow specification of "end" - the vfs lseek interface is
defined such that any offset past eof/i_size shall return -ENXIO,
but we will use this for quota code which does not maintain i_size,
and we want to be able to SEEK_DATA past i_size as well.  So the
lseek path can send in i_size, and the quota code can determine
its own ending offset.

Signed-off-by: default avatarEric Sandeen <sandeen@redhat.com>
Reviewed-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarDave Chinner <david@fromorbit.com>
parent 4d4d9523

fs/xfs/xfs_file.c

+57 −25
Original line number Diff line number Diff line
@@ -1337,31 +1337,31 @@ xfs_find_get_desired_pgoff( 
	return found;

}



STATIC loff_t

xfs_seek_hole_data(

	struct file		*file,

/*

 * caller must lock inode with xfs_ilock_data_map_shared,

 * can we craft an appropriate ASSERT?

 *

 * end is because the VFS-level lseek interface is defined such that any

 * offset past i_size shall return -ENXIO, but we use this for quota code

 * which does not maintain i_size, and we want to SEEK_DATA past i_size.

 */

loff_t

__xfs_seek_hole_data(

	struct inode		*inode,

	loff_t			start,

	loff_t			end,

	int			whence)

{

	struct inode		*inode = file->f_mapping->host;

	struct xfs_inode	*ip = XFS_I(inode);

	struct xfs_mount	*mp = ip->i_mount;

	loff_t			uninitialized_var(offset);

	xfs_fsize_t		isize;

	xfs_fileoff_t		fsbno;

	xfs_filblks_t		end;

	uint			lock;

	xfs_filblks_t		lastbno;

	int			error;



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	lock = xfs_ilock_data_map_shared(ip);



	isize = i_size_read(inode);

	if (start >= isize) {

	if (start >= end) {

		error = -ENXIO;

		goto out_unlock;

		goto out_error;

	}



	/*
@@ -1369,22 +1369,22 @@ xfs_seek_hole_data( 
	 * by fsbno to the end block of the file.

	 */

	fsbno = XFS_B_TO_FSBT(mp, start);

	end = XFS_B_TO_FSB(mp, isize);

	lastbno = XFS_B_TO_FSB(mp, end);



	for (;;) {

		struct xfs_bmbt_irec	map[2];

		int			nmap = 2;

		unsigned int		i;



		error = xfs_bmapi_read(ip, fsbno, end - fsbno, map, &nmap,

		error = xfs_bmapi_read(ip, fsbno, lastbno - fsbno, map, &nmap,

				       XFS_BMAPI_ENTIRE);

		if (error)

			goto out_unlock;

			goto out_error;



		/* No extents at given offset, must be beyond EOF */

		if (nmap == 0) {

			error = -ENXIO;

			goto out_unlock;

			goto out_error;

		}



		for (i = 0; i < nmap; i++) {
@@ -1426,7 +1426,7 @@ xfs_seek_hole_data( 
			 * hole at the end of any file).

		 	 */

			if (whence == SEEK_HOLE) {

				offset = isize;

				offset = end;

				break;

			}

			/*
@@ -1434,7 +1434,7 @@ xfs_seek_hole_data( 
			 */

			ASSERT(whence == SEEK_DATA);

			error = -ENXIO;

			goto out_unlock;

			goto out_error;

		}



		ASSERT(i > 1);
@@ -1445,14 +1445,14 @@ xfs_seek_hole_data( 
		 */

		fsbno = map[i - 1].br_startoff + map[i - 1].br_blockcount;

		start = XFS_FSB_TO_B(mp, fsbno);

		if (start >= isize) {

		if (start >= end) {

			if (whence == SEEK_HOLE) {

				offset = isize;

				offset = end;

				break;

			}

			ASSERT(whence == SEEK_DATA);

			error = -ENXIO;

			goto out_unlock;

			goto out_error;

		}

	}
@@ -1464,7 +1464,39 @@ xfs_seek_hole_data( 
	 * situation in particular.

	 */

	if (whence == SEEK_HOLE)

		offset = min_t(loff_t, offset, isize);

		offset = min_t(loff_t, offset, end);



	return offset;



out_error:

	return error;

}



STATIC loff_t

xfs_seek_hole_data(

	struct file		*file,

	loff_t			start,

	int			whence)

{

	struct inode		*inode = file->f_mapping->host;

	struct xfs_inode	*ip = XFS_I(inode);

	struct xfs_mount	*mp = ip->i_mount;

	uint			lock;

	loff_t			offset, end;

	int			error = 0;



	if (XFS_FORCED_SHUTDOWN(mp))

		return -EIO;



	lock = xfs_ilock_data_map_shared(ip);



	end = i_size_read(inode);

	offset = __xfs_seek_hole_data(inode, start, end, whence);

	if (offset < 0) {

		error = offset;

		goto out_unlock;

	}



	offset = vfs_setpos(file, offset, inode->i_sb->s_maxbytes);



out_unlock:

fs/xfs/xfs_inode.h

+2 −0
Original line number Diff line number Diff line
@@ -437,6 +437,8 @@ int xfs_update_prealloc_flags(struct xfs_inode *ip, 
int	xfs_zero_eof(struct xfs_inode *ip, xfs_off_t offset,

		     xfs_fsize_t isize, bool *did_zeroing);

int	xfs_iozero(struct xfs_inode *ip, loff_t pos, size_t count);

loff_t	__xfs_seek_hole_data(struct inode *inode, loff_t start,

			     loff_t eof, int whence);





/* from xfs_iops.c */