Commit 9f6c92b9 authored by Lachlan McIlroy's avatar Lachlan McIlroy
Browse files

[XFS] Fix speculative allocation beyond eof 



Speculative allocation beyond eof doesn't work properly.  It was
broken some time ago after a code cleanup that moved what is now
xfs_iomap_eof_align_last_fsb() and xfs_iomap_eof_want_preallocate()
out of xfs_iomap_write_delay() into separate functions.  The code
used to use the current file size in various checks but got changed
to be max(file_size, i_new_size).  Since i_new_size is the result
of 'offset + count' then in xfs_iomap_eof_want_preallocate() the
check for '(offset + count) <= isize' will always be true.

ie if 'offset + count' is > ip->i_size then isize will be i_new_size
and equal to 'offset + count'.

This change fixes all the places that used to use the current file
size.

Reviewed-by: default avatarChristoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarLachlan McIlroy <lachlan@sgi.com>
parent 4fdc7781

fs/xfs/xfs_iomap.c

+7 −21
Original line number Diff line number Diff line
@@ -290,7 +290,6 @@ STATIC int 
xfs_iomap_eof_align_last_fsb(

	xfs_mount_t	*mp,

	xfs_inode_t	*ip,

	xfs_fsize_t	isize,

	xfs_extlen_t	extsize,

	xfs_fileoff_t	*last_fsb)

{
@@ -306,14 +305,14 @@ xfs_iomap_eof_align_last_fsb( 
	 * stripe width and we are allocating past the allocation eof.

	 */

	else if (mp->m_swidth && (mp->m_flags & XFS_MOUNT_SWALLOC) &&

	        (isize >= XFS_FSB_TO_B(mp, mp->m_swidth)))

	        (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_swidth)))

		new_last_fsb = roundup_64(*last_fsb, mp->m_swidth);

	/*

	 * Roundup the allocation request to a stripe unit (m_dalign) boundary

	 * if the file size is >= stripe unit size, and we are allocating past

	 * the allocation eof.

	 */

	else if (mp->m_dalign && (isize >= XFS_FSB_TO_B(mp, mp->m_dalign)))

	else if (mp->m_dalign && (ip->i_size >= XFS_FSB_TO_B(mp, mp->m_dalign)))

		new_last_fsb = roundup_64(*last_fsb, mp->m_dalign);



	/*
@@ -403,7 +402,6 @@ xfs_iomap_write_direct( 
	xfs_filblks_t	count_fsb, resaligned;

	xfs_fsblock_t	firstfsb;

	xfs_extlen_t	extsz, temp;

	xfs_fsize_t	isize;

	int		nimaps;

	int		bmapi_flag;

	int		quota_flag;
@@ -426,15 +424,10 @@ xfs_iomap_write_direct( 
	rt = XFS_IS_REALTIME_INODE(ip);

	extsz = xfs_get_extsz_hint(ip);



	isize = ip->i_size;

	if (ip->i_new_size > isize)

		isize = ip->i_new_size;



	offset_fsb = XFS_B_TO_FSBT(mp, offset);

	last_fsb = XFS_B_TO_FSB(mp, ((xfs_ufsize_t)(offset + count)));

	if ((offset + count) > isize) {

		error = xfs_iomap_eof_align_last_fsb(mp, ip, isize, extsz,

							&last_fsb);

	if ((offset + count) > ip->i_size) {

		error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);

		if (error)

			goto error_out;

	} else {
@@ -559,7 +552,6 @@ STATIC int 
xfs_iomap_eof_want_preallocate(

	xfs_mount_t	*mp,

	xfs_inode_t	*ip,

	xfs_fsize_t	isize,

	xfs_off_t	offset,

	size_t		count,

	int		ioflag,
@@ -573,7 +565,7 @@ xfs_iomap_eof_want_preallocate( 
	int		n, error, imaps;



	*prealloc = 0;

	if ((ioflag & BMAPI_SYNC) || (offset + count) <= isize)

	if ((ioflag & BMAPI_SYNC) || (offset + count) <= ip->i_size)

		return 0;



	/*
@@ -617,7 +609,6 @@ xfs_iomap_write_delay( 
	xfs_fileoff_t	ioalign;

	xfs_fsblock_t	firstblock;

	xfs_extlen_t	extsz;

	xfs_fsize_t	isize;

	int		nimaps;

	xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];

	int		prealloc, fsynced = 0;
@@ -637,11 +628,7 @@ xfs_iomap_write_delay( 
	offset_fsb = XFS_B_TO_FSBT(mp, offset);



retry:

	isize = ip->i_size;

	if (ip->i_new_size > isize)

		isize = ip->i_new_size;



	error = xfs_iomap_eof_want_preallocate(mp, ip, isize, offset, count,

	error = xfs_iomap_eof_want_preallocate(mp, ip, offset, count,

				ioflag, imap, XFS_WRITE_IMAPS, &prealloc);

	if (error)

		return error;
@@ -655,8 +642,7 @@ retry: 
	}



	if (prealloc || extsz) {

		error = xfs_iomap_eof_align_last_fsb(mp, ip, isize, extsz,

							&last_fsb);

		error = xfs_iomap_eof_align_last_fsb(mp, ip, extsz, &last_fsb);

		if (error)

			return error;

	}

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