Commit 92dfe8d2 authored by David Chinner's avatar David Chinner Committed by Tim Shimmin
Browse files

[XFS] Make hole punching at EOF atomic. 



If hole punching at EOF is done as two steps (i.e. truncate then extend)
the file is in a transient state between the two steps where an
application can see the incorrect file size. Punching a hole to EOF needs
to be treated in teh same way as all other hole punching cases so that the
file size is never seen to change.

SGI-PV: 962012
SGI-Modid: xfs-linux-melb:xfs-kern:28641a

Signed-off-by: default avatarDavid Chinner <dgc@sgi.com>
Signed-off-by: default avatarVlad Apostolov <vapo@sgi.com>
Signed-off-by: default avatarTim Shimmin <tes@sgi.com>
parent 511105b3

fs/xfs/xfs_rw.h

+11 −3
Original line number Diff line number Diff line
@@ -71,6 +71,12 @@ xfs_fsb_to_db_io(struct xfs_iocore *io, xfs_fsblock_t fsb) 
		 XFS_FSB_TO_DADDR((io)->io_mount, (fsb)));

}



/*

 * Flags for xfs_free_eofblocks

 */

#define XFS_FREE_EOF_LOCK	(1<<0)

#define XFS_FREE_EOF_NOLOCK	(1<<1)



/*

 * Prototypes for functions in xfs_rw.c.

 */
@@ -96,5 +102,7 @@ extern int xfs_change_file_space(bhv_desc_t *bdp, int cmd, xfs_flock64_t *bf, 
			xfs_off_t offset, cred_t *credp, int flags);

extern int xfs_set_dmattrs(bhv_desc_t *bdp, u_int evmask, u_int16_t state,

			cred_t *credp);

extern int xfs_free_eofblocks(struct xfs_mount *mp, struct xfs_inode *ip,

			int flags);



#endif /* __XFS_RW_H__ */

fs/xfs/xfs_vnodeops.c

+18 −10
Original line number Diff line number Diff line
@@ -1201,13 +1201,15 @@ xfs_fsync( 
}



/*

 * This is called by xfs_inactive to free any blocks beyond eof,

 * when the link count isn't zero.

 * This is called by xfs_inactive to free any blocks beyond eof

 * when the link count isn't zero and by xfs_dm_punch_hole() when

 * punching a hole to EOF.

 */

STATIC int

xfs_inactive_free_eofblocks(

int

xfs_free_eofblocks(

	xfs_mount_t	*mp,

	xfs_inode_t	*ip)

	xfs_inode_t	*ip,

	int		flags)

{

	xfs_trans_t	*tp;

	int		error;
@@ -1216,6 +1218,7 @@ xfs_inactive_free_eofblocks( 
	xfs_filblks_t	map_len;

	int		nimaps;

	xfs_bmbt_irec_t	imap;

	int		use_iolock = (flags & XFS_FREE_EOF_LOCK);



	/*

	 * Figure out if there are any blocks beyond the end
@@ -1256,10 +1259,12 @@ xfs_inactive_free_eofblocks( 
		 * cache and we can't

		 * do that within a transaction.

		 */

		if (use_iolock)

			xfs_ilock(ip, XFS_IOLOCK_EXCL);

		error = xfs_itruncate_start(ip, XFS_ITRUNC_DEFINITE,

				    ip->i_size);

		if (error) {

			if (use_iolock)

				xfs_iunlock(ip, XFS_IOLOCK_EXCL);

			return error;

		}
@@ -1297,7 +1302,8 @@ xfs_inactive_free_eofblocks( 
			error = xfs_trans_commit(tp,

						XFS_TRANS_RELEASE_LOG_RES);

		}

		xfs_iunlock(ip, XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL);

		xfs_iunlock(ip, (use_iolock ? (XFS_IOLOCK_EXCL|XFS_ILOCK_EXCL)

					    : XFS_ILOCK_EXCL));

	}

	return error;

}
@@ -1573,7 +1579,8 @@ xfs_release( 
		     (ip->i_df.if_flags & XFS_IFEXTENTS))  &&

		    (!(ip->i_d.di_flags &

				(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)))) {

			if ((error = xfs_inactive_free_eofblocks(mp, ip)))

			error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);

			if (error)

				return error;

			/* Update linux inode block count after free above */

			vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,
@@ -1654,7 +1661,8 @@ xfs_inactive( 
		     (!(ip->i_d.di_flags &

				(XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) ||

		      (ip->i_delayed_blks != 0)))) {

			if ((error = xfs_inactive_free_eofblocks(mp, ip)))

			error = xfs_free_eofblocks(mp, ip, XFS_FREE_EOF_LOCK);

			if (error)

				return VN_INACTIVE_CACHE;

			/* Update linux inode block count after free above */

			vn_to_inode(vp)->i_blocks = XFS_FSB_TO_BB(mp,

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