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Commit e84661aa authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Alex Elder
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xfs: add online discard support 



Now that we have reliably tracking of deleted extents in a
transaction we can easily implement "online" discard support
which calls blkdev_issue_discard once a transaction commits.

The actual discard is a two stage operation as we first have
to mark the busy extent as not available for reuse before we
can start the actual discard.  Note that we don't bother
supporting discard for the non-delaylog mode.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAlex Elder <aelder@sgi.com>
parent bf59170a

Documentation/filesystems/xfs.txt

+6 −0
Original line number Diff line number Diff line
@@ -39,6 +39,12 @@ When mounting an XFS filesystem, the following options are accepted. 
	drive level write caching to be enabled, for devices that

	support write barriers.



  discard

	Issue command to let the block device reclaim space freed by the

	filesystem.  This is useful for SSD devices, thinly provisioned

	LUNs and virtual machine images, but may have a performance

	impact.  This option is incompatible with the nodelaylog option.



  dmapi

	Enable the DMAPI (Data Management API) event callouts.

	Use with the "mtpt" option.

fs/xfs/linux-2.6/xfs_discard.c

+29 −0
Original line number Diff line number Diff line
@@ -191,3 +191,32 @@ xfs_ioc_trim( 
		return -XFS_ERROR(EFAULT);

	return 0;

}



int

xfs_discard_extents(

	struct xfs_mount	*mp,

	struct list_head	*list)

{

	struct xfs_busy_extent	*busyp;

	int			error = 0;



	list_for_each_entry(busyp, list, list) {

		trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,

					 busyp->length);



		error = -blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,

				XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),

				XFS_FSB_TO_BB(mp, busyp->length),

				GFP_NOFS, 0);

		if (error && error != EOPNOTSUPP) {

			xfs_info(mp,

	 "discard failed for extent [0x%llu,%u], error %d",

				 (unsigned long long)busyp->bno,

				 busyp->length,

				 error);

			return error;

		}

	}



	return 0;

}

fs/xfs/linux-2.6/xfs_discard.h

+2 −0
Original line number Diff line number Diff line
@@ -2,7 +2,9 @@ 
#define XFS_DISCARD_H 1



struct fstrim_range;

struct list_head;



extern int	xfs_ioc_trim(struct xfs_mount *, struct fstrim_range __user *);

extern int	xfs_discard_extents(struct xfs_mount *, struct list_head *);



#endif /* XFS_DISCARD_H */

fs/xfs/linux-2.6/xfs_super.c

+16 −2
Original line number Diff line number Diff line
@@ -110,8 +110,10 @@ mempool_t *xfs_ioend_pool; 
#define MNTOPT_GQUOTANOENF "gqnoenforce"/* group quota limit enforcement */

#define MNTOPT_PQUOTANOENF "pqnoenforce"/* project quota limit enforcement */

#define MNTOPT_QUOTANOENF  "qnoenforce"	/* same as uqnoenforce */

#define MNTOPT_DELAYLOG   "delaylog"	/* Delayed loging enabled */

#define MNTOPT_NODELAYLOG "nodelaylog"	/* Delayed loging disabled */

#define MNTOPT_DELAYLOG    "delaylog"	/* Delayed logging enabled */

#define MNTOPT_NODELAYLOG  "nodelaylog"	/* Delayed logging disabled */

#define MNTOPT_DISCARD	   "discard"	/* Discard unused blocks */

#define MNTOPT_NODISCARD   "nodiscard"	/* Do not discard unused blocks */



/*

 * Table driven mount option parser.
@@ -355,6 +357,10 @@ xfs_parseargs( 
			mp->m_flags |= XFS_MOUNT_DELAYLOG;

		} else if (!strcmp(this_char, MNTOPT_NODELAYLOG)) {

			mp->m_flags &= ~XFS_MOUNT_DELAYLOG;

		} else if (!strcmp(this_char, MNTOPT_DISCARD)) {

			mp->m_flags |= XFS_MOUNT_DISCARD;

		} else if (!strcmp(this_char, MNTOPT_NODISCARD)) {

			mp->m_flags &= ~XFS_MOUNT_DISCARD;

		} else if (!strcmp(this_char, "ihashsize")) {

			xfs_warn(mp,

	"ihashsize no longer used, option is deprecated.");
@@ -388,6 +394,13 @@ xfs_parseargs( 
		return EINVAL;

	}



	if ((mp->m_flags & XFS_MOUNT_DISCARD) &&

	    !(mp->m_flags & XFS_MOUNT_DELAYLOG)) {

		xfs_warn(mp,

	"the discard option is incompatible with the nodelaylog option");

		return EINVAL;

	}



#ifndef CONFIG_XFS_QUOTA

	if (XFS_IS_QUOTA_RUNNING(mp)) {

		xfs_warn(mp, "quota support not available in this kernel.");
@@ -488,6 +501,7 @@ xfs_showargs( 
		{ XFS_MOUNT_FILESTREAMS,	"," MNTOPT_FILESTREAM },

		{ XFS_MOUNT_GRPID,		"," MNTOPT_GRPID },

		{ XFS_MOUNT_DELAYLOG,		"," MNTOPT_DELAYLOG },

		{ XFS_MOUNT_DISCARD,		"," MNTOPT_DISCARD },

		{ 0, NULL }

	};

	static struct proc_xfs_info xfs_info_unset[] = {

fs/xfs/xfs_ag.h

+2 −0
Original line number Diff line number Diff line
@@ -187,6 +187,8 @@ struct xfs_busy_extent { 
	xfs_agnumber_t	agno;

	xfs_agblock_t	bno;

	xfs_extlen_t	length;

	unsigned int	flags;

#define XFS_ALLOC_BUSY_DISCARDED	0x01	/* undergoing a discard op. */

};



/*