Allow manual discards from userspace using the FITRIM ioctl. This is not
intended to be run during normal workloads, as the freepsace btree walks
can cause large performance degradation.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: linux-2.6/fs/xfs/xfs_alloc.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_alloc.c 2010-11-25 11:30:29.425010758 +0100
+++ linux-2.6/fs/xfs/xfs_alloc.c 2010-11-25 11:30:36.408013342 +0100
@@ -41,10 +41,6 @@
#define XFSA_FIXUP_BNO_OK 1
#define XFSA_FIXUP_CNT_OK 2
-static int
-xfs_alloc_busy_search(struct xfs_mount *mp, xfs_agnumber_t agno,
- xfs_agblock_t bno, xfs_extlen_t len);
-
/*
* Prototypes for per-ag allocation routines
*/
@@ -94,7 +90,7 @@ xfs_alloc_lookup_ge(
* Lookup the first record less than or equal to [bno, len]
* in the btree given by cur.
*/
-STATIC int /* error */
+int /* error */
xfs_alloc_lookup_le(
struct xfs_btree_cur *cur, /* btree cursor */
xfs_agblock_t bno, /* starting block of extent */
@@ -127,7 +123,7 @@ xfs_alloc_update(
/*
* Get the data from the pointed-to record.
*/
-STATIC int /* error */
+int /* error */
xfs_alloc_get_rec(
struct xfs_btree_cur *cur, /* btree cursor */
xfs_agblock_t *bno, /* output: starting block of extent */
@@ -2676,7 +2672,7 @@ restart:
* will require a synchronous transaction, but it can still be
* used to distinguish between a partial or exact match.
*/
-static int
+int
xfs_alloc_busy_search(
struct xfs_mount *mp,
xfs_agnumber_t agno,
Index: linux-2.6/fs/xfs/xfs_alloc.h
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_alloc.h 2010-11-25 11:30:29.431003844 +0100
+++ linux-2.6/fs/xfs/xfs_alloc.h 2010-11-25 11:30:36.408013342 +0100
@@ -19,6 +19,7 @@
#define __XFS_ALLOC_H__
struct xfs_buf;
+struct xfs_btree_cur;
struct xfs_mount;
struct xfs_perag;
struct xfs_trans;
@@ -118,16 +119,16 @@ xfs_alloc_longest_free_extent(struct xfs
struct xfs_perag *pag);
#ifdef __KERNEL__
-
void
-xfs_alloc_busy_insert(xfs_trans_t *tp,
- xfs_agnumber_t agno,
- xfs_agblock_t bno,
- xfs_extlen_t len);
+xfs_alloc_busy_insert(struct xfs_trans *tp, xfs_agnumber_t agno,
+ xfs_agblock_t bno, xfs_extlen_t len);
void
xfs_alloc_busy_clear(struct xfs_mount *mp, struct xfs_busy_extent *busyp);
+int
+xfs_alloc_busy_search(struct xfs_mount *mp, xfs_agnumber_t agno,
+ xfs_agblock_t bno, xfs_extlen_t len);
#endif /* __KERNEL__ */
/*
@@ -205,4 +206,18 @@ xfs_free_extent(
xfs_fsblock_t bno, /* starting block number of extent */
xfs_extlen_t len); /* length of extent */
+int /* error */
+xfs_alloc_lookup_le(
+ struct xfs_btree_cur *cur, /* btree cursor */
+ xfs_agblock_t bno, /* starting block of extent */
+ xfs_extlen_t len, /* length of extent */
+ int *stat); /* success/failure */
+
+int /* error */
+xfs_alloc_get_rec(
+ struct xfs_btree_cur *cur, /* btree cursor */
+ xfs_agblock_t *bno, /* output: starting block of extent */
+ xfs_extlen_t *len, /* output: length of extent */
+ int *stat); /* output: success/failure */
+
#endif /* __XFS_ALLOC_H__ */
Index: linux-2.6/fs/xfs/Makefile
===================================================================
--- linux-2.6.orig/fs/xfs/Makefile 2010-11-25 11:30:29.437012364 +0100
+++ linux-2.6/fs/xfs/Makefile 2010-11-25 11:30:36.409023608 +0100
@@ -98,6 +98,7 @@ xfs-y += $(addprefix $(XFS_LINUX)/, \
kmem.o \
xfs_aops.o \
xfs_buf.o \
+ xfs_discard.o \
xfs_export.o \
xfs_file.o \
xfs_fs_subr.o \
Index: linux-2.6/fs/xfs/linux-2.6/xfs_discard.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/fs/xfs/linux-2.6/xfs_discard.c 2010-11-25 12:14:43.270005863 +0100
@@ -0,0 +1,187 @@
+/*
+ * Copyright (C) 2010 Red Hat, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "xfs.h"
+#include "xfs_sb.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_quota.h"
+#include "xfs_trans.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_btree.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_error.h"
+#include "xfs_discard.h"
+#include "xfs_trace.h"
+
+STATIC int
+xfs_trim_extents(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agno,
+ xfs_fsblock_t start,
+ xfs_fsblock_t len,
+ xfs_fsblock_t minlen)
+{
+ struct block_device *bdev = mp->m_ddev_targp->bt_bdev;
+ struct xfs_btree_cur *cur;
+ struct xfs_buf *agbp;
+ struct xfs_perag *pag;
+ int error;
+ int i;
+
+ pag = xfs_perag_get(mp, agno);
+
+ error = xfs_alloc_read_agf(mp, NULL, agno,
+ XFS_ALLOC_FLAG_TRYLOCK, &agbp);
+ if (error || !agbp) {
+ if (error == EAGAIN)
+ error = 0;
+ goto out_put_perag;
+ }
+
+ cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
+
+ /*
+ * Force out the log. This means any transactions that might have freed
+ * space before we took the AGF buffer lock are now on disk, and the
+ * volatile disk cache is flushed.
+ */
+ xfs_log_force(mp, XFS_LOG_SYNC);
+
+ /*
+ * Look up the longest btree in the AGF and start with it.
+ */
+ error = xfs_alloc_lookup_le(cur, 0,
+ XFS_BUF_TO_AGF(agbp)->agf_longest, &i);
+ if (error)
+ goto out_del_cursor;
+
+ /*
+ * Loop until we are done with all extents that are large
+ * enough to be worth discarding.
+ */
+ while (i) {
+ xfs_agblock_t fbno;
+ xfs_extlen_t flen;
+
+ error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
+ if (error)
+ goto out_del_cursor;
+ XFS_WANT_CORRUPTED_GOTO(i == 1, out_del_cursor);
+ ASSERT(flen <= XFS_BUF_TO_AGF(agbp)->agf_longest);
+
+ /*
+ * Too small? Give up.
+ */
+ if (flen < minlen) {
+ trace_xfs_discard_toosmall(mp, agno, fbno, flen);
+ goto out_del_cursor;
+ }
+
+ /*
+ * If the extent is entirely outside of the range we are
+ * supposed to discard skip it. Do not bother to trim
+ * down partially overlapping ranges for now.
+ */
+ if (XFS_AGB_TO_FSB(mp, agno, fbno) + flen < start ||
+ XFS_AGB_TO_FSB(mp, agno, fbno) > start + len) {
+ trace_xfs_discard_exclude(mp, agno, fbno, flen);
+ goto next_extent;
+ }
+
+ /*
+ * If any blocks in the range are still busy, skip the
+ * discard and try again the next time.
+ */
+ if (xfs_alloc_busy_search(mp, agno, fbno, flen)) {
+ trace_xfs_discard_busy(mp, agno, fbno, flen);
+ goto next_extent;
+ }
+
+ trace_xfs_discard_extent(mp, agno, fbno, flen);
+ error = -blkdev_issue_discard(bdev,
+ XFS_AGB_TO_DADDR(mp, agno, fbno),
+ XFS_FSB_TO_BB(mp, flen),
+ GFP_NOFS, 0);
+ if (error)
+ goto out_del_cursor;
+
+next_extent:
+ error = xfs_btree_decrement(cur, 0, &i);
+ if (error)
+ goto out_del_cursor;
+ }
+
+out_del_cursor:
+ xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
+ xfs_buf_relse(agbp);
+out_put_perag:
+ xfs_perag_put(pag);
+ return error;
+}
+
+int
+xfs_ioc_trim(
+ struct xfs_mount *mp,
+ struct fstrim_range *urange)
+{
+ struct request_queue *q = mp->m_ddev_targp->bt_bdev->bd_disk->queue;
+ unsigned int granularity = q->limits.discard_granularity;
+ struct fstrim_range range;
+ xfs_fsblock_t start, len, minlen;
+ xfs_agnumber_t start_agno, end_agno, agno;
+ int error, last_error = 0;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -XFS_ERROR(EPERM);
+ if (copy_from_user(&range, urange, sizeof(range)))
+ return -XFS_ERROR(EFAULT);
+
+ /*
+ * Truncating down the len isn't actually quite correct, but using
+ * XFS_B_TO_FSB would mean we trivially get overflows for values
+ * of ULLONG_MAX or slightly lower. And ULLONG_MAX is the default
+ * used by the fstrim application. In the end it really doesn't
+ * matter as trimming blocks is an advisory interface.
+ */
+ start = XFS_B_TO_FSBT(mp, range.start);
+ len = XFS_B_TO_FSBT(mp, range.len);
+ minlen = XFS_B_TO_FSB(mp, max_t(u64, granularity, range.minlen));
+
+ start_agno = XFS_FSB_TO_AGNO(mp, start);
+ if (start_agno >= mp->m_sb.sb_agcount)
+ return -XFS_ERROR(EINVAL);
+
+ end_agno = XFS_FSB_TO_AGNO(mp, start + len);
+ if (end_agno >= mp->m_sb.sb_agcount)
+ end_agno = mp->m_sb.sb_agcount - 1;
+
+ for (agno = start_agno; agno <= end_agno; agno++) {
+ error = -xfs_trim_extents(mp, agno, start, len, minlen);
+ if (error)
+ last_error = error;
+ }
+
+ if (copy_to_user(urange, &range, sizeof(range)))
+ return -XFS_ERROR(EFAULT);
+ return last_error;
+}
Index: linux-2.6/fs/xfs/linux-2.6/xfs_discard.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/fs/xfs/linux-2.6/xfs_discard.h 2010-11-25 11:30:36.419276716 +0100
@@ -0,0 +1,8 @@
+#ifndef XFS_DISCARD_H
+#define XFS_DISCARD_H 1
+
+struct fstrim_range;
+
+extern int xfs_ioc_trim(struct xfs_mount *, struct fstrim_range *);
+
+#endif /* XFS_DISCARD_H */
Index: linux-2.6/fs/xfs/linux-2.6/xfs_trace.h
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_trace.h 2010-11-25 11:30:29.461011526 +0100
+++ linux-2.6/fs/xfs/linux-2.6/xfs_trace.h 2010-11-25 11:30:36.427255554 +0100
@@ -1752,6 +1752,39 @@ DEFINE_LOG_RECOVER_INO_ITEM(xfs_log_reco
DEFINE_LOG_RECOVER_INO_ITEM(xfs_log_recover_inode_cancel);
DEFINE_LOG_RECOVER_INO_ITEM(xfs_log_recover_inode_skip);
+DECLARE_EVENT_CLASS(xfs_discard_class,
+ TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno,
+ xfs_agblock_t agbno, xfs_extlen_t len),
+ TP_ARGS(mp, agno, agbno, len),
+ TP_STRUCT__entry(
+ __field(dev_t, dev)
+ __field(xfs_agnumber_t, agno)
+ __field(xfs_agblock_t, agbno)
+ __field(xfs_extlen_t, len)
+ ),
+ TP_fast_assign(
+ __entry->dev = mp->m_super->s_dev;
+ __entry->agno = agno;
+ __entry->agbno = agbno;
+ __entry->len = len;
+ ),
+ TP_printk("dev %d:%d agno %u agbno %u len %u\n",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ __entry->agno,
+ __entry->agbno,
+ __entry->len)
+)
+
+#define DEFINE_DISCARD_EVENT(name) \
+DEFINE_EVENT(xfs_discard_class, name, \
+ TP_PROTO(struct xfs_mount *mp, xfs_agnumber_t agno, \
+ xfs_agblock_t agbno, xfs_extlen_t len), \
+ TP_ARGS(mp, agno, agbno, len))
+DEFINE_DISCARD_EVENT(xfs_discard_extent);
+DEFINE_DISCARD_EVENT(xfs_discard_toosmall);
+DEFINE_DISCARD_EVENT(xfs_discard_exclude);
+DEFINE_DISCARD_EVENT(xfs_discard_busy);
+
#endif /* _TRACE_XFS_H */
#undef TRACE_INCLUDE_PATH
Index: linux-2.6/fs/xfs/linux-2.6/xfs_ioctl.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_ioctl.c 2010-11-25 11:30:29.468004752 +0100
+++ linux-2.6/fs/xfs/linux-2.6/xfs_ioctl.c 2010-11-25 11:30:36.434255275 +0100
@@ -39,6 +39,7 @@
#include "xfs_dfrag.h"
#include "xfs_fsops.h"
#include "xfs_vnodeops.h"
+#include "xfs_discard.h"
#include "xfs_quota.h"
#include "xfs_inode_item.h"
#include "xfs_export.h"
@@ -1294,6 +1295,8 @@ xfs_file_ioctl(
trace_xfs_file_ioctl(ip);
switch (cmd) {
+ case FITRIM:
+ return xfs_ioc_trim(mp, arg);
case XFS_IOC_ALLOCSP:
case XFS_IOC_FREESP:
case XFS_IOC_RESVSP:
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