summaryrefslogtreecommitdiffstats
path: root/fs/xfs/linux-2.6/xfs_discard.c
blob: d61611c88012c8daaab1840f9534983fac62bd2d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
/*
 * 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,
	__uint64_t		*blocks_trimmed)
{
	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, 0, &agbp);
	if (error || !agbp)
		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;
		*blocks_trimmed += flen;

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 __user	*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;
	__uint64_t		blocks_trimmed = 0;
	int			error, last_error = 0;

	if (!capable(CAP_SYS_ADMIN))
		return -XFS_ERROR(EPERM);
	if (!blk_queue_discard(q))
		return -XFS_ERROR(EOPNOTSUPP);
	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,
					  &blocks_trimmed);
		if (error)
			last_error = error;
	}

	if (last_error)
		return last_error;

	range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
	if (copy_to_user(urange, &range, sizeof(range)))
		return -XFS_ERROR(EFAULT);
	return 0;
}