xfs_discard.c revision 0560f31a
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2010 Red Hat, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include "xfs_shared.h"
8#include "xfs_format.h"
9#include "xfs_log_format.h"
10#include "xfs_trans_resv.h"
11#include "xfs_mount.h"
12#include "xfs_btree.h"
13#include "xfs_alloc_btree.h"
14#include "xfs_alloc.h"
15#include "xfs_discard.h"
16#include "xfs_error.h"
17#include "xfs_extent_busy.h"
18#include "xfs_trace.h"
19#include "xfs_log.h"
20#include "xfs_ag.h"
21
22STATIC int
23xfs_trim_extents(
24	struct xfs_mount	*mp,
25	xfs_agnumber_t		agno,
26	xfs_daddr_t		start,
27	xfs_daddr_t		end,
28	xfs_daddr_t		minlen,
29	uint64_t		*blocks_trimmed)
30{
31	struct block_device	*bdev = mp->m_ddev_targp->bt_bdev;
32	struct xfs_btree_cur	*cur;
33	struct xfs_buf		*agbp;
34	struct xfs_agf		*agf;
35	struct xfs_perag	*pag;
36	int			error;
37	int			i;
38
39	pag = xfs_perag_get(mp, agno);
40
41	/*
42	 * Force out the log.  This means any transactions that might have freed
43	 * space before we take the AGF buffer lock are now on disk, and the
44	 * volatile disk cache is flushed.
45	 */
46	xfs_log_force(mp, XFS_LOG_SYNC);
47
48	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
49	if (error)
50		goto out_put_perag;
51	agf = agbp->b_addr;
52
53	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT);
54
55	/*
56	 * Look up the longest btree in the AGF and start with it.
57	 */
58	error = xfs_alloc_lookup_ge(cur, 0, be32_to_cpu(agf->agf_longest), &i);
59	if (error)
60		goto out_del_cursor;
61
62	/*
63	 * Loop until we are done with all extents that are large
64	 * enough to be worth discarding.
65	 */
66	while (i) {
67		xfs_agblock_t	fbno;
68		xfs_extlen_t	flen;
69		xfs_daddr_t	dbno;
70		xfs_extlen_t	dlen;
71
72		error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
73		if (error)
74			goto out_del_cursor;
75		if (XFS_IS_CORRUPT(mp, i != 1)) {
76			error = -EFSCORRUPTED;
77			goto out_del_cursor;
78		}
79		ASSERT(flen <= be32_to_cpu(agf->agf_longest));
80
81		/*
82		 * use daddr format for all range/len calculations as that is
83		 * the format the range/len variables are supplied in by
84		 * userspace.
85		 */
86		dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
87		dlen = XFS_FSB_TO_BB(mp, flen);
88
89		/*
90		 * Too small?  Give up.
91		 */
92		if (dlen < minlen) {
93			trace_xfs_discard_toosmall(mp, agno, fbno, flen);
94			goto out_del_cursor;
95		}
96
97		/*
98		 * If the extent is entirely outside of the range we are
99		 * supposed to discard skip it.  Do not bother to trim
100		 * down partially overlapping ranges for now.
101		 */
102		if (dbno + dlen < start || dbno > end) {
103			trace_xfs_discard_exclude(mp, agno, fbno, flen);
104			goto next_extent;
105		}
106
107		/*
108		 * If any blocks in the range are still busy, skip the
109		 * discard and try again the next time.
110		 */
111		if (xfs_extent_busy_search(mp, pag, fbno, flen)) {
112			trace_xfs_discard_busy(mp, agno, fbno, flen);
113			goto next_extent;
114		}
115
116		trace_xfs_discard_extent(mp, agno, fbno, flen);
117		error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
118		if (error)
119			goto out_del_cursor;
120		*blocks_trimmed += flen;
121
122next_extent:
123		error = xfs_btree_decrement(cur, 0, &i);
124		if (error)
125			goto out_del_cursor;
126
127		if (fatal_signal_pending(current)) {
128			error = -ERESTARTSYS;
129			goto out_del_cursor;
130		}
131	}
132
133out_del_cursor:
134	xfs_btree_del_cursor(cur, error);
135	xfs_buf_relse(agbp);
136out_put_perag:
137	xfs_perag_put(pag);
138	return error;
139}
140
141/*
142 * trim a range of the filesystem.
143 *
144 * Note: the parameters passed from userspace are byte ranges into the
145 * filesystem which does not match to the format we use for filesystem block
146 * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
147 * is a linear address range. Hence we need to use DADDR based conversions and
148 * comparisons for determining the correct offset and regions to trim.
149 */
150int
151xfs_ioc_trim(
152	struct xfs_mount		*mp,
153	struct fstrim_range __user	*urange)
154{
155	struct request_queue	*q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
156	unsigned int		granularity = q->limits.discard_granularity;
157	struct fstrim_range	range;
158	xfs_daddr_t		start, end, minlen;
159	xfs_agnumber_t		start_agno, end_agno, agno;
160	uint64_t		blocks_trimmed = 0;
161	int			error, last_error = 0;
162
163	if (!capable(CAP_SYS_ADMIN))
164		return -EPERM;
165	if (!blk_queue_discard(q))
166		return -EOPNOTSUPP;
167
168	/*
169	 * We haven't recovered the log, so we cannot use our bnobt-guided
170	 * storage zapping commands.
171	 */
172	if (xfs_has_norecovery(mp))
173		return -EROFS;
174
175	if (copy_from_user(&range, urange, sizeof(range)))
176		return -EFAULT;
177
178	range.minlen = max_t(u64, granularity, range.minlen);
179	minlen = BTOBB(range.minlen);
180	/*
181	 * Truncating down the len isn't actually quite correct, but using
182	 * BBTOB would mean we trivially get overflows for values
183	 * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
184	 * used by the fstrim application.  In the end it really doesn't
185	 * matter as trimming blocks is an advisory interface.
186	 */
187	if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
188	    range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
189	    range.len < mp->m_sb.sb_blocksize)
190		return -EINVAL;
191
192	start = BTOBB(range.start);
193	end = start + BTOBBT(range.len) - 1;
194
195	if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
196		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
197
198	start_agno = xfs_daddr_to_agno(mp, start);
199	end_agno = xfs_daddr_to_agno(mp, end);
200
201	for (agno = start_agno; agno <= end_agno; agno++) {
202		error = xfs_trim_extents(mp, agno, start, end, minlen,
203					  &blocks_trimmed);
204		if (error) {
205			last_error = error;
206			if (error == -ERESTARTSYS)
207				break;
208		}
209	}
210
211	if (last_error)
212		return last_error;
213
214	range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
215	if (copy_to_user(urange, &range, sizeof(range)))
216		return -EFAULT;
217	return 0;
218}
219