xref: /openbmc/linux/fs/xfs/xfs_discard.c (revision ae213c44)
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_format.h"
8 #include "xfs_log_format.h"
9 #include "xfs_trans_resv.h"
10 #include "xfs_sb.h"
11 #include "xfs_mount.h"
12 #include "xfs_quota.h"
13 #include "xfs_inode.h"
14 #include "xfs_btree.h"
15 #include "xfs_alloc_btree.h"
16 #include "xfs_alloc.h"
17 #include "xfs_error.h"
18 #include "xfs_extent_busy.h"
19 #include "xfs_discard.h"
20 #include "xfs_trace.h"
21 #include "xfs_log.h"
22 
23 STATIC int
24 xfs_trim_extents(
25 	struct xfs_mount	*mp,
26 	xfs_agnumber_t		agno,
27 	xfs_daddr_t		start,
28 	xfs_daddr_t		end,
29 	xfs_daddr_t		minlen,
30 	uint64_t		*blocks_trimmed)
31 {
32 	struct block_device	*bdev = mp->m_ddev_targp->bt_bdev;
33 	struct xfs_btree_cur	*cur;
34 	struct xfs_buf		*agbp;
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 || !agbp)
50 		goto out_put_perag;
51 
52 	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
53 
54 	/*
55 	 * Look up the longest btree in the AGF and start with it.
56 	 */
57 	error = xfs_alloc_lookup_ge(cur, 0,
58 			    be32_to_cpu(XFS_BUF_TO_AGF(agbp)->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 		XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
76 		ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
77 
78 		/*
79 		 * use daddr format for all range/len calculations as that is
80 		 * the format the range/len variables are supplied in by
81 		 * userspace.
82 		 */
83 		dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
84 		dlen = XFS_FSB_TO_BB(mp, flen);
85 
86 		/*
87 		 * Too small?  Give up.
88 		 */
89 		if (dlen < minlen) {
90 			trace_xfs_discard_toosmall(mp, agno, fbno, flen);
91 			goto out_del_cursor;
92 		}
93 
94 		/*
95 		 * If the extent is entirely outside of the range we are
96 		 * supposed to discard skip it.  Do not bother to trim
97 		 * down partially overlapping ranges for now.
98 		 */
99 		if (dbno + dlen < start || dbno > end) {
100 			trace_xfs_discard_exclude(mp, agno, fbno, flen);
101 			goto next_extent;
102 		}
103 
104 		/*
105 		 * If any blocks in the range are still busy, skip the
106 		 * discard and try again the next time.
107 		 */
108 		if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
109 			trace_xfs_discard_busy(mp, agno, fbno, flen);
110 			goto next_extent;
111 		}
112 
113 		trace_xfs_discard_extent(mp, agno, fbno, flen);
114 		error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
115 		if (error)
116 			goto out_del_cursor;
117 		*blocks_trimmed += flen;
118 
119 next_extent:
120 		error = xfs_btree_decrement(cur, 0, &i);
121 		if (error)
122 			goto out_del_cursor;
123 
124 		if (fatal_signal_pending(current)) {
125 			error = -ERESTARTSYS;
126 			goto out_del_cursor;
127 		}
128 	}
129 
130 out_del_cursor:
131 	xfs_btree_del_cursor(cur, error);
132 	xfs_buf_relse(agbp);
133 out_put_perag:
134 	xfs_perag_put(pag);
135 	return error;
136 }
137 
138 /*
139  * trim a range of the filesystem.
140  *
141  * Note: the parameters passed from userspace are byte ranges into the
142  * filesystem which does not match to the format we use for filesystem block
143  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
144  * is a linear address range. Hence we need to use DADDR based conversions and
145  * comparisons for determining the correct offset and regions to trim.
146  */
147 int
148 xfs_ioc_trim(
149 	struct xfs_mount		*mp,
150 	struct fstrim_range __user	*urange)
151 {
152 	struct request_queue	*q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
153 	unsigned int		granularity = q->limits.discard_granularity;
154 	struct fstrim_range	range;
155 	xfs_daddr_t		start, end, minlen;
156 	xfs_agnumber_t		start_agno, end_agno, agno;
157 	uint64_t		blocks_trimmed = 0;
158 	int			error, last_error = 0;
159 
160 	if (!capable(CAP_SYS_ADMIN))
161 		return -EPERM;
162 	if (!blk_queue_discard(q))
163 		return -EOPNOTSUPP;
164 
165 	/*
166 	 * We haven't recovered the log, so we cannot use our bnobt-guided
167 	 * storage zapping commands.
168 	 */
169 	if (mp->m_flags & XFS_MOUNT_NORECOVERY)
170 		return -EROFS;
171 
172 	if (copy_from_user(&range, urange, sizeof(range)))
173 		return -EFAULT;
174 
175 	range.minlen = max_t(u64, granularity, range.minlen);
176 	minlen = BTOBB(range.minlen);
177 	/*
178 	 * Truncating down the len isn't actually quite correct, but using
179 	 * BBTOB would mean we trivially get overflows for values
180 	 * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
181 	 * used by the fstrim application.  In the end it really doesn't
182 	 * matter as trimming blocks is an advisory interface.
183 	 */
184 	if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
185 	    range.minlen > XFS_FSB_TO_B(mp, mp->m_ag_max_usable) ||
186 	    range.len < mp->m_sb.sb_blocksize)
187 		return -EINVAL;
188 
189 	start = BTOBB(range.start);
190 	end = start + BTOBBT(range.len) - 1;
191 
192 	if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
193 		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
194 
195 	start_agno = xfs_daddr_to_agno(mp, start);
196 	end_agno = xfs_daddr_to_agno(mp, end);
197 
198 	for (agno = start_agno; agno <= end_agno; agno++) {
199 		error = xfs_trim_extents(mp, agno, start, end, minlen,
200 					  &blocks_trimmed);
201 		if (error) {
202 			last_error = error;
203 			if (error == -ERESTARTSYS)
204 				break;
205 		}
206 	}
207 
208 	if (last_error)
209 		return last_error;
210 
211 	range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
212 	if (copy_to_user(urange, &range, sizeof(range)))
213 		return -EFAULT;
214 	return 0;
215 }
216