xref: /openbmc/linux/fs/xfs/xfs_discard.c (revision a06c488d)
1 /*
2  * Copyright (C) 2010 Red Hat, Inc.
3  * All Rights Reserved.
4  *
5  * This program is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU General Public License as
7  * published by the Free Software Foundation.
8  *
9  * This program is distributed in the hope that it would be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write the Free Software Foundation,
16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17  */
18 #include "xfs.h"
19 #include "xfs_format.h"
20 #include "xfs_log_format.h"
21 #include "xfs_trans_resv.h"
22 #include "xfs_sb.h"
23 #include "xfs_mount.h"
24 #include "xfs_quota.h"
25 #include "xfs_inode.h"
26 #include "xfs_btree.h"
27 #include "xfs_alloc_btree.h"
28 #include "xfs_alloc.h"
29 #include "xfs_error.h"
30 #include "xfs_extent_busy.h"
31 #include "xfs_discard.h"
32 #include "xfs_trace.h"
33 #include "xfs_log.h"
34 
35 STATIC int
36 xfs_trim_extents(
37 	struct xfs_mount	*mp,
38 	xfs_agnumber_t		agno,
39 	xfs_daddr_t		start,
40 	xfs_daddr_t		end,
41 	xfs_daddr_t		minlen,
42 	__uint64_t		*blocks_trimmed)
43 {
44 	struct block_device	*bdev = mp->m_ddev_targp->bt_bdev;
45 	struct xfs_btree_cur	*cur;
46 	struct xfs_buf		*agbp;
47 	struct xfs_perag	*pag;
48 	int			error;
49 	int			i;
50 
51 	pag = xfs_perag_get(mp, agno);
52 
53 	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
54 	if (error || !agbp)
55 		goto out_put_perag;
56 
57 	cur = xfs_allocbt_init_cursor(mp, NULL, agbp, agno, XFS_BTNUM_CNT);
58 
59 	/*
60 	 * Force out the log.  This means any transactions that might have freed
61 	 * space before we took the AGF buffer lock are now on disk, and the
62 	 * volatile disk cache is flushed.
63 	 */
64 	xfs_log_force(mp, XFS_LOG_SYNC);
65 
66 	/*
67 	 * Look up the longest btree in the AGF and start with it.
68 	 */
69 	error = xfs_alloc_lookup_ge(cur, 0,
70 			    be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest), &i);
71 	if (error)
72 		goto out_del_cursor;
73 
74 	/*
75 	 * Loop until we are done with all extents that are large
76 	 * enough to be worth discarding.
77 	 */
78 	while (i) {
79 		xfs_agblock_t	fbno;
80 		xfs_extlen_t	flen;
81 		xfs_daddr_t	dbno;
82 		xfs_extlen_t	dlen;
83 
84 		error = xfs_alloc_get_rec(cur, &fbno, &flen, &i);
85 		if (error)
86 			goto out_del_cursor;
87 		XFS_WANT_CORRUPTED_GOTO(mp, i == 1, out_del_cursor);
88 		ASSERT(flen <= be32_to_cpu(XFS_BUF_TO_AGF(agbp)->agf_longest));
89 
90 		/*
91 		 * use daddr format for all range/len calculations as that is
92 		 * the format the range/len variables are supplied in by
93 		 * userspace.
94 		 */
95 		dbno = XFS_AGB_TO_DADDR(mp, agno, fbno);
96 		dlen = XFS_FSB_TO_BB(mp, flen);
97 
98 		/*
99 		 * Too small?  Give up.
100 		 */
101 		if (dlen < minlen) {
102 			trace_xfs_discard_toosmall(mp, agno, fbno, flen);
103 			goto out_del_cursor;
104 		}
105 
106 		/*
107 		 * If the extent is entirely outside of the range we are
108 		 * supposed to discard skip it.  Do not bother to trim
109 		 * down partially overlapping ranges for now.
110 		 */
111 		if (dbno + dlen < start || dbno > end) {
112 			trace_xfs_discard_exclude(mp, agno, fbno, flen);
113 			goto next_extent;
114 		}
115 
116 		/*
117 		 * If any blocks in the range are still busy, skip the
118 		 * discard and try again the next time.
119 		 */
120 		if (xfs_extent_busy_search(mp, agno, fbno, flen)) {
121 			trace_xfs_discard_busy(mp, agno, fbno, flen);
122 			goto next_extent;
123 		}
124 
125 		trace_xfs_discard_extent(mp, agno, fbno, flen);
126 		error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS, 0);
127 		if (error)
128 			goto out_del_cursor;
129 		*blocks_trimmed += flen;
130 
131 next_extent:
132 		error = xfs_btree_decrement(cur, 0, &i);
133 		if (error)
134 			goto out_del_cursor;
135 	}
136 
137 out_del_cursor:
138 	xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
139 	xfs_buf_relse(agbp);
140 out_put_perag:
141 	xfs_perag_put(pag);
142 	return error;
143 }
144 
145 /*
146  * trim a range of the filesystem.
147  *
148  * Note: the parameters passed from userspace are byte ranges into the
149  * filesystem which does not match to the format we use for filesystem block
150  * addressing. FSB addressing is sparse (AGNO|AGBNO), while the incoming format
151  * is a linear address range. Hence we need to use DADDR based conversions and
152  * comparisons for determining the correct offset and regions to trim.
153  */
154 int
155 xfs_ioc_trim(
156 	struct xfs_mount		*mp,
157 	struct fstrim_range __user	*urange)
158 {
159 	struct request_queue	*q = bdev_get_queue(mp->m_ddev_targp->bt_bdev);
160 	unsigned int		granularity = q->limits.discard_granularity;
161 	struct fstrim_range	range;
162 	xfs_daddr_t		start, end, minlen;
163 	xfs_agnumber_t		start_agno, end_agno, agno;
164 	__uint64_t		blocks_trimmed = 0;
165 	int			error, last_error = 0;
166 
167 	if (!capable(CAP_SYS_ADMIN))
168 		return -EPERM;
169 	if (!blk_queue_discard(q))
170 		return -EOPNOTSUPP;
171 	if (copy_from_user(&range, urange, sizeof(range)))
172 		return -EFAULT;
173 
174 	/*
175 	 * Truncating down the len isn't actually quite correct, but using
176 	 * BBTOB would mean we trivially get overflows for values
177 	 * of ULLONG_MAX or slightly lower.  And ULLONG_MAX is the default
178 	 * used by the fstrim application.  In the end it really doesn't
179 	 * matter as trimming blocks is an advisory interface.
180 	 */
181 	if (range.start >= XFS_FSB_TO_B(mp, mp->m_sb.sb_dblocks) ||
182 	    range.minlen > XFS_FSB_TO_B(mp, XFS_ALLOC_AG_MAX_USABLE(mp)) ||
183 	    range.len < mp->m_sb.sb_blocksize)
184 		return -EINVAL;
185 
186 	start = BTOBB(range.start);
187 	end = start + BTOBBT(range.len) - 1;
188 	minlen = BTOBB(max_t(u64, granularity, range.minlen));
189 
190 	if (end > XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks) - 1)
191 		end = XFS_FSB_TO_BB(mp, mp->m_sb.sb_dblocks)- 1;
192 
193 	start_agno = xfs_daddr_to_agno(mp, start);
194 	end_agno = xfs_daddr_to_agno(mp, end);
195 
196 	for (agno = start_agno; agno <= end_agno; agno++) {
197 		error = xfs_trim_extents(mp, agno, start, end, minlen,
198 					  &blocks_trimmed);
199 		if (error)
200 			last_error = error;
201 	}
202 
203 	if (last_error)
204 		return last_error;
205 
206 	range.len = XFS_FSB_TO_B(mp, blocks_trimmed);
207 	if (copy_to_user(urange, &range, sizeof(range)))
208 		return -EFAULT;
209 	return 0;
210 }
211 
212 int
213 xfs_discard_extents(
214 	struct xfs_mount	*mp,
215 	struct list_head	*list)
216 {
217 	struct xfs_extent_busy	*busyp;
218 	int			error = 0;
219 
220 	list_for_each_entry(busyp, list, list) {
221 		trace_xfs_discard_extent(mp, busyp->agno, busyp->bno,
222 					 busyp->length);
223 
224 		error = blkdev_issue_discard(mp->m_ddev_targp->bt_bdev,
225 				XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno),
226 				XFS_FSB_TO_BB(mp, busyp->length),
227 				GFP_NOFS, 0);
228 		if (error && error != -EOPNOTSUPP) {
229 			xfs_info(mp,
230 	 "discard failed for extent [0x%llu,%u], error %d",
231 				 (unsigned long long)busyp->bno,
232 				 busyp->length,
233 				 error);
234 			return error;
235 		}
236 	}
237 
238 	return 0;
239 }
240