1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (c) 2006-2007 Silicon Graphics, Inc.
4 * Copyright (c) 2014 Christoph Hellwig.
5 * All Rights Reserved.
6 */
7 #include "xfs.h"
8 #include "xfs_shared.h"
9 #include "xfs_format.h"
10 #include "xfs_log_format.h"
11 #include "xfs_trans_resv.h"
12 #include "xfs_mount.h"
13 #include "xfs_inode.h"
14 #include "xfs_bmap.h"
15 #include "xfs_bmap_util.h"
16 #include "xfs_alloc.h"
17 #include "xfs_mru_cache.h"
18 #include "xfs_trace.h"
19 #include "xfs_ag.h"
20 #include "xfs_ag_resv.h"
21 #include "xfs_trans.h"
22 #include "xfs_filestream.h"
23
24 struct xfs_fstrm_item {
25 struct xfs_mru_cache_elem mru;
26 struct xfs_perag *pag; /* AG in use for this directory */
27 };
28
29 enum xfs_fstrm_alloc {
30 XFS_PICK_USERDATA = 1,
31 XFS_PICK_LOWSPACE = 2,
32 };
33
34 static void
xfs_fstrm_free_func(void * data,struct xfs_mru_cache_elem * mru)35 xfs_fstrm_free_func(
36 void *data,
37 struct xfs_mru_cache_elem *mru)
38 {
39 struct xfs_fstrm_item *item =
40 container_of(mru, struct xfs_fstrm_item, mru);
41 struct xfs_perag *pag = item->pag;
42
43 trace_xfs_filestream_free(pag, mru->key);
44 atomic_dec(&pag->pagf_fstrms);
45 xfs_perag_rele(pag);
46
47 kfree(item);
48 }
49
50 /*
51 * Scan the AGs starting at start_agno looking for an AG that isn't in use and
52 * has at least minlen blocks free. If no AG is found to match the allocation
53 * requirements, pick the AG with the most free space in it.
54 */
55 static int
xfs_filestream_pick_ag(struct xfs_alloc_arg * args,xfs_ino_t pino,xfs_agnumber_t start_agno,int flags,xfs_extlen_t * longest)56 xfs_filestream_pick_ag(
57 struct xfs_alloc_arg *args,
58 xfs_ino_t pino,
59 xfs_agnumber_t start_agno,
60 int flags,
61 xfs_extlen_t *longest)
62 {
63 struct xfs_mount *mp = args->mp;
64 struct xfs_perag *pag;
65 struct xfs_perag *max_pag = NULL;
66 xfs_extlen_t minlen = *longest;
67 xfs_extlen_t minfree, maxfree = 0;
68 xfs_agnumber_t agno;
69 bool first_pass = true;
70
71 /* 2% of an AG's blocks must be free for it to be chosen. */
72 minfree = mp->m_sb.sb_agblocks / 50;
73
74 restart:
75 for_each_perag_wrap(mp, start_agno, agno, pag) {
76 int err;
77
78 trace_xfs_filestream_scan(pag, pino);
79
80 *longest = 0;
81 err = xfs_bmap_longest_free_extent(pag, NULL, longest);
82 if (err) {
83 if (err == -EAGAIN) {
84 /* Couldn't lock the AGF, skip this AG. */
85 err = 0;
86 continue;
87 }
88 xfs_perag_rele(pag);
89 if (max_pag)
90 xfs_perag_rele(max_pag);
91 return err;
92 }
93
94 /* Keep track of the AG with the most free blocks. */
95 if (pag->pagf_freeblks > maxfree) {
96 maxfree = pag->pagf_freeblks;
97 if (max_pag)
98 xfs_perag_rele(max_pag);
99 atomic_inc(&pag->pag_active_ref);
100 max_pag = pag;
101 }
102
103 /*
104 * The AG reference count does two things: it enforces mutual
105 * exclusion when examining the suitability of an AG in this
106 * loop, and it guards against two filestreams being established
107 * in the same AG as each other.
108 */
109 if (atomic_inc_return(&pag->pagf_fstrms) <= 1) {
110 if (((minlen && *longest >= minlen) ||
111 (!minlen && pag->pagf_freeblks >= minfree)) &&
112 (!xfs_perag_prefers_metadata(pag) ||
113 !(flags & XFS_PICK_USERDATA) ||
114 (flags & XFS_PICK_LOWSPACE))) {
115 /* Break out, retaining the reference on the AG. */
116 if (max_pag)
117 xfs_perag_rele(max_pag);
118 goto done;
119 }
120 }
121
122 /* Drop the reference on this AG, it's not usable. */
123 atomic_dec(&pag->pagf_fstrms);
124 }
125
126 /*
127 * Allow a second pass to give xfs_bmap_longest_free_extent() another
128 * attempt at locking AGFs that it might have skipped over before we
129 * fail.
130 */
131 if (first_pass) {
132 first_pass = false;
133 goto restart;
134 }
135
136 /*
137 * We must be low on data space, so run a final lowspace optimised
138 * selection pass if we haven't already.
139 */
140 if (!(flags & XFS_PICK_LOWSPACE)) {
141 flags |= XFS_PICK_LOWSPACE;
142 goto restart;
143 }
144
145 /*
146 * No unassociated AGs are available, so select the AG with the most
147 * free space, regardless of whether it's already in use by another
148 * filestream. It none suit, just use whatever AG we can grab.
149 */
150 if (!max_pag) {
151 for_each_perag_wrap(args->mp, 0, start_agno, pag) {
152 max_pag = pag;
153 break;
154 }
155
156 /* Bail if there are no AGs at all to select from. */
157 if (!max_pag)
158 return -ENOSPC;
159 }
160
161 pag = max_pag;
162 atomic_inc(&pag->pagf_fstrms);
163 done:
164 trace_xfs_filestream_pick(pag, pino);
165 args->pag = pag;
166 return 0;
167 }
168
169 static struct xfs_inode *
xfs_filestream_get_parent(struct xfs_inode * ip)170 xfs_filestream_get_parent(
171 struct xfs_inode *ip)
172 {
173 struct inode *inode = VFS_I(ip), *dir = NULL;
174 struct dentry *dentry, *parent;
175
176 dentry = d_find_alias(inode);
177 if (!dentry)
178 goto out;
179
180 parent = dget_parent(dentry);
181 if (!parent)
182 goto out_dput;
183
184 dir = igrab(d_inode(parent));
185 dput(parent);
186
187 out_dput:
188 dput(dentry);
189 out:
190 return dir ? XFS_I(dir) : NULL;
191 }
192
193 /*
194 * Lookup the mru cache for an existing association. If one exists and we can
195 * use it, return with an active perag reference indicating that the allocation
196 * will proceed with that association.
197 *
198 * If we have no association, or we cannot use the current one and have to
199 * destroy it, return with longest = 0 to tell the caller to create a new
200 * association.
201 */
202 static int
xfs_filestream_lookup_association(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_ino_t pino,xfs_extlen_t * longest)203 xfs_filestream_lookup_association(
204 struct xfs_bmalloca *ap,
205 struct xfs_alloc_arg *args,
206 xfs_ino_t pino,
207 xfs_extlen_t *longest)
208 {
209 struct xfs_mount *mp = args->mp;
210 struct xfs_perag *pag;
211 struct xfs_mru_cache_elem *mru;
212 int error = 0;
213
214 *longest = 0;
215 mru = xfs_mru_cache_lookup(mp->m_filestream, pino);
216 if (!mru)
217 return 0;
218 /*
219 * Grab the pag and take an extra active reference for the caller whilst
220 * the mru item cannot go away. This means we'll pin the perag with
221 * the reference we get here even if the filestreams association is torn
222 * down immediately after we mark the lookup as done.
223 */
224 pag = container_of(mru, struct xfs_fstrm_item, mru)->pag;
225 atomic_inc(&pag->pag_active_ref);
226 xfs_mru_cache_done(mp->m_filestream);
227
228 trace_xfs_filestream_lookup(pag, ap->ip->i_ino);
229
230 ap->blkno = XFS_AGB_TO_FSB(args->mp, pag->pag_agno, 0);
231 xfs_bmap_adjacent(ap);
232
233 /*
234 * If there is very little free space before we start a filestreams
235 * allocation, we're almost guaranteed to fail to find a large enough
236 * free space available so just use the cached AG.
237 */
238 if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
239 *longest = 1;
240 goto out_done;
241 }
242
243 error = xfs_bmap_longest_free_extent(pag, args->tp, longest);
244 if (error == -EAGAIN)
245 error = 0;
246 if (error || *longest < args->maxlen) {
247 /* We aren't going to use this perag */
248 *longest = 0;
249 xfs_perag_rele(pag);
250 return error;
251 }
252
253 out_done:
254 args->pag = pag;
255 return 0;
256 }
257
258 static int
xfs_filestream_create_association(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_ino_t pino,xfs_extlen_t * longest)259 xfs_filestream_create_association(
260 struct xfs_bmalloca *ap,
261 struct xfs_alloc_arg *args,
262 xfs_ino_t pino,
263 xfs_extlen_t *longest)
264 {
265 struct xfs_mount *mp = args->mp;
266 struct xfs_mru_cache_elem *mru;
267 struct xfs_fstrm_item *item;
268 xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, pino);
269 int flags = 0;
270 int error;
271
272 /* Changing parent AG association now, so remove the existing one. */
273 mru = xfs_mru_cache_remove(mp->m_filestream, pino);
274 if (mru) {
275 struct xfs_fstrm_item *item =
276 container_of(mru, struct xfs_fstrm_item, mru);
277
278 agno = (item->pag->pag_agno + 1) % mp->m_sb.sb_agcount;
279 xfs_fstrm_free_func(mp, mru);
280 } else if (xfs_is_inode32(mp)) {
281 xfs_agnumber_t rotorstep = xfs_rotorstep;
282
283 agno = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
284 mp->m_agfrotor = (mp->m_agfrotor + 1) %
285 (mp->m_sb.sb_agcount * rotorstep);
286 }
287
288 ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
289 xfs_bmap_adjacent(ap);
290
291 if (ap->datatype & XFS_ALLOC_USERDATA)
292 flags |= XFS_PICK_USERDATA;
293 if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
294 flags |= XFS_PICK_LOWSPACE;
295
296 *longest = ap->length;
297 error = xfs_filestream_pick_ag(args, pino, agno, flags, longest);
298 if (error)
299 return error;
300
301 /*
302 * We are going to use this perag now, so create an assoication for it.
303 * xfs_filestream_pick_ag() has already bumped the perag fstrms counter
304 * for us, so all we need to do here is take another active reference to
305 * the perag for the cached association.
306 *
307 * If we fail to store the association, we need to drop the fstrms
308 * counter as well as drop the perag reference we take here for the
309 * item. We do not need to return an error for this failure - as long as
310 * we return a referenced AG, the allocation can still go ahead just
311 * fine.
312 */
313 item = kmalloc(sizeof(*item), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
314 if (!item)
315 goto out_put_fstrms;
316
317 atomic_inc(&args->pag->pag_active_ref);
318 item->pag = args->pag;
319 error = xfs_mru_cache_insert(mp->m_filestream, pino, &item->mru);
320 if (error)
321 goto out_free_item;
322 return 0;
323
324 out_free_item:
325 xfs_perag_rele(item->pag);
326 kfree(item);
327 out_put_fstrms:
328 atomic_dec(&args->pag->pagf_fstrms);
329 return 0;
330 }
331
332 /*
333 * Search for an allocation group with a single extent large enough for
334 * the request. First we look for an existing association and use that if it
335 * is found. Otherwise, we create a new association by selecting an AG that fits
336 * the allocation criteria.
337 *
338 * We return with a referenced perag in args->pag to indicate which AG we are
339 * allocating into or an error with no references held.
340 */
341 int
xfs_filestream_select_ag(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_extlen_t * longest)342 xfs_filestream_select_ag(
343 struct xfs_bmalloca *ap,
344 struct xfs_alloc_arg *args,
345 xfs_extlen_t *longest)
346 {
347 struct xfs_mount *mp = args->mp;
348 struct xfs_inode *pip;
349 xfs_ino_t ino = 0;
350 int error = 0;
351
352 *longest = 0;
353 args->total = ap->total;
354 pip = xfs_filestream_get_parent(ap->ip);
355 if (pip) {
356 ino = pip->i_ino;
357 error = xfs_filestream_lookup_association(ap, args, ino,
358 longest);
359 xfs_irele(pip);
360 if (error)
361 return error;
362 if (*longest >= args->maxlen)
363 goto out_select;
364 if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
365 goto out_select;
366 }
367
368 error = xfs_filestream_create_association(ap, args, ino, longest);
369 if (error)
370 return error;
371
372 out_select:
373 ap->blkno = XFS_AGB_TO_FSB(mp, args->pag->pag_agno, 0);
374 return 0;
375 }
376
377 void
xfs_filestream_deassociate(struct xfs_inode * ip)378 xfs_filestream_deassociate(
379 struct xfs_inode *ip)
380 {
381 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
382 }
383
384 int
xfs_filestream_mount(xfs_mount_t * mp)385 xfs_filestream_mount(
386 xfs_mount_t *mp)
387 {
388 /*
389 * The filestream timer tunable is currently fixed within the range of
390 * one second to four minutes, with five seconds being the default. The
391 * group count is somewhat arbitrary, but it'd be nice to adhere to the
392 * timer tunable to within about 10 percent. This requires at least 10
393 * groups.
394 */
395 return xfs_mru_cache_create(&mp->m_filestream, mp,
396 xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
397 }
398
399 void
xfs_filestream_unmount(xfs_mount_t * mp)400 xfs_filestream_unmount(
401 xfs_mount_t *mp)
402 {
403 xfs_mru_cache_destroy(mp->m_filestream);
404 }
405