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 kmem_free(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 free = 0, minfree, maxfree = 0;
68 xfs_agnumber_t agno;
69 bool first_pass = true;
70 int err;
71
72 /* 2% of an AG's blocks must be free for it to be chosen. */
73 minfree = mp->m_sb.sb_agblocks / 50;
74
75 restart:
76 for_each_perag_wrap(mp, start_agno, agno, pag) {
77 trace_xfs_filestream_scan(pag, pino);
78 *longest = 0;
79 err = xfs_bmap_longest_free_extent(pag, NULL, longest);
80 if (err) {
81 if (err != -EAGAIN)
82 break;
83 /* Couldn't lock the AGF, skip this AG. */
84 err = 0;
85 continue;
86 }
87
88 /* Keep track of the AG with the most free blocks. */
89 if (pag->pagf_freeblks > maxfree) {
90 maxfree = pag->pagf_freeblks;
91 if (max_pag)
92 xfs_perag_rele(max_pag);
93 atomic_inc(&pag->pag_active_ref);
94 max_pag = pag;
95 }
96
97 /*
98 * The AG reference count does two things: it enforces mutual
99 * exclusion when examining the suitability of an AG in this
100 * loop, and it guards against two filestreams being established
101 * in the same AG as each other.
102 */
103 if (atomic_inc_return(&pag->pagf_fstrms) <= 1) {
104 if (((minlen && *longest >= minlen) ||
105 (!minlen && pag->pagf_freeblks >= minfree)) &&
106 (!xfs_perag_prefers_metadata(pag) ||
107 !(flags & XFS_PICK_USERDATA) ||
108 (flags & XFS_PICK_LOWSPACE))) {
109 /* Break out, retaining the reference on the AG. */
110 free = pag->pagf_freeblks;
111 break;
112 }
113 }
114
115 /* Drop the reference on this AG, it's not usable. */
116 atomic_dec(&pag->pagf_fstrms);
117 }
118
119 if (err) {
120 xfs_perag_rele(pag);
121 if (max_pag)
122 xfs_perag_rele(max_pag);
123 return err;
124 }
125
126 if (!pag) {
127 /*
128 * Allow a second pass to give xfs_bmap_longest_free_extent()
129 * another attempt at locking AGFs that it might have skipped
130 * over before we fail.
131 */
132 if (first_pass) {
133 first_pass = false;
134 goto restart;
135 }
136
137 /*
138 * We must be low on data space, so run a final lowspace
139 * optimised selection pass if we haven't already.
140 */
141 if (!(flags & XFS_PICK_LOWSPACE)) {
142 flags |= XFS_PICK_LOWSPACE;
143 goto restart;
144 }
145
146 /*
147 * No unassociated AGs are available, so select the AG with the
148 * most free space, regardless of whether it's already in use by
149 * another filestream. It none suit, just use whatever AG we can
150 * grab.
151 */
152 if (!max_pag) {
153 for_each_perag_wrap(args->mp, 0, start_agno, args->pag)
154 break;
155 atomic_inc(&args->pag->pagf_fstrms);
156 *longest = 0;
157 } else {
158 pag = max_pag;
159 free = maxfree;
160 atomic_inc(&pag->pagf_fstrms);
161 }
162 } else if (max_pag) {
163 xfs_perag_rele(max_pag);
164 }
165
166 trace_xfs_filestream_pick(pag, pino, free);
167 args->pag = pag;
168 return 0;
169
170 }
171
172 static struct xfs_inode *
xfs_filestream_get_parent(struct xfs_inode * ip)173 xfs_filestream_get_parent(
174 struct xfs_inode *ip)
175 {
176 struct inode *inode = VFS_I(ip), *dir = NULL;
177 struct dentry *dentry, *parent;
178
179 dentry = d_find_alias(inode);
180 if (!dentry)
181 goto out;
182
183 parent = dget_parent(dentry);
184 if (!parent)
185 goto out_dput;
186
187 dir = igrab(d_inode(parent));
188 dput(parent);
189
190 out_dput:
191 dput(dentry);
192 out:
193 return dir ? XFS_I(dir) : NULL;
194 }
195
196 /*
197 * Lookup the mru cache for an existing association. If one exists and we can
198 * use it, return with an active perag reference indicating that the allocation
199 * will proceed with that association.
200 *
201 * If we have no association, or we cannot use the current one and have to
202 * destroy it, return with longest = 0 to tell the caller to create a new
203 * association.
204 */
205 static int
xfs_filestream_lookup_association(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_ino_t pino,xfs_extlen_t * longest)206 xfs_filestream_lookup_association(
207 struct xfs_bmalloca *ap,
208 struct xfs_alloc_arg *args,
209 xfs_ino_t pino,
210 xfs_extlen_t *longest)
211 {
212 struct xfs_mount *mp = args->mp;
213 struct xfs_perag *pag;
214 struct xfs_mru_cache_elem *mru;
215 int error = 0;
216
217 *longest = 0;
218 mru = xfs_mru_cache_lookup(mp->m_filestream, pino);
219 if (!mru)
220 return 0;
221 /*
222 * Grab the pag and take an extra active reference for the caller whilst
223 * the mru item cannot go away. This means we'll pin the perag with
224 * the reference we get here even if the filestreams association is torn
225 * down immediately after we mark the lookup as done.
226 */
227 pag = container_of(mru, struct xfs_fstrm_item, mru)->pag;
228 atomic_inc(&pag->pag_active_ref);
229 xfs_mru_cache_done(mp->m_filestream);
230
231 trace_xfs_filestream_lookup(pag, ap->ip->i_ino);
232
233 ap->blkno = XFS_AGB_TO_FSB(args->mp, pag->pag_agno, 0);
234 xfs_bmap_adjacent(ap);
235
236 /*
237 * If there is very little free space before we start a filestreams
238 * allocation, we're almost guaranteed to fail to find a large enough
239 * free space available so just use the cached AG.
240 */
241 if (ap->tp->t_flags & XFS_TRANS_LOWMODE) {
242 *longest = 1;
243 goto out_done;
244 }
245
246 error = xfs_bmap_longest_free_extent(pag, args->tp, longest);
247 if (error == -EAGAIN)
248 error = 0;
249 if (error || *longest < args->maxlen) {
250 /* We aren't going to use this perag */
251 *longest = 0;
252 xfs_perag_rele(pag);
253 return error;
254 }
255
256 out_done:
257 args->pag = pag;
258 return 0;
259 }
260
261 static int
xfs_filestream_create_association(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_ino_t pino,xfs_extlen_t * longest)262 xfs_filestream_create_association(
263 struct xfs_bmalloca *ap,
264 struct xfs_alloc_arg *args,
265 xfs_ino_t pino,
266 xfs_extlen_t *longest)
267 {
268 struct xfs_mount *mp = args->mp;
269 struct xfs_mru_cache_elem *mru;
270 struct xfs_fstrm_item *item;
271 xfs_agnumber_t agno = XFS_INO_TO_AGNO(mp, pino);
272 int flags = 0;
273 int error;
274
275 /* Changing parent AG association now, so remove the existing one. */
276 mru = xfs_mru_cache_remove(mp->m_filestream, pino);
277 if (mru) {
278 struct xfs_fstrm_item *item =
279 container_of(mru, struct xfs_fstrm_item, mru);
280
281 agno = (item->pag->pag_agno + 1) % mp->m_sb.sb_agcount;
282 xfs_fstrm_free_func(mp, mru);
283 } else if (xfs_is_inode32(mp)) {
284 xfs_agnumber_t rotorstep = xfs_rotorstep;
285
286 agno = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
287 mp->m_agfrotor = (mp->m_agfrotor + 1) %
288 (mp->m_sb.sb_agcount * rotorstep);
289 }
290
291 ap->blkno = XFS_AGB_TO_FSB(args->mp, agno, 0);
292 xfs_bmap_adjacent(ap);
293
294 if (ap->datatype & XFS_ALLOC_USERDATA)
295 flags |= XFS_PICK_USERDATA;
296 if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
297 flags |= XFS_PICK_LOWSPACE;
298
299 *longest = ap->length;
300 error = xfs_filestream_pick_ag(args, pino, agno, flags, longest);
301 if (error)
302 return error;
303
304 /*
305 * We are going to use this perag now, so create an assoication for it.
306 * xfs_filestream_pick_ag() has already bumped the perag fstrms counter
307 * for us, so all we need to do here is take another active reference to
308 * the perag for the cached association.
309 *
310 * If we fail to store the association, we need to drop the fstrms
311 * counter as well as drop the perag reference we take here for the
312 * item. We do not need to return an error for this failure - as long as
313 * we return a referenced AG, the allocation can still go ahead just
314 * fine.
315 */
316 item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
317 if (!item)
318 goto out_put_fstrms;
319
320 atomic_inc(&args->pag->pag_active_ref);
321 item->pag = args->pag;
322 error = xfs_mru_cache_insert(mp->m_filestream, pino, &item->mru);
323 if (error)
324 goto out_free_item;
325 return 0;
326
327 out_free_item:
328 xfs_perag_rele(item->pag);
329 kmem_free(item);
330 out_put_fstrms:
331 atomic_dec(&args->pag->pagf_fstrms);
332 return 0;
333 }
334
335 /*
336 * Search for an allocation group with a single extent large enough for
337 * the request. First we look for an existing association and use that if it
338 * is found. Otherwise, we create a new association by selecting an AG that fits
339 * the allocation criteria.
340 *
341 * We return with a referenced perag in args->pag to indicate which AG we are
342 * allocating into or an error with no references held.
343 */
344 int
xfs_filestream_select_ag(struct xfs_bmalloca * ap,struct xfs_alloc_arg * args,xfs_extlen_t * longest)345 xfs_filestream_select_ag(
346 struct xfs_bmalloca *ap,
347 struct xfs_alloc_arg *args,
348 xfs_extlen_t *longest)
349 {
350 struct xfs_mount *mp = args->mp;
351 struct xfs_inode *pip;
352 xfs_ino_t ino = 0;
353 int error = 0;
354
355 *longest = 0;
356 args->total = ap->total;
357 pip = xfs_filestream_get_parent(ap->ip);
358 if (pip) {
359 ino = pip->i_ino;
360 error = xfs_filestream_lookup_association(ap, args, ino,
361 longest);
362 xfs_irele(pip);
363 if (error)
364 return error;
365 if (*longest >= args->maxlen)
366 goto out_select;
367 if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
368 goto out_select;
369 }
370
371 error = xfs_filestream_create_association(ap, args, ino, longest);
372 if (error)
373 return error;
374
375 out_select:
376 ap->blkno = XFS_AGB_TO_FSB(mp, args->pag->pag_agno, 0);
377 return 0;
378 }
379
380 void
xfs_filestream_deassociate(struct xfs_inode * ip)381 xfs_filestream_deassociate(
382 struct xfs_inode *ip)
383 {
384 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
385 }
386
387 int
xfs_filestream_mount(xfs_mount_t * mp)388 xfs_filestream_mount(
389 xfs_mount_t *mp)
390 {
391 /*
392 * The filestream timer tunable is currently fixed within the range of
393 * one second to four minutes, with five seconds being the default. The
394 * group count is somewhat arbitrary, but it'd be nice to adhere to the
395 * timer tunable to within about 10 percent. This requires at least 10
396 * groups.
397 */
398 return xfs_mru_cache_create(&mp->m_filestream, mp,
399 xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
400 }
401
402 void
xfs_filestream_unmount(xfs_mount_t * mp)403 xfs_filestream_unmount(
404 xfs_mount_t *mp)
405 {
406 xfs_mru_cache_destroy(mp->m_filestream);
407 }
408