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1/*
2 * Copyright (c) 2006-2007 Silicon Graphics, Inc.
3 * Copyright (c) 2014 Christoph Hellwig.
4 * All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19#include "xfs.h"
20#include "xfs_format.h"
21#include "xfs_log_format.h"
22#include "xfs_trans_resv.h"
23#include "xfs_sb.h"
24#include "xfs_mount.h"
25#include "xfs_defer.h"
26#include "xfs_inode.h"
27#include "xfs_bmap.h"
28#include "xfs_bmap_util.h"
29#include "xfs_alloc.h"
30#include "xfs_mru_cache.h"
31#include "xfs_filestream.h"
32#include "xfs_trace.h"
33#include "xfs_ag_resv.h"
34
35struct xfs_fstrm_item {
36 struct xfs_mru_cache_elem mru;
37 xfs_agnumber_t ag; /* AG in use for this directory */
38};
39
40enum xfs_fstrm_alloc {
41 XFS_PICK_USERDATA = 1,
42 XFS_PICK_LOWSPACE = 2,
43};
44
45/*
46 * Allocation group filestream associations are tracked with per-ag atomic
47 * counters. These counters allow xfs_filestream_pick_ag() to tell whether a
48 * particular AG already has active filestreams associated with it. The mount
49 * point's m_peraglock is used to protect these counters from per-ag array
50 * re-allocation during a growfs operation. When xfs_growfs_data_private() is
51 * about to reallocate the array, it calls xfs_filestream_flush() with the
52 * m_peraglock held in write mode.
53 *
54 * Since xfs_mru_cache_flush() guarantees that all the free functions for all
55 * the cache elements have finished executing before it returns, it's safe for
56 * the free functions to use the atomic counters without m_peraglock protection.
57 * This allows the implementation of xfs_fstrm_free_func() to be agnostic about
58 * whether it was called with the m_peraglock held in read mode, write mode or
59 * not held at all. The race condition this addresses is the following:
60 *
61 * - The work queue scheduler fires and pulls a filestream directory cache
62 * element off the LRU end of the cache for deletion, then gets pre-empted.
63 * - A growfs operation grabs the m_peraglock in write mode, flushes all the
64 * remaining items from the cache and reallocates the mount point's per-ag
65 * array, resetting all the counters to zero.
66 * - The work queue thread resumes and calls the free function for the element
67 * it started cleaning up earlier. In the process it decrements the
68 * filestreams counter for an AG that now has no references.
69 *
70 * With a shrinkfs feature, the above scenario could panic the system.
71 *
72 * All other uses of the following macros should be protected by either the
73 * m_peraglock held in read mode, or the cache's internal locking exposed by the
74 * interval between a call to xfs_mru_cache_lookup() and a call to
75 * xfs_mru_cache_done(). In addition, the m_peraglock must be held in read mode
76 * when new elements are added to the cache.
77 *
78 * Combined, these locking rules ensure that no associations will ever exist in
79 * the cache that reference per-ag array elements that have since been
80 * reallocated.
81 */
82int
83xfs_filestream_peek_ag(
84 xfs_mount_t *mp,
85 xfs_agnumber_t agno)
86{
87 struct xfs_perag *pag;
88 int ret;
89
90 pag = xfs_perag_get(mp, agno);
91 ret = atomic_read(&pag->pagf_fstrms);
92 xfs_perag_put(pag);
93 return ret;
94}
95
96static int
97xfs_filestream_get_ag(
98 xfs_mount_t *mp,
99 xfs_agnumber_t agno)
100{
101 struct xfs_perag *pag;
102 int ret;
103
104 pag = xfs_perag_get(mp, agno);
105 ret = atomic_inc_return(&pag->pagf_fstrms);
106 xfs_perag_put(pag);
107 return ret;
108}
109
110static void
111xfs_filestream_put_ag(
112 xfs_mount_t *mp,
113 xfs_agnumber_t agno)
114{
115 struct xfs_perag *pag;
116
117 pag = xfs_perag_get(mp, agno);
118 atomic_dec(&pag->pagf_fstrms);
119 xfs_perag_put(pag);
120}
121
122static void
123xfs_fstrm_free_func(
124 void *data,
125 struct xfs_mru_cache_elem *mru)
126{
127 struct xfs_mount *mp = data;
128 struct xfs_fstrm_item *item =
129 container_of(mru, struct xfs_fstrm_item, mru);
130
131 xfs_filestream_put_ag(mp, item->ag);
132 trace_xfs_filestream_free(mp, mru->key, item->ag);
133
134 kmem_free(item);
135}
136
137/*
138 * Scan the AGs starting at startag looking for an AG that isn't in use and has
139 * at least minlen blocks free.
140 */
141static int
142xfs_filestream_pick_ag(
143 struct xfs_inode *ip,
144 xfs_agnumber_t startag,
145 xfs_agnumber_t *agp,
146 int flags,
147 xfs_extlen_t minlen)
148{
149 struct xfs_mount *mp = ip->i_mount;
150 struct xfs_fstrm_item *item;
151 struct xfs_perag *pag;
152 xfs_extlen_t longest, free = 0, minfree, maxfree = 0;
153 xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
154 int err, trylock, nscan;
155
156 ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
157
158 /* 2% of an AG's blocks must be free for it to be chosen. */
159 minfree = mp->m_sb.sb_agblocks / 50;
160
161 ag = startag;
162 *agp = NULLAGNUMBER;
163
164 /* For the first pass, don't sleep trying to init the per-AG. */
165 trylock = XFS_ALLOC_FLAG_TRYLOCK;
166
167 for (nscan = 0; 1; nscan++) {
168 trace_xfs_filestream_scan(mp, ip->i_ino, ag);
169
170 pag = xfs_perag_get(mp, ag);
171
172 if (!pag->pagf_init) {
173 err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
174 if (err && !trylock) {
175 xfs_perag_put(pag);
176 return err;
177 }
178 }
179
180 /* Might fail sometimes during the 1st pass with trylock set. */
181 if (!pag->pagf_init)
182 goto next_ag;
183
184 /* Keep track of the AG with the most free blocks. */
185 if (pag->pagf_freeblks > maxfree) {
186 maxfree = pag->pagf_freeblks;
187 max_ag = ag;
188 }
189
190 /*
191 * The AG reference count does two things: it enforces mutual
192 * exclusion when examining the suitability of an AG in this
193 * loop, and it guards against two filestreams being established
194 * in the same AG as each other.
195 */
196 if (xfs_filestream_get_ag(mp, ag) > 1) {
197 xfs_filestream_put_ag(mp, ag);
198 goto next_ag;
199 }
200
201 longest = xfs_alloc_longest_free_extent(pag,
202 xfs_alloc_min_freelist(mp, pag),
203 xfs_ag_resv_needed(pag, XFS_AG_RESV_NONE));
204 if (((minlen && longest >= minlen) ||
205 (!minlen && pag->pagf_freeblks >= minfree)) &&
206 (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
207 (flags & XFS_PICK_LOWSPACE))) {
208
209 /* Break out, retaining the reference on the AG. */
210 free = pag->pagf_freeblks;
211 xfs_perag_put(pag);
212 *agp = ag;
213 break;
214 }
215
216 /* Drop the reference on this AG, it's not usable. */
217 xfs_filestream_put_ag(mp, ag);
218next_ag:
219 xfs_perag_put(pag);
220 /* Move to the next AG, wrapping to AG 0 if necessary. */
221 if (++ag >= mp->m_sb.sb_agcount)
222 ag = 0;
223
224 /* If a full pass of the AGs hasn't been done yet, continue. */
225 if (ag != startag)
226 continue;
227
228 /* Allow sleeping in xfs_alloc_pagf_init() on the 2nd pass. */
229 if (trylock != 0) {
230 trylock = 0;
231 continue;
232 }
233
234 /* Finally, if lowspace wasn't set, set it for the 3rd pass. */
235 if (!(flags & XFS_PICK_LOWSPACE)) {
236 flags |= XFS_PICK_LOWSPACE;
237 continue;
238 }
239
240 /*
241 * Take the AG with the most free space, regardless of whether
242 * it's already in use by another filestream.
243 */
244 if (max_ag != NULLAGNUMBER) {
245 xfs_filestream_get_ag(mp, max_ag);
246 free = maxfree;
247 *agp = max_ag;
248 break;
249 }
250
251 /* take AG 0 if none matched */
252 trace_xfs_filestream_pick(ip, *agp, free, nscan);
253 *agp = 0;
254 return 0;
255 }
256
257 trace_xfs_filestream_pick(ip, *agp, free, nscan);
258
259 if (*agp == NULLAGNUMBER)
260 return 0;
261
262 err = -ENOMEM;
263 item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
264 if (!item)
265 goto out_put_ag;
266
267 item->ag = *agp;
268
269 err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);
270 if (err) {
271 if (err == -EEXIST)
272 err = 0;
273 goto out_free_item;
274 }
275
276 return 0;
277
278out_free_item:
279 kmem_free(item);
280out_put_ag:
281 xfs_filestream_put_ag(mp, *agp);
282 return err;
283}
284
285static struct xfs_inode *
286xfs_filestream_get_parent(
287 struct xfs_inode *ip)
288{
289 struct inode *inode = VFS_I(ip), *dir = NULL;
290 struct dentry *dentry, *parent;
291
292 dentry = d_find_alias(inode);
293 if (!dentry)
294 goto out;
295
296 parent = dget_parent(dentry);
297 if (!parent)
298 goto out_dput;
299
300 dir = igrab(d_inode(parent));
301 dput(parent);
302
303out_dput:
304 dput(dentry);
305out:
306 return dir ? XFS_I(dir) : NULL;
307}
308
309/*
310 * Find the right allocation group for a file, either by finding an
311 * existing file stream or creating a new one.
312 *
313 * Returns NULLAGNUMBER in case of an error.
314 */
315xfs_agnumber_t
316xfs_filestream_lookup_ag(
317 struct xfs_inode *ip)
318{
319 struct xfs_mount *mp = ip->i_mount;
320 struct xfs_inode *pip = NULL;
321 xfs_agnumber_t startag, ag = NULLAGNUMBER;
322 struct xfs_mru_cache_elem *mru;
323
324 ASSERT(S_ISREG(VFS_I(ip)->i_mode));
325
326 pip = xfs_filestream_get_parent(ip);
327 if (!pip)
328 return NULLAGNUMBER;
329
330 mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
331 if (mru) {
332 ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
333 xfs_mru_cache_done(mp->m_filestream);
334
335 trace_xfs_filestream_lookup(mp, ip->i_ino, ag);
336 goto out;
337 }
338
339 /*
340 * Set the starting AG using the rotor for inode32, otherwise
341 * use the directory inode's AG.
342 */
343 if (mp->m_flags & XFS_MOUNT_32BITINODES) {
344 xfs_agnumber_t rotorstep = xfs_rotorstep;
345 startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
346 mp->m_agfrotor = (mp->m_agfrotor + 1) %
347 (mp->m_sb.sb_agcount * rotorstep);
348 } else
349 startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
350
351 if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
352 ag = NULLAGNUMBER;
353out:
354 IRELE(pip);
355 return ag;
356}
357
358/*
359 * Pick a new allocation group for the current file and its file stream.
360 *
361 * This is called when the allocator can't find a suitable extent in the
362 * current AG, and we have to move the stream into a new AG with more space.
363 */
364int
365xfs_filestream_new_ag(
366 struct xfs_bmalloca *ap,
367 xfs_agnumber_t *agp)
368{
369 struct xfs_inode *ip = ap->ip, *pip;
370 struct xfs_mount *mp = ip->i_mount;
371 xfs_extlen_t minlen = ap->length;
372 xfs_agnumber_t startag = 0;
373 int flags = 0;
374 int err = 0;
375 struct xfs_mru_cache_elem *mru;
376
377 *agp = NULLAGNUMBER;
378
379 pip = xfs_filestream_get_parent(ip);
380 if (!pip)
381 goto exit;
382
383 mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
384 if (mru) {
385 struct xfs_fstrm_item *item =
386 container_of(mru, struct xfs_fstrm_item, mru);
387 startag = (item->ag + 1) % mp->m_sb.sb_agcount;
388 }
389
390 if (xfs_alloc_is_userdata(ap->datatype))
391 flags |= XFS_PICK_USERDATA;
392 if (ap->dfops->dop_low)
393 flags |= XFS_PICK_LOWSPACE;
394
395 err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
396
397 /*
398 * Only free the item here so we skip over the old AG earlier.
399 */
400 if (mru)
401 xfs_fstrm_free_func(mp, mru);
402
403 IRELE(pip);
404exit:
405 if (*agp == NULLAGNUMBER)
406 *agp = 0;
407 return err;
408}
409
410void
411xfs_filestream_deassociate(
412 struct xfs_inode *ip)
413{
414 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
415}
416
417int
418xfs_filestream_mount(
419 xfs_mount_t *mp)
420{
421 /*
422 * The filestream timer tunable is currently fixed within the range of
423 * one second to four minutes, with five seconds being the default. The
424 * group count is somewhat arbitrary, but it'd be nice to adhere to the
425 * timer tunable to within about 10 percent. This requires at least 10
426 * groups.
427 */
428 return xfs_mru_cache_create(&mp->m_filestream, mp,
429 xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
430}
431
432void
433xfs_filestream_unmount(
434 xfs_mount_t *mp)
435{
436 xfs_mru_cache_destroy(mp->m_filestream);
437}
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
24struct xfs_fstrm_item {
25 struct xfs_mru_cache_elem mru;
26 struct xfs_perag *pag; /* AG in use for this directory */
27};
28
29enum xfs_fstrm_alloc {
30 XFS_PICK_USERDATA = 1,
31 XFS_PICK_LOWSPACE = 2,
32};
33
34static void
35xfs_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 */
55static int
56xfs_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
74restart:
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_group(pag)->xg_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);
163done:
164 trace_xfs_filestream_pick(pag, pino);
165 args->pag = pag;
166 return 0;
167}
168
169static struct xfs_inode *
170xfs_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
187out_dput:
188 dput(dentry);
189out:
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 */
202static int
203xfs_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_group(pag)->xg_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_agbno_to_fsb(pag, 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
253out_done:
254 args->pag = pag;
255 return 0;
256}
257
258static int
259xfs_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 = (pag_agno(item->pag) + 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(&pag_group(args->pag)->xg_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
324out_free_item:
325 xfs_perag_rele(item->pag);
326 kfree(item);
327out_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 */
341int
342xfs_filestream_select_ag(
343 struct xfs_bmalloca *ap,
344 struct xfs_alloc_arg *args,
345 xfs_extlen_t *longest)
346{
347 struct xfs_inode *pip;
348 xfs_ino_t ino = 0;
349 int error = 0;
350
351 *longest = 0;
352 args->total = ap->total;
353 pip = xfs_filestream_get_parent(ap->ip);
354 if (pip) {
355 ino = pip->i_ino;
356 error = xfs_filestream_lookup_association(ap, args, ino,
357 longest);
358 xfs_irele(pip);
359 if (error)
360 return error;
361 if (*longest >= args->maxlen)
362 goto out_select;
363 if (ap->tp->t_flags & XFS_TRANS_LOWMODE)
364 goto out_select;
365 }
366
367 error = xfs_filestream_create_association(ap, args, ino, longest);
368 if (error)
369 return error;
370
371out_select:
372 ap->blkno = xfs_agbno_to_fsb(args->pag, 0);
373 return 0;
374}
375
376void
377xfs_filestream_deassociate(
378 struct xfs_inode *ip)
379{
380 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
381}
382
383int
384xfs_filestream_mount(
385 xfs_mount_t *mp)
386{
387 /*
388 * The filestream timer tunable is currently fixed within the range of
389 * one second to four minutes, with five seconds being the default. The
390 * group count is somewhat arbitrary, but it'd be nice to adhere to the
391 * timer tunable to within about 10 percent. This requires at least 10
392 * groups.
393 */
394 return xfs_mru_cache_create(&mp->m_filestream, mp,
395 xfs_fstrm_centisecs * 10, 10, xfs_fstrm_free_func);
396}
397
398void
399xfs_filestream_unmount(
400 xfs_mount_t *mp)
401{
402 xfs_mru_cache_destroy(mp->m_filestream);
403}