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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 struct xfs_inode *ip;
38 xfs_agnumber_t ag; /* AG in use for this directory */
39};
40
41enum xfs_fstrm_alloc {
42 XFS_PICK_USERDATA = 1,
43 XFS_PICK_LOWSPACE = 2,
44};
45
46/*
47 * Allocation group filestream associations are tracked with per-ag atomic
48 * counters. These counters allow xfs_filestream_pick_ag() to tell whether a
49 * particular AG already has active filestreams associated with it. The mount
50 * point's m_peraglock is used to protect these counters from per-ag array
51 * re-allocation during a growfs operation. When xfs_growfs_data_private() is
52 * about to reallocate the array, it calls xfs_filestream_flush() with the
53 * m_peraglock held in write mode.
54 *
55 * Since xfs_mru_cache_flush() guarantees that all the free functions for all
56 * the cache elements have finished executing before it returns, it's safe for
57 * the free functions to use the atomic counters without m_peraglock protection.
58 * This allows the implementation of xfs_fstrm_free_func() to be agnostic about
59 * whether it was called with the m_peraglock held in read mode, write mode or
60 * not held at all. The race condition this addresses is the following:
61 *
62 * - The work queue scheduler fires and pulls a filestream directory cache
63 * element off the LRU end of the cache for deletion, then gets pre-empted.
64 * - A growfs operation grabs the m_peraglock in write mode, flushes all the
65 * remaining items from the cache and reallocates the mount point's per-ag
66 * array, resetting all the counters to zero.
67 * - The work queue thread resumes and calls the free function for the element
68 * it started cleaning up earlier. In the process it decrements the
69 * filestreams counter for an AG that now has no references.
70 *
71 * With a shrinkfs feature, the above scenario could panic the system.
72 *
73 * All other uses of the following macros should be protected by either the
74 * m_peraglock held in read mode, or the cache's internal locking exposed by the
75 * interval between a call to xfs_mru_cache_lookup() and a call to
76 * xfs_mru_cache_done(). In addition, the m_peraglock must be held in read mode
77 * when new elements are added to the cache.
78 *
79 * Combined, these locking rules ensure that no associations will ever exist in
80 * the cache that reference per-ag array elements that have since been
81 * reallocated.
82 */
83int
84xfs_filestream_peek_ag(
85 xfs_mount_t *mp,
86 xfs_agnumber_t agno)
87{
88 struct xfs_perag *pag;
89 int ret;
90
91 pag = xfs_perag_get(mp, agno);
92 ret = atomic_read(&pag->pagf_fstrms);
93 xfs_perag_put(pag);
94 return ret;
95}
96
97static int
98xfs_filestream_get_ag(
99 xfs_mount_t *mp,
100 xfs_agnumber_t agno)
101{
102 struct xfs_perag *pag;
103 int ret;
104
105 pag = xfs_perag_get(mp, agno);
106 ret = atomic_inc_return(&pag->pagf_fstrms);
107 xfs_perag_put(pag);
108 return ret;
109}
110
111static void
112xfs_filestream_put_ag(
113 xfs_mount_t *mp,
114 xfs_agnumber_t agno)
115{
116 struct xfs_perag *pag;
117
118 pag = xfs_perag_get(mp, agno);
119 atomic_dec(&pag->pagf_fstrms);
120 xfs_perag_put(pag);
121}
122
123static void
124xfs_fstrm_free_func(
125 struct xfs_mru_cache_elem *mru)
126{
127 struct xfs_fstrm_item *item =
128 container_of(mru, struct xfs_fstrm_item, mru);
129
130 xfs_filestream_put_ag(item->ip->i_mount, item->ag);
131
132 trace_xfs_filestream_free(item->ip, 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(ip, 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(mp, 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 item->ip = ip;
269
270 err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);
271 if (err) {
272 if (err == -EEXIST)
273 err = 0;
274 goto out_free_item;
275 }
276
277 return 0;
278
279out_free_item:
280 kmem_free(item);
281out_put_ag:
282 xfs_filestream_put_ag(mp, *agp);
283 return err;
284}
285
286static struct xfs_inode *
287xfs_filestream_get_parent(
288 struct xfs_inode *ip)
289{
290 struct inode *inode = VFS_I(ip), *dir = NULL;
291 struct dentry *dentry, *parent;
292
293 dentry = d_find_alias(inode);
294 if (!dentry)
295 goto out;
296
297 parent = dget_parent(dentry);
298 if (!parent)
299 goto out_dput;
300
301 dir = igrab(d_inode(parent));
302 dput(parent);
303
304out_dput:
305 dput(dentry);
306out:
307 return dir ? XFS_I(dir) : NULL;
308}
309
310/*
311 * Find the right allocation group for a file, either by finding an
312 * existing file stream or creating a new one.
313 *
314 * Returns NULLAGNUMBER in case of an error.
315 */
316xfs_agnumber_t
317xfs_filestream_lookup_ag(
318 struct xfs_inode *ip)
319{
320 struct xfs_mount *mp = ip->i_mount;
321 struct xfs_inode *pip = NULL;
322 xfs_agnumber_t startag, ag = NULLAGNUMBER;
323 struct xfs_mru_cache_elem *mru;
324
325 ASSERT(S_ISREG(VFS_I(ip)->i_mode));
326
327 pip = xfs_filestream_get_parent(ip);
328 if (!pip)
329 return NULLAGNUMBER;
330
331 mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
332 if (mru) {
333 ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
334 xfs_mru_cache_done(mp->m_filestream);
335
336 trace_xfs_filestream_lookup(ip, ag);
337 goto out;
338 }
339
340 /*
341 * Set the starting AG using the rotor for inode32, otherwise
342 * use the directory inode's AG.
343 */
344 if (mp->m_flags & XFS_MOUNT_32BITINODES) {
345 xfs_agnumber_t rotorstep = xfs_rotorstep;
346 startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
347 mp->m_agfrotor = (mp->m_agfrotor + 1) %
348 (mp->m_sb.sb_agcount * rotorstep);
349 } else
350 startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
351
352 if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
353 ag = NULLAGNUMBER;
354out:
355 IRELE(pip);
356 return ag;
357}
358
359/*
360 * Pick a new allocation group for the current file and its file stream.
361 *
362 * This is called when the allocator can't find a suitable extent in the
363 * current AG, and we have to move the stream into a new AG with more space.
364 */
365int
366xfs_filestream_new_ag(
367 struct xfs_bmalloca *ap,
368 xfs_agnumber_t *agp)
369{
370 struct xfs_inode *ip = ap->ip, *pip;
371 struct xfs_mount *mp = ip->i_mount;
372 xfs_extlen_t minlen = ap->length;
373 xfs_agnumber_t startag = 0;
374 int flags = 0;
375 int err = 0;
376 struct xfs_mru_cache_elem *mru;
377
378 *agp = NULLAGNUMBER;
379
380 pip = xfs_filestream_get_parent(ip);
381 if (!pip)
382 goto exit;
383
384 mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
385 if (mru) {
386 struct xfs_fstrm_item *item =
387 container_of(mru, struct xfs_fstrm_item, mru);
388 startag = (item->ag + 1) % mp->m_sb.sb_agcount;
389 }
390
391 if (xfs_alloc_is_userdata(ap->datatype))
392 flags |= XFS_PICK_USERDATA;
393 if (ap->dfops->dop_low)
394 flags |= XFS_PICK_LOWSPACE;
395
396 err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
397
398 /*
399 * Only free the item here so we skip over the old AG earlier.
400 */
401 if (mru)
402 xfs_fstrm_free_func(mru);
403
404 IRELE(pip);
405exit:
406 if (*agp == NULLAGNUMBER)
407 *agp = 0;
408 return err;
409}
410
411void
412xfs_filestream_deassociate(
413 struct xfs_inode *ip)
414{
415 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
416}
417
418int
419xfs_filestream_mount(
420 xfs_mount_t *mp)
421{
422 /*
423 * The filestream timer tunable is currently fixed within the range of
424 * one second to four minutes, with five seconds being the default. The
425 * group count is somewhat arbitrary, but it'd be nice to adhere to the
426 * timer tunable to within about 10 percent. This requires at least 10
427 * groups.
428 */
429 return xfs_mru_cache_create(&mp->m_filestream, xfs_fstrm_centisecs * 10,
430 10, xfs_fstrm_free_func);
431}
432
433void
434xfs_filestream_unmount(
435 xfs_mount_t *mp)
436{
437 xfs_mru_cache_destroy(mp->m_filestream);
438}
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_inode.h"
26#include "xfs_bmap.h"
27#include "xfs_bmap_util.h"
28#include "xfs_alloc.h"
29#include "xfs_mru_cache.h"
30#include "xfs_filestream.h"
31#include "xfs_trace.h"
32
33struct xfs_fstrm_item {
34 struct xfs_mru_cache_elem mru;
35 struct xfs_inode *ip;
36 xfs_agnumber_t ag; /* AG in use for this directory */
37};
38
39enum xfs_fstrm_alloc {
40 XFS_PICK_USERDATA = 1,
41 XFS_PICK_LOWSPACE = 2,
42};
43
44/*
45 * Allocation group filestream associations are tracked with per-ag atomic
46 * counters. These counters allow xfs_filestream_pick_ag() to tell whether a
47 * particular AG already has active filestreams associated with it. The mount
48 * point's m_peraglock is used to protect these counters from per-ag array
49 * re-allocation during a growfs operation. When xfs_growfs_data_private() is
50 * about to reallocate the array, it calls xfs_filestream_flush() with the
51 * m_peraglock held in write mode.
52 *
53 * Since xfs_mru_cache_flush() guarantees that all the free functions for all
54 * the cache elements have finished executing before it returns, it's safe for
55 * the free functions to use the atomic counters without m_peraglock protection.
56 * This allows the implementation of xfs_fstrm_free_func() to be agnostic about
57 * whether it was called with the m_peraglock held in read mode, write mode or
58 * not held at all. The race condition this addresses is the following:
59 *
60 * - The work queue scheduler fires and pulls a filestream directory cache
61 * element off the LRU end of the cache for deletion, then gets pre-empted.
62 * - A growfs operation grabs the m_peraglock in write mode, flushes all the
63 * remaining items from the cache and reallocates the mount point's per-ag
64 * array, resetting all the counters to zero.
65 * - The work queue thread resumes and calls the free function for the element
66 * it started cleaning up earlier. In the process it decrements the
67 * filestreams counter for an AG that now has no references.
68 *
69 * With a shrinkfs feature, the above scenario could panic the system.
70 *
71 * All other uses of the following macros should be protected by either the
72 * m_peraglock held in read mode, or the cache's internal locking exposed by the
73 * interval between a call to xfs_mru_cache_lookup() and a call to
74 * xfs_mru_cache_done(). In addition, the m_peraglock must be held in read mode
75 * when new elements are added to the cache.
76 *
77 * Combined, these locking rules ensure that no associations will ever exist in
78 * the cache that reference per-ag array elements that have since been
79 * reallocated.
80 */
81int
82xfs_filestream_peek_ag(
83 xfs_mount_t *mp,
84 xfs_agnumber_t agno)
85{
86 struct xfs_perag *pag;
87 int ret;
88
89 pag = xfs_perag_get(mp, agno);
90 ret = atomic_read(&pag->pagf_fstrms);
91 xfs_perag_put(pag);
92 return ret;
93}
94
95static int
96xfs_filestream_get_ag(
97 xfs_mount_t *mp,
98 xfs_agnumber_t agno)
99{
100 struct xfs_perag *pag;
101 int ret;
102
103 pag = xfs_perag_get(mp, agno);
104 ret = atomic_inc_return(&pag->pagf_fstrms);
105 xfs_perag_put(pag);
106 return ret;
107}
108
109static void
110xfs_filestream_put_ag(
111 xfs_mount_t *mp,
112 xfs_agnumber_t agno)
113{
114 struct xfs_perag *pag;
115
116 pag = xfs_perag_get(mp, agno);
117 atomic_dec(&pag->pagf_fstrms);
118 xfs_perag_put(pag);
119}
120
121static void
122xfs_fstrm_free_func(
123 struct xfs_mru_cache_elem *mru)
124{
125 struct xfs_fstrm_item *item =
126 container_of(mru, struct xfs_fstrm_item, mru);
127
128 xfs_filestream_put_ag(item->ip->i_mount, item->ag);
129
130 trace_xfs_filestream_free(item->ip, item->ag);
131
132 kmem_free(item);
133}
134
135/*
136 * Scan the AGs starting at startag looking for an AG that isn't in use and has
137 * at least minlen blocks free.
138 */
139static int
140xfs_filestream_pick_ag(
141 struct xfs_inode *ip,
142 xfs_agnumber_t startag,
143 xfs_agnumber_t *agp,
144 int flags,
145 xfs_extlen_t minlen)
146{
147 struct xfs_mount *mp = ip->i_mount;
148 struct xfs_fstrm_item *item;
149 struct xfs_perag *pag;
150 xfs_extlen_t longest, free = 0, minfree, maxfree = 0;
151 xfs_agnumber_t ag, max_ag = NULLAGNUMBER;
152 int err, trylock, nscan;
153
154 ASSERT(S_ISDIR(VFS_I(ip)->i_mode));
155
156 /* 2% of an AG's blocks must be free for it to be chosen. */
157 minfree = mp->m_sb.sb_agblocks / 50;
158
159 ag = startag;
160 *agp = NULLAGNUMBER;
161
162 /* For the first pass, don't sleep trying to init the per-AG. */
163 trylock = XFS_ALLOC_FLAG_TRYLOCK;
164
165 for (nscan = 0; 1; nscan++) {
166 trace_xfs_filestream_scan(ip, ag);
167
168 pag = xfs_perag_get(mp, ag);
169
170 if (!pag->pagf_init) {
171 err = xfs_alloc_pagf_init(mp, NULL, ag, trylock);
172 if (err && !trylock) {
173 xfs_perag_put(pag);
174 return err;
175 }
176 }
177
178 /* Might fail sometimes during the 1st pass with trylock set. */
179 if (!pag->pagf_init)
180 goto next_ag;
181
182 /* Keep track of the AG with the most free blocks. */
183 if (pag->pagf_freeblks > maxfree) {
184 maxfree = pag->pagf_freeblks;
185 max_ag = ag;
186 }
187
188 /*
189 * The AG reference count does two things: it enforces mutual
190 * exclusion when examining the suitability of an AG in this
191 * loop, and it guards against two filestreams being established
192 * in the same AG as each other.
193 */
194 if (xfs_filestream_get_ag(mp, ag) > 1) {
195 xfs_filestream_put_ag(mp, ag);
196 goto next_ag;
197 }
198
199 longest = xfs_alloc_longest_free_extent(mp, pag,
200 xfs_alloc_min_freelist(mp, pag));
201 if (((minlen && longest >= minlen) ||
202 (!minlen && pag->pagf_freeblks >= minfree)) &&
203 (!pag->pagf_metadata || !(flags & XFS_PICK_USERDATA) ||
204 (flags & XFS_PICK_LOWSPACE))) {
205
206 /* Break out, retaining the reference on the AG. */
207 free = pag->pagf_freeblks;
208 xfs_perag_put(pag);
209 *agp = ag;
210 break;
211 }
212
213 /* Drop the reference on this AG, it's not usable. */
214 xfs_filestream_put_ag(mp, ag);
215next_ag:
216 xfs_perag_put(pag);
217 /* Move to the next AG, wrapping to AG 0 if necessary. */
218 if (++ag >= mp->m_sb.sb_agcount)
219 ag = 0;
220
221 /* If a full pass of the AGs hasn't been done yet, continue. */
222 if (ag != startag)
223 continue;
224
225 /* Allow sleeping in xfs_alloc_pagf_init() on the 2nd pass. */
226 if (trylock != 0) {
227 trylock = 0;
228 continue;
229 }
230
231 /* Finally, if lowspace wasn't set, set it for the 3rd pass. */
232 if (!(flags & XFS_PICK_LOWSPACE)) {
233 flags |= XFS_PICK_LOWSPACE;
234 continue;
235 }
236
237 /*
238 * Take the AG with the most free space, regardless of whether
239 * it's already in use by another filestream.
240 */
241 if (max_ag != NULLAGNUMBER) {
242 xfs_filestream_get_ag(mp, max_ag);
243 free = maxfree;
244 *agp = max_ag;
245 break;
246 }
247
248 /* take AG 0 if none matched */
249 trace_xfs_filestream_pick(ip, *agp, free, nscan);
250 *agp = 0;
251 return 0;
252 }
253
254 trace_xfs_filestream_pick(ip, *agp, free, nscan);
255
256 if (*agp == NULLAGNUMBER)
257 return 0;
258
259 err = -ENOMEM;
260 item = kmem_alloc(sizeof(*item), KM_MAYFAIL);
261 if (!item)
262 goto out_put_ag;
263
264 item->ag = *agp;
265 item->ip = ip;
266
267 err = xfs_mru_cache_insert(mp->m_filestream, ip->i_ino, &item->mru);
268 if (err) {
269 if (err == -EEXIST)
270 err = 0;
271 goto out_free_item;
272 }
273
274 return 0;
275
276out_free_item:
277 kmem_free(item);
278out_put_ag:
279 xfs_filestream_put_ag(mp, *agp);
280 return err;
281}
282
283static struct xfs_inode *
284xfs_filestream_get_parent(
285 struct xfs_inode *ip)
286{
287 struct inode *inode = VFS_I(ip), *dir = NULL;
288 struct dentry *dentry, *parent;
289
290 dentry = d_find_alias(inode);
291 if (!dentry)
292 goto out;
293
294 parent = dget_parent(dentry);
295 if (!parent)
296 goto out_dput;
297
298 dir = igrab(d_inode(parent));
299 dput(parent);
300
301out_dput:
302 dput(dentry);
303out:
304 return dir ? XFS_I(dir) : NULL;
305}
306
307/*
308 * Find the right allocation group for a file, either by finding an
309 * existing file stream or creating a new one.
310 *
311 * Returns NULLAGNUMBER in case of an error.
312 */
313xfs_agnumber_t
314xfs_filestream_lookup_ag(
315 struct xfs_inode *ip)
316{
317 struct xfs_mount *mp = ip->i_mount;
318 struct xfs_inode *pip = NULL;
319 xfs_agnumber_t startag, ag = NULLAGNUMBER;
320 struct xfs_mru_cache_elem *mru;
321
322 ASSERT(S_ISREG(VFS_I(ip)->i_mode));
323
324 pip = xfs_filestream_get_parent(ip);
325 if (!pip)
326 return NULLAGNUMBER;
327
328 mru = xfs_mru_cache_lookup(mp->m_filestream, pip->i_ino);
329 if (mru) {
330 ag = container_of(mru, struct xfs_fstrm_item, mru)->ag;
331 xfs_mru_cache_done(mp->m_filestream);
332
333 trace_xfs_filestream_lookup(ip, ag);
334 goto out;
335 }
336
337 /*
338 * Set the starting AG using the rotor for inode32, otherwise
339 * use the directory inode's AG.
340 */
341 if (mp->m_flags & XFS_MOUNT_32BITINODES) {
342 xfs_agnumber_t rotorstep = xfs_rotorstep;
343 startag = (mp->m_agfrotor / rotorstep) % mp->m_sb.sb_agcount;
344 mp->m_agfrotor = (mp->m_agfrotor + 1) %
345 (mp->m_sb.sb_agcount * rotorstep);
346 } else
347 startag = XFS_INO_TO_AGNO(mp, pip->i_ino);
348
349 if (xfs_filestream_pick_ag(pip, startag, &ag, 0, 0))
350 ag = NULLAGNUMBER;
351out:
352 IRELE(pip);
353 return ag;
354}
355
356/*
357 * Pick a new allocation group for the current file and its file stream.
358 *
359 * This is called when the allocator can't find a suitable extent in the
360 * current AG, and we have to move the stream into a new AG with more space.
361 */
362int
363xfs_filestream_new_ag(
364 struct xfs_bmalloca *ap,
365 xfs_agnumber_t *agp)
366{
367 struct xfs_inode *ip = ap->ip, *pip;
368 struct xfs_mount *mp = ip->i_mount;
369 xfs_extlen_t minlen = ap->length;
370 xfs_agnumber_t startag = 0;
371 int flags, err = 0;
372 struct xfs_mru_cache_elem *mru;
373
374 *agp = NULLAGNUMBER;
375
376 pip = xfs_filestream_get_parent(ip);
377 if (!pip)
378 goto exit;
379
380 mru = xfs_mru_cache_remove(mp->m_filestream, pip->i_ino);
381 if (mru) {
382 struct xfs_fstrm_item *item =
383 container_of(mru, struct xfs_fstrm_item, mru);
384 startag = (item->ag + 1) % mp->m_sb.sb_agcount;
385 }
386
387 flags = (ap->userdata ? XFS_PICK_USERDATA : 0) |
388 (ap->flist->xbf_low ? XFS_PICK_LOWSPACE : 0);
389
390 err = xfs_filestream_pick_ag(pip, startag, agp, flags, minlen);
391
392 /*
393 * Only free the item here so we skip over the old AG earlier.
394 */
395 if (mru)
396 xfs_fstrm_free_func(mru);
397
398 IRELE(pip);
399exit:
400 if (*agp == NULLAGNUMBER)
401 *agp = 0;
402 return err;
403}
404
405void
406xfs_filestream_deassociate(
407 struct xfs_inode *ip)
408{
409 xfs_mru_cache_delete(ip->i_mount->m_filestream, ip->i_ino);
410}
411
412int
413xfs_filestream_mount(
414 xfs_mount_t *mp)
415{
416 /*
417 * The filestream timer tunable is currently fixed within the range of
418 * one second to four minutes, with five seconds being the default. The
419 * group count is somewhat arbitrary, but it'd be nice to adhere to the
420 * timer tunable to within about 10 percent. This requires at least 10
421 * groups.
422 */
423 return xfs_mru_cache_create(&mp->m_filestream, xfs_fstrm_centisecs * 10,
424 10, xfs_fstrm_free_func);
425}
426
427void
428xfs_filestream_unmount(
429 xfs_mount_t *mp)
430{
431 xfs_mru_cache_destroy(mp->m_filestream);
432}