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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* AFS filesystem directory editing
3 *
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/kernel.h>
9#include <linux/fs.h>
10#include <linux/namei.h>
11#include <linux/pagemap.h>
12#include <linux/iversion.h>
13#include "internal.h"
14#include "xdr_fs.h"
15
16/*
17 * Find a number of contiguous clear bits in a directory block bitmask.
18 *
19 * There are 64 slots, which means we can load the entire bitmap into a
20 * variable. The first bit doesn't count as it corresponds to the block header
21 * slot. nr_slots is between 1 and 9.
22 */
23static int afs_find_contig_bits(union afs_xdr_dir_block *block, unsigned int nr_slots)
24{
25 u64 bitmap;
26 u32 mask;
27 int bit, n;
28
29 bitmap = (u64)block->hdr.bitmap[0] << 0 * 8;
30 bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
31 bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
32 bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
33 bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
34 bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
35 bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
36 bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
37 bitmap >>= 1; /* The first entry is metadata */
38 bit = 1;
39 mask = (1 << nr_slots) - 1;
40
41 do {
42 if (sizeof(unsigned long) == 8)
43 n = ffz(bitmap);
44 else
45 n = ((u32)bitmap) != 0 ?
46 ffz((u32)bitmap) :
47 ffz((u32)(bitmap >> 32)) + 32;
48 bitmap >>= n;
49 bit += n;
50
51 if ((bitmap & mask) == 0) {
52 if (bit > 64 - nr_slots)
53 return -1;
54 return bit;
55 }
56
57 n = __ffs(bitmap);
58 bitmap >>= n;
59 bit += n;
60 } while (bitmap);
61
62 return -1;
63}
64
65/*
66 * Set a number of contiguous bits in the directory block bitmap.
67 */
68static void afs_set_contig_bits(union afs_xdr_dir_block *block,
69 int bit, unsigned int nr_slots)
70{
71 u64 mask;
72
73 mask = (1 << nr_slots) - 1;
74 mask <<= bit;
75
76 block->hdr.bitmap[0] |= (u8)(mask >> 0 * 8);
77 block->hdr.bitmap[1] |= (u8)(mask >> 1 * 8);
78 block->hdr.bitmap[2] |= (u8)(mask >> 2 * 8);
79 block->hdr.bitmap[3] |= (u8)(mask >> 3 * 8);
80 block->hdr.bitmap[4] |= (u8)(mask >> 4 * 8);
81 block->hdr.bitmap[5] |= (u8)(mask >> 5 * 8);
82 block->hdr.bitmap[6] |= (u8)(mask >> 6 * 8);
83 block->hdr.bitmap[7] |= (u8)(mask >> 7 * 8);
84}
85
86/*
87 * Clear a number of contiguous bits in the directory block bitmap.
88 */
89static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
90 int bit, unsigned int nr_slots)
91{
92 u64 mask;
93
94 mask = (1 << nr_slots) - 1;
95 mask <<= bit;
96
97 block->hdr.bitmap[0] &= ~(u8)(mask >> 0 * 8);
98 block->hdr.bitmap[1] &= ~(u8)(mask >> 1 * 8);
99 block->hdr.bitmap[2] &= ~(u8)(mask >> 2 * 8);
100 block->hdr.bitmap[3] &= ~(u8)(mask >> 3 * 8);
101 block->hdr.bitmap[4] &= ~(u8)(mask >> 4 * 8);
102 block->hdr.bitmap[5] &= ~(u8)(mask >> 5 * 8);
103 block->hdr.bitmap[6] &= ~(u8)(mask >> 6 * 8);
104 block->hdr.bitmap[7] &= ~(u8)(mask >> 7 * 8);
105}
106
107/*
108 * Get a new directory folio.
109 */
110static struct folio *afs_dir_get_folio(struct afs_vnode *vnode, pgoff_t index)
111{
112 struct address_space *mapping = vnode->netfs.inode.i_mapping;
113 struct folio *folio;
114
115 folio = __filemap_get_folio(mapping, index,
116 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
117 mapping->gfp_mask);
118 if (IS_ERR(folio)) {
119 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
120 return NULL;
121 }
122 if (!folio_test_private(folio))
123 folio_attach_private(folio, (void *)1);
124 return folio;
125}
126
127/*
128 * Scan a directory block looking for a dirent of the right name.
129 */
130static int afs_dir_scan_block(union afs_xdr_dir_block *block, struct qstr *name,
131 unsigned int blocknum)
132{
133 union afs_xdr_dirent *de;
134 u64 bitmap;
135 int d, len, n;
136
137 _enter("");
138
139 bitmap = (u64)block->hdr.bitmap[0] << 0 * 8;
140 bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
141 bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
142 bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
143 bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
144 bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
145 bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
146 bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
147
148 for (d = (blocknum == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
149 d < AFS_DIR_SLOTS_PER_BLOCK;
150 d++) {
151 if (!((bitmap >> d) & 1))
152 continue;
153 de = &block->dirents[d];
154 if (de->u.valid != 1)
155 continue;
156
157 /* The block was NUL-terminated by afs_dir_check_page(). */
158 len = strlen(de->u.name);
159 if (len == name->len &&
160 memcmp(de->u.name, name->name, name->len) == 0)
161 return d;
162
163 n = round_up(12 + len + 1 + 4, AFS_DIR_DIRENT_SIZE);
164 n /= AFS_DIR_DIRENT_SIZE;
165 d += n - 1;
166 }
167
168 return -1;
169}
170
171/*
172 * Initialise a new directory block. Note that block 0 is special and contains
173 * some extra metadata.
174 */
175static void afs_edit_init_block(union afs_xdr_dir_block *meta,
176 union afs_xdr_dir_block *block, int block_num)
177{
178 memset(block, 0, sizeof(*block));
179 block->hdr.npages = htons(1);
180 block->hdr.magic = AFS_DIR_MAGIC;
181 block->hdr.bitmap[0] = 1;
182
183 if (block_num == 0) {
184 block->hdr.bitmap[0] = 0xff;
185 block->hdr.bitmap[1] = 0x1f;
186 memset(block->meta.alloc_ctrs,
187 AFS_DIR_SLOTS_PER_BLOCK,
188 sizeof(block->meta.alloc_ctrs));
189 meta->meta.alloc_ctrs[0] =
190 AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS0;
191 }
192
193 if (block_num < AFS_DIR_BLOCKS_WITH_CTR)
194 meta->meta.alloc_ctrs[block_num] =
195 AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS;
196}
197
198/*
199 * Edit a directory's file data to add a new directory entry. Doing this after
200 * create, mkdir, symlink, link or rename if the data version number is
201 * incremented by exactly one avoids the need to re-download the entire
202 * directory contents.
203 *
204 * The caller must hold the inode locked.
205 */
206void afs_edit_dir_add(struct afs_vnode *vnode,
207 struct qstr *name, struct afs_fid *new_fid,
208 enum afs_edit_dir_reason why)
209{
210 union afs_xdr_dir_block *meta, *block;
211 union afs_xdr_dirent *de;
212 struct folio *folio0, *folio;
213 unsigned int need_slots, nr_blocks, b;
214 pgoff_t index;
215 loff_t i_size;
216 int slot;
217
218 _enter(",,{%d,%s},", name->len, name->name);
219
220 i_size = i_size_read(&vnode->netfs.inode);
221 if (i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
222 (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
223 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
224 return;
225 }
226
227 folio0 = afs_dir_get_folio(vnode, 0);
228 if (!folio0) {
229 _leave(" [fgp]");
230 return;
231 }
232
233 /* Work out how many slots we're going to need. */
234 need_slots = afs_dir_calc_slots(name->len);
235
236 meta = kmap_local_folio(folio0, 0);
237 if (i_size == 0)
238 goto new_directory;
239 nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
240
241 /* Find a block that has sufficient slots available. Each folio
242 * contains two or more directory blocks.
243 */
244 for (b = 0; b < nr_blocks + 1; b++) {
245 /* If the directory extended into a new folio, then we need to
246 * tack a new folio on the end.
247 */
248 index = b / AFS_DIR_BLOCKS_PER_PAGE;
249 if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
250 goto error;
251 if (index >= folio_nr_pages(folio0)) {
252 folio = afs_dir_get_folio(vnode, index);
253 if (!folio)
254 goto error;
255 } else {
256 folio = folio0;
257 }
258
259 block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
260
261 /* Abandon the edit if we got a callback break. */
262 if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
263 goto invalidated;
264
265 _debug("block %u: %2u %3u %u",
266 b,
267 (b < AFS_DIR_BLOCKS_WITH_CTR) ? meta->meta.alloc_ctrs[b] : 99,
268 ntohs(block->hdr.npages),
269 ntohs(block->hdr.magic));
270
271 /* Initialise the block if necessary. */
272 if (b == nr_blocks) {
273 _debug("init %u", b);
274 afs_edit_init_block(meta, block, b);
275 afs_set_i_size(vnode, (b + 1) * AFS_DIR_BLOCK_SIZE);
276 }
277
278 /* Only lower dir blocks have a counter in the header. */
279 if (b >= AFS_DIR_BLOCKS_WITH_CTR ||
280 meta->meta.alloc_ctrs[b] >= need_slots) {
281 /* We need to try and find one or more consecutive
282 * slots to hold the entry.
283 */
284 slot = afs_find_contig_bits(block, need_slots);
285 if (slot >= 0) {
286 _debug("slot %u", slot);
287 goto found_space;
288 }
289 }
290
291 kunmap_local(block);
292 if (folio != folio0) {
293 folio_unlock(folio);
294 folio_put(folio);
295 }
296 }
297
298 /* There are no spare slots of sufficient size, yet the operation
299 * succeeded. Download the directory again.
300 */
301 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_nospc, 0, 0, 0, 0, name->name);
302 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
303 goto out_unmap;
304
305new_directory:
306 afs_edit_init_block(meta, meta, 0);
307 i_size = AFS_DIR_BLOCK_SIZE;
308 afs_set_i_size(vnode, i_size);
309 slot = AFS_DIR_RESV_BLOCKS0;
310 folio = folio0;
311 block = kmap_local_folio(folio, 0);
312 nr_blocks = 1;
313 b = 0;
314
315found_space:
316 /* Set the dirent slot. */
317 trace_afs_edit_dir(vnode, why, afs_edit_dir_create, b, slot,
318 new_fid->vnode, new_fid->unique, name->name);
319 de = &block->dirents[slot];
320 de->u.valid = 1;
321 de->u.unused[0] = 0;
322 de->u.hash_next = 0; // TODO: Really need to maintain this
323 de->u.vnode = htonl(new_fid->vnode);
324 de->u.unique = htonl(new_fid->unique);
325 memcpy(de->u.name, name->name, name->len + 1);
326 de->u.name[name->len] = 0;
327
328 /* Adjust the bitmap. */
329 afs_set_contig_bits(block, slot, need_slots);
330 kunmap_local(block);
331 if (folio != folio0) {
332 folio_unlock(folio);
333 folio_put(folio);
334 }
335
336 /* Adjust the allocation counter. */
337 if (b < AFS_DIR_BLOCKS_WITH_CTR)
338 meta->meta.alloc_ctrs[b] -= need_slots;
339
340 inode_inc_iversion_raw(&vnode->netfs.inode);
341 afs_stat_v(vnode, n_dir_cr);
342 _debug("Insert %s in %u[%u]", name->name, b, slot);
343
344out_unmap:
345 kunmap_local(meta);
346 folio_unlock(folio0);
347 folio_put(folio0);
348 _leave("");
349 return;
350
351invalidated:
352 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
353 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
354 kunmap_local(block);
355 if (folio != folio0) {
356 folio_unlock(folio);
357 folio_put(folio);
358 }
359 goto out_unmap;
360
361error:
362 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_error, 0, 0, 0, 0, name->name);
363 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
364 goto out_unmap;
365}
366
367/*
368 * Edit a directory's file data to remove a new directory entry. Doing this
369 * after unlink, rmdir or rename if the data version number is incremented by
370 * exactly one avoids the need to re-download the entire directory contents.
371 *
372 * The caller must hold the inode locked.
373 */
374void afs_edit_dir_remove(struct afs_vnode *vnode,
375 struct qstr *name, enum afs_edit_dir_reason why)
376{
377 union afs_xdr_dir_block *meta, *block;
378 union afs_xdr_dirent *de;
379 struct folio *folio0, *folio;
380 unsigned int need_slots, nr_blocks, b;
381 pgoff_t index;
382 loff_t i_size;
383 int slot;
384
385 _enter(",,{%d,%s},", name->len, name->name);
386
387 i_size = i_size_read(&vnode->netfs.inode);
388 if (i_size < AFS_DIR_BLOCK_SIZE ||
389 i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
390 (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
391 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
392 return;
393 }
394 nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
395
396 folio0 = afs_dir_get_folio(vnode, 0);
397 if (!folio0) {
398 _leave(" [fgp]");
399 return;
400 }
401
402 /* Work out how many slots we're going to discard. */
403 need_slots = afs_dir_calc_slots(name->len);
404
405 meta = kmap_local_folio(folio0, 0);
406
407 /* Find a block that has sufficient slots available. Each folio
408 * contains two or more directory blocks.
409 */
410 for (b = 0; b < nr_blocks; b++) {
411 index = b / AFS_DIR_BLOCKS_PER_PAGE;
412 if (index >= folio_nr_pages(folio0)) {
413 folio = afs_dir_get_folio(vnode, index);
414 if (!folio)
415 goto error;
416 } else {
417 folio = folio0;
418 }
419
420 block = kmap_local_folio(folio, b * AFS_DIR_BLOCK_SIZE - folio_file_pos(folio));
421
422 /* Abandon the edit if we got a callback break. */
423 if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
424 goto invalidated;
425
426 if (b > AFS_DIR_BLOCKS_WITH_CTR ||
427 meta->meta.alloc_ctrs[b] <= AFS_DIR_SLOTS_PER_BLOCK - 1 - need_slots) {
428 slot = afs_dir_scan_block(block, name, b);
429 if (slot >= 0)
430 goto found_dirent;
431 }
432
433 kunmap_local(block);
434 if (folio != folio0) {
435 folio_unlock(folio);
436 folio_put(folio);
437 }
438 }
439
440 /* Didn't find the dirent to clobber. Download the directory again. */
441 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_noent,
442 0, 0, 0, 0, name->name);
443 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
444 goto out_unmap;
445
446found_dirent:
447 de = &block->dirents[slot];
448
449 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete, b, slot,
450 ntohl(de->u.vnode), ntohl(de->u.unique),
451 name->name);
452
453 memset(de, 0, sizeof(*de) * need_slots);
454
455 /* Adjust the bitmap. */
456 afs_clear_contig_bits(block, slot, need_slots);
457 kunmap_local(block);
458 if (folio != folio0) {
459 folio_unlock(folio);
460 folio_put(folio);
461 }
462
463 /* Adjust the allocation counter. */
464 if (b < AFS_DIR_BLOCKS_WITH_CTR)
465 meta->meta.alloc_ctrs[b] += need_slots;
466
467 inode_set_iversion_raw(&vnode->netfs.inode, vnode->status.data_version);
468 afs_stat_v(vnode, n_dir_rm);
469 _debug("Remove %s from %u[%u]", name->name, b, slot);
470
471out_unmap:
472 kunmap_local(meta);
473 folio_unlock(folio0);
474 folio_put(folio0);
475 _leave("");
476 return;
477
478invalidated:
479 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
480 0, 0, 0, 0, name->name);
481 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
482 kunmap_local(block);
483 if (folio != folio0) {
484 folio_unlock(folio);
485 folio_put(folio);
486 }
487 goto out_unmap;
488
489error:
490 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_error,
491 0, 0, 0, 0, name->name);
492 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
493 goto out_unmap;
494}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* AFS filesystem directory editing
3 *
4 * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8#include <linux/kernel.h>
9#include <linux/fs.h>
10#include <linux/namei.h>
11#include <linux/pagemap.h>
12#include <linux/iversion.h>
13#include "internal.h"
14#include "xdr_fs.h"
15
16/*
17 * Find a number of contiguous clear bits in a directory block bitmask.
18 *
19 * There are 64 slots, which means we can load the entire bitmap into a
20 * variable. The first bit doesn't count as it corresponds to the block header
21 * slot. nr_slots is between 1 and 9.
22 */
23static int afs_find_contig_bits(union afs_xdr_dir_block *block, unsigned int nr_slots)
24{
25 u64 bitmap;
26 u32 mask;
27 int bit, n;
28
29 bitmap = (u64)block->hdr.bitmap[0] << 0 * 8;
30 bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
31 bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
32 bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
33 bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
34 bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
35 bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
36 bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
37 bitmap >>= 1; /* The first entry is metadata */
38 bit = 1;
39 mask = (1 << nr_slots) - 1;
40
41 do {
42 if (sizeof(unsigned long) == 8)
43 n = ffz(bitmap);
44 else
45 n = ((u32)bitmap) != 0 ?
46 ffz((u32)bitmap) :
47 ffz((u32)(bitmap >> 32)) + 32;
48 bitmap >>= n;
49 bit += n;
50
51 if ((bitmap & mask) == 0) {
52 if (bit > 64 - nr_slots)
53 return -1;
54 return bit;
55 }
56
57 n = __ffs(bitmap);
58 bitmap >>= n;
59 bit += n;
60 } while (bitmap);
61
62 return -1;
63}
64
65/*
66 * Set a number of contiguous bits in the directory block bitmap.
67 */
68static void afs_set_contig_bits(union afs_xdr_dir_block *block,
69 int bit, unsigned int nr_slots)
70{
71 u64 mask, before, after;
72
73 mask = (1 << nr_slots) - 1;
74 mask <<= bit;
75
76 before = *(u64 *)block->hdr.bitmap;
77
78 block->hdr.bitmap[0] |= (u8)(mask >> 0 * 8);
79 block->hdr.bitmap[1] |= (u8)(mask >> 1 * 8);
80 block->hdr.bitmap[2] |= (u8)(mask >> 2 * 8);
81 block->hdr.bitmap[3] |= (u8)(mask >> 3 * 8);
82 block->hdr.bitmap[4] |= (u8)(mask >> 4 * 8);
83 block->hdr.bitmap[5] |= (u8)(mask >> 5 * 8);
84 block->hdr.bitmap[6] |= (u8)(mask >> 6 * 8);
85 block->hdr.bitmap[7] |= (u8)(mask >> 7 * 8);
86
87 after = *(u64 *)block->hdr.bitmap;
88}
89
90/*
91 * Clear a number of contiguous bits in the directory block bitmap.
92 */
93static void afs_clear_contig_bits(union afs_xdr_dir_block *block,
94 int bit, unsigned int nr_slots)
95{
96 u64 mask, before, after;
97
98 mask = (1 << nr_slots) - 1;
99 mask <<= bit;
100
101 before = *(u64 *)block->hdr.bitmap;
102
103 block->hdr.bitmap[0] &= ~(u8)(mask >> 0 * 8);
104 block->hdr.bitmap[1] &= ~(u8)(mask >> 1 * 8);
105 block->hdr.bitmap[2] &= ~(u8)(mask >> 2 * 8);
106 block->hdr.bitmap[3] &= ~(u8)(mask >> 3 * 8);
107 block->hdr.bitmap[4] &= ~(u8)(mask >> 4 * 8);
108 block->hdr.bitmap[5] &= ~(u8)(mask >> 5 * 8);
109 block->hdr.bitmap[6] &= ~(u8)(mask >> 6 * 8);
110 block->hdr.bitmap[7] &= ~(u8)(mask >> 7 * 8);
111
112 after = *(u64 *)block->hdr.bitmap;
113}
114
115/*
116 * Scan a directory block looking for a dirent of the right name.
117 */
118static int afs_dir_scan_block(union afs_xdr_dir_block *block, struct qstr *name,
119 unsigned int blocknum)
120{
121 union afs_xdr_dirent *de;
122 u64 bitmap;
123 int d, len, n;
124
125 _enter("");
126
127 bitmap = (u64)block->hdr.bitmap[0] << 0 * 8;
128 bitmap |= (u64)block->hdr.bitmap[1] << 1 * 8;
129 bitmap |= (u64)block->hdr.bitmap[2] << 2 * 8;
130 bitmap |= (u64)block->hdr.bitmap[3] << 3 * 8;
131 bitmap |= (u64)block->hdr.bitmap[4] << 4 * 8;
132 bitmap |= (u64)block->hdr.bitmap[5] << 5 * 8;
133 bitmap |= (u64)block->hdr.bitmap[6] << 6 * 8;
134 bitmap |= (u64)block->hdr.bitmap[7] << 7 * 8;
135
136 for (d = (blocknum == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
137 d < AFS_DIR_SLOTS_PER_BLOCK;
138 d++) {
139 if (!((bitmap >> d) & 1))
140 continue;
141 de = &block->dirents[d];
142 if (de->u.valid != 1)
143 continue;
144
145 /* The block was NUL-terminated by afs_dir_check_page(). */
146 len = strlen(de->u.name);
147 if (len == name->len &&
148 memcmp(de->u.name, name->name, name->len) == 0)
149 return d;
150
151 n = round_up(12 + len + 1 + 4, AFS_DIR_DIRENT_SIZE);
152 n /= AFS_DIR_DIRENT_SIZE;
153 d += n - 1;
154 }
155
156 return -1;
157}
158
159/*
160 * Initialise a new directory block. Note that block 0 is special and contains
161 * some extra metadata.
162 */
163static void afs_edit_init_block(union afs_xdr_dir_block *meta,
164 union afs_xdr_dir_block *block, int block_num)
165{
166 memset(block, 0, sizeof(*block));
167 block->hdr.npages = htons(1);
168 block->hdr.magic = AFS_DIR_MAGIC;
169 block->hdr.bitmap[0] = 1;
170
171 if (block_num == 0) {
172 block->hdr.bitmap[0] = 0xff;
173 block->hdr.bitmap[1] = 0x1f;
174 memset(block->meta.alloc_ctrs,
175 AFS_DIR_SLOTS_PER_BLOCK,
176 sizeof(block->meta.alloc_ctrs));
177 meta->meta.alloc_ctrs[0] =
178 AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS0;
179 }
180
181 if (block_num < AFS_DIR_BLOCKS_WITH_CTR)
182 meta->meta.alloc_ctrs[block_num] =
183 AFS_DIR_SLOTS_PER_BLOCK - AFS_DIR_RESV_BLOCKS;
184}
185
186/*
187 * Edit a directory's file data to add a new directory entry. Doing this after
188 * create, mkdir, symlink, link or rename if the data version number is
189 * incremented by exactly one avoids the need to re-download the entire
190 * directory contents.
191 *
192 * The caller must hold the inode locked.
193 */
194void afs_edit_dir_add(struct afs_vnode *vnode,
195 struct qstr *name, struct afs_fid *new_fid,
196 enum afs_edit_dir_reason why)
197{
198 union afs_xdr_dir_block *meta, *block;
199 struct afs_xdr_dir_page *meta_page, *dir_page;
200 union afs_xdr_dirent *de;
201 struct page *page0, *page;
202 unsigned int need_slots, nr_blocks, b;
203 pgoff_t index;
204 loff_t i_size;
205 gfp_t gfp;
206 int slot;
207
208 _enter(",,{%d,%s},", name->len, name->name);
209
210 i_size = i_size_read(&vnode->vfs_inode);
211 if (i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
212 (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
213 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
214 return;
215 }
216
217 gfp = vnode->vfs_inode.i_mapping->gfp_mask;
218 page0 = find_or_create_page(vnode->vfs_inode.i_mapping, 0, gfp);
219 if (!page0) {
220 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
221 _leave(" [fgp]");
222 return;
223 }
224
225 /* Work out how many slots we're going to need. */
226 need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE);
227 need_slots /= AFS_DIR_DIRENT_SIZE;
228
229 meta_page = kmap(page0);
230 meta = &meta_page->blocks[0];
231 if (i_size == 0)
232 goto new_directory;
233 nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
234
235 /* Find a block that has sufficient slots available. Each VM page
236 * contains two or more directory blocks.
237 */
238 for (b = 0; b < nr_blocks + 1; b++) {
239 /* If the directory extended into a new page, then we need to
240 * tack a new page on the end.
241 */
242 index = b / AFS_DIR_BLOCKS_PER_PAGE;
243 if (index == 0) {
244 page = page0;
245 dir_page = meta_page;
246 } else {
247 if (nr_blocks >= AFS_DIR_MAX_BLOCKS)
248 goto error;
249 gfp = vnode->vfs_inode.i_mapping->gfp_mask;
250 page = find_or_create_page(vnode->vfs_inode.i_mapping,
251 index, gfp);
252 if (!page)
253 goto error;
254 if (!PagePrivate(page)) {
255 set_page_private(page, 1);
256 SetPagePrivate(page);
257 }
258 dir_page = kmap(page);
259 }
260
261 /* Abandon the edit if we got a callback break. */
262 if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
263 goto invalidated;
264
265 block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
266
267 _debug("block %u: %2u %3u %u",
268 b,
269 (b < AFS_DIR_BLOCKS_WITH_CTR) ? meta->meta.alloc_ctrs[b] : 99,
270 ntohs(block->hdr.npages),
271 ntohs(block->hdr.magic));
272
273 /* Initialise the block if necessary. */
274 if (b == nr_blocks) {
275 _debug("init %u", b);
276 afs_edit_init_block(meta, block, b);
277 i_size_write(&vnode->vfs_inode, (b + 1) * AFS_DIR_BLOCK_SIZE);
278 }
279
280 /* Only lower dir pages have a counter in the header. */
281 if (b >= AFS_DIR_BLOCKS_WITH_CTR ||
282 meta->meta.alloc_ctrs[b] >= need_slots) {
283 /* We need to try and find one or more consecutive
284 * slots to hold the entry.
285 */
286 slot = afs_find_contig_bits(block, need_slots);
287 if (slot >= 0) {
288 _debug("slot %u", slot);
289 goto found_space;
290 }
291 }
292
293 if (page != page0) {
294 unlock_page(page);
295 kunmap(page);
296 put_page(page);
297 }
298 }
299
300 /* There are no spare slots of sufficient size, yet the operation
301 * succeeded. Download the directory again.
302 */
303 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_nospc, 0, 0, 0, 0, name->name);
304 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
305 goto out_unmap;
306
307new_directory:
308 afs_edit_init_block(meta, meta, 0);
309 i_size = AFS_DIR_BLOCK_SIZE;
310 i_size_write(&vnode->vfs_inode, i_size);
311 slot = AFS_DIR_RESV_BLOCKS0;
312 page = page0;
313 block = meta;
314 nr_blocks = 1;
315 b = 0;
316
317found_space:
318 /* Set the dirent slot. */
319 trace_afs_edit_dir(vnode, why, afs_edit_dir_create, b, slot,
320 new_fid->vnode, new_fid->unique, name->name);
321 de = &block->dirents[slot];
322 de->u.valid = 1;
323 de->u.unused[0] = 0;
324 de->u.hash_next = 0; // TODO: Really need to maintain this
325 de->u.vnode = htonl(new_fid->vnode);
326 de->u.unique = htonl(new_fid->unique);
327 memcpy(de->u.name, name->name, name->len + 1);
328 de->u.name[name->len] = 0;
329
330 /* Adjust the bitmap. */
331 afs_set_contig_bits(block, slot, need_slots);
332 if (page != page0) {
333 unlock_page(page);
334 kunmap(page);
335 put_page(page);
336 }
337
338 /* Adjust the allocation counter. */
339 if (b < AFS_DIR_BLOCKS_WITH_CTR)
340 meta->meta.alloc_ctrs[b] -= need_slots;
341
342 inode_inc_iversion_raw(&vnode->vfs_inode);
343 afs_stat_v(vnode, n_dir_cr);
344 _debug("Insert %s in %u[%u]", name->name, b, slot);
345
346out_unmap:
347 unlock_page(page0);
348 kunmap(page0);
349 put_page(page0);
350 _leave("");
351 return;
352
353invalidated:
354 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_inval, 0, 0, 0, 0, name->name);
355 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
356 if (page != page0) {
357 kunmap(page);
358 put_page(page);
359 }
360 goto out_unmap;
361
362error:
363 trace_afs_edit_dir(vnode, why, afs_edit_dir_create_error, 0, 0, 0, 0, name->name);
364 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
365 goto out_unmap;
366}
367
368/*
369 * Edit a directory's file data to remove a new directory entry. Doing this
370 * after unlink, rmdir or rename if the data version number is incremented by
371 * exactly one avoids the need to re-download the entire directory contents.
372 *
373 * The caller must hold the inode locked.
374 */
375void afs_edit_dir_remove(struct afs_vnode *vnode,
376 struct qstr *name, enum afs_edit_dir_reason why)
377{
378 struct afs_xdr_dir_page *meta_page, *dir_page;
379 union afs_xdr_dir_block *meta, *block;
380 union afs_xdr_dirent *de;
381 struct page *page0, *page;
382 unsigned int need_slots, nr_blocks, b;
383 pgoff_t index;
384 loff_t i_size;
385 int slot;
386
387 _enter(",,{%d,%s},", name->len, name->name);
388
389 i_size = i_size_read(&vnode->vfs_inode);
390 if (i_size < AFS_DIR_BLOCK_SIZE ||
391 i_size > AFS_DIR_BLOCK_SIZE * AFS_DIR_MAX_BLOCKS ||
392 (i_size & (AFS_DIR_BLOCK_SIZE - 1))) {
393 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
394 return;
395 }
396 nr_blocks = i_size / AFS_DIR_BLOCK_SIZE;
397
398 page0 = find_lock_page(vnode->vfs_inode.i_mapping, 0);
399 if (!page0) {
400 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
401 _leave(" [fgp]");
402 return;
403 }
404
405 /* Work out how many slots we're going to discard. */
406 need_slots = round_up(12 + name->len + 1 + 4, AFS_DIR_DIRENT_SIZE);
407 need_slots /= AFS_DIR_DIRENT_SIZE;
408
409 meta_page = kmap(page0);
410 meta = &meta_page->blocks[0];
411
412 /* Find a page that has sufficient slots available. Each VM page
413 * contains two or more directory blocks.
414 */
415 for (b = 0; b < nr_blocks; b++) {
416 index = b / AFS_DIR_BLOCKS_PER_PAGE;
417 if (index != 0) {
418 page = find_lock_page(vnode->vfs_inode.i_mapping, index);
419 if (!page)
420 goto error;
421 dir_page = kmap(page);
422 } else {
423 page = page0;
424 dir_page = meta_page;
425 }
426
427 /* Abandon the edit if we got a callback break. */
428 if (!test_bit(AFS_VNODE_DIR_VALID, &vnode->flags))
429 goto invalidated;
430
431 block = &dir_page->blocks[b % AFS_DIR_BLOCKS_PER_PAGE];
432
433 if (b > AFS_DIR_BLOCKS_WITH_CTR ||
434 meta->meta.alloc_ctrs[b] <= AFS_DIR_SLOTS_PER_BLOCK - 1 - need_slots) {
435 slot = afs_dir_scan_block(block, name, b);
436 if (slot >= 0)
437 goto found_dirent;
438 }
439
440 if (page != page0) {
441 unlock_page(page);
442 kunmap(page);
443 put_page(page);
444 }
445 }
446
447 /* Didn't find the dirent to clobber. Download the directory again. */
448 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_noent,
449 0, 0, 0, 0, name->name);
450 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
451 goto out_unmap;
452
453found_dirent:
454 de = &block->dirents[slot];
455
456 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete, b, slot,
457 ntohl(de->u.vnode), ntohl(de->u.unique),
458 name->name);
459
460 memset(de, 0, sizeof(*de) * need_slots);
461
462 /* Adjust the bitmap. */
463 afs_clear_contig_bits(block, slot, need_slots);
464 if (page != page0) {
465 unlock_page(page);
466 kunmap(page);
467 put_page(page);
468 }
469
470 /* Adjust the allocation counter. */
471 if (b < AFS_DIR_BLOCKS_WITH_CTR)
472 meta->meta.alloc_ctrs[b] += need_slots;
473
474 inode_set_iversion_raw(&vnode->vfs_inode, vnode->status.data_version);
475 afs_stat_v(vnode, n_dir_rm);
476 _debug("Remove %s from %u[%u]", name->name, b, slot);
477
478out_unmap:
479 unlock_page(page0);
480 kunmap(page0);
481 put_page(page0);
482 _leave("");
483 return;
484
485invalidated:
486 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_inval,
487 0, 0, 0, 0, name->name);
488 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
489 if (page != page0) {
490 unlock_page(page);
491 kunmap(page);
492 put_page(page);
493 }
494 goto out_unmap;
495
496error:
497 trace_afs_edit_dir(vnode, why, afs_edit_dir_delete_error,
498 0, 0, 0, 0, name->name);
499 clear_bit(AFS_VNODE_DIR_VALID, &vnode->flags);
500 goto out_unmap;
501}