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9bccf70c | 1 | /* |
fe8ab488 | 2 | * Copyright (c) 2002-2014 Apple Inc. All rights reserved. |
9bccf70c | 3 | * |
2d21ac55 | 4 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
9bccf70c | 5 | * |
2d21ac55 A |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License | |
8 | * Version 2.0 (the 'License'). You may not use this file except in | |
9 | * compliance with the License. The rights granted to you under the License | |
10 | * may not be used to create, or enable the creation or redistribution of, | |
11 | * unlawful or unlicensed copies of an Apple operating system, or to | |
12 | * circumvent, violate, or enable the circumvention or violation of, any | |
13 | * terms of an Apple operating system software license agreement. | |
8f6c56a5 | 14 | * |
2d21ac55 A |
15 | * Please obtain a copy of the License at |
16 | * http://www.opensource.apple.com/apsl/ and read it before using this file. | |
17 | * | |
18 | * The Original Code and all software distributed under the License are | |
19 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
8f6c56a5 A |
20 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
21 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
2d21ac55 A |
22 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
23 | * Please see the License for the specific language governing rights and | |
24 | * limitations under the License. | |
8f6c56a5 | 25 | * |
2d21ac55 | 26 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
9bccf70c A |
27 | */ |
28 | #ifndef _HFS_CNODE_H_ | |
29 | #define _HFS_CNODE_H_ | |
30 | ||
31 | #include <sys/appleapiopts.h> | |
32 | ||
33 | #ifdef KERNEL | |
34 | #ifdef __APPLE_API_PRIVATE | |
fe8ab488 | 35 | #include <stdbool.h> |
9bccf70c | 36 | #include <sys/types.h> |
9bccf70c A |
37 | #include <sys/queue.h> |
38 | #include <sys/stat.h> | |
39 | #include <sys/vnode.h> | |
40 | #include <sys/quota.h> | |
41 | ||
91447636 A |
42 | #include <kern/locks.h> |
43 | ||
9bccf70c A |
44 | #include <hfs/hfs_catalog.h> |
45 | #include <hfs/rangelist.h> | |
b0d623f7 A |
46 | #if HFS_COMPRESSION |
47 | #include <sys/decmpfs.h> | |
48 | #endif | |
6d2010ae A |
49 | #if CONFIG_PROTECT |
50 | #include <sys/cprotect.h> | |
51 | #endif | |
52 | ||
9bccf70c A |
53 | |
54 | /* | |
55 | * The filefork is used to represent an HFS file fork (data or resource). | |
56 | * Reading or writing any of these fields requires holding cnode lock. | |
57 | */ | |
58 | struct filefork { | |
91447636 A |
59 | struct cnode *ff_cp; /* cnode associated with this fork */ |
60 | struct rl_head ff_invalidranges; /* Areas of disk that should read back as zeroes */ | |
9bccf70c | 61 | union { |
91447636 A |
62 | void *ffu_sysfileinfo; /* additional info for system files */ |
63 | char *ffu_symlinkptr; /* symbolic link pathname */ | |
64 | } ff_union; | |
65 | struct cat_fork ff_data; /* fork data (size, extents) */ | |
9bccf70c | 66 | }; |
55e303ae | 67 | typedef struct filefork filefork_t; |
9bccf70c | 68 | |
316670eb A |
69 | |
70 | #define HFS_TEMPLOOKUP_NAMELEN 32 | |
71 | ||
72 | /* | |
73 | * Catalog Lookup struct (runtime) | |
74 | * | |
75 | * This is used so that when we need to malloc a container for a catalog | |
76 | * lookup operation, we can acquire memory for everything in one fell swoop | |
77 | * as opposed to putting many of these objects on the stack. The cat_fork | |
78 | * data structure can take up 100+bytes easily, and that can add to stack | |
79 | * overhead. | |
80 | * | |
81 | * As a result, we use this to easily pass around the memory needed for a | |
82 | * lookup operation. | |
83 | */ | |
84 | struct cat_lookup_buffer { | |
85 | struct cat_desc lookup_desc; | |
86 | struct cat_attr lookup_attr; | |
87 | struct filefork lookup_fork; | |
88 | struct componentname lookup_cn; | |
89 | char lookup_name[HFS_TEMPLOOKUP_NAMELEN]; /* for open-unlinked paths only */ | |
90 | }; | |
91 | ||
92 | ||
9bccf70c | 93 | /* Aliases for common fields */ |
91447636 | 94 | #define ff_size ff_data.cf_size |
593a1d5f | 95 | #define ff_new_size ff_data.cf_new_size |
91447636 A |
96 | #define ff_clumpsize ff_data.cf_clump |
97 | #define ff_bytesread ff_data.cf_bytesread | |
98 | #define ff_blocks ff_data.cf_blocks | |
99 | #define ff_extents ff_data.cf_extents | |
55e303ae A |
100 | #define ff_unallocblocks ff_data.cf_vblocks |
101 | ||
91447636 A |
102 | #define ff_symlinkptr ff_union.ffu_symlinkptr |
103 | #define ff_sysfileinfo ff_union.ffu_sysfileinfo | |
9bccf70c A |
104 | |
105 | ||
106 | /* The btree code still needs these... */ | |
91447636 A |
107 | #define fcbEOF ff_size |
108 | #define fcbExtents ff_extents | |
109 | #define fcbBTCBPtr ff_sysfileinfo | |
9bccf70c | 110 | |
91447636 | 111 | typedef u_int8_t atomicflag_t; |
2d21ac55 A |
112 | |
113 | ||
114 | /* | |
115 | * Hardlink Origin (for hardlinked directories). | |
116 | */ | |
117 | struct linkorigin { | |
118 | TAILQ_ENTRY(linkorigin) lo_link; /* chain */ | |
119 | void * lo_thread; /* thread that performed the lookup */ | |
120 | cnid_t lo_cnid; /* hardlink's cnid */ | |
121 | cnid_t lo_parentcnid; /* hardlink's parent cnid */ | |
122 | }; | |
123 | typedef struct linkorigin linkorigin_t; | |
124 | ||
125 | #define MAX_CACHED_ORIGINS 10 | |
935ed37a | 126 | #define MAX_CACHED_FILE_ORIGINS 8 |
2d21ac55 | 127 | |
9bccf70c A |
128 | /* |
129 | * The cnode is used to represent each active (or recently active) | |
130 | * file or directory in the HFS filesystem. | |
131 | * | |
132 | * Reading or writing any of these fields requires holding c_lock. | |
133 | */ | |
134 | struct cnode { | |
91447636 | 135 | lck_rw_t c_rwlock; /* cnode's lock */ |
fe8ab488 | 136 | thread_t c_lockowner; /* cnode's lock owner (exclusive case only) */ |
91447636 | 137 | lck_rw_t c_truncatelock; /* protects file from truncation during read/write */ |
fe8ab488 | 138 | thread_t c_truncatelockowner; /* truncate lock owner (exclusive case only) */ |
9bccf70c A |
139 | LIST_ENTRY(cnode) c_hash; /* cnode's hash chain */ |
140 | u_int32_t c_flag; /* cnode's runtime flags */ | |
91447636 | 141 | u_int32_t c_hflag; /* cnode's flags for maintaining hash - protected by global hash lock */ |
9bccf70c A |
142 | struct vnode *c_vp; /* vnode for data fork or dir */ |
143 | struct vnode *c_rsrc_vp; /* vnode for resource fork */ | |
b0d623f7 | 144 | struct dquot *c_dquot[MAXQUOTAS]; /* cnode's quota info */ |
2d21ac55 A |
145 | u_int32_t c_childhint; /* catalog hint for children (small dirs only) */ |
146 | u_int32_t c_dirthreadhint; /* catalog hint for directory's thread rec */ | |
9bccf70c A |
147 | struct cat_desc c_desc; /* cnode's descriptor */ |
148 | struct cat_attr c_attr; /* cnode's attributes */ | |
2d21ac55 A |
149 | TAILQ_HEAD(hfs_originhead, linkorigin) c_originlist; /* hardlink origin cache */ |
150 | TAILQ_HEAD(hfs_hinthead, directoryhint) c_hintlist; /* readdir directory hint list */ | |
91447636 A |
151 | int16_t c_dirhinttag; /* directory hint tag */ |
152 | union { | |
153 | int16_t cu_dirhintcnt; /* directory hint count */ | |
154 | int16_t cu_syslockcount; /* system file use only */ | |
155 | } c_union; | |
2d21ac55 | 156 | u_int32_t c_dirchangecnt; /* changes each insert/delete (in-core only) */ |
9bccf70c A |
157 | struct filefork *c_datafork; /* cnode's data fork */ |
158 | struct filefork *c_rsrcfork; /* cnode's rsrc fork */ | |
91447636 A |
159 | atomicflag_t c_touch_acctime; |
160 | atomicflag_t c_touch_chgtime; | |
161 | atomicflag_t c_touch_modtime; | |
fe8ab488 A |
162 | |
163 | // The following flags are protected by the truncate lock | |
164 | union { | |
165 | struct { | |
166 | bool c_need_dvnode_put_after_truncate_unlock : 1; | |
167 | bool c_need_rvnode_put_after_truncate_unlock : 1; | |
168 | #if HFS_COMPRESSION | |
169 | bool c_need_decmpfs_reset : 1; | |
170 | #endif | |
171 | }; | |
172 | uint8_t c_tflags; | |
173 | }; | |
174 | ||
b0d623f7 A |
175 | #if HFS_COMPRESSION |
176 | decmpfs_cnode *c_decmp; | |
177 | #endif /* HFS_COMPRESSION */ | |
6d2010ae A |
178 | #if CONFIG_PROTECT |
179 | cprotect_t c_cpentry; /* content protection data */ | |
180 | #endif | |
181 | ||
9bccf70c | 182 | }; |
55e303ae | 183 | typedef struct cnode cnode_t; |
9bccf70c A |
184 | |
185 | /* Aliases for common cnode fields */ | |
186 | #define c_cnid c_desc.cd_cnid | |
187 | #define c_hint c_desc.cd_hint | |
188 | #define c_parentcnid c_desc.cd_parentcnid | |
189 | #define c_encoding c_desc.cd_encoding | |
190 | ||
191 | #define c_fileid c_attr.ca_fileid | |
192 | #define c_mode c_attr.ca_mode | |
2d21ac55 | 193 | #define c_linkcount c_attr.ca_linkcount |
9bccf70c A |
194 | #define c_uid c_attr.ca_uid |
195 | #define c_gid c_attr.ca_gid | |
2d21ac55 | 196 | #define c_rdev c_attr.ca_union1.cau_rdev |
9bccf70c A |
197 | #define c_atime c_attr.ca_atime |
198 | #define c_mtime c_attr.ca_mtime | |
9bccf70c A |
199 | #define c_ctime c_attr.ca_ctime |
200 | #define c_itime c_attr.ca_itime | |
201 | #define c_btime c_attr.ca_btime | |
316670eb | 202 | #define c_bsdflags c_attr.ca_flags |
9bccf70c | 203 | #define c_finderinfo c_attr.ca_finderinfo |
2d21ac55 A |
204 | #define c_blocks c_attr.ca_union2.cau_blocks |
205 | #define c_entries c_attr.ca_union2.cau_entries | |
9bccf70c A |
206 | #define c_zftimeout c_childhint |
207 | ||
91447636 A |
208 | #define c_dirhintcnt c_union.cu_dirhintcnt |
209 | #define c_syslockcount c_union.cu_syslockcount | |
9bccf70c | 210 | |
55e303ae | 211 | |
91447636 A |
212 | /* hash maintenance flags kept in c_hflag and protected by hfs_chash_mutex */ |
213 | #define H_ALLOC 0x00001 /* CNode is being allocated */ | |
214 | #define H_ATTACH 0x00002 /* CNode is being attached to by another vnode */ | |
215 | #define H_TRANSIT 0x00004 /* CNode is getting recycled */ | |
216 | #define H_WAITING 0x00008 /* CNode is being waited for */ | |
217 | ||
9bccf70c | 218 | |
fe8ab488 A |
219 | /* |
220 | * Runtime cnode flags (kept in c_flag) | |
221 | */ | |
222 | #define C_NEED_RVNODE_PUT 0x0000001 /* Need to do a vnode_put on c_rsrc_vp after the unlock */ | |
223 | #define C_NEED_DVNODE_PUT 0x0000002 /* Need to do a vnode_put on c_vp after the unlock */ | |
224 | #define C_ZFWANTSYNC 0x0000004 /* fsync requested and file has holes */ | |
225 | #define C_FROMSYNC 0x0000008 /* fsync was called from sync */ | |
226 | ||
227 | #define C_MODIFIED 0x0000010 /* CNode has been modified */ | |
228 | #define C_NOEXISTS 0x0000020 /* CNode has been deleted, catalog entry is gone */ | |
229 | #define C_DELETED 0x0000040 /* CNode has been marked to be deleted */ | |
230 | #define C_HARDLINK 0x0000080 /* CNode is a hard link (file or dir) */ | |
231 | ||
232 | #define C_FORCEUPDATE 0x0000100 /* force the catalog entry update */ | |
233 | #define C_HASXATTRS 0x0000200 /* cnode has extended attributes */ | |
234 | #define C_NEG_ENTRIES 0x0000400 /* directory has negative name entries */ | |
316670eb A |
235 | /* |
236 | * For C_SSD_STATIC: SSDs may want to deal with the file payload data in a | |
237 | * different manner knowing that the content is not likely to be modified. This is | |
238 | * purely advisory at the HFS level, and is not maintained after the cnode goes out of core. | |
239 | */ | |
fe8ab488 A |
240 | #define C_SSD_STATIC 0x0000800 /* Assume future writes contain static content */ |
241 | ||
242 | #define C_NEED_DATA_SETSIZE 0x0001000 /* Do a ubc_setsize(0) on c_rsrc_vp after the unlock */ | |
243 | #define C_NEED_RSRC_SETSIZE 0x0002000 /* Do a ubc_setsize(0) on c_vp after the unlock */ | |
244 | #define C_DIR_MODIFICATION 0x0004000 /* Directory is being modified, wait for lookups */ | |
245 | #define C_ALWAYS_ZEROFILL 0x0008000 /* Always zero-fill the file on an fsync */ | |
9bccf70c | 246 | |
fe8ab488 A |
247 | #define C_RENAMED 0x0010000 /* cnode was deleted as part of rename; C_DELETED should also be set */ |
248 | #define C_NEEDS_DATEADDED 0x0020000 /* cnode needs date-added written to the finderinfo bit */ | |
249 | #define C_BACKINGSTORE 0x0040000 /* cnode is a backing store for an existing or currently-mounting filesystem */ | |
9bccf70c | 250 | |
fe8ab488 A |
251 | /* |
252 | * This flag indicates the cnode might be dirty because it | |
253 | * was mapped writable so if we get any page-outs, update | |
254 | * the modification and change times. | |
255 | */ | |
256 | #define C_MIGHT_BE_DIRTY_FROM_MAPPING 0x0080000 | |
316670eb | 257 | |
39236c6e A |
258 | /* |
259 | * For C_SSD_GREEDY_MODE: SSDs may want to write the file payload data using the greedy mode knowing | |
260 | * that the content needs to be written out to the disk quicker than normal at the expense of storage efficiency. | |
261 | * This is purely advisory at the HFS level, and is not maintained after the cnode goes out of core. | |
262 | */ | |
fe8ab488 A |
263 | #define C_SSD_GREEDY_MODE 0x0100000 /* Assume future writes are recommended to be written in SLC mode */ |
264 | ||
265 | /* 0x0200000 is currently unused */ | |
266 | ||
267 | #define C_IO_ISOCHRONOUS 0x0400000 /* device-specific isochronous throughput I/O */ | |
316670eb | 268 | |
9bccf70c A |
269 | #define ZFTIMELIMIT (5 * 60) |
270 | ||
2d21ac55 A |
271 | /* |
272 | * The following is the "invisible" bit from the fdFlags field | |
273 | * in the FndrFileInfo. | |
274 | */ | |
275 | enum { kFinderInvisibleMask = 1 << 14 }; | |
276 | ||
277 | ||
9bccf70c A |
278 | /* |
279 | * Convert between cnode pointers and vnode pointers | |
280 | */ | |
91447636 | 281 | #define VTOC(vp) ((struct cnode *)vnode_fsnode((vp))) |
9bccf70c A |
282 | |
283 | #define CTOV(cp,rsrc) (((rsrc) && S_ISREG((cp)->c_mode)) ? \ | |
284 | (cp)->c_rsrc_vp : (cp)->c_vp) | |
285 | ||
286 | /* | |
287 | * Convert between vnode pointers and file forks | |
288 | * | |
289 | * Note: no CTOF since that is ambiguous | |
290 | */ | |
291 | ||
292 | #define FTOC(fp) ((fp)->ff_cp) | |
293 | ||
294 | #define VTOF(vp) ((vp) == VTOC((vp))->c_rsrc_vp ? \ | |
295 | VTOC((vp))->c_rsrcfork : \ | |
296 | VTOC((vp))->c_datafork) | |
297 | ||
2d21ac55 A |
298 | #define VCTOF(vp, cp) ((vp) == (cp)->c_rsrc_vp ? \ |
299 | (cp)->c_rsrcfork : \ | |
300 | (cp)->c_datafork) | |
301 | ||
9bccf70c A |
302 | #define FTOV(fp) ((fp) == FTOC(fp)->c_rsrcfork ? \ |
303 | FTOC(fp)->c_rsrc_vp : \ | |
304 | FTOC(fp)->c_vp) | |
305 | ||
b7266188 A |
306 | /* |
307 | * This is a helper function used for determining whether or not a cnode has become open | |
308 | * unlinked in between the time we acquired its vnode and the time we acquire the cnode lock | |
309 | * to start manipulating it. Due to the SMP nature of VFS, it is probably necessary to | |
310 | * use this macro every time we acquire a cnode lock, as the content of the Cnode may have | |
311 | * been modified in betweeen the lookup and a VNOP. Whether or not to call this is dependent | |
312 | * upon the VNOP in question. Sometimes it is OK to use an open-unlinked file, for example, in, | |
313 | * reading. But other times, such as on the source of a VNOP_RENAME, it should be disallowed. | |
314 | */ | |
6d2010ae | 315 | int hfs_checkdeleted(struct cnode *cp); |
55e303ae | 316 | |
9bccf70c A |
317 | /* |
318 | * Test for a resource fork | |
319 | */ | |
320 | #define FORK_IS_RSRC(fp) ((fp) == FTOC(fp)->c_rsrcfork) | |
321 | ||
322 | #define VNODE_IS_RSRC(vp) ((vp) == VTOC((vp))->c_rsrc_vp) | |
323 | ||
b0d623f7 A |
324 | #if HFS_COMPRESSION |
325 | /* | |
326 | * VTOCMP(vp) returns a pointer to vp's decmpfs_cnode; this could be NULL | |
327 | * if the file is not compressed or if hfs_file_is_compressed() hasn't | |
328 | * yet been called on this file. | |
329 | */ | |
330 | #define VTOCMP(vp) (VTOC((vp))->c_decmp) | |
331 | int hfs_file_is_compressed(struct cnode *cp, int skiplock); | |
332 | int hfs_uncompressed_size_of_compressed_file(struct hfsmount *hfsmp, struct vnode *vp, cnid_t fid, off_t *size, int skiplock); | |
333 | int hfs_hides_rsrc(vfs_context_t ctx, struct cnode *cp, int skiplock); | |
334 | int hfs_hides_xattr(vfs_context_t ctx, struct cnode *cp, const char *name, int skiplock); | |
335 | #endif | |
9bccf70c | 336 | |
55e303ae | 337 | #define ATIME_ONDISK_ACCURACY 300 |
9bccf70c | 338 | |
91447636 A |
339 | |
340 | /* This overlays the FileID portion of NFS file handles. */ | |
9bccf70c | 341 | struct hfsfid { |
9bccf70c A |
342 | u_int32_t hfsfid_cnid; /* Catalog node ID. */ |
343 | u_int32_t hfsfid_gen; /* Generation number (create date). */ | |
344 | }; | |
345 | ||
346 | ||
2d21ac55 A |
347 | /* Get new default vnode */ |
348 | extern int hfs_getnewvnode(struct hfsmount *hfsmp, struct vnode *dvp, struct componentname *cnp, | |
349 | struct cat_desc *descp, int flags, struct cat_attr *attrp, | |
6d2010ae | 350 | struct cat_fork *forkp, struct vnode **vpp, int *out_flags); |
2d21ac55 | 351 | |
6d2010ae | 352 | /* Input flags for hfs_getnewvnode */ |
2d21ac55 A |
353 | |
354 | #define GNV_WANTRSRC 0x01 /* Request the resource fork vnode. */ | |
355 | #define GNV_SKIPLOCK 0x02 /* Skip taking the cnode lock (when getting resource fork). */ | |
356 | #define GNV_CREATE 0x04 /* The vnode is for a newly created item. */ | |
6d2010ae | 357 | #define GNV_NOCACHE 0x08 /* Delay entering this item in the name cache */ |
2d21ac55 | 358 | |
6d2010ae A |
359 | /* Output flags for hfs_getnewvnode */ |
360 | #define GNV_CHASH_RENAMED 0x01 /* The cnode was renamed in-flight */ | |
361 | #define GNV_CAT_DELETED 0x02 /* The cnode was deleted from the catalog */ | |
362 | #define GNV_NEW_CNODE 0x04 /* We are vending out a newly initialized cnode */ | |
363 | #define GNV_CAT_ATTRCHANGED 0x08 /* Something in struct cat_attr changed in between cat_lookups */ | |
2d21ac55 A |
364 | |
365 | /* Touch cnode times based on c_touch_xxx flags */ | |
91447636 | 366 | extern void hfs_touchtimes(struct hfsmount *, struct cnode *); |
6d2010ae A |
367 | extern void hfs_write_dateadded (struct cat_attr *cattrp, u_int32_t dateadded); |
368 | extern u_int32_t hfs_get_dateadded (struct cnode *cp); | |
fe8ab488 | 369 | extern u_int32_t hfs_get_dateadded_from_blob(const uint8_t * /* finderinfo */, mode_t /* mode */); |
6d2010ae | 370 | |
39236c6e A |
371 | /* Gen counter methods */ |
372 | extern void hfs_write_gencount(struct cat_attr *cattrp, uint32_t gencount); | |
373 | extern uint32_t hfs_get_gencount(struct cnode *cp); | |
374 | extern uint32_t hfs_incr_gencount (struct cnode *cp); | |
fe8ab488 | 375 | extern uint32_t hfs_get_gencount_from_blob(const uint8_t * /* finderinfo */, mode_t /* mode */); |
39236c6e | 376 | |
22ba694c A |
377 | /* Document id methods */ |
378 | extern uint32_t hfs_get_document_id(struct cnode * /* cp */); | |
379 | extern uint32_t hfs_get_document_id_from_blob(const uint8_t * /* finderinfo */, mode_t /* mode */); | |
380 | ||
6d2010ae | 381 | /* Zero-fill file and push regions out to disk */ |
fe8ab488 A |
382 | enum { |
383 | // Use this flag if you're going to sync later | |
384 | HFS_FILE_DONE_NO_SYNC = 1, | |
385 | }; | |
386 | typedef uint32_t hfs_file_done_opts_t; | |
387 | extern int hfs_filedone(struct vnode *vp, vfs_context_t context, | |
388 | hfs_file_done_opts_t opts); | |
91447636 | 389 | |
9bccf70c A |
390 | /* |
391 | * HFS cnode hash functions. | |
392 | */ | |
393 | extern void hfs_chashinit(void); | |
b0d623f7 A |
394 | extern void hfs_chashinit_finish(struct hfsmount *hfsmp); |
395 | extern void hfs_delete_chash(struct hfsmount *hfsmp); | |
396 | extern int hfs_chashremove(struct hfsmount *hfsmp, struct cnode *cp); | |
397 | extern void hfs_chash_abort(struct hfsmount *hfsmp, struct cnode *cp); | |
398 | extern void hfs_chash_rehash(struct hfsmount *hfsmp, struct cnode *cp1, struct cnode *cp2); | |
399 | extern void hfs_chashwakeup(struct hfsmount *hfsmp, struct cnode *cp, int flags); | |
400 | extern void hfs_chash_mark_in_transit(struct hfsmount *hfsmp, struct cnode *cp); | |
401 | ||
316670eb A |
402 | extern struct vnode * hfs_chash_getvnode(struct hfsmount *hfsmp, ino_t inum, int wantrsrc, |
403 | int skiplock, int allow_deleted); | |
6d2010ae A |
404 | extern struct cnode * hfs_chash_getcnode(struct hfsmount *hfsmp, ino_t inum, struct vnode **vpp, |
405 | int wantrsrc, int skiplock, int *out_flags, int *hflags); | |
fe8ab488 | 406 | extern int hfs_chash_snoop(struct hfsmount *, ino_t, int, int (*)(const cnode_t *, void *), void *); |
6d2010ae A |
407 | extern int hfs_valid_cnode(struct hfsmount *hfsmp, struct vnode *dvp, struct componentname *cnp, |
408 | cnid_t cnid, struct cat_attr *cattr, int *error); | |
fe8ab488 | 409 | |
b0d623f7 | 410 | extern int hfs_chash_set_childlinkbit(struct hfsmount *hfsmp, cnid_t cnid); |
91447636 A |
411 | |
412 | /* | |
413 | * HFS cnode lock functions. | |
414 | * | |
415 | * HFS Locking Order: | |
416 | * | |
fe8ab488 A |
417 | * 1. cnode truncate lock (if needed) -- see below for more on this |
418 | * | |
419 | * + hfs_vnop_pagein/out handles recursive use of this lock (by | |
420 | * using flag option HFS_LOCK_SKIP_IF_EXCLUSIVE) although there | |
421 | * are issues with this (see #16620278). | |
422 | * | |
423 | * + If locking multiple cnodes then the truncate lock must be taken on | |
424 | * both (in address order), before taking the cnode locks. | |
425 | * | |
91447636 | 426 | * 2. cnode lock (in parent-child order if related, otherwise by address order) |
fe8ab488 | 427 | * |
91447636 | 428 | * 3. journal (if needed) |
fe8ab488 | 429 | * |
91447636 | 430 | * 4. system files (as needed) |
fe8ab488 | 431 | * |
91447636 A |
432 | * A. Catalog B-tree file |
433 | * B. Attributes B-tree file | |
2d21ac55 A |
434 | * C. Startup file (if there is one) |
435 | * D. Allocation Bitmap file (always exclusive, supports recursion) | |
436 | * E. Overflow Extents B-tree file (always exclusive, supports recursion) | |
fe8ab488 | 437 | * |
91447636 A |
438 | * 5. hfs mount point (always last) |
439 | * | |
ebb1b9f4 A |
440 | * |
441 | * I. HFS cnode hash lock (must not acquire any new locks while holding this lock, always taken last) | |
91447636 | 442 | */ |
39236c6e | 443 | |
fe8ab488 A |
444 | /* |
445 | * -- The Truncate Lock -- | |
446 | * | |
447 | * The truncate lock is used for a few purposes (more than its name | |
448 | * might suggest). The first thing to note is that the cnode lock | |
449 | * cannot be held whilst issuing any I/O other than metadata changes, | |
450 | * so the truncate lock, in either shared or exclusive form, must | |
451 | * usually be held in these cases. This includes calls to ubc_setsize | |
452 | * where the new size is less than the current size known to the VM | |
453 | * subsystem (for two reasons: a) because reaping pages can block | |
454 | * (e.g. on pages that are busy or being cleaned); b) reaping pages | |
455 | * might require page-in for tasks that have that region mapped | |
456 | * privately). The same applies to other calls into the VM subsystem. | |
457 | * | |
458 | * Here are some (but not necessarily all) cases that the truncate | |
459 | * lock protects for: | |
460 | * | |
461 | * + When reading and writing a file, we hold the truncate lock | |
462 | * shared to ensure that the underlying blocks cannot be deleted | |
463 | * and on systems that use content protection, this also ensures | |
464 | * the keys remain valid (which might be being used by the | |
465 | * underlying layers). | |
466 | * | |
467 | * + We need to protect against the following sequence of events: | |
468 | * | |
469 | * A file is initially size X. A thread issues an append to that | |
470 | * file. Another thread truncates the file and then extends it | |
471 | * to a a new size Y. Now the append can be applied at offset X | |
472 | * and then the data is lost when the file is truncated; or it | |
473 | * could be applied after the truncate, i.e. at offset 0; or it | |
474 | * can be applied at offset Y. What we *cannot* do is apply the | |
475 | * append at offset X and for the data to be visible at the end. | |
476 | * (Note that we are free to choose when we apply the append | |
477 | * operation.) | |
478 | * | |
479 | * To solve this, we keep things simple and take the truncate lock | |
480 | * exclusively in order to sequence the append with other size | |
481 | * changes. Therefore any size change must take the truncate lock | |
482 | * exclusively. | |
483 | * | |
484 | * (N.B. we could do better and allow readers to run concurrently | |
485 | * during the append and other size changes.) | |
486 | * | |
487 | * So here are the rules: | |
488 | * | |
489 | * + If you plan to change ff_size, you must take the truncate lock | |
490 | * exclusively, *but* be careful what I/O you do whilst you have | |
491 | * the truncate lock exclusively and try and avoid it if you can: | |
492 | * if the VM subsystem tries to do something with some pages on a | |
493 | * different thread and you try and do some I/O with those same | |
494 | * pages, we will deadlock. (See #16620278.) | |
495 | * | |
496 | * + If you do anything that requires blocks to not be deleted or | |
497 | * encrpytion keys to remain valid, you must take the truncate lock | |
498 | * shared. | |
499 | * | |
500 | * + And it follows therefore, that if you want to delete blocks or | |
501 | * delete keys, you must take the truncate lock exclusively. | |
502 | * | |
503 | * N.B. ff_size is actually protected by the cnode lock and so you | |
504 | * must hold the cnode lock exclusively to change it and shared to | |
505 | * read it. | |
506 | * | |
507 | */ | |
39236c6e A |
508 | |
509 | enum hfs_locktype { | |
510 | HFS_SHARED_LOCK = 1, | |
511 | HFS_EXCLUSIVE_LOCK = 2 | |
512 | }; | |
513 | ||
514 | /* Option flags for cnode and truncate lock functions */ | |
515 | enum hfs_lockflags { | |
516 | HFS_LOCK_DEFAULT = 0x0, /* Default flag, no options provided */ | |
517 | HFS_LOCK_ALLOW_NOEXISTS = 0x1, /* Allow locking of all cnodes, including cnode marked deleted with no catalog entry */ | |
fe8ab488 A |
518 | HFS_LOCK_SKIP_IF_EXCLUSIVE = 0x2, /* Skip locking if the current thread already holds the lock exclusive */ |
519 | ||
520 | // Used when you do not want to check return from hfs_lock | |
521 | HFS_LOCK_ALWAYS = HFS_LOCK_ALLOW_NOEXISTS, | |
39236c6e | 522 | }; |
91447636 A |
523 | #define HFS_SHARED_OWNER (void *)0xffffffff |
524 | ||
fe8ab488 | 525 | void hfs_lock_always(cnode_t *cnode, enum hfs_locktype); |
39236c6e A |
526 | int hfs_lock(struct cnode *, enum hfs_locktype, enum hfs_lockflags); |
527 | int hfs_lockpair(struct cnode *, struct cnode *, enum hfs_locktype); | |
6d2010ae | 528 | int hfs_lockfour(struct cnode *, struct cnode *, struct cnode *, struct cnode *, |
39236c6e | 529 | enum hfs_locktype, struct cnode **); |
91447636 | 530 | |
6d2010ae A |
531 | void hfs_unlock(struct cnode *); |
532 | void hfs_unlockpair(struct cnode *, struct cnode *); | |
533 | void hfs_unlockfour(struct cnode *, struct cnode *, struct cnode *, struct cnode *); | |
534 | ||
39236c6e A |
535 | void hfs_lock_truncate(struct cnode *, enum hfs_locktype, enum hfs_lockflags); |
536 | void hfs_unlock_truncate(struct cnode *, enum hfs_lockflags); | |
537 | int hfs_try_trunclock(struct cnode *, enum hfs_locktype, enum hfs_lockflags); | |
9bccf70c | 538 | |
fe8ab488 A |
539 | void hfs_clear_might_be_dirty_flag(cnode_t *cp); |
540 | ||
541 | // cnode must be locked | |
542 | static inline __attribute__((pure)) | |
543 | bool hfs_has_rsrc(const cnode_t *cp) | |
544 | { | |
545 | if (cp->c_rsrcfork) | |
546 | return cp->c_rsrcfork->ff_blocks > 0; | |
547 | else | |
548 | return cp->c_datafork && cp->c_blocks > cp->c_datafork->ff_blocks; | |
549 | } | |
550 | ||
9bccf70c A |
551 | #endif /* __APPLE_API_PRIVATE */ |
552 | #endif /* KERNEL */ | |
553 | ||
554 | #endif /* ! _HFS_CNODE_H_ */ |