fs/xfs/linux-2.6/xfs_vnode.c

   1 /*
   2  * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of version 2 of the GNU General Public License as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it would be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  11  *
  12  * Further, this software is distributed without any warranty that it is
  13  * free of the rightful claim of any third person regarding infringement
  14  * or the like.  Any license provided herein, whether implied or
  15  * otherwise, applies only to this software file.  Patent licenses, if
  16  * any, provided herein do not apply to combinations of this program with
  17  * other software, or any other product whatsoever.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write the Free Software Foundation, Inc., 59
  21  * Temple Place - Suite 330, Boston MA 02111-1307, USA.
  22  *
  23  * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
  24  * Mountain View, CA  94043, or:
  25  *
  26  * http://www.sgi.com
  27  *
  28  * For further information regarding this notice, see:
  29  *
  30  * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
  31  */
  32
  33 #include "xfs.h"
  34
  35
  36 uint64_t vn_generation;         /* vnode generation number */
  37 DEFINE_SPINLOCK(vnumber_lock);
  38
  39 /*
  40  * Dedicated vnode inactive/reclaim sync semaphores.
  41  * Prime number of hash buckets since address is used as the key.
  42  */
  43 #define NVSYNC                  37
  44 #define vptosync(v)             (&vsync[((unsigned long)v) % NVSYNC])
  45 sv_t vsync[NVSYNC];
  46
  47 /*
  48  * Translate stat(2) file types to vnode types and vice versa.
  49  * Aware of numeric order of S_IFMT and vnode type values.
  50  */
  51 enum vtype iftovt_tab[] = {
  52         VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
  53         VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VNON
  54 };
  55
  56 u_short vttoif_tab[] = {
  57         0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK, S_IFIFO, 0, S_IFSOCK
  58 };
  59
  60
  61 void
  62 vn_init(void)
  63 {
  64         register sv_t *svp;
  65         register int i;
  66
  67         for (svp = vsync, i = 0; i < NVSYNC; i++, svp++)
  68                 init_sv(svp, SV_DEFAULT, "vsy", i);
  69 }
  70
  71 /*
  72  * Clean a vnode of filesystem-specific data and prepare it for reuse.
  73  */
  74 STATIC int
  75 vn_reclaim(
  76         struct vnode    *vp)
  77 {
  78         int             error;
  79
  80         XFS_STATS_INC(vn_reclaim);
  81         vn_trace_entry(vp, "vn_reclaim", (inst_t *)__return_address);
  82
  83         /*
  84          * Only make the VOP_RECLAIM call if there are behaviors
  85          * to call.
  86          */
  87         if (vp->v_fbhv) {
  88                 VOP_RECLAIM(vp, error);
  89                 if (error)
  90                         return -error;
  91         }
  92         ASSERT(vp->v_fbhv == NULL);
  93
  94         VN_LOCK(vp);
  95         vp->v_flag &= (VRECLM|VWAIT);
  96         VN_UNLOCK(vp, 0);
  97
  98         vp->v_type = VNON;
  99         vp->v_fbhv = NULL;
 100
 101 #ifdef XFS_VNODE_TRACE
 102         ktrace_free(vp->v_trace);
 103         vp->v_trace = NULL;
 104 #endif
 105
 106         return 0;
 107 }
 108
 109 STATIC void
 110 vn_wakeup(
 111         struct vnode    *vp)
 112 {
 113         VN_LOCK(vp);
 114         if (vp->v_flag & VWAIT)
 115                 sv_broadcast(vptosync(vp));
 116         vp->v_flag &= ~(VRECLM|VWAIT|VMODIFIED);
 117         VN_UNLOCK(vp, 0);
 118 }
 119
 120 int
 121 vn_wait(
 122         struct vnode    *vp)
 123 {
 124         VN_LOCK(vp);
 125         if (vp->v_flag & (VINACT | VRECLM)) {
 126                 vp->v_flag |= VWAIT;
 127                 sv_wait(vptosync(vp), PINOD, &vp->v_lock, 0);
 128                 return 1;
 129         }
 130         VN_UNLOCK(vp, 0);
 131         return 0;
 132 }
 133
 134 struct vnode *
 135 vn_initialize(
 136         struct inode    *inode)
 137 {
 138         struct vnode    *vp = LINVFS_GET_VP(inode);
 139
 140         XFS_STATS_INC(vn_active);
 141         XFS_STATS_INC(vn_alloc);
 142
 143         vp->v_flag = VMODIFIED;
 144         spinlock_init(&vp->v_lock, "v_lock");
 145
 146         spin_lock(&vnumber_lock);
 147         if (!++vn_generation)   /* v_number shouldn't be zero */
 148                 vn_generation++;
 149         vp->v_number = vn_generation;
 150         spin_unlock(&vnumber_lock);
 151
 152         ASSERT(VN_CACHED(vp) == 0);
 153
 154         /* Initialize the first behavior and the behavior chain head. */
 155         vn_bhv_head_init(VN_BHV_HEAD(vp), "vnode");
 156
 157 #ifdef  XFS_VNODE_TRACE
 158         vp->v_trace = ktrace_alloc(VNODE_TRACE_SIZE, KM_SLEEP);
 159         printk("Allocated VNODE_TRACE at 0x%p\n", vp->v_trace);
 160 #endif  /* XFS_VNODE_TRACE */
 161
 162         vn_trace_exit(vp, "vn_initialize", (inst_t *)__return_address);
 163         return vp;
 164 }
 165
 166 /*
 167  * Get a reference on a vnode.
 168  */
 169 vnode_t *
 170 vn_get(
 171         struct vnode    *vp,
 172         vmap_t          *vmap)
 173 {
 174         struct inode    *inode;
 175
 176         XFS_STATS_INC(vn_get);
 177         inode = LINVFS_GET_IP(vp);
 178         if (inode->i_state & I_FREEING)
 179                 return NULL;
 180
 181         inode = ilookup(vmap->v_vfsp->vfs_super, vmap->v_ino);
 182         if (!inode)     /* Inode not present */
 183                 return NULL;
 184
 185         vn_trace_exit(vp, "vn_get", (inst_t *)__return_address);
 186
 187         return vp;
 188 }
 189
 190 /*
 191  * Revalidate the Linux inode from the vattr.
 192  * Note: i_size _not_ updated; we must hold the inode
 193  * semaphore when doing that - callers responsibility.
 194  */
 195 void
 196 vn_revalidate_core(
 197         struct vnode    *vp,
 198         vattr_t         *vap)
 199 {
 200         struct inode    *inode = LINVFS_GET_IP(vp);
 201
 202         inode->i_mode       = VTTOIF(vap->va_type) | vap->va_mode;
 203         inode->i_nlink      = vap->va_nlink;
 204         inode->i_uid        = vap->va_uid;
 205         inode->i_gid        = vap->va_gid;
 206         inode->i_blocks     = vap->va_nblocks;
 207         inode->i_mtime      = vap->va_mtime;
 208         inode->i_ctime      = vap->va_ctime;
 209         inode->i_atime      = vap->va_atime;
 210         if (vap->va_xflags & XFS_XFLAG_IMMUTABLE)
 211                 inode->i_flags |= S_IMMUTABLE;
 212         else
 213                 inode->i_flags &= ~S_IMMUTABLE;
 214         if (vap->va_xflags & XFS_XFLAG_APPEND)
 215                 inode->i_flags |= S_APPEND;
 216         else
 217                 inode->i_flags &= ~S_APPEND;
 218         if (vap->va_xflags & XFS_XFLAG_SYNC)
 219                 inode->i_flags |= S_SYNC;
 220         else
 221                 inode->i_flags &= ~S_SYNC;
 222         if (vap->va_xflags & XFS_XFLAG_NOATIME)
 223                 inode->i_flags |= S_NOATIME;
 224         else
 225                 inode->i_flags &= ~S_NOATIME;
 226 }
 227
 228 /*
 229  * Revalidate the Linux inode from the vnode.
 230  */
 231 int
 232 vn_revalidate(
 233         struct vnode    *vp)
 234 {
 235         vattr_t         va;
 236         int             error;
 237
 238         vn_trace_entry(vp, "vn_revalidate", (inst_t *)__return_address);
 239         ASSERT(vp->v_fbhv != NULL);
 240
 241         va.va_mask = XFS_AT_STAT|XFS_AT_XFLAGS;
 242         VOP_GETATTR(vp, &va, 0, NULL, error);
 243         if (!error) {
 244                 vn_revalidate_core(vp, &va);
 245                 VUNMODIFY(vp);
 246         }
 247         return -error;
 248 }
 249
 250 /*
 251  * purge a vnode from the cache
 252  * At this point the vnode is guaranteed to have no references (vn_count == 0)
 253  * The caller has to make sure that there are no ways someone could
 254  * get a handle (via vn_get) on the vnode (usually done via a mount/vfs lock).
 255  */
 256 void
 257 vn_purge(
 258         struct vnode    *vp,
 259         vmap_t          *vmap)
 260 {
 261         vn_trace_entry(vp, "vn_purge", (inst_t *)__return_address);
 262
 263 again:
 264         /*
 265          * Check whether vp has already been reclaimed since our caller
 266          * sampled its version while holding a filesystem cache lock that
 267          * its VOP_RECLAIM function acquires.
 268          */
 269         VN_LOCK(vp);
 270         if (vp->v_number != vmap->v_number) {
 271                 VN_UNLOCK(vp, 0);
 272                 return;
 273         }
 274
 275         /*
 276          * If vp is being reclaimed or inactivated, wait until it is inert,
 277          * then proceed.  Can't assume that vnode is actually reclaimed
 278          * just because the reclaimed flag is asserted -- a vn_alloc
 279          * reclaim can fail.
 280          */
 281         if (vp->v_flag & (VINACT | VRECLM)) {
 282                 ASSERT(vn_count(vp) == 0);
 283                 vp->v_flag |= VWAIT;
 284                 sv_wait(vptosync(vp), PINOD, &vp->v_lock, 0);
 285                 goto again;
 286         }
 287
 288         /*
 289          * Another process could have raced in and gotten this vnode...
 290          */
 291         if (vn_count(vp) > 0) {
 292                 VN_UNLOCK(vp, 0);
 293                 return;
 294         }
 295
 296         XFS_STATS_DEC(vn_active);
 297         vp->v_flag |= VRECLM;
 298         VN_UNLOCK(vp, 0);
 299
 300         /*
 301          * Call VOP_RECLAIM and clean vp. The FSYNC_INVAL flag tells
 302          * vp's filesystem to flush and invalidate all cached resources.
 303          * When vn_reclaim returns, vp should have no private data,
 304          * either in a system cache or attached to v_data.
 305          */
 306         if (vn_reclaim(vp) != 0)
 307                 panic("vn_purge: cannot reclaim");
 308
 309         /*
 310          * Wakeup anyone waiting for vp to be reclaimed.
 311          */
 312         vn_wakeup(vp);
 313 }
 314
 315 /*
 316  * Add a reference to a referenced vnode.
 317  */
 318 struct vnode *
 319 vn_hold(
 320         struct vnode    *vp)
 321 {
 322         struct inode    *inode;
 323
 324         XFS_STATS_INC(vn_hold);
 325
 326         VN_LOCK(vp);
 327         inode = igrab(LINVFS_GET_IP(vp));
 328         ASSERT(inode);
 329         VN_UNLOCK(vp, 0);
 330
 331         return vp;
 332 }
 333
 334 /*
 335  *  Call VOP_INACTIVE on last reference.
 336  */
 337 void
 338 vn_rele(
 339         struct vnode    *vp)
 340 {
 341         int             vcnt;
 342         int             cache;
 343
 344         XFS_STATS_INC(vn_rele);
 345
 346         VN_LOCK(vp);
 347
 348         vn_trace_entry(vp, "vn_rele", (inst_t *)__return_address);
 349         vcnt = vn_count(vp);
 350
 351         /*
 352          * Since we always get called from put_inode we know
 353          * that i_count won't be decremented after we
 354          * return.
 355          */
 356         if (!vcnt) {
 357                 /*
 358                  * As soon as we turn this on, noone can find us in vn_get
 359                  * until we turn off VINACT or VRECLM
 360                  */
 361                 vp->v_flag |= VINACT;
 362                 VN_UNLOCK(vp, 0);
 363
 364                 /*
 365                  * Do not make the VOP_INACTIVE call if there
 366                  * are no behaviors attached to the vnode to call.
 367                  */
 368                 if (vp->v_fbhv)
 369                         VOP_INACTIVE(vp, NULL, cache);
 370
 371                 VN_LOCK(vp);
 372                 if (vp->v_flag & VWAIT)
 373                         sv_broadcast(vptosync(vp));
 374
 375                 vp->v_flag &= ~(VINACT|VWAIT|VRECLM|VMODIFIED);
 376         }
 377
 378         VN_UNLOCK(vp, 0);
 379
 380         vn_trace_exit(vp, "vn_rele", (inst_t *)__return_address);
 381 }
 382
 383 /*
 384  * Finish the removal of a vnode.
 385  */
 386 void
 387 vn_remove(
 388         struct vnode    *vp)
 389 {
 390         vmap_t          vmap;
 391
 392         /* Make sure we don't do this to the same vnode twice */
 393         if (!(vp->v_fbhv))
 394                 return;
 395
 396         XFS_STATS_INC(vn_remove);
 397         vn_trace_exit(vp, "vn_remove", (inst_t *)__return_address);
 398
 399         /*
 400          * After the following purge the vnode
 401          * will no longer exist.
 402          */
 403         VMAP(vp, vmap);
 404         vn_purge(vp, &vmap);
 405 }
 406
 407
 408 #ifdef  XFS_VNODE_TRACE
 409
 410 #define KTRACE_ENTER(vp, vk, s, line, ra)                       \
 411         ktrace_enter(   (vp)->v_trace,                          \
 412 /*  0 */                (void *)(__psint_t)(vk),                \
 413 /*  1 */                (void *)(s),                            \
 414 /*  2 */                (void *)(__psint_t) line,               \
 415 /*  3 */                (void *)(vn_count(vp)), \
 416 /*  4 */                (void *)(ra),                           \
 417 /*  5 */                (void *)(__psunsigned_t)(vp)->v_flag,   \
 418 /*  6 */                (void *)(__psint_t)current_cpu(),       \
 419 /*  7 */                (void *)(__psint_t)current_pid(),       \
 420 /*  8 */                (void *)__return_address,               \
 421 /*  9 */                0, 0, 0, 0, 0, 0, 0)
 422
 423 /*
 424  * Vnode tracing code.
 425  */
 426 void
 427 vn_trace_entry(vnode_t *vp, char *func, inst_t *ra)
 428 {
 429         KTRACE_ENTER(vp, VNODE_KTRACE_ENTRY, func, 0, ra);
 430 }
 431
 432 void
 433 vn_trace_exit(vnode_t *vp, char *func, inst_t *ra)
 434 {
 435         KTRACE_ENTER(vp, VNODE_KTRACE_EXIT, func, 0, ra);
 436 }
 437
 438 void
 439 vn_trace_hold(vnode_t *vp, char *file, int line, inst_t *ra)
 440 {
 441         KTRACE_ENTER(vp, VNODE_KTRACE_HOLD, file, line, ra);
 442 }
 443
 444 void
 445 vn_trace_ref(vnode_t *vp, char *file, int line, inst_t *ra)
 446 {
 447         KTRACE_ENTER(vp, VNODE_KTRACE_REF, file, line, ra);
 448 }
 449
 450 void
 451 vn_trace_rele(vnode_t *vp, char *file, int line, inst_t *ra)
 452 {
 453         KTRACE_ENTER(vp, VNODE_KTRACE_RELE, file, line, ra);
 454 }
 455 #endif  /* XFS_VNODE_TRACE */