fs/gfs2/ops_file.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4  *
   5  * This copyrighted material is made available to anyone wishing to use,
   6  * modify, copy, or redistribute it subject to the terms and conditions
   7  * of the GNU General Public License v.2.
   8  */
   9
  10 #include <linux/sched.h>
  11 #include <linux/slab.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/completion.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/pagemap.h>
  16 #include <linux/uio.h>
  17 #include <linux/blkdev.h>
  18 #include <linux/mm.h>
  19 #include <linux/smp_lock.h>
  20 #include <linux/fs.h>
  21 #include <linux/gfs2_ondisk.h>
  22 #include <linux/ext2_fs.h>
  23 #include <linux/crc32.h>
  24 #include <linux/iflags.h>
  25 #include <asm/uaccess.h>
  26
  27 #include "gfs2.h"
  28 #include "lm_interface.h"
  29 #include "incore.h"
  30 #include "bmap.h"
  31 #include "dir.h"
  32 #include "glock.h"
  33 #include "glops.h"
  34 #include "inode.h"
  35 #include "lm.h"
  36 #include "log.h"
  37 #include "meta_io.h"
  38 #include "ops_file.h"
  39 #include "ops_vm.h"
  40 #include "quota.h"
  41 #include "rgrp.h"
  42 #include "trans.h"
  43 #include "util.h"
  44 #include "eaops.h"
  45
  46 /* "bad" is for NFS support */
  47 struct filldir_bad_entry {
  48         char *fbe_name;
  49         unsigned int fbe_length;
  50         uint64_t fbe_offset;
  51         struct gfs2_inum fbe_inum;
  52         unsigned int fbe_type;
  53 };
  54
  55 struct filldir_bad {
  56         struct gfs2_sbd *fdb_sbd;
  57
  58         struct filldir_bad_entry *fdb_entry;
  59         unsigned int fdb_entry_num;
  60         unsigned int fdb_entry_off;
  61
  62         char *fdb_name;
  63         unsigned int fdb_name_size;
  64         unsigned int fdb_name_off;
  65 };
  66
  67 /* For regular, non-NFS */
  68 struct filldir_reg {
  69         struct gfs2_sbd *fdr_sbd;
  70         int fdr_prefetch;
  71
  72         filldir_t fdr_filldir;
  73         void *fdr_opaque;
  74 };
  75
  76 /*
  77  * Most fields left uninitialised to catch anybody who tries to
  78  * use them. f_flags set to prevent file_accessed() from touching
  79  * any other part of this. Its use is purely as a flag so that we
  80  * know (in readpage()) whether or not do to locking.
  81  */
  82 struct file gfs2_internal_file_sentinal = {
  83         .f_flags = O_NOATIME|O_RDONLY,
  84 };
  85
  86 static int gfs2_read_actor(read_descriptor_t *desc, struct page *page,
  87                            unsigned long offset, unsigned long size)
  88 {
  89         char *kaddr;
  90         unsigned long count = desc->count;
  91
  92         if (size > count)
  93                 size = count;
  94
  95         kaddr = kmap(page);
  96         memcpy(desc->arg.buf, kaddr + offset, size);
  97         kunmap(page);
  98
  99         desc->count = count - size;
 100         desc->written += size;
 101         desc->arg.buf += size;
 102         return size;
 103 }
 104
 105 int gfs2_internal_read(struct gfs2_inode *ip, struct file_ra_state *ra_state,
 106                        char *buf, loff_t *pos, unsigned size)
 107 {
 108         struct inode *inode = &ip->i_inode;
 109         read_descriptor_t desc;
 110         desc.written = 0;
 111         desc.arg.buf = buf;
 112         desc.count = size;
 113         desc.error = 0;
 114         do_generic_mapping_read(inode->i_mapping, ra_state,
 115                                 &gfs2_internal_file_sentinal, pos, &desc,
 116                                 gfs2_read_actor);
 117         return desc.written ? desc.written : desc.error;
 118 }
 119
 120 /**
 121  * gfs2_llseek - seek to a location in a file
 122  * @file: the file
 123  * @offset: the offset
 124  * @origin: Where to seek from (SEEK_SET, SEEK_CUR, or SEEK_END)
 125  *
 126  * SEEK_END requires the glock for the file because it references the
 127  * file's size.
 128  *
 129  * Returns: The new offset, or errno
 130  */
 131
 132 static loff_t gfs2_llseek(struct file *file, loff_t offset, int origin)
 133 {
 134         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 135         struct gfs2_holder i_gh;
 136         loff_t error;
 137
 138         if (origin == 2) {
 139                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
 140                                            &i_gh);
 141                 if (!error) {
 142                         error = remote_llseek(file, offset, origin);
 143                         gfs2_glock_dq_uninit(&i_gh);
 144                 }
 145         } else
 146                 error = remote_llseek(file, offset, origin);
 147
 148         return error;
 149 }
 150
 151 /**
 152  * filldir_reg_func - Report a directory entry to the caller of gfs2_dir_read()
 153  * @opaque: opaque data used by the function
 154  * @name: the name of the directory entry
 155  * @length: the length of the name
 156  * @offset: the entry's offset in the directory
 157  * @inum: the inode number the entry points to
 158  * @type: the type of inode the entry points to
 159  *
 160  * Returns: 0 on success, 1 if buffer full
 161  */
 162
 163 static int filldir_reg_func(void *opaque, const char *name, unsigned int length,
 164                             uint64_t offset, struct gfs2_inum *inum,
 165                             unsigned int type)
 166 {
 167         struct filldir_reg *fdr = (struct filldir_reg *)opaque;
 168         struct gfs2_sbd *sdp = fdr->fdr_sbd;
 169         int error;
 170
 171         error = fdr->fdr_filldir(fdr->fdr_opaque, name, length, offset,
 172                                  inum->no_addr, type);
 173         if (error)
 174                 return 1;
 175
 176         if (fdr->fdr_prefetch && !(length == 1 && *name == '.')) {
 177                 gfs2_glock_prefetch_num(sdp,
 178                                        inum->no_addr, &gfs2_inode_glops,
 179                                        LM_ST_SHARED, LM_FLAG_TRY | LM_FLAG_ANY);
 180                 gfs2_glock_prefetch_num(sdp,
 181                                        inum->no_addr, &gfs2_iopen_glops,
 182                                        LM_ST_SHARED, LM_FLAG_TRY);
 183         }
 184
 185         return 0;
 186 }
 187
 188 /**
 189  * readdir_reg - Read directory entries from a directory
 190  * @file: The directory to read from
 191  * @dirent: Buffer for dirents
 192  * @filldir: Function used to do the copying
 193  *
 194  * Returns: errno
 195  */
 196
 197 static int readdir_reg(struct file *file, void *dirent, filldir_t filldir)
 198 {
 199         struct inode *dir = file->f_mapping->host;
 200         struct gfs2_inode *dip = GFS2_I(dir);
 201         struct filldir_reg fdr;
 202         struct gfs2_holder d_gh;
 203         uint64_t offset = file->f_pos;
 204         int error;
 205
 206         fdr.fdr_sbd = GFS2_SB(dir);
 207         fdr.fdr_prefetch = 1;
 208         fdr.fdr_filldir = filldir;
 209         fdr.fdr_opaque = dirent;
 210
 211         gfs2_holder_init(dip->i_gl, LM_ST_SHARED, GL_ATIME, &d_gh);
 212         error = gfs2_glock_nq_atime(&d_gh);
 213         if (error) {
 214                 gfs2_holder_uninit(&d_gh);
 215                 return error;
 216         }
 217
 218         error = gfs2_dir_read(dir, &offset, &fdr, filldir_reg_func);
 219
 220         gfs2_glock_dq_uninit(&d_gh);
 221
 222         file->f_pos = offset;
 223
 224         return error;
 225 }
 226
 227 /**
 228  * filldir_bad_func - Report a directory entry to the caller of gfs2_dir_read()
 229  * @opaque: opaque data used by the function
 230  * @name: the name of the directory entry
 231  * @length: the length of the name
 232  * @offset: the entry's offset in the directory
 233  * @inum: the inode number the entry points to
 234  * @type: the type of inode the entry points to
 235  *
 236  * For supporting NFS.
 237  *
 238  * Returns: 0 on success, 1 if buffer full
 239  */
 240
 241 static int filldir_bad_func(void *opaque, const char *name, unsigned int length,
 242                             uint64_t offset, struct gfs2_inum *inum,
 243                             unsigned int type)
 244 {
 245         struct filldir_bad *fdb = (struct filldir_bad *)opaque;
 246         struct gfs2_sbd *sdp = fdb->fdb_sbd;
 247         struct filldir_bad_entry *fbe;
 248
 249         if (fdb->fdb_entry_off == fdb->fdb_entry_num ||
 250             fdb->fdb_name_off + length > fdb->fdb_name_size)
 251                 return 1;
 252
 253         fbe = &fdb->fdb_entry[fdb->fdb_entry_off];
 254         fbe->fbe_name = fdb->fdb_name + fdb->fdb_name_off;
 255         memcpy(fbe->fbe_name, name, length);
 256         fbe->fbe_length = length;
 257         fbe->fbe_offset = offset;
 258         fbe->fbe_inum = *inum;
 259         fbe->fbe_type = type;
 260
 261         fdb->fdb_entry_off++;
 262         fdb->fdb_name_off += length;
 263
 264         if (!(length == 1 && *name == '.')) {
 265                 gfs2_glock_prefetch_num(sdp,
 266                                        inum->no_addr, &gfs2_inode_glops,
 267                                        LM_ST_SHARED, LM_FLAG_TRY | LM_FLAG_ANY);
 268                 gfs2_glock_prefetch_num(sdp,
 269                                        inum->no_addr, &gfs2_iopen_glops,
 270                                        LM_ST_SHARED, LM_FLAG_TRY);
 271         }
 272
 273         return 0;
 274 }
 275
 276 /**
 277  * readdir_bad - Read directory entries from a directory
 278  * @file: The directory to read from
 279  * @dirent: Buffer for dirents
 280  * @filldir: Function used to do the copying
 281  *
 282  * For supporting NFS.
 283  *
 284  * Returns: errno
 285  */
 286
 287 static int readdir_bad(struct file *file, void *dirent, filldir_t filldir)
 288 {
 289         struct inode *dir = file->f_mapping->host;
 290         struct gfs2_inode *dip = GFS2_I(dir);
 291         struct gfs2_sbd *sdp = GFS2_SB(dir);
 292         struct filldir_reg fdr;
 293         unsigned int entries, size;
 294         struct filldir_bad *fdb;
 295         struct gfs2_holder d_gh;
 296         uint64_t offset = file->f_pos;
 297         unsigned int x;
 298         struct filldir_bad_entry *fbe;
 299         int error;
 300
 301         entries = gfs2_tune_get(sdp, gt_entries_per_readdir);
 302         size = sizeof(struct filldir_bad) +
 303             entries * (sizeof(struct filldir_bad_entry) + GFS2_FAST_NAME_SIZE);
 304
 305         fdb = kzalloc(size, GFP_KERNEL);
 306         if (!fdb)
 307                 return -ENOMEM;
 308
 309         fdb->fdb_sbd = sdp;
 310         fdb->fdb_entry = (struct filldir_bad_entry *)(fdb + 1);
 311         fdb->fdb_entry_num = entries;
 312         fdb->fdb_name = ((char *)fdb) + sizeof(struct filldir_bad) +
 313                 entries * sizeof(struct filldir_bad_entry);
 314         fdb->fdb_name_size = entries * GFS2_FAST_NAME_SIZE;
 315
 316         gfs2_holder_init(dip->i_gl, LM_ST_SHARED, GL_ATIME, &d_gh);
 317         error = gfs2_glock_nq_atime(&d_gh);
 318         if (error) {
 319                 gfs2_holder_uninit(&d_gh);
 320                 goto out;
 321         }
 322
 323         error = gfs2_dir_read(dir, &offset, fdb, filldir_bad_func);
 324
 325         gfs2_glock_dq_uninit(&d_gh);
 326
 327         fdr.fdr_sbd = sdp;
 328         fdr.fdr_prefetch = 0;
 329         fdr.fdr_filldir = filldir;
 330         fdr.fdr_opaque = dirent;
 331
 332         for (x = 0; x < fdb->fdb_entry_off; x++) {
 333                 fbe = &fdb->fdb_entry[x];
 334
 335                 error = filldir_reg_func(&fdr,
 336                                          fbe->fbe_name, fbe->fbe_length,
 337                                          fbe->fbe_offset,
 338                                          &fbe->fbe_inum, fbe->fbe_type);
 339                 if (error) {
 340                         file->f_pos = fbe->fbe_offset;
 341                         error = 0;
 342                         goto out;
 343                 }
 344         }
 345
 346         file->f_pos = offset;
 347
 348  out:
 349         kfree(fdb);
 350
 351         return error;
 352 }
 353
 354 /**
 355  * gfs2_readdir - Read directory entries from a directory
 356  * @file: The directory to read from
 357  * @dirent: Buffer for dirents
 358  * @filldir: Function used to do the copying
 359  *
 360  * Returns: errno
 361  */
 362
 363 static int gfs2_readdir(struct file *file, void *dirent, filldir_t filldir)
 364 {
 365         int error;
 366
 367         if (strcmp(current->comm, "nfsd") != 0)
 368                 error = readdir_reg(file, dirent, filldir);
 369         else
 370                 error = readdir_bad(file, dirent, filldir);
 371
 372         return error;
 373 }
 374
 375 static const u32 iflags_to_gfs2[32] = {
 376         [iflag_Sync] = GFS2_DIF_SYNC,
 377         [iflag_Immutable] = GFS2_DIF_IMMUTABLE,
 378         [iflag_Append] = GFS2_DIF_APPENDONLY,
 379         [iflag_NoAtime] = GFS2_DIF_NOATIME,
 380         [iflag_Index] = GFS2_DIF_EXHASH,
 381         [iflag_JournalData] = GFS2_DIF_JDATA,
 382         [iflag_DirectIO] = GFS2_DIF_DIRECTIO,
 383 };
 384
 385 static const u32 gfs2_to_iflags[32] = {
 386         [gfs2fl_Sync] = IFLAG_SYNC,
 387         [gfs2fl_Immutable] = IFLAG_IMMUTABLE,
 388         [gfs2fl_AppendOnly] = IFLAG_APPEND,
 389         [gfs2fl_NoAtime] = IFLAG_NOATIME,
 390         [gfs2fl_ExHash] = IFLAG_INDEX,
 391         [gfs2fl_Jdata] = IFLAG_JOURNAL_DATA,
 392         [gfs2fl_Directio] = IFLAG_DIRECTIO,
 393         [gfs2fl_InheritDirectio] = IFLAG_DIRECTIO,
 394         [gfs2fl_InheritJdata] = IFLAG_JOURNAL_DATA,
 395 };
 396
 397 static int gfs2_get_flags(struct file *filp, u32 __user *ptr)
 398 {
 399         struct inode *inode = filp->f_dentry->d_inode;
 400         struct gfs2_inode *ip = GFS2_I(inode);
 401         struct gfs2_holder gh;
 402         int error;
 403         u32 iflags;
 404
 405         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &gh);
 406         error = gfs2_glock_nq_m_atime(1, &gh);
 407         if (error)
 408                 return error;
 409
 410         iflags = iflags_cvt(gfs2_to_iflags, ip->i_di.di_flags);
 411         if (put_user(iflags, ptr))
 412                 error = -EFAULT;
 413
 414         gfs2_glock_dq_m(1, &gh);
 415         gfs2_holder_uninit(&gh);
 416         return error;
 417 }
 418
 419 /* Flags that can be set by user space */
 420 #define GFS2_FLAGS_USER_SET (GFS2_DIF_JDATA|                    \
 421                              GFS2_DIF_DIRECTIO|                 \
 422                              GFS2_DIF_IMMUTABLE|                \
 423                              GFS2_DIF_APPENDONLY|               \
 424                              GFS2_DIF_NOATIME|                  \
 425                              GFS2_DIF_SYNC|                     \
 426                              GFS2_DIF_SYSTEM|                   \
 427                              GFS2_DIF_INHERIT_DIRECTIO|         \
 428                              GFS2_DIF_INHERIT_JDATA)
 429
 430 /**
 431  * gfs2_set_flags - set flags on an inode
 432  * @inode: The inode
 433  * @flags: The flags to set
 434  * @mask: Indicates which flags are valid
 435  *
 436  */
 437 static int do_gfs2_set_flags(struct file *filp, u32 reqflags, u32 mask)
 438 {
 439         struct inode *inode = filp->f_dentry->d_inode;
 440         struct gfs2_inode *ip = GFS2_I(inode);
 441         struct gfs2_sbd *sdp = GFS2_SB(inode);
 442         struct buffer_head *bh;
 443         struct gfs2_holder gh;
 444         int error;
 445         u32 new_flags, flags;
 446
 447         error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
 448         if (error)
 449                 return error;
 450
 451         flags = ip->i_di.di_flags;
 452         new_flags = (flags & ~mask) | (reqflags & mask);
 453         if ((new_flags ^ flags) == 0)
 454                 goto out;
 455
 456         if (S_ISDIR(inode->i_mode)) {
 457                 if ((new_flags ^ flags) & GFS2_DIF_JDATA)
 458                         new_flags ^= (GFS2_DIF_JDATA|GFS2_DIF_INHERIT_JDATA);
 459                 if ((new_flags ^ flags) & GFS2_DIF_DIRECTIO)
 460                         new_flags ^= (GFS2_DIF_DIRECTIO|GFS2_DIF_INHERIT_DIRECTIO);
 461         }
 462
 463         error = -EINVAL;
 464         if ((new_flags ^ flags) & ~GFS2_FLAGS_USER_SET)
 465                 goto out;
 466
 467         error = -EPERM;
 468         if (IS_IMMUTABLE(inode) && (new_flags & GFS2_DIF_IMMUTABLE))
 469                 goto out;
 470         if (IS_APPEND(inode) && (new_flags & GFS2_DIF_APPENDONLY))
 471                 goto out;
 472         if (((new_flags ^ flags) & GFS2_DIF_IMMUTABLE) &&
 473             !capable(CAP_LINUX_IMMUTABLE))
 474                 goto out;
 475         if (!IS_IMMUTABLE(inode)) {
 476                 error = permission(inode, MAY_WRITE, NULL);
 477                 if (error)
 478                         goto out;
 479         }
 480
 481         error = gfs2_trans_begin(sdp, RES_DINODE, 0);
 482         if (error)
 483                 goto out;
 484         error = gfs2_meta_inode_buffer(ip, &bh);
 485         if (error)
 486                 goto out_trans_end;
 487         gfs2_trans_add_bh(ip->i_gl, bh, 1);
 488         ip->i_di.di_flags = new_flags;
 489         gfs2_dinode_out(&ip->i_di, bh->b_data);
 490         brelse(bh);
 491 out_trans_end:
 492         gfs2_trans_end(sdp);
 493 out:
 494         gfs2_glock_dq_uninit(&gh);
 495         return error;
 496 }
 497
 498 static int gfs2_set_flags(struct file *filp, u32 __user *ptr)
 499 {
 500         u32 iflags, gfsflags;
 501         if (get_user(iflags, ptr))
 502                 return -EFAULT;
 503         gfsflags = iflags_cvt(iflags_to_gfs2, iflags);
 504         return do_gfs2_set_flags(filp, gfsflags, ~0);
 505 }
 506
 507 static long gfs2_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 508 {
 509         switch(cmd) {
 510         case IFLAGS_GET_IOC:
 511                 return gfs2_get_flags(filp, (u32 __user *)arg);
 512         case IFLAGS_SET_IOC:
 513                 return gfs2_set_flags(filp, (u32 __user *)arg);
 514         }
 515         return -ENOTTY;
 516 }
 517
 518
 519 /**
 520  * gfs2_mmap -
 521  * @file: The file to map
 522  * @vma: The VMA which described the mapping
 523  *
 524  * Returns: 0 or error code
 525  */
 526
 527 static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
 528 {
 529         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 530         struct gfs2_holder i_gh;
 531         int error;
 532
 533         gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME, &i_gh);
 534         error = gfs2_glock_nq_atime(&i_gh);
 535         if (error) {
 536                 gfs2_holder_uninit(&i_gh);
 537                 return error;
 538         }
 539
 540         /* This is VM_MAYWRITE instead of VM_WRITE because a call
 541            to mprotect() can turn on VM_WRITE later. */
 542
 543         if ((vma->vm_flags & (VM_MAYSHARE | VM_MAYWRITE)) ==
 544             (VM_MAYSHARE | VM_MAYWRITE))
 545                 vma->vm_ops = &gfs2_vm_ops_sharewrite;
 546         else
 547                 vma->vm_ops = &gfs2_vm_ops_private;
 548
 549         gfs2_glock_dq_uninit(&i_gh);
 550
 551         return error;
 552 }
 553
 554 /**
 555  * gfs2_open - open a file
 556  * @inode: the inode to open
 557  * @file: the struct file for this opening
 558  *
 559  * Returns: errno
 560  */
 561
 562 static int gfs2_open(struct inode *inode, struct file *file)
 563 {
 564         struct gfs2_inode *ip = GFS2_I(inode);
 565         struct gfs2_holder i_gh;
 566         struct gfs2_file *fp;
 567         int error;
 568
 569         fp = kzalloc(sizeof(struct gfs2_file), GFP_KERNEL);
 570         if (!fp)
 571                 return -ENOMEM;
 572
 573         mutex_init(&fp->f_fl_mutex);
 574
 575         gfs2_assert_warn(GFS2_SB(inode), !file->private_data);
 576         file->private_data = fp;
 577
 578         if (S_ISREG(ip->i_di.di_mode)) {
 579                 error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY,
 580                                            &i_gh);
 581                 if (error)
 582                         goto fail;
 583
 584                 if (!(file->f_flags & O_LARGEFILE) &&
 585                     ip->i_di.di_size > MAX_NON_LFS) {
 586                         error = -EFBIG;
 587                         goto fail_gunlock;
 588                 }
 589
 590                 /* Listen to the Direct I/O flag */
 591
 592                 if (ip->i_di.di_flags & GFS2_DIF_DIRECTIO)
 593                         file->f_flags |= O_DIRECT;
 594
 595                 gfs2_glock_dq_uninit(&i_gh);
 596         }
 597
 598         return 0;
 599
 600  fail_gunlock:
 601         gfs2_glock_dq_uninit(&i_gh);
 602
 603  fail:
 604         file->private_data = NULL;
 605         kfree(fp);
 606
 607         return error;
 608 }
 609
 610 /**
 611  * gfs2_close - called to close a struct file
 612  * @inode: the inode the struct file belongs to
 613  * @file: the struct file being closed
 614  *
 615  * Returns: errno
 616  */
 617
 618 static int gfs2_close(struct inode *inode, struct file *file)
 619 {
 620         struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
 621         struct gfs2_file *fp;
 622
 623         fp = file->private_data;
 624         file->private_data = NULL;
 625
 626         if (gfs2_assert_warn(sdp, fp))
 627                 return -EIO;
 628
 629         kfree(fp);
 630
 631         return 0;
 632 }
 633
 634 /**
 635  * gfs2_fsync - sync the dirty data for a file (across the cluster)
 636  * @file: the file that points to the dentry (we ignore this)
 637  * @dentry: the dentry that points to the inode to sync
 638  *
 639  * Returns: errno
 640  */
 641
 642 static int gfs2_fsync(struct file *file, struct dentry *dentry, int datasync)
 643 {
 644         struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
 645
 646         gfs2_log_flush(ip->i_gl->gl_sbd, ip->i_gl);
 647
 648         return 0;
 649 }
 650
 651 /**
 652  * gfs2_lock - acquire/release a posix lock on a file
 653  * @file: the file pointer
 654  * @cmd: either modify or retrieve lock state, possibly wait
 655  * @fl: type and range of lock
 656  *
 657  * Returns: errno
 658  */
 659
 660 static int gfs2_lock(struct file *file, int cmd, struct file_lock *fl)
 661 {
 662         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 663         struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
 664         struct lm_lockname name =
 665                 { .ln_number = ip->i_num.no_addr,
 666                   .ln_type = LM_TYPE_PLOCK };
 667
 668         if (!(fl->fl_flags & FL_POSIX))
 669                 return -ENOLCK;
 670         if ((ip->i_di.di_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 671                 return -ENOLCK;
 672
 673         if (sdp->sd_args.ar_localflocks) {
 674                 if (IS_GETLK(cmd)) {
 675                         struct file_lock tmp;
 676                         int ret;
 677                         ret = posix_test_lock(file, fl, &tmp);
 678                         fl->fl_type = F_UNLCK;
 679                         if (ret)
 680                                 memcpy(fl, &tmp, sizeof(struct file_lock));
 681                         return 0;
 682                 } else {
 683                         return posix_lock_file_wait(file, fl);
 684                 }
 685         }
 686
 687         if (IS_GETLK(cmd))
 688                 return gfs2_lm_plock_get(sdp, &name, file, fl);
 689         else if (fl->fl_type == F_UNLCK)
 690                 return gfs2_lm_punlock(sdp, &name, file, fl);
 691         else
 692                 return gfs2_lm_plock(sdp, &name, file, cmd, fl);
 693 }
 694
 695 static int do_flock(struct file *file, int cmd, struct file_lock *fl)
 696 {
 697         struct gfs2_file *fp = file->private_data;
 698         struct gfs2_holder *fl_gh = &fp->f_fl_gh;
 699         struct gfs2_inode *ip = GFS2_I(file->f_dentry->d_inode);
 700         struct gfs2_glock *gl;
 701         unsigned int state;
 702         int flags;
 703         int error = 0;
 704
 705         state = (fl->fl_type == F_WRLCK) ? LM_ST_EXCLUSIVE : LM_ST_SHARED;
 706         flags = ((IS_SETLKW(cmd)) ? 0 : LM_FLAG_TRY) | GL_EXACT | GL_NOCACHE;
 707
 708         mutex_lock(&fp->f_fl_mutex);
 709
 710         gl = fl_gh->gh_gl;
 711         if (gl) {
 712                 if (fl_gh->gh_state == state)
 713                         goto out;
 714                 gfs2_glock_hold(gl);
 715                 flock_lock_file_wait(file,
 716                                      &(struct file_lock){.fl_type = F_UNLCK});
 717                 gfs2_glock_dq_uninit(fl_gh);
 718         } else {
 719                 error = gfs2_glock_get(GFS2_SB(&ip->i_inode),
 720                                       ip->i_num.no_addr, &gfs2_flock_glops,
 721                                       CREATE, &gl);
 722                 if (error)
 723                         goto out;
 724         }
 725
 726         gfs2_holder_init(gl, state, flags, fl_gh);
 727         gfs2_glock_put(gl);
 728
 729         error = gfs2_glock_nq(fl_gh);
 730         if (error) {
 731                 gfs2_holder_uninit(fl_gh);
 732                 if (error == GLR_TRYFAILED)
 733                         error = -EAGAIN;
 734         } else {
 735                 error = flock_lock_file_wait(file, fl);
 736                 gfs2_assert_warn(GFS2_SB(&ip->i_inode), !error);
 737         }
 738
 739  out:
 740         mutex_unlock(&fp->f_fl_mutex);
 741
 742         return error;
 743 }
 744
 745 static void do_unflock(struct file *file, struct file_lock *fl)
 746 {
 747         struct gfs2_file *fp = file->private_data;
 748         struct gfs2_holder *fl_gh = &fp->f_fl_gh;
 749
 750         mutex_lock(&fp->f_fl_mutex);
 751         flock_lock_file_wait(file, fl);
 752         if (fl_gh->gh_gl)
 753                 gfs2_glock_dq_uninit(fl_gh);
 754         mutex_unlock(&fp->f_fl_mutex);
 755 }
 756
 757 /**
 758  * gfs2_flock - acquire/release a flock lock on a file
 759  * @file: the file pointer
 760  * @cmd: either modify or retrieve lock state, possibly wait
 761  * @fl: type and range of lock
 762  *
 763  * Returns: errno
 764  */
 765
 766 static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
 767 {
 768         struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
 769         struct gfs2_sbd *sdp = GFS2_SB(file->f_mapping->host);
 770
 771         if (!(fl->fl_flags & FL_FLOCK))
 772                 return -ENOLCK;
 773         if ((ip->i_di.di_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
 774                 return -ENOLCK;
 775
 776         if (sdp->sd_args.ar_localflocks)
 777                 return flock_lock_file_wait(file, fl);
 778
 779         if (fl->fl_type == F_UNLCK) {
 780                 do_unflock(file, fl);
 781                 return 0;
 782         } else
 783                 return do_flock(file, cmd, fl);
 784 }
 785
 786 const struct file_operations gfs2_file_fops = {
 787         .llseek = gfs2_llseek,
 788         .read = generic_file_read,
 789         .readv = generic_file_readv,
 790         .aio_read = generic_file_aio_read,
 791         .write = generic_file_write,
 792         .writev = generic_file_writev,
 793         .aio_write = generic_file_aio_write,
 794         .unlocked_ioctl = gfs2_ioctl,
 795         .mmap = gfs2_mmap,
 796         .open = gfs2_open,
 797         .release = gfs2_close,
 798         .fsync = gfs2_fsync,
 799         .lock = gfs2_lock,
 800         .sendfile = generic_file_sendfile,
 801         .flock = gfs2_flock,
 802         .splice_read = generic_file_splice_read,
 803         .splice_write = generic_file_splice_write,
 804 };
 805
 806 const struct file_operations gfs2_dir_fops = {
 807         .readdir = gfs2_readdir,
 808         .unlocked_ioctl = gfs2_ioctl,
 809         .open = gfs2_open,
 810         .release = gfs2_close,
 811         .fsync = gfs2_fsync,
 812         .lock = gfs2_lock,
 813         .flock = gfs2_flock,
 814 };
 815