fs/jfs/jfs_extent.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Copyright (C) International Business Machines Corp., 2000-2004
   4  */
   5
   6 #include <linux/fs.h>
   7 #include <linux/quotaops.h>
   8 #include "jfs_incore.h"
   9 #include "jfs_inode.h"
  10 #include "jfs_superblock.h"
  11 #include "jfs_dmap.h"
  12 #include "jfs_extent.h"
  13 #include "jfs_debug.h"
  14
  15 /*
  16  * forward references
  17  */
  18 static int extBalloc(struct inode *, s64, s64 *, s64 *);
  19 static s64 extRoundDown(s64 nb);
  20
  21 #define DPD(a)          (printk("(a): %d\n",(a)))
  22 #define DPC(a)          (printk("(a): %c\n",(a)))
  23 #define DPL1(a)                                 \
  24 {                                               \
  25         if ((a) >> 32)                          \
  26                 printk("(a): %x%08x  ",(a));    \
  27         else                                    \
  28                 printk("(a): %x  ",(a) << 32);  \
  29 }
  30 #define DPL(a)                                  \
  31 {                                               \
  32         if ((a) >> 32)                          \
  33                 printk("(a): %x%08x\n",(a));    \
  34         else                                    \
  35                 printk("(a): %x\n",(a) << 32);  \
  36 }
  37
  38 #define DPD1(a)         (printk("(a): %d  ",(a)))
  39 #define DPX(a)          (printk("(a): %08x\n",(a)))
  40 #define DPX1(a)         (printk("(a): %08x  ",(a)))
  41 #define DPS(a)          (printk("%s\n",(a)))
  42 #define DPE(a)          (printk("\nENTERING: %s\n",(a)))
  43 #define DPE1(a)         (printk("\nENTERING: %s",(a)))
  44 #define DPS1(a)         (printk("  %s  ",(a)))
  45
  46
  47 /*
  48  * NAME:        extAlloc()
  49  *
  50  * FUNCTION:    allocate an extent for a specified page range within a
  51  *              file.
  52  *
  53  * PARAMETERS:
  54  *      ip      - the inode of the file.
  55  *      xlen    - requested extent length.
  56  *      pno     - the starting page number with the file.
  57  *      xp      - pointer to an xad.  on entry, xad describes an
  58  *                extent that is used as an allocation hint if the
  59  *                xaddr of the xad is non-zero.  on successful exit,
  60  *                the xad describes the newly allocated extent.
  61  *      abnr    - bool indicating whether the newly allocated extent
  62  *                should be marked as allocated but not recorded.
  63  *
  64  * RETURN VALUES:
  65  *      0       - success
  66  *      -EIO    - i/o error.
  67  *      -ENOSPC - insufficient disk resources.
  68  */
  69 int
  70 extAlloc(struct inode *ip, s64 xlen, s64 pno, xad_t * xp, bool abnr)
  71 {
  72         struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
  73         s64 nxlen, nxaddr, xoff, hint, xaddr = 0;
  74         int rc;
  75         int xflag;
  76
  77         /* This blocks if we are low on resources */
  78         txBeginAnon(ip->i_sb);
  79
  80         /* Avoid race with jfs_commit_inode() */
  81         mutex_lock(&JFS_IP(ip)->commit_mutex);
  82
  83         /* validate extent length */
  84         if (xlen > MAXXLEN)
  85                 xlen = MAXXLEN;
  86
  87         /* get the page's starting extent offset */
  88         xoff = pno << sbi->l2nbperpage;
  89
  90         /* check if an allocation hint was provided */
  91         if ((hint = addressXAD(xp))) {
  92                 /* get the size of the extent described by the hint */
  93                 nxlen = lengthXAD(xp);
  94
  95                 /* check if the hint is for the portion of the file
  96                  * immediately previous to the current allocation
  97                  * request and if hint extent has the same abnr
  98                  * value as the current request.  if so, we can
  99                  * extend the hint extent to include the current
 100                  * extent if we can allocate the blocks immediately
 101                  * following the hint extent.
 102                  */
 103                 if (offsetXAD(xp) + nxlen == xoff &&
 104                     abnr == ((xp->flag & XAD_NOTRECORDED) ? true : false))
 105                         xaddr = hint + nxlen;
 106
 107                 /* adjust the hint to the last block of the extent */
 108                 hint += (nxlen - 1);
 109         }
 110
 111         /* allocate the disk blocks for the extent.  initially, extBalloc()
 112          * will try to allocate disk blocks for the requested size (xlen).
 113          * if this fails (xlen contiguous free blocks not available), it'll
 114          * try to allocate a smaller number of blocks (producing a smaller
 115          * extent), with this smaller number of blocks consisting of the
 116          * requested number of blocks rounded down to the next smaller
 117          * power of 2 number (i.e. 16 -> 8).  it'll continue to round down
 118          * and retry the allocation until the number of blocks to allocate
 119          * is smaller than the number of blocks per page.
 120          */
 121         nxlen = xlen;
 122         if ((rc = extBalloc(ip, hint ? hint : INOHINT(ip), &nxlen, &nxaddr))) {
 123                 mutex_unlock(&JFS_IP(ip)->commit_mutex);
 124                 return (rc);
 125         }
 126
 127         /* Allocate blocks to quota. */
 128         rc = dquot_alloc_block(ip, nxlen);
 129         if (rc) {
 130                 dbFree(ip, nxaddr, (s64) nxlen);
 131                 mutex_unlock(&JFS_IP(ip)->commit_mutex);
 132                 return rc;
 133         }
 134
 135         /* determine the value of the extent flag */
 136         xflag = abnr ? XAD_NOTRECORDED : 0;
 137
 138         /* if we can extend the hint extent to cover the current request,
 139          * extend it.  otherwise, insert a new extent to
 140          * cover the current request.
 141          */
 142         if (xaddr && xaddr == nxaddr)
 143                 rc = xtExtend(0, ip, xoff, (int) nxlen, 0);
 144         else
 145                 rc = xtInsert(0, ip, xflag, xoff, (int) nxlen, &nxaddr, 0);
 146
 147         /* if the extend or insert failed,
 148          * free the newly allocated blocks and return the error.
 149          */
 150         if (rc) {
 151                 dbFree(ip, nxaddr, nxlen);
 152                 dquot_free_block(ip, nxlen);
 153                 mutex_unlock(&JFS_IP(ip)->commit_mutex);
 154                 return (rc);
 155         }
 156
 157         /* set the results of the extent allocation */
 158         XADaddress(xp, nxaddr);
 159         XADlength(xp, nxlen);
 160         XADoffset(xp, xoff);
 161         xp->flag = xflag;
 162
 163         mark_inode_dirty(ip);
 164
 165         mutex_unlock(&JFS_IP(ip)->commit_mutex);
 166         /*
 167          * COMMIT_SyncList flags an anonymous tlock on page that is on
 168          * sync list.
 169          * We need to commit the inode to get the page written to the disk.
 170          */
 171         if (test_and_clear_cflag(COMMIT_Synclist,ip))
 172                 jfs_commit_inode(ip, 0);
 173
 174         return (0);
 175 }
 176
 177 /*
 178  * NAME:        extHint()
 179  *
 180  * FUNCTION:    produce an extent allocation hint for a file offset.
 181  *
 182  * PARAMETERS:
 183  *      ip      - the inode of the file.
 184  *      offset  - file offset for which the hint is needed.
 185  *      xp      - pointer to the xad that is to be filled in with
 186  *                the hint.
 187  *
 188  * RETURN VALUES:
 189  *      0       - success
 190  *      -EIO    - i/o error.
 191  */
 192 int extHint(struct inode *ip, s64 offset, xad_t * xp)
 193 {
 194         struct super_block *sb = ip->i_sb;
 195         int nbperpage = JFS_SBI(sb)->nbperpage;
 196         s64 prev;
 197         int rc = 0;
 198         s64 xaddr;
 199         int xlen;
 200         int xflag;
 201
 202         /* init the hint as "no hint provided" */
 203         XADaddress(xp, 0);
 204
 205         /* determine the starting extent offset of the page previous
 206          * to the page containing the offset.
 207          */
 208         prev = ((offset & ~POFFSET) >> JFS_SBI(sb)->l2bsize) - nbperpage;
 209
 210         /* if the offset is in the first page of the file, no hint provided.
 211          */
 212         if (prev < 0)
 213                 goto out;
 214
 215         rc = xtLookup(ip, prev, nbperpage, &xflag, &xaddr, &xlen, 0);
 216
 217         if ((rc == 0) && xlen) {
 218                 if (xlen != nbperpage) {
 219                         jfs_error(ip->i_sb, "corrupt xtree\n");
 220                         rc = -EIO;
 221                 }
 222                 XADaddress(xp, xaddr);
 223                 XADlength(xp, xlen);
 224                 XADoffset(xp, prev);
 225                 /*
 226                  * only preserve the abnr flag within the xad flags
 227                  * of the returned hint.
 228                  */
 229                 xp->flag  = xflag & XAD_NOTRECORDED;
 230         } else
 231                 rc = 0;
 232
 233 out:
 234         return (rc);
 235 }
 236
 237
 238 /*
 239  * NAME:        extRecord()
 240  *
 241  * FUNCTION:    change a page with a file from not recorded to recorded.
 242  *
 243  * PARAMETERS:
 244  *      ip      - inode of the file.
 245  *      cp      - cbuf of the file page.
 246  *
 247  * RETURN VALUES:
 248  *      0       - success
 249  *      -EIO    - i/o error.
 250  *      -ENOSPC - insufficient disk resources.
 251  */
 252 int extRecord(struct inode *ip, xad_t * xp)
 253 {
 254         int rc;
 255
 256         txBeginAnon(ip->i_sb);
 257
 258         mutex_lock(&JFS_IP(ip)->commit_mutex);
 259
 260         /* update the extent */
 261         rc = xtUpdate(0, ip, xp);
 262
 263         mutex_unlock(&JFS_IP(ip)->commit_mutex);
 264         return rc;
 265 }
 266
 267 /*
 268  * NAME:        extBalloc()
 269  *
 270  * FUNCTION:    allocate disk blocks to form an extent.
 271  *
 272  *              initially, we will try to allocate disk blocks for the
 273  *              requested size (nblocks).  if this fails (nblocks
 274  *              contiguous free blocks not available), we'll try to allocate
 275  *              a smaller number of blocks (producing a smaller extent), with
 276  *              this smaller number of blocks consisting of the requested
 277  *              number of blocks rounded down to the next smaller power of 2
 278  *              number (i.e. 16 -> 8).  we'll continue to round down and
 279  *              retry the allocation until the number of blocks to allocate
 280  *              is smaller than the number of blocks per page.
 281  *
 282  * PARAMETERS:
 283  *      ip       - the inode of the file.
 284  *      hint     - disk block number to be used as an allocation hint.
 285  *      *nblocks - pointer to an s64 value.  on entry, this value specifies
 286  *                 the desired number of block to be allocated. on successful
 287  *                 exit, this value is set to the number of blocks actually
 288  *                 allocated.
 289  *      blkno    - pointer to a block address that is filled in on successful
 290  *                 return with the starting block number of the newly
 291  *                 allocated block range.
 292  *
 293  * RETURN VALUES:
 294  *      0       - success
 295  *      -EIO    - i/o error.
 296  *      -ENOSPC - insufficient disk resources.
 297  */
 298 static int
 299 extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
 300 {
 301         struct jfs_inode_info *ji = JFS_IP(ip);
 302         struct jfs_sb_info *sbi = JFS_SBI(ip->i_sb);
 303         s64 nb, nblks, daddr, max;
 304         int rc, nbperpage = sbi->nbperpage;
 305         struct bmap *bmp = sbi->bmap;
 306         int ag;
 307
 308         /* get the number of blocks to initially attempt to allocate.
 309          * we'll first try the number of blocks requested unless this
 310          * number is greater than the maximum number of contiguous free
 311          * blocks in the map. in that case, we'll start off with the
 312          * maximum free.
 313          */
 314
 315         /* give up if no space left */
 316         if (bmp->db_maxfreebud == -1)
 317                 return -ENOSPC;
 318
 319         max = (s64) 1 << bmp->db_maxfreebud;
 320         if (*nblocks >= max && *nblocks > nbperpage)
 321                 nb = nblks = (max > nbperpage) ? max : nbperpage;
 322         else
 323                 nb = nblks = *nblocks;
 324
 325         /* try to allocate blocks */
 326         while ((rc = dbAlloc(ip, hint, nb, &daddr)) != 0) {
 327                 /* if something other than an out of space error,
 328                  * stop and return this error.
 329                  */
 330                 if (rc != -ENOSPC)
 331                         return (rc);
 332
 333                 /* decrease the allocation request size */
 334                 nb = min(nblks, extRoundDown(nb));
 335
 336                 /* give up if we cannot cover a page */
 337                 if (nb < nbperpage)
 338                         return (rc);
 339         }
 340
 341         *nblocks = nb;
 342         *blkno = daddr;
 343
 344         if (S_ISREG(ip->i_mode) && (ji->fileset == FILESYSTEM_I)) {
 345                 ag = BLKTOAG(daddr, sbi);
 346                 spin_lock_irq(&ji->ag_lock);
 347                 if (ji->active_ag == -1) {
 348                         atomic_inc(&bmp->db_active[ag]);
 349                         ji->active_ag = ag;
 350                 } else if (ji->active_ag != ag) {
 351                         atomic_dec(&bmp->db_active[ji->active_ag]);
 352                         atomic_inc(&bmp->db_active[ag]);
 353                         ji->active_ag = ag;
 354                 }
 355                 spin_unlock_irq(&ji->ag_lock);
 356         }
 357
 358         return (0);
 359 }
 360
 361 /*
 362  * NAME:        extRoundDown()
 363  *
 364  * FUNCTION:    round down a specified number of blocks to the next
 365  *              smallest power of 2 number.
 366  *
 367  * PARAMETERS:
 368  *      nb      - the inode of the file.
 369  *
 370  * RETURN VALUES:
 371  *      next smallest power of 2 number.
 372  */
 373 static s64 extRoundDown(s64 nb)
 374 {
 375         int i;
 376         u64 m, k;
 377
 378         for (i = 0, m = (u64) 1 << 63; i < 64; i++, m >>= 1) {
 379                 if (m & nb)
 380                         break;
 381         }
 382
 383         i = 63 - i;
 384         k = (u64) 1 << i;
 385         k = ((k - 1) & nb) ? k : k >> 1;
 386
 387         return (k);
 388 }