931 
 932         /*
 933          * See if we have an existing shadow
 934          * If none, we have to manufacture one
 935          */
 936         mutex_enter(&dctable_lock);
 937         dp = dcfind(vp);
 938         mutex_exit(&dctable_lock);
 939         if (dp != NULL)
 940                 return (DCTOV(dp));
 941 
 942         /*
 943          * Make sure it's a valid compressed file
 944          */
 945         hdr = &thdr;
 946         error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, sizeof (struct comphdr), 0,
 947             UIO_SYSSPACE, 0, 0, cred, NULL);
 948         if (error || hdr->ch_magic != CH_MAGIC_ZLIB ||
 949             hdr->ch_version != CH_VERSION || hdr->ch_algorithm != CH_ALG_ZLIB ||
 950             hdr->ch_fsize == 0 || hdr->ch_blksize < PAGESIZE ||
 951             hdr->ch_blksize > ptob(DCCACHESIZE) ||
 952             (hdr->ch_blksize & (hdr->ch_blksize - 1)) != 0)
 953                 return (NULL);
 954 
 955         /* get underlying file size */
 956         if (VOP_GETATTR(vp, &vattr, 0, cred, ctp) != 0)
 957                 return (NULL);
 958 
 959         /*
 960          * Re-read entire header
 961          */
 962         hdrsize = hdr->ch_blkmap[0] + sizeof (uint64_t);
 963         hdr = kmem_alloc(hdrsize, KM_SLEEP);
 964         error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, hdrsize, 0, UIO_SYSSPACE,
 965             0, 0, cred, NULL);
 966         if (error) {
 967                 kmem_free(hdr, hdrsize);
 968                 return (NULL);
 969         }
 970 
 971         /*
 972          * add extra blkmap entry to make dc_getblock()'s

 931 
 932         /*
 933          * See if we have an existing shadow
 934          * If none, we have to manufacture one
 935          */
 936         mutex_enter(&dctable_lock);
 937         dp = dcfind(vp);
 938         mutex_exit(&dctable_lock);
 939         if (dp != NULL)
 940                 return (DCTOV(dp));
 941 
 942         /*
 943          * Make sure it's a valid compressed file
 944          */
 945         hdr = &thdr;
 946         error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, sizeof (struct comphdr), 0,
 947             UIO_SYSSPACE, 0, 0, cred, NULL);
 948         if (error || hdr->ch_magic != CH_MAGIC_ZLIB ||
 949             hdr->ch_version != CH_VERSION || hdr->ch_algorithm != CH_ALG_ZLIB ||
 950             hdr->ch_fsize == 0 || hdr->ch_blksize < PAGESIZE ||
 951             hdr->ch_blksize > ptob(DCCACHESIZE) || !ISP2(hdr->ch_blksize))

 952                 return (NULL);
 953 
 954         /* get underlying file size */
 955         if (VOP_GETATTR(vp, &vattr, 0, cred, ctp) != 0)
 956                 return (NULL);
 957 
 958         /*
 959          * Re-read entire header
 960          */
 961         hdrsize = hdr->ch_blkmap[0] + sizeof (uint64_t);
 962         hdr = kmem_alloc(hdrsize, KM_SLEEP);
 963         error = vn_rdwr(UIO_READ, vp, (caddr_t)hdr, hdrsize, 0, UIO_SYSSPACE,
 964             0, 0, cred, NULL);
 965         if (error) {
 966                 kmem_free(hdr, hdrsize);
 967                 return (NULL);
 968         }
 969 
 970         /*
 971          * add extra blkmap entry to make dc_getblock()'s