/* * linux/fs/ufs/cylinder.c * * Copyright (C) 1998 * Daniel Pirkl <daniel.pirkl@email.cz> * Charles University, Faculty of Mathematics and Physics * * ext2 - inode (block) bitmap caching inspired */ #include <linux/fs.h> #include <linux/ufs_fs.h> #include <linux/time.h> #include <linux/stat.h> #include <linux/string.h> #include <linux/bitops.h> #include <asm/byteorder.h> #include "ufs.h" #include "swab.h" #include "util.h" /* * Read cylinder group into cache. The memory space for ufs_cg_private_info * structure is already allocated during ufs_read_super. */ static void ufs_read_cylinder (struct super_block * sb, unsigned cgno, unsigned bitmap_nr) { struct ufs_sb_info * sbi = UFS_SB(sb); struct ufs_sb_private_info * uspi; struct ufs_cg_private_info * ucpi; struct ufs_cylinder_group * ucg; unsigned i, j; UFSD("ENTER, cgno %u, bitmap_nr %u\n", cgno, bitmap_nr); uspi = sbi->s_uspi; ucpi = sbi->s_ucpi[bitmap_nr]; ucg = (struct ufs_cylinder_group *)sbi->s_ucg[cgno]->b_data; UCPI_UBH(ucpi)->fragment = ufs_cgcmin(cgno); UCPI_UBH(ucpi)->count = uspi->s_cgsize >> sb->s_blocksize_bits; /* * We have already the first fragment of cylinder group block in buffer */ UCPI_UBH(ucpi)->bh[0] = sbi->s_ucg[cgno]; for (i = 1; i < UCPI_UBH(ucpi)->count; i++) if (!(UCPI_UBH(ucpi)->bh[i] = sb_bread(sb, UCPI_UBH(ucpi)->fragment + i))) goto failed; sbi->s_cgno[bitmap_nr] = cgno; ucpi->c_cgx = fs32_to_cpu(sb, ucg->cg_cgx); ucpi->c_ncyl = fs16_to_cpu(sb, ucg->cg_ncyl); ucpi->c_niblk = fs16_to_cpu(sb, ucg->cg_niblk); ucpi->c_ndblk = fs32_to_cpu(sb, ucg->cg_ndblk); ucpi->c_rotor = fs32_to_cpu(sb, ucg->cg_rotor); ucpi->c_frotor = fs32_to_cpu(sb, ucg->cg_frotor); ucpi->c_irotor = fs32_to_cpu(sb, ucg->cg_irotor); ucpi->c_btotoff = fs32_to_cpu(sb, ucg->cg_btotoff); ucpi->c_boff = fs32_to_cpu(sb, ucg->cg_boff); ucpi->c_iusedoff = fs32_to_cpu(sb, ucg->cg_iusedoff); ucpi->c_freeoff = fs32_to_cpu(sb, ucg->cg_freeoff); ucpi->c_nextfreeoff = fs32_to_cpu(sb, ucg->cg_nextfreeoff); ucpi->c_clustersumoff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clustersumoff); ucpi->c_clusteroff = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_clusteroff); ucpi->c_nclusterblks = fs32_to_cpu(sb, ucg->cg_u.cg_44.cg_nclusterblks); UFSD("EXIT\n"); return; failed: for (j = 1; j < i; j++) brelse (sbi->s_ucg[j]); sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY; ufs_error (sb, "ufs_read_cylinder", "can't read cylinder group block %u", cgno); } /* * Remove cylinder group from cache, doesn't release memory * allocated for cylinder group (this is done at ufs_put_super only). */ void ufs_put_cylinder (struct super_block * sb, unsigned bitmap_nr) { struct ufs_sb_info * sbi = UFS_SB(sb); struct ufs_sb_private_info * uspi; struct ufs_cg_private_info * ucpi; struct ufs_cylinder_group * ucg; unsigned i; UFSD("ENTER, bitmap_nr %u\n", bitmap_nr); uspi = sbi->s_uspi; if (sbi->s_cgno[bitmap_nr] == UFS_CGNO_EMPTY) { UFSD("EXIT\n"); return; } ucpi = sbi->s_ucpi[bitmap_nr]; ucg = ubh_get_ucg(UCPI_UBH(ucpi)); if (uspi->s_ncg > UFS_MAX_GROUP_LOADED && bitmap_nr >= sbi->s_cg_loaded) { ufs_panic (sb, "ufs_put_cylinder", "internal error"); return; } /* * rotor is not so important data, so we put it to disk * at the end of working with cylinder */ ucg->cg_rotor = cpu_to_fs32(sb, ucpi->c_rotor); ucg->cg_frotor = cpu_to_fs32(sb, ucpi->c_frotor); ucg->cg_irotor = cpu_to_fs32(sb, ucpi->c_irotor); ubh_mark_buffer_dirty (UCPI_UBH(ucpi)); for (i = 1; i < UCPI_UBH(ucpi)->count; i++) { brelse (UCPI_UBH(ucpi)->bh[i]); } sbi->s_cgno[bitmap_nr] = UFS_CGNO_EMPTY; UFSD("EXIT\n"); } /* * Find cylinder group in cache and return it as pointer. * If cylinder group is not in cache, we will load it from disk. * * The cache is managed by LRU algorithm. */ struct ufs_cg_private_info * ufs_load_cylinder ( struct super_block * sb, unsigned cgno) { struct ufs_sb_info * sbi = UFS_SB(sb); struct ufs_sb_private_info * uspi; struct ufs_cg_private_info * ucpi; unsigned cg, i, j; UFSD("ENTER, cgno %u\n", cgno); uspi = sbi->s_uspi; if (cgno >= uspi->s_ncg) { ufs_panic (sb, "ufs_load_cylinder", "internal error, high number of cg"); return NULL; } /* * Cylinder group number cg it in cache and it was last used */ if (sbi->s_cgno[0] == cgno) { UFSD("EXIT\n"); return sbi->s_ucpi[0]; } /* * Number of cylinder groups is not higher than UFS_MAX_GROUP_LOADED */ if (uspi->s_ncg <= UFS_MAX_GROUP_LOADED) { if (sbi->s_cgno[cgno] != UFS_CGNO_EMPTY) { if (sbi->s_cgno[cgno] != cgno) { ufs_panic (sb, "ufs_load_cylinder", "internal error, wrong number of cg in cache"); UFSD("EXIT (FAILED)\n"); return NULL; } else { UFSD("EXIT\n"); return sbi->s_ucpi[cgno]; } } else { ufs_read_cylinder (sb, cgno, cgno); UFSD("EXIT\n"); return sbi->s_ucpi[cgno]; } } /* * Cylinder group number cg is in cache but it was not last used, * we will move to the first position */ for (i = 0; i < sbi->s_cg_loaded && sbi->s_cgno[i] != cgno; i++); if (i < sbi->s_cg_loaded && sbi->s_cgno[i] == cgno) { cg = sbi->s_cgno[i]; ucpi = sbi->s_ucpi[i]; for (j = i; j > 0; j--) { sbi->s_cgno[j] = sbi->s_cgno[j-1]; sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; } sbi->s_cgno[0] = cg; sbi->s_ucpi[0] = ucpi; /* * Cylinder group number cg is not in cache, we will read it from disk * and put it to the first position */ } else { if (sbi->s_cg_loaded < UFS_MAX_GROUP_LOADED) sbi->s_cg_loaded++; else ufs_put_cylinder (sb, UFS_MAX_GROUP_LOADED-1); ucpi = sbi->s_ucpi[sbi->s_cg_loaded - 1]; for (j = sbi->s_cg_loaded - 1; j > 0; j--) { sbi->s_cgno[j] = sbi->s_cgno[j-1]; sbi->s_ucpi[j] = sbi->s_ucpi[j-1]; } sbi->s_ucpi[0] = ucpi; ufs_read_cylinder (sb, cgno, 0); } UFSD("EXIT\n"); return sbi->s_ucpi[0]; }