From 3e41f597b1595479e4a1b2e6b17b3542120ef165 Mon Sep 17 00:00:00 2001 From: Evgeniy Dushistov Date: Sun, 25 Jun 2006 05:47:23 -0700 Subject: [PATCH] ufs: not usual amounts of fragments per block The writing to UFS file system with block/fragment!=8 may cause bogus behaviour. The problem in "ufs_bitmap_search" function, which doesn't work correctly in "block/fragment!=8" case. The idea is stolen from BSD code. Signed-off-by: Evgeniy Dushistov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ufs/balloc.c | 132 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 87 insertions(+), 45 deletions(-) (limited to 'fs/ufs/balloc.c') diff --git a/fs/ufs/balloc.c b/fs/ufs/balloc.c index 68de1312e4b..343eaf4542f 100644 --- a/fs/ufs/balloc.c +++ b/fs/ufs/balloc.c @@ -726,18 +726,63 @@ gotit: return result; } -static unsigned ufs_bitmap_search (struct super_block * sb, - struct ufs_cg_private_info * ucpi, unsigned goal, unsigned count) +static unsigned ubh_scanc(struct ufs_sb_private_info *uspi, + struct ufs_buffer_head *ubh, + unsigned begin, unsigned size, + unsigned char *table, unsigned char mask) { - struct ufs_sb_private_info * uspi; - struct ufs_super_block_first * usb1; - struct ufs_cylinder_group * ucg; - unsigned start, length, location, result; - unsigned possition, fragsize, blockmap, mask; - - UFSD(("ENTER, cg %u, goal %u, count %u\n", ucpi->c_cgx, goal, count)) + unsigned rest, offset; + unsigned char *cp; + + + offset = begin & ~uspi->s_fmask; + begin >>= uspi->s_fshift; + for (;;) { + if ((offset + size) < uspi->s_fsize) + rest = size; + else + rest = uspi->s_fsize - offset; + size -= rest; + cp = ubh->bh[begin]->b_data + offset; + while ((table[*cp++] & mask) == 0 && --rest) + ; + if (rest || !size) + break; + begin++; + offset = 0; + } + return (size + rest); +} + +/* + * Find a block of the specified size in the specified cylinder group. + * @sp: pointer to super block + * @ucpi: pointer to cylinder group info + * @goal: near which block we want find new one + * @count: specified size + */ +static unsigned ufs_bitmap_search(struct super_block *sb, + struct ufs_cg_private_info *ucpi, + unsigned goal, unsigned count) +{ + /* + * Bit patterns for identifying fragments in the block map + * used as ((map & mask_arr) == want_arr) + */ + static const int mask_arr[9] = { + 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff, 0x1ff, 0x3ff + }; + static const int want_arr[9] = { + 0x0, 0x2, 0x6, 0xe, 0x1e, 0x3e, 0x7e, 0xfe, 0x1fe + }; + struct ufs_sb_private_info *uspi = UFS_SB(sb)->s_uspi; + struct ufs_super_block_first *usb1; + struct ufs_cylinder_group *ucg; + unsigned start, length, loc, result; + unsigned pos, want, blockmap, mask, end; + + UFSD(("ENTER, cg %u, goal %u, count %u\n", ucpi->c_cgx, goal, count)); - uspi = UFS_SB(sb)->s_uspi; usb1 = ubh_get_usb_first (uspi); ucg = ubh_get_ucg(UCPI_UBH(ucpi)); @@ -747,53 +792,50 @@ static unsigned ufs_bitmap_search (struct super_block * sb, start = ucpi->c_frotor >> 3; length = ((uspi->s_fpg + 7) >> 3) - start; - location = ubh_scanc(UCPI_UBH(ucpi), ucpi->c_freeoff + start, length, + loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff + start, length, (uspi->s_fpb == 8) ? ufs_fragtable_8fpb : ufs_fragtable_other, 1 << (count - 1 + (uspi->s_fpb & 7))); - if (location == 0) { + if (loc == 0) { length = start + 1; - location = ubh_scanc(UCPI_UBH(ucpi), ucpi->c_freeoff, length, - (uspi->s_fpb == 8) ? ufs_fragtable_8fpb : ufs_fragtable_other, - 1 << (count - 1 + (uspi->s_fpb & 7))); - if (location == 0) { - ufs_error (sb, "ufs_bitmap_search", - "bitmap corrupted on cg %u, start %u, length %u, count %u, freeoff %u\n", - ucpi->c_cgx, start, length, count, ucpi->c_freeoff); + loc = ubh_scanc(uspi, UCPI_UBH(ucpi), ucpi->c_freeoff, length, + (uspi->s_fpb == 8) ? ufs_fragtable_8fpb : + ufs_fragtable_other, + 1 << (count - 1 + (uspi->s_fpb & 7))); + if (loc == 0) { + ufs_error(sb, "ufs_bitmap_search", + "bitmap corrupted on cg %u, start %u," + " length %u, count %u, freeoff %u\n", + ucpi->c_cgx, start, length, count, + ucpi->c_freeoff); return (unsigned)-1; } start = 0; } - result = (start + length - location) << 3; + result = (start + length - loc) << 3; ucpi->c_frotor = result; /* * found the byte in the map */ - blockmap = ubh_blkmap(UCPI_UBH(ucpi), ucpi->c_freeoff, result); - fragsize = 0; - for (possition = 0, mask = 1; possition < 8; possition++, mask <<= 1) { - if (blockmap & mask) { - if (!(possition & uspi->s_fpbmask)) - fragsize = 1; - else - fragsize++; - } - else { - if (fragsize == count) { - result += possition - count; - UFSD(("EXIT, result %u\n", result)) - return result; - } - fragsize = 0; - } - } - if (fragsize == count) { - result += possition - count; - UFSD(("EXIT, result %u\n", result)) - return result; - } - ufs_error (sb, "ufs_bitmap_search", "block not in map on cg %u\n", ucpi->c_cgx); - UFSD(("EXIT (FAILED)\n")) + + for (end = result + 8; result < end; result += uspi->s_fpb) { + blockmap = ubh_blkmap(UCPI_UBH(ucpi), ucpi->c_freeoff, result); + blockmap <<= 1; + mask = mask_arr[count]; + want = want_arr[count]; + for (pos = 0; pos <= uspi->s_fpb - count; pos++) { + if ((blockmap & mask) == want) { + UFSD(("EXIT, result %u\n", result)); + return result + pos; + } + mask <<= 1; + want <<= 1; + } + } + + ufs_error(sb, "ufs_bitmap_search", "block not in map on cg %u\n", + ucpi->c_cgx); + UFSD(("EXIT (FAILED)\n")); return (unsigned)-1; } -- cgit v1.2.3