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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/hfs/extent.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/hfs/extent.c')
-rw-r--r-- | fs/hfs/extent.c | 527 |
1 files changed, 527 insertions, 0 deletions
diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c new file mode 100644 index 0000000..cbc8510 --- /dev/null +++ b/fs/hfs/extent.c @@ -0,0 +1,527 @@ +/* + * linux/fs/hfs/extent.c + * + * Copyright (C) 1995-1997 Paul H. Hargrove + * (C) 2003 Ardis Technologies <roman@ardistech.com> + * This file may be distributed under the terms of the GNU General Public License. + * + * This file contains the functions related to the extents B-tree. + */ + +#include <linux/pagemap.h> + +#include "hfs_fs.h" +#include "btree.h" + +/*================ File-local functions ================*/ + +/* + * build_key + */ +static void hfs_ext_build_key(hfs_btree_key *key, u32 cnid, u16 block, u8 type) +{ + key->key_len = 7; + key->ext.FkType = type; + key->ext.FNum = cpu_to_be32(cnid); + key->ext.FABN = cpu_to_be16(block); +} + +/* + * hfs_ext_compare() + * + * Description: + * This is the comparison function used for the extents B-tree. In + * comparing extent B-tree entries, the file id is the most + * significant field (compared as unsigned ints); the fork type is + * the second most significant field (compared as unsigned chars); + * and the allocation block number field is the least significant + * (compared as unsigned ints). + * Input Variable(s): + * struct hfs_ext_key *key1: pointer to the first key to compare + * struct hfs_ext_key *key2: pointer to the second key to compare + * Output Variable(s): + * NONE + * Returns: + * int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2 + * Preconditions: + * key1 and key2 point to "valid" (struct hfs_ext_key)s. + * Postconditions: + * This function has no side-effects */ +int hfs_ext_keycmp(const btree_key *key1, const btree_key *key2) +{ + __be32 fnum1, fnum2; + __be16 block1, block2; + + fnum1 = key1->ext.FNum; + fnum2 = key2->ext.FNum; + if (fnum1 != fnum2) + return be32_to_cpu(fnum1) < be32_to_cpu(fnum2) ? -1 : 1; + if (key1->ext.FkType != key2->ext.FkType) + return key1->ext.FkType < key2->ext.FkType ? -1 : 1; + + block1 = key1->ext.FABN; + block2 = key2->ext.FABN; + if (block1 == block2) + return 0; + return be16_to_cpu(block1) < be16_to_cpu(block2) ? -1 : 1; +} + +/* + * hfs_ext_find_block + * + * Find a block within an extent record + */ +static u16 hfs_ext_find_block(struct hfs_extent *ext, u16 off) +{ + int i; + u16 count; + + for (i = 0; i < 3; ext++, i++) { + count = be16_to_cpu(ext->count); + if (off < count) + return be16_to_cpu(ext->block) + off; + off -= count; + } + /* panic? */ + return 0; +} + +static int hfs_ext_block_count(struct hfs_extent *ext) +{ + int i; + u16 count = 0; + + for (i = 0; i < 3; ext++, i++) + count += be16_to_cpu(ext->count); + return count; +} + +static u16 hfs_ext_lastblock(struct hfs_extent *ext) +{ + int i; + + ext += 2; + for (i = 0; i < 2; ext--, i++) + if (ext->count) + break; + return be16_to_cpu(ext->block) + be16_to_cpu(ext->count); +} + +static void __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd) +{ + int res; + + hfs_ext_build_key(fd->search_key, inode->i_ino, HFS_I(inode)->cached_start, + HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA); + res = hfs_brec_find(fd); + if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) { + if (res != -ENOENT) + return; + hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec)); + HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW); + } else { + if (res) + return; + hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength); + HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY; + } +} + +void hfs_ext_write_extent(struct inode *inode) +{ + struct hfs_find_data fd; + + if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) { + hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd); + __hfs_ext_write_extent(inode, &fd); + hfs_find_exit(&fd); + } +} + +static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent, + u32 cnid, u32 block, u8 type) +{ + int res; + + hfs_ext_build_key(fd->search_key, cnid, block, type); + fd->key->ext.FNum = 0; + res = hfs_brec_find(fd); + if (res && res != -ENOENT) + return res; + if (fd->key->ext.FNum != fd->search_key->ext.FNum || + fd->key->ext.FkType != fd->search_key->ext.FkType) + return -ENOENT; + if (fd->entrylength != sizeof(hfs_extent_rec)) + return -EIO; + hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfs_extent_rec)); + return 0; +} + +static inline int __hfs_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block) +{ + int res; + + if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) + __hfs_ext_write_extent(inode, fd); + + res = __hfs_ext_read_extent(fd, HFS_I(inode)->cached_extents, inode->i_ino, + block, HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA); + if (!res) { + HFS_I(inode)->cached_start = be16_to_cpu(fd->key->ext.FABN); + HFS_I(inode)->cached_blocks = hfs_ext_block_count(HFS_I(inode)->cached_extents); + } else { + HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0; + HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW); + } + return res; +} + +static int hfs_ext_read_extent(struct inode *inode, u16 block) +{ + struct hfs_find_data fd; + int res; + + if (block >= HFS_I(inode)->cached_start && + block < HFS_I(inode)->cached_start + HFS_I(inode)->cached_blocks) + return 0; + + hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd); + res = __hfs_ext_cache_extent(&fd, inode, block); + hfs_find_exit(&fd); + return res; +} + +static void hfs_dump_extent(struct hfs_extent *extent) +{ + int i; + + dprint(DBG_EXTENT, " "); + for (i = 0; i < 3; i++) + dprint(DBG_EXTENT, " %u:%u", be16_to_cpu(extent[i].block), + be16_to_cpu(extent[i].count)); + dprint(DBG_EXTENT, "\n"); +} + +static int hfs_add_extent(struct hfs_extent *extent, u16 offset, + u16 alloc_block, u16 block_count) +{ + u16 count, start; + int i; + + hfs_dump_extent(extent); + for (i = 0; i < 3; extent++, i++) { + count = be16_to_cpu(extent->count); + if (offset == count) { + start = be16_to_cpu(extent->block); + if (alloc_block != start + count) { + if (++i >= 3) + return -ENOSPC; + extent++; + extent->block = cpu_to_be16(alloc_block); + } else + block_count += count; + extent->count = cpu_to_be16(block_count); + return 0; + } else if (offset < count) + break; + offset -= count; + } + /* panic? */ + return -EIO; +} + +static int hfs_free_extents(struct super_block *sb, struct hfs_extent *extent, + u16 offset, u16 block_nr) +{ + u16 count, start; + int i; + + hfs_dump_extent(extent); + for (i = 0; i < 3; extent++, i++) { + count = be16_to_cpu(extent->count); + if (offset == count) + goto found; + else if (offset < count) + break; + offset -= count; + } + /* panic? */ + return -EIO; +found: + for (;;) { + start = be16_to_cpu(extent->block); + if (count <= block_nr) { + hfs_clear_vbm_bits(sb, start, count); + extent->block = 0; + extent->count = 0; + block_nr -= count; + } else { + count -= block_nr; + hfs_clear_vbm_bits(sb, start + count, block_nr); + extent->count = cpu_to_be16(count); + block_nr = 0; + } + if (!block_nr || !i) + return 0; + i--; + extent--; + count = be16_to_cpu(extent->count); + } +} + +int hfs_free_fork(struct super_block *sb, struct hfs_cat_file *file, int type) +{ + struct hfs_find_data fd; + u32 total_blocks, blocks, start; + u32 cnid = be32_to_cpu(file->FlNum); + struct hfs_extent *extent; + int res, i; + + if (type == HFS_FK_DATA) { + total_blocks = be32_to_cpu(file->PyLen); + extent = file->ExtRec; + } else { + total_blocks = be32_to_cpu(file->RPyLen); + extent = file->RExtRec; + } + total_blocks /= HFS_SB(sb)->alloc_blksz; + if (!total_blocks) + return 0; + + blocks = 0; + for (i = 0; i < 3; extent++, i++) + blocks += be16_to_cpu(extent[i].count); + + res = hfs_free_extents(sb, extent, blocks, blocks); + if (res) + return res; + if (total_blocks == blocks) + return 0; + + hfs_find_init(HFS_SB(sb)->ext_tree, &fd); + do { + res = __hfs_ext_read_extent(&fd, extent, cnid, total_blocks, type); + if (res) + break; + start = be16_to_cpu(fd.key->ext.FABN); + hfs_free_extents(sb, extent, total_blocks - start, total_blocks); + hfs_brec_remove(&fd); + total_blocks = start; + } while (total_blocks > blocks); + hfs_find_exit(&fd); + + return res; +} + +/* + * hfs_get_block + */ +int hfs_get_block(struct inode *inode, sector_t block, + struct buffer_head *bh_result, int create) +{ + struct super_block *sb; + u16 dblock, ablock; + int res; + + sb = inode->i_sb; + /* Convert inode block to disk allocation block */ + ablock = (u32)block / HFS_SB(sb)->fs_div; + + if (block >= HFS_I(inode)->fs_blocks) { + if (block > HFS_I(inode)->fs_blocks || !create) + return -EIO; + if (ablock >= HFS_I(inode)->alloc_blocks) { + res = hfs_extend_file(inode); + if (res) + return res; + } + } else + create = 0; + + if (ablock < HFS_I(inode)->first_blocks) { + dblock = hfs_ext_find_block(HFS_I(inode)->first_extents, ablock); + goto done; + } + + down(&HFS_I(inode)->extents_lock); + res = hfs_ext_read_extent(inode, ablock); + if (!res) + dblock = hfs_ext_find_block(HFS_I(inode)->cached_extents, + ablock - HFS_I(inode)->cached_start); + else { + up(&HFS_I(inode)->extents_lock); + return -EIO; + } + up(&HFS_I(inode)->extents_lock); + +done: + map_bh(bh_result, sb, HFS_SB(sb)->fs_start + + dblock * HFS_SB(sb)->fs_div + + (u32)block % HFS_SB(sb)->fs_div); + + if (create) { + set_buffer_new(bh_result); + HFS_I(inode)->phys_size += sb->s_blocksize; + HFS_I(inode)->fs_blocks++; + inode_add_bytes(inode, sb->s_blocksize); + mark_inode_dirty(inode); + } + return 0; +} + +int hfs_extend_file(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + u32 start, len, goal; + int res; + + down(&HFS_I(inode)->extents_lock); + if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) + goal = hfs_ext_lastblock(HFS_I(inode)->first_extents); + else { + res = hfs_ext_read_extent(inode, HFS_I(inode)->alloc_blocks); + if (res) + goto out; + goal = hfs_ext_lastblock(HFS_I(inode)->cached_extents); + } + + len = HFS_I(inode)->clump_blocks; + start = hfs_vbm_search_free(sb, goal, &len); + if (!len) { + res = -ENOSPC; + goto out; + } + + dprint(DBG_EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len); + if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) { + if (!HFS_I(inode)->first_blocks) { + dprint(DBG_EXTENT, "first extents\n"); + /* no extents yet */ + HFS_I(inode)->first_extents[0].block = cpu_to_be16(start); + HFS_I(inode)->first_extents[0].count = cpu_to_be16(len); + res = 0; + } else { + /* try to append to extents in inode */ + res = hfs_add_extent(HFS_I(inode)->first_extents, + HFS_I(inode)->alloc_blocks, + start, len); + if (res == -ENOSPC) + goto insert_extent; + } + if (!res) { + hfs_dump_extent(HFS_I(inode)->first_extents); + HFS_I(inode)->first_blocks += len; + } + } else { + res = hfs_add_extent(HFS_I(inode)->cached_extents, + HFS_I(inode)->alloc_blocks - + HFS_I(inode)->cached_start, + start, len); + if (!res) { + hfs_dump_extent(HFS_I(inode)->cached_extents); + HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY; + HFS_I(inode)->cached_blocks += len; + } else if (res == -ENOSPC) + goto insert_extent; + } +out: + up(&HFS_I(inode)->extents_lock); + if (!res) { + HFS_I(inode)->alloc_blocks += len; + mark_inode_dirty(inode); + if (inode->i_ino < HFS_FIRSTUSER_CNID) + set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags); + set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags); + sb->s_dirt = 1; + } + return res; + +insert_extent: + dprint(DBG_EXTENT, "insert new extent\n"); + hfs_ext_write_extent(inode); + + memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec)); + HFS_I(inode)->cached_extents[0].block = cpu_to_be16(start); + HFS_I(inode)->cached_extents[0].count = cpu_to_be16(len); + hfs_dump_extent(HFS_I(inode)->cached_extents); + HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW; + HFS_I(inode)->cached_start = HFS_I(inode)->alloc_blocks; + HFS_I(inode)->cached_blocks = len; + + res = 0; + goto out; +} + +void hfs_file_truncate(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + struct hfs_find_data fd; + u16 blk_cnt, alloc_cnt, start; + u32 size; + int res; + + dprint(DBG_INODE, "truncate: %lu, %Lu -> %Lu\n", inode->i_ino, + (long long)HFS_I(inode)->phys_size, inode->i_size); + if (inode->i_size > HFS_I(inode)->phys_size) { + struct address_space *mapping = inode->i_mapping; + struct page *page; + int res; + + size = inode->i_size - 1; + page = grab_cache_page(mapping, size >> PAGE_CACHE_SHIFT); + if (!page) + return; + size &= PAGE_CACHE_SIZE - 1; + size++; + res = mapping->a_ops->prepare_write(NULL, page, size, size); + if (!res) + res = mapping->a_ops->commit_write(NULL, page, size, size); + if (res) + inode->i_size = HFS_I(inode)->phys_size; + unlock_page(page); + page_cache_release(page); + mark_inode_dirty(inode); + return; + } + size = inode->i_size + HFS_SB(sb)->alloc_blksz - 1; + blk_cnt = size / HFS_SB(sb)->alloc_blksz; + alloc_cnt = HFS_I(inode)->alloc_blocks; + if (blk_cnt == alloc_cnt) + goto out; + + down(&HFS_I(inode)->extents_lock); + hfs_find_init(HFS_SB(sb)->ext_tree, &fd); + while (1) { + if (alloc_cnt == HFS_I(inode)->first_blocks) { + hfs_free_extents(sb, HFS_I(inode)->first_extents, + alloc_cnt, alloc_cnt - blk_cnt); + hfs_dump_extent(HFS_I(inode)->first_extents); + HFS_I(inode)->first_blocks = blk_cnt; + break; + } + res = __hfs_ext_cache_extent(&fd, inode, alloc_cnt); + if (res) + break; + start = HFS_I(inode)->cached_start; + hfs_free_extents(sb, HFS_I(inode)->cached_extents, + alloc_cnt - start, alloc_cnt - blk_cnt); + hfs_dump_extent(HFS_I(inode)->cached_extents); + if (blk_cnt > start) { + HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY; + break; + } + alloc_cnt = start; + HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0; + HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW); + hfs_brec_remove(&fd); + } + hfs_find_exit(&fd); + up(&HFS_I(inode)->extents_lock); + + HFS_I(inode)->alloc_blocks = blk_cnt; +out: + HFS_I(inode)->phys_size = inode->i_size; + HFS_I(inode)->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >> sb->s_blocksize_bits; + inode_set_bytes(inode, HFS_I(inode)->fs_blocks << sb->s_blocksize_bits); + mark_inode_dirty(inode); +} |