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fs/hfs/extent.c
13.8 KB
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/* * 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); } |
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static int __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd) |
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{ 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) |
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return res; |
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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) |
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return res; |
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hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength); HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY; } |
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return 0; |
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} |
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int hfs_ext_write_extent(struct inode *inode) |
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{ struct hfs_find_data fd; |
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int res = 0; |
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if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) { |
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res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd); if (res) return res; res = __hfs_ext_write_extent(inode, &fd); |
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hfs_find_exit(&fd); } |
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return res; |
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} 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; |
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if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) { res = __hfs_ext_write_extent(inode, fd); if (res) return res; } |
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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; |
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res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd); if (!res) { res = __hfs_ext_cache_extent(&fd, inode, block); hfs_find_exit(&fd); } |
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return res; } static void hfs_dump_extent(struct hfs_extent *extent) { int i; |
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hfs_dbg(EXTENT, " "); |
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for (i = 0; i < 3; i++) |
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hfs_dbg_cont(EXTENT, " %u:%u", be16_to_cpu(extent[i].block), be16_to_cpu(extent[i].count)); hfs_dbg_cont(EXTENT, " "); |
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} 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; |
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res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd); if (res) return res; |
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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; } |
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mutex_lock(&HFS_I(inode)->extents_lock); |
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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 { |
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mutex_unlock(&HFS_I(inode)->extents_lock); |
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return -EIO; } |
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mutex_unlock(&HFS_I(inode)->extents_lock); |
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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; |
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mutex_lock(&HFS_I(inode)->extents_lock); |
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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; } |
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hfs_dbg(EXTENT, "extend %lu: %u,%u ", inode->i_ino, start, len); |
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if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) { if (!HFS_I(inode)->first_blocks) { |
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hfs_dbg(EXTENT, "first extents "); |
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/* 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: |
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mutex_unlock(&HFS_I(inode)->extents_lock); |
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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); |
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hfs_mark_mdb_dirty(sb); |
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} return res; insert_extent: |
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hfs_dbg(EXTENT, "insert new extent "); |
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res = hfs_ext_write_extent(inode); if (res) goto out; |
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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; |
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hfs_dbg(INODE, "truncate: %lu, %Lu -> %Lu ", inode->i_ino, (long long)HFS_I(inode)->phys_size, inode->i_size); |
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if (inode->i_size > HFS_I(inode)->phys_size) { struct address_space *mapping = inode->i_mapping; |
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void *fsdata; |
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struct page *page; |
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|
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/* XXX: Can use generic_cont_expand? */ |
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size = inode->i_size - 1; |
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res = pagecache_write_begin(NULL, mapping, size+1, 0, AOP_FLAG_UNINTERRUPTIBLE, &page, &fsdata); if (!res) { res = pagecache_write_end(NULL, mapping, size+1, 0, 0, page, fsdata); } |
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if (res) inode->i_size = HFS_I(inode)->phys_size; |
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return; |
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} else if (inode->i_size == HFS_I(inode)->phys_size) return; |
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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; |
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mutex_lock(&HFS_I(inode)->extents_lock); |
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res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd); if (res) { mutex_unlock(&HFS_I(inode)->extents_lock); /* XXX: We lack error handling of hfs_file_truncate() */ return; } |
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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); |
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mutex_unlock(&HFS_I(inode)->extents_lock); |
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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); } |