--- /dev/null
+/*
+ * 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 int __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 res;
+ 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 res;
+ hfs_bnode_write(fd->bnode, HFS_I(inode)->cached_extents, fd->entryoffset, fd->entrylength);
+ HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
+ }
+ return 0;
+}
+
+int hfs_ext_write_extent(struct inode *inode)
+{
+ struct hfs_find_data fd;
+ int res = 0;
+
+ if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
+ res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
+ if (res)
+ return res;
+ res = __hfs_ext_write_extent(inode, &fd);
+ hfs_find_exit(&fd);
+ }
+ return res;
+}
+
+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) {
+ res = __hfs_ext_write_extent(inode, fd);
+ if (res)
+ return res;
+ }
+
+ 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;
+
+ 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);
+ }
+ return res;
+}
+
+static void hfs_dump_extent(struct hfs_extent *extent)
+{
+ int i;
+
+ hfs_dbg(EXTENT, " ");
+ for (i = 0; i < 3; i++)
+ hfs_dbg_cont(EXTENT, " %u:%u",
+ be16_to_cpu(extent[i].block),
+ be16_to_cpu(extent[i].count));
+ hfs_dbg_cont(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;
+
+ res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
+ if (res)
+ return res;
+ 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;
+ }
+
+ mutex_lock(&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 {
+ mutex_unlock(&HFS_I(inode)->extents_lock);
+ return -EIO;
+ }
+ mutex_unlock(&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;
+
+ mutex_lock(&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;
+ }
+
+ hfs_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) {
+ hfs_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:
+ mutex_unlock(&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);
+ hfs_mark_mdb_dirty(sb);
+ }
+ return res;
+
+insert_extent:
+ hfs_dbg(EXTENT, "insert new extent\n");
+ res = hfs_ext_write_extent(inode);
+ if (res)
+ goto out;
+
+ 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;
+
+ hfs_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;
+ void *fsdata;
+ struct page *page;
+
+ /* XXX: Can use generic_cont_expand? */
+ size = inode->i_size - 1;
+ 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);
+ }
+ if (res)
+ inode->i_size = HFS_I(inode)->phys_size;
+ return;
+ } else if (inode->i_size == HFS_I(inode)->phys_size)
+ 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;
+
+ mutex_lock(&HFS_I(inode)->extents_lock);
+ 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;
+ }
+ 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);
+ mutex_unlock(&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);
+}
Code Review / kvmfornfv.git / blobdiff