552 lines
14 KiB
C
552 lines
14 KiB
C
/*
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* linux/fs/hfs/extent.c
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*
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* Copyright (C) 1995-1997 Paul H. Hargrove
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* (C) 2003 Ardis Technologies <roman@ardistech.com>
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* This file may be distributed under the terms of the GNU General Public License.
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*
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* This file contains the functions related to the extents B-tree.
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*/
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#include <linux/pagemap.h>
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#include "hfs_fs.h"
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#include "btree.h"
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/*================ File-local functions ================*/
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/*
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* build_key
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*/
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static void hfs_ext_build_key(hfs_btree_key *key, u32 cnid, u16 block, u8 type)
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{
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key->key_len = 7;
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key->ext.FkType = type;
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key->ext.FNum = cpu_to_be32(cnid);
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key->ext.FABN = cpu_to_be16(block);
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}
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/*
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* hfs_ext_compare()
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*
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* Description:
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* This is the comparison function used for the extents B-tree. In
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* comparing extent B-tree entries, the file id is the most
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* significant field (compared as unsigned ints); the fork type is
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* the second most significant field (compared as unsigned chars);
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* and the allocation block number field is the least significant
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* (compared as unsigned ints).
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* Input Variable(s):
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* struct hfs_ext_key *key1: pointer to the first key to compare
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* struct hfs_ext_key *key2: pointer to the second key to compare
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* Output Variable(s):
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* NONE
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* Returns:
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* int: negative if key1<key2, positive if key1>key2, and 0 if key1==key2
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* Preconditions:
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* key1 and key2 point to "valid" (struct hfs_ext_key)s.
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* Postconditions:
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* This function has no side-effects */
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int hfs_ext_keycmp(const btree_key *key1, const btree_key *key2)
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{
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__be32 fnum1, fnum2;
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__be16 block1, block2;
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fnum1 = key1->ext.FNum;
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fnum2 = key2->ext.FNum;
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if (fnum1 != fnum2)
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return be32_to_cpu(fnum1) < be32_to_cpu(fnum2) ? -1 : 1;
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if (key1->ext.FkType != key2->ext.FkType)
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return key1->ext.FkType < key2->ext.FkType ? -1 : 1;
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block1 = key1->ext.FABN;
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block2 = key2->ext.FABN;
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if (block1 == block2)
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return 0;
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return be16_to_cpu(block1) < be16_to_cpu(block2) ? -1 : 1;
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}
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/*
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* hfs_ext_find_block
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*
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* Find a block within an extent record
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*/
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static u16 hfs_ext_find_block(struct hfs_extent *ext, u16 off)
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{
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int i;
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u16 count;
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for (i = 0; i < 3; ext++, i++) {
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count = be16_to_cpu(ext->count);
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if (off < count)
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return be16_to_cpu(ext->block) + off;
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off -= count;
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}
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/* panic? */
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return 0;
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}
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static int hfs_ext_block_count(struct hfs_extent *ext)
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{
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int i;
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u16 count = 0;
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for (i = 0; i < 3; ext++, i++)
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count += be16_to_cpu(ext->count);
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return count;
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}
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static u16 hfs_ext_lastblock(struct hfs_extent *ext)
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{
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int i;
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ext += 2;
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for (i = 0; i < 2; ext--, i++)
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if (ext->count)
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break;
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return be16_to_cpu(ext->block) + be16_to_cpu(ext->count);
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}
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static int __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
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{
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int res;
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hfs_ext_build_key(fd->search_key, inode->i_ino, HFS_I(inode)->cached_start,
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HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
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res = hfs_brec_find(fd);
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if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) {
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if (res != -ENOENT)
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return res;
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/* Fail early and avoid ENOSPC during the btree operation */
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res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
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if (res)
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return res;
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hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec));
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HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
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} else {
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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);
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HFS_I(inode)->flags &= ~HFS_FLG_EXT_DIRTY;
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}
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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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{
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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);
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if (res)
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return res;
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res = __hfs_ext_write_extent(inode, &fd);
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hfs_find_exit(&fd);
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}
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return res;
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}
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static inline int __hfs_ext_read_extent(struct hfs_find_data *fd, struct hfs_extent *extent,
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u32 cnid, u32 block, u8 type)
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{
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int res;
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hfs_ext_build_key(fd->search_key, cnid, block, type);
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fd->key->ext.FNum = 0;
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res = hfs_brec_find(fd);
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if (res && res != -ENOENT)
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return res;
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if (fd->key->ext.FNum != fd->search_key->ext.FNum ||
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fd->key->ext.FkType != fd->search_key->ext.FkType)
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return -ENOENT;
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if (fd->entrylength != sizeof(hfs_extent_rec))
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return -EIO;
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hfs_bnode_read(fd->bnode, extent, fd->entryoffset, sizeof(hfs_extent_rec));
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return 0;
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}
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static inline int __hfs_ext_cache_extent(struct hfs_find_data *fd, struct inode *inode, u32 block)
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{
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int res;
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if (HFS_I(inode)->flags & HFS_FLG_EXT_DIRTY) {
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res = __hfs_ext_write_extent(inode, fd);
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if (res)
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return res;
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}
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res = __hfs_ext_read_extent(fd, HFS_I(inode)->cached_extents, inode->i_ino,
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block, HFS_IS_RSRC(inode) ? HFS_FK_RSRC : HFS_FK_DATA);
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if (!res) {
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HFS_I(inode)->cached_start = be16_to_cpu(fd->key->ext.FABN);
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HFS_I(inode)->cached_blocks = hfs_ext_block_count(HFS_I(inode)->cached_extents);
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} else {
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HFS_I(inode)->cached_start = HFS_I(inode)->cached_blocks = 0;
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HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
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}
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return res;
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}
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static int hfs_ext_read_extent(struct inode *inode, u16 block)
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{
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struct hfs_find_data fd;
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int res;
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if (block >= HFS_I(inode)->cached_start &&
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block < HFS_I(inode)->cached_start + HFS_I(inode)->cached_blocks)
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return 0;
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res = hfs_find_init(HFS_SB(inode->i_sb)->ext_tree, &fd);
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if (!res) {
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res = __hfs_ext_cache_extent(&fd, inode, block);
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hfs_find_exit(&fd);
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}
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return res;
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}
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static void hfs_dump_extent(struct hfs_extent *extent)
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{
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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",
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be16_to_cpu(extent[i].block),
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be16_to_cpu(extent[i].count));
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hfs_dbg_cont(EXTENT, "\n");
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}
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static int hfs_add_extent(struct hfs_extent *extent, u16 offset,
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u16 alloc_block, u16 block_count)
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{
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u16 count, start;
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int i;
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hfs_dump_extent(extent);
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for (i = 0; i < 3; extent++, i++) {
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count = be16_to_cpu(extent->count);
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if (offset == count) {
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start = be16_to_cpu(extent->block);
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if (alloc_block != start + count) {
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if (++i >= 3)
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return -ENOSPC;
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extent++;
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extent->block = cpu_to_be16(alloc_block);
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} else
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block_count += count;
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extent->count = cpu_to_be16(block_count);
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return 0;
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} else if (offset < count)
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break;
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offset -= count;
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}
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/* panic? */
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return -EIO;
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}
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static int hfs_free_extents(struct super_block *sb, struct hfs_extent *extent,
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u16 offset, u16 block_nr)
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{
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u16 count, start;
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int i;
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hfs_dump_extent(extent);
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for (i = 0; i < 3; extent++, i++) {
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count = be16_to_cpu(extent->count);
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if (offset == count)
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goto found;
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else if (offset < count)
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break;
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offset -= count;
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}
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/* panic? */
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return -EIO;
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found:
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for (;;) {
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start = be16_to_cpu(extent->block);
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if (count <= block_nr) {
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hfs_clear_vbm_bits(sb, start, count);
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extent->block = 0;
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extent->count = 0;
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block_nr -= count;
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} else {
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count -= block_nr;
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hfs_clear_vbm_bits(sb, start + count, block_nr);
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extent->count = cpu_to_be16(count);
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block_nr = 0;
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}
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if (!block_nr || !i)
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return 0;
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i--;
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extent--;
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count = be16_to_cpu(extent->count);
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}
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}
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int hfs_free_fork(struct super_block *sb, struct hfs_cat_file *file, int type)
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{
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struct hfs_find_data fd;
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u32 total_blocks, blocks, start;
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u32 cnid = be32_to_cpu(file->FlNum);
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struct hfs_extent *extent;
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int res, i;
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if (type == HFS_FK_DATA) {
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total_blocks = be32_to_cpu(file->PyLen);
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extent = file->ExtRec;
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} else {
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total_blocks = be32_to_cpu(file->RPyLen);
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extent = file->RExtRec;
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}
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total_blocks /= HFS_SB(sb)->alloc_blksz;
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if (!total_blocks)
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return 0;
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blocks = 0;
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for (i = 0; i < 3; i++)
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blocks += be16_to_cpu(extent[i].count);
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res = hfs_free_extents(sb, extent, blocks, blocks);
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if (res)
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return res;
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if (total_blocks == blocks)
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return 0;
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res = hfs_find_init(HFS_SB(sb)->ext_tree, &fd);
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if (res)
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return res;
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do {
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res = __hfs_ext_read_extent(&fd, extent, cnid, total_blocks, type);
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if (res)
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break;
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start = be16_to_cpu(fd.key->ext.FABN);
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hfs_free_extents(sb, extent, total_blocks - start, total_blocks);
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hfs_brec_remove(&fd);
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total_blocks = start;
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} while (total_blocks > blocks);
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hfs_find_exit(&fd);
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return res;
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}
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/*
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* hfs_get_block
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*/
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int hfs_get_block(struct inode *inode, sector_t block,
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struct buffer_head *bh_result, int create)
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{
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struct super_block *sb;
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u16 dblock, ablock;
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int res;
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sb = inode->i_sb;
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/* Convert inode block to disk allocation block */
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ablock = (u32)block / HFS_SB(sb)->fs_div;
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if (block >= HFS_I(inode)->fs_blocks) {
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if (!create)
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return 0;
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if (block > HFS_I(inode)->fs_blocks)
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return -EIO;
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if (ablock >= HFS_I(inode)->alloc_blocks) {
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res = hfs_extend_file(inode);
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if (res)
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return res;
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}
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} else
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create = 0;
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if (ablock < HFS_I(inode)->first_blocks) {
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dblock = hfs_ext_find_block(HFS_I(inode)->first_extents, ablock);
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goto done;
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}
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mutex_lock(&HFS_I(inode)->extents_lock);
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res = hfs_ext_read_extent(inode, ablock);
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if (!res)
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dblock = hfs_ext_find_block(HFS_I(inode)->cached_extents,
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ablock - HFS_I(inode)->cached_start);
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else {
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mutex_unlock(&HFS_I(inode)->extents_lock);
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return -EIO;
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}
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mutex_unlock(&HFS_I(inode)->extents_lock);
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done:
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map_bh(bh_result, sb, HFS_SB(sb)->fs_start +
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dblock * HFS_SB(sb)->fs_div +
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(u32)block % HFS_SB(sb)->fs_div);
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if (create) {
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set_buffer_new(bh_result);
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HFS_I(inode)->phys_size += sb->s_blocksize;
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HFS_I(inode)->fs_blocks++;
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inode_add_bytes(inode, sb->s_blocksize);
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mark_inode_dirty(inode);
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}
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return 0;
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}
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int hfs_extend_file(struct inode *inode)
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{
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struct super_block *sb = inode->i_sb;
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u32 start, len, goal;
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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)
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goal = hfs_ext_lastblock(HFS_I(inode)->first_extents);
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else {
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res = hfs_ext_read_extent(inode, HFS_I(inode)->alloc_blocks);
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if (res)
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goto out;
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goal = hfs_ext_lastblock(HFS_I(inode)->cached_extents);
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}
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len = HFS_I(inode)->clump_blocks;
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start = hfs_vbm_search_free(sb, goal, &len);
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if (!len) {
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res = -ENOSPC;
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goto out;
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}
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hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
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if (HFS_I(inode)->alloc_blocks == HFS_I(inode)->first_blocks) {
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if (!HFS_I(inode)->first_blocks) {
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hfs_dbg(EXTENT, "first extents\n");
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/* no extents yet */
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HFS_I(inode)->first_extents[0].block = cpu_to_be16(start);
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HFS_I(inode)->first_extents[0].count = cpu_to_be16(len);
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res = 0;
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} else {
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/* try to append to extents in inode */
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res = hfs_add_extent(HFS_I(inode)->first_extents,
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HFS_I(inode)->alloc_blocks,
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start, len);
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if (res == -ENOSPC)
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goto insert_extent;
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}
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if (!res) {
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hfs_dump_extent(HFS_I(inode)->first_extents);
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HFS_I(inode)->first_blocks += len;
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}
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} else {
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res = hfs_add_extent(HFS_I(inode)->cached_extents,
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HFS_I(inode)->alloc_blocks -
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HFS_I(inode)->cached_start,
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start, len);
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if (!res) {
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hfs_dump_extent(HFS_I(inode)->cached_extents);
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HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY;
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HFS_I(inode)->cached_blocks += len;
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} else if (res == -ENOSPC)
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goto insert_extent;
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}
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out:
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mutex_unlock(&HFS_I(inode)->extents_lock);
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if (!res) {
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HFS_I(inode)->alloc_blocks += len;
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mark_inode_dirty(inode);
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if (inode->i_ino < HFS_FIRSTUSER_CNID)
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set_bit(HFS_FLG_ALT_MDB_DIRTY, &HFS_SB(sb)->flags);
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set_bit(HFS_FLG_MDB_DIRTY, &HFS_SB(sb)->flags);
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hfs_mark_mdb_dirty(sb);
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}
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return res;
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insert_extent:
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hfs_dbg(EXTENT, "insert new extent\n");
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res = hfs_ext_write_extent(inode);
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if (res)
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goto out;
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memset(HFS_I(inode)->cached_extents, 0, sizeof(hfs_extent_rec));
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HFS_I(inode)->cached_extents[0].block = cpu_to_be16(start);
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HFS_I(inode)->cached_extents[0].count = cpu_to_be16(len);
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hfs_dump_extent(HFS_I(inode)->cached_extents);
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HFS_I(inode)->flags |= HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW;
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HFS_I(inode)->cached_start = HFS_I(inode)->alloc_blocks;
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HFS_I(inode)->cached_blocks = len;
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res = 0;
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goto out;
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}
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void hfs_file_truncate(struct inode *inode)
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{
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struct super_block *sb = inode->i_sb;
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struct hfs_find_data fd;
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u16 blk_cnt, alloc_cnt, start;
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u32 size;
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int res;
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hfs_dbg(INODE, "truncate: %lu, %Lu -> %Lu\n",
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|
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, 0,
|
|
&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);
|
|
}
|