- 根目录:
- fs
- hfsplus
- extents.c
/*
* linux/fs/hfsplus/extents.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handling of Extents both in catalog and extents overflow trees
*/
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/pagemap.h>
#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
/* Compare two extents keys, returns 0 on same, pos/neg for difference */
int hfsplus_ext_cmp_key(const hfsplus_btree_key *k1,
const hfsplus_btree_key *k2)
{
__be32 k1id, k2id;
__be32 k1s, k2s;
k1id = k1->ext.cnid;
k2id = k2->ext.cnid;
if (k1id != k2id)
return be32_to_cpu(k1id) < be32_to_cpu(k2id) ? -1 : 1;
if (k1->ext.fork_type != k2->ext.fork_type)
return k1->ext.fork_type < k2->ext.fork_type ? -1 : 1;
k1s = k1->ext.start_block;
k2s = k2->ext.start_block;
if (k1s == k2s)
return 0;
return be32_to_cpu(k1s) < be32_to_cpu(k2s) ? -1 : 1;
}
static void hfsplus_ext_build_key(hfsplus_btree_key *key, u32 cnid,
u32 block, u8 type)
{
key->key_len = cpu_to_be16(HFSPLUS_EXT_KEYLEN - 2);
key->ext.cnid = cpu_to_be32(cnid);
key->ext.start_block = cpu_to_be32(block);
key->ext.fork_type = type;
key->ext.pad = 0;
}
static u32 hfsplus_ext_find_block(struct hfsplus_extent *ext, u32 off)
{
int i;
u32 count;
for (i = 0; i < 8; ext++, i++) {
count = be32_to_cpu(ext->block_count);
if (off < count)
return be32_to_cpu(ext->start_block) + off;
off -= count;
}
/* panic? */
return 0;
}
static int hfsplus_ext_block_count(struct hfsplus_extent *ext)
{
int i;
u32 count = 0;
for (i = 0; i < 8; ext++, i++)
count += be32_to_cpu(ext->block_count);
return count;
}
static u32 hfsplus_ext_lastblock(struct hfsplus_extent *ext)
{
int i;
ext += 7;
for (i = 0; i < 7; ext--, i++)
if (ext->block_count)
break;
return be32_to_cpu(ext->start_block) + be32_to_cpu(ext->block_count);
}
static int __hfsplus_ext_write_extent(struct inode *inode,
struct hfs_find_data *fd)
{
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res;
WARN_ON(!mutex_is_locked(&hip->extents_lock));
hfsplus_ext_build_key(fd->search_key, inode->i_ino, hip->cached_start,
HFSPLUS_IS_RSRC(inode) ?
HFSPLUS_TYPE_RSRC : HFSPLUS_TYPE_DATA);
res = hfs_brec_find(fd, hfs_find_rec_by_key);
if (hip->extent_state & HFSPLUS_EXT_NEW) {
if (res != -ENOENT)
return res;
hfs_brec_insert(fd, hip->cached_extents,
sizeof(hfsplus_extent_rec));
hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
} else {
if (res)
return res;
hfs_bnode_write(fd->bnode, hip->cached_extents,
fd->entryoffset, fd->entrylength);
hip->extent_state &= ~HFSPLUS_EXT_DIRTY;
}
/*
* We can't just use hfsplus_mark_inode_dirty here, because we
* also get called from hfsplus_write_inode, which should not
* redirty the inode. Instead the callers have to be careful
* to explicily mark the inode dirty, too.
*/
set_bit(HFSPLUS_I_EXT_DIRTY, &hip->flags);
return 0;
}
static int hfsplus_ext_write_extent_locked(struct inode *inode)
{
int res = 0;
if (HFSPLUS_I(inode)->extent_state & HFSPLUS_EXT_DIRTY) {
struct hfs_find_data fd;
res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
if (res)
return res;
res = __hfsplus_ext_write_extent(inode, &fd);
hfs_find_exit(&fd);
}
return res;
}
int hfsplus_ext_write_extent(struct inode *inode)
{
int res;
mutex_lock(&HFSPLUS_I(inode)->extents_lock);
res = hfsplus_ext_write_extent_locked(inode);
mutex_unlock(&HFSPLUS_I(inode)->extents_lock);
return res;
}
static inline int __hfsplus_ext_read_extent(struct hfs_find_data *fd,
struct hfsplus_extent *extent,
u32 cnid, u32 block, u8 type)
{
int res;
hfsplus_ext_build_key(fd->search_key, cnid, block, type);
fd->key->ext.cnid = 0;
res = hfs_brec_find(fd, hfs_find_rec_by_key);
if (res && res != -ENOENT)
return res;
if (fd->key->ext.cnid != fd->search_key->ext.cnid ||
fd->key->ext.fork_type != fd->search_key->ext.fork_type)
return -ENOENT;
if (fd->entrylength != sizeof(hfsplus_extent_rec))
return -EIO;
hfs_bnode_read(fd->bnode, extent, fd->entryoffset,
sizeof(hfsplus_extent_rec));
return 0;
}
static inline int __hfsplus_ext_cache_extent(struct hfs_find_data *fd,
struct inode *inode, u32 block)
{
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res;
WARN_ON(!mutex_is_locked(&hip->extents_lock));
if (hip->extent_state & HFSPLUS_EXT_DIRTY) {
res = __hfsplus_ext_write_extent(inode, fd);
if (res)
return res;
}
res = __hfsplus_ext_read_extent(fd, hip->cached_extents, inode->i_ino,
block, HFSPLUS_IS_RSRC(inode) ?
HFSPLUS_TYPE_RSRC :
HFSPLUS_TYPE_DATA);
if (!res) {
hip->cached_start = be32_to_cpu(fd->key->ext.start_block);
hip->cached_blocks =
hfsplus_ext_block_count(hip->cached_extents);
} else {
hip->cached_start = hip->cached_blocks = 0;
hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
}
return res;
}
static int hfsplus_ext_read_extent(struct inode *inode, u32 block)
{
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
struct hfs_find_data fd;
int res;
if (block >= hip->cached_start &&
block < hip->cached_start + hip->cached_blocks)
return 0;
res = hfs_find_init(HFSPLUS_SB(inode->i_sb)->ext_tree, &fd);
if (!res) {
res = __hfsplus_ext_cache_extent(&fd, inode, block);
hfs_find_exit(&fd);
}
return res;
}
/* Get a block at iblock for inode, possibly allocating if create */
int hfsplus_get_block(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create)
{
struct super_block *sb = inode->i_sb;
struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
int res = -EIO;
u32 ablock, dblock, mask;
sector_t sector;
int was_dirty = 0;
int shift;
/* Convert inode block to disk allocation block */
shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
ablock = iblock >> sbi->fs_shift;
if (iblock >= hip->fs_blocks) {
if (iblock > hip->fs_blocks || !create)
return -EIO;
if (ablock >= hip->alloc_blocks) {
res = hfsplus_file_extend(inode);
if (res)
return res;
}
} else
create = 0;
if (ablock < hip->first_blocks) {
dblock = hfsplus_ext_find_block(hip->first_extents, ablock);
goto done;
}
if (inode->i_ino == HFSPLUS_EXT_CNID)
return -EIO;
mutex_lock(&hip->extents_lock);
/*
* hfsplus_ext_read_extent will write out a cached extent into
* the extents btree. In that case we may have to mark the inode
* dirty even for a pure read of an extent here.
*/
was_dirty = (hip->extent_state & HFSPLUS_EXT_DIRTY);
res = hfsplus_ext_read_extent(inode, ablock);
if (res) {
mutex_unlock(&hip->extents_lock);
return -EIO;
}
dblock = hfsplus_ext_find_block(hip->cached_extents,
ablock - hip->cached_start);
mutex_unlock(&hip->extents_lock);
done:
hfs_dbg(EXTENT, "get_block(%lu): %llu - %u\n",
inode->i_ino, (long long)iblock, dblock);
mask = (1 << sbi->fs_shift) - 1;
sector = ((sector_t)dblock << sbi->fs_shift) +
sbi->blockoffset + (iblock & mask);
map_bh(bh_result, sb, sector);
if (create) {
set_buffer_new(bh_result);
hip->phys_size += sb->s_blocksize;
hip->fs_blocks++;
inode_add_bytes(inode, sb->s_blocksize);
}
if (create || was_dirty)
mark_inode_dirty(inode);
return 0;
}
static void hfsplus_dump_extent(struct hfsplus_extent *extent)
{
int i;
hfs_dbg(EXTENT, " ");
for (i = 0; i < 8; i++)
hfs_dbg_cont(EXTENT, " %u:%u",
be32_to_cpu(extent[i].start_block),
be32_to_cpu(extent[i].block_count));
hfs_dbg_cont(EXTENT, "\n");
}
static int hfsplus_add_extent(struct hfsplus_extent *extent, u32 offset,
u32 alloc_block, u32 block_count)
{
u32 count, start;
int i;
hfsplus_dump_extent(extent);
for (i = 0; i < 8; extent++, i++) {
count = be32_to_cpu(extent->block_count);
if (offset == count) {
start = be32_to_cpu(extent->start_block);
if (alloc_block != start + count) {
if (++i >= 8)
return -ENOSPC;
extent++;
extent->start_block = cpu_to_be32(alloc_block);
} else
block_count += count;
extent->block_count = cpu_to_be32(block_count);
return 0;
} else if (offset < count)
break;
offset -= count;
}
/* panic? */
return -EIO;
}
static int hfsplus_free_extents(struct super_block *sb,
struct hfsplus_extent *extent,
u32 offset, u32 block_nr)
{
u32 count, start;
int i;
int err = 0;
hfsplus_dump_extent(extent);
for (i = 0; i < 8; extent++, i++) {
count = be32_to_cpu(extent->block_count);
if (offset == count)
goto found;
else if (offset < count)
break;
offset -= count;
}
/* panic? */
return -EIO;
found:
for (;;) {
start = be32_to_cpu(extent->start_block);
if (count <= block_nr) {
err = hfsplus_block_free(sb, start, count);
if (err) {
pr_err("can't free extent\n");
hfs_dbg(EXTENT, " start: %u count: %u\n",
start, count);
}
extent->block_count = 0;
extent->start_block = 0;
block_nr -= count;
} else {
count -= block_nr;
err = hfsplus_block_free(sb, start + count, block_nr);
if (err) {
pr_err("can't free extent\n");
hfs_dbg(EXTENT, " start: %u count: %u\n",
start, count);
}
extent->block_count = cpu_to_be32(count);
block_nr = 0;
}
if (!block_nr || !i) {
/*
* Try to free all extents and
* return only last error
*/
return err;
}
i--;
extent--;
count = be32_to_cpu(extent->block_count);
}
}
int hfsplus_free_fork(struct super_block *sb, u32 cnid,
struct hfsplus_fork_raw *fork, int type)
{
struct hfs_find_data fd;
hfsplus_extent_rec ext_entry;
u32 total_blocks, blocks, start;
int res, i;
total_blocks = be32_to_cpu(fork->total_blocks);
if (!total_blocks)
return 0;
blocks = 0;
for (i = 0; i < 8; i++)
blocks += be32_to_cpu(fork->extents[i].block_count);
res = hfsplus_free_extents(sb, fork->extents, blocks, blocks);
if (res)
return res;
if (total_blocks == blocks)
return 0;
res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
if (res)
return res;
do {
res = __hfsplus_ext_read_extent(&fd, ext_entry, cnid,
total_blocks, type);
if (res)
break;
start = be32_to_cpu(fd.key->ext.start_block);
hfsplus_free_extents(sb, ext_entry,
total_blocks - start,
total_blocks);
hfs_brec_remove(&fd);
total_blocks = start;
} while (total_blocks > blocks);
hfs_find_exit(&fd);
return res;
}
int hfsplus_file_extend(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
u32 start, len, goal;
int res;
if (sbi->alloc_file->i_size * 8 <
sbi->total_blocks - sbi->free_blocks + 8) {
/* extend alloc file */
pr_err("extend alloc file! "
"(%llu,%u,%u)\n",
sbi->alloc_file->i_size * 8,
sbi->total_blocks, sbi->free_blocks);
return -ENOSPC;
}
mutex_lock(&hip->extents_lock);
if (hip->alloc_blocks == hip->first_blocks)
goal = hfsplus_ext_lastblock(hip->first_extents);
else {
res = hfsplus_ext_read_extent(inode, hip->alloc_blocks);
if (res)
goto out;
goal = hfsplus_ext_lastblock(hip->cached_extents);
}
len = hip->clump_blocks;
start = hfsplus_block_allocate(sb, sbi->total_blocks, goal, &len);
if (start >= sbi->total_blocks) {
start = hfsplus_block_allocate(sb, goal, 0, &len);
if (start >= goal) {
res = -ENOSPC;
goto out;
}
}
hfs_dbg(EXTENT, "extend %lu: %u,%u\n", inode->i_ino, start, len);
if (hip->alloc_blocks <= hip->first_blocks) {
if (!hip->first_blocks) {
hfs_dbg(EXTENT, "first extents\n");
/* no extents yet */
hip->first_extents[0].start_block = cpu_to_be32(start);
hip->first_extents[0].block_count = cpu_to_be32(len);
res = 0;
} else {
/* try to append to extents in inode */
res = hfsplus_add_extent(hip->first_extents,
hip->alloc_blocks,
start, len);
if (res == -ENOSPC)
goto insert_extent;
}
if (!res) {
hfsplus_dump_extent(hip->first_extents);
hip->first_blocks += len;
}
} else {
res = hfsplus_add_extent(hip->cached_extents,
hip->alloc_blocks - hip->cached_start,
start, len);
if (!res) {
hfsplus_dump_extent(hip->cached_extents);
hip->extent_state |= HFSPLUS_EXT_DIRTY;
hip->cached_blocks += len;
} else if (res == -ENOSPC)
goto insert_extent;
}
out:
mutex_unlock(&hip->extents_lock);
if (!res) {
hip->alloc_blocks += len;
hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
}
return res;
insert_extent:
hfs_dbg(EXTENT, "insert new extent\n");
res = hfsplus_ext_write_extent_locked(inode);
if (res)
goto out;
memset(hip->cached_extents, 0, sizeof(hfsplus_extent_rec));
hip->cached_extents[0].start_block = cpu_to_be32(start);
hip->cached_extents[0].block_count = cpu_to_be32(len);
hfsplus_dump_extent(hip->cached_extents);
hip->extent_state |= HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW;
hip->cached_start = hip->alloc_blocks;
hip->cached_blocks = len;
res = 0;
goto out;
}
void hfsplus_file_truncate(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
struct hfs_find_data fd;
u32 alloc_cnt, blk_cnt, start;
int res;
hfs_dbg(INODE, "truncate: %lu, %llu -> %llu\n",
inode->i_ino, (long long)hip->phys_size, inode->i_size);
if (inode->i_size > hip->phys_size) {
struct address_space *mapping = inode->i_mapping;
struct page *page;
void *fsdata;
loff_t size = inode->i_size;
res = pagecache_write_begin(NULL, mapping, size, 0,
AOP_FLAG_UNINTERRUPTIBLE,
&page, &fsdata);
if (res)
return;
res = pagecache_write_end(NULL, mapping, size,
0, 0, page, fsdata);
if (res < 0)
return;
mark_inode_dirty(inode);
return;
} else if (inode->i_size == hip->phys_size)
return;
blk_cnt = (inode->i_size + HFSPLUS_SB(sb)->alloc_blksz - 1) >>
HFSPLUS_SB(sb)->alloc_blksz_shift;
alloc_cnt = hip->alloc_blocks;
if (blk_cnt == alloc_cnt)
goto out;
mutex_lock(&hip->extents_lock);
res = hfs_find_init(HFSPLUS_SB(sb)->ext_tree, &fd);
if (res) {
mutex_unlock(&hip->extents_lock);
/* XXX: We lack error handling of hfsplus_file_truncate() */
return;
}
while (1) {
if (alloc_cnt == hip->first_blocks) {
hfsplus_free_extents(sb, hip->first_extents,
alloc_cnt, alloc_cnt - blk_cnt);
hfsplus_dump_extent(hip->first_extents);
hip->first_blocks = blk_cnt;
break;
}
res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt);
if (res)
break;
start = hip->cached_start;
hfsplus_free_extents(sb, hip->cached_extents,
alloc_cnt - start, alloc_cnt - blk_cnt);
hfsplus_dump_extent(hip->cached_extents);
if (blk_cnt > start) {
hip->extent_state |= HFSPLUS_EXT_DIRTY;
break;
}
alloc_cnt = start;
hip->cached_start = hip->cached_blocks = 0;
hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
hfs_brec_remove(&fd);
}
hfs_find_exit(&fd);
mutex_unlock(&hip->extents_lock);
hip->alloc_blocks = blk_cnt;
out:
hip->phys_size = inode->i_size;
hip->fs_blocks = (inode->i_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
inode_set_bytes(inode, hip->fs_blocks << sb->s_blocksize_bits);
hfsplus_mark_inode_dirty(inode, HFSPLUS_I_ALLOC_DIRTY);
}