static inline int get_block(struct inode * inode, sector_t block,
struct buffer_head *bh, int create)
{
int err = -EIO;
int offsets[DEPTH];
Indirect chain[DEPTH];
Indirect *partial;
int left;
int depth = block_to_path(inode, block, offsets);
if (depth == 0)
goto out;
reread:
partial = get_branch(inode, depth, offsets, chain, &err);
if (!partial) {
got_it:
map_bh(bh, inode->i_sb, block_to_cpu(chain[depth-1].key));
partial = chain+depth-1;
goto cleanup;
}
if (!create || err == -EIO) {
cleanup:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
out:
return err;
}
if (err == -EAGAIN)
goto changed;
left = (chain + depth) - partial;
err = alloc_branch(inode, left, offsets+(partial-chain), partial);
if (err)
goto cleanup;
if (splice_branch(inode, chain, partial, left) < 0)
goto changed;
set_buffer_new(bh);
goto got_it;
changed:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
goto reread;
}
static inline void truncate (struct inode * inode)
{
struct super_block *sb = inode->i_sb;
block_t *idata = i_data(inode);
int offsets[DEPTH];
Indirect chain[DEPTH];
Indirect *partial;
block_t nr = 0;
int n;
int first_whole;
long iblock;
iblock = (inode->i_size + sb->s_blocksize -1) >> sb->s_blocksize_bits;
block_truncate_page(inode->i_mapping, inode->i_size, get_block);
n = block_to_path(inode, iblock, offsets);
if (!n)
return;
if (n == 1) {
free_data(inode, idata+offsets[0], idata + DIRECT);
first_whole = 0;
goto do_indirects;
}
first_whole = offsets[0] + 1 - DIRECT;
partial = find_shared(inode, n, offsets, chain, &nr);
if (nr) {
if (partial == chain)
mark_inode_dirty(inode);
else
mark_buffer_dirty_inode(partial->bh, inode);
free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
}
/* Clear the ends of indirect blocks on the shared branch */
while (partial > chain) {
free_branches(inode, partial->p + 1, block_end(partial->bh),
(chain+n-1) - partial);
mark_buffer_dirty_inode(partial->bh, inode);
brelse (partial->bh);
partial--;
}
do_indirects:
/* Kill the remaining (whole) subtrees */
while (first_whole < DEPTH-1) {
nr = idata[DIRECT+first_whole];
if (nr) {
idata[DIRECT+first_whole] = 0;
mark_inode_dirty(inode);
free_branches(inode, &nr, &nr+1, first_whole+1);
}
first_whole++;
}
inode->i_mtime = inode->i_ctime = current_time(inode);
mark_inode_dirty(inode);
}
static inline int get_block(struct inode * inode, sector_t block,
struct buffer_head *bh, int create)
{
int err = -EIO;
int offsets[DEPTH];
Indirect chain[DEPTH];
Indirect *partial;
int left;
int depth = block_to_path(inode, block, offsets);
if (depth == 0)
goto out;
reread:
partial = get_branch(inode, depth, offsets, chain, &err);
/* Simplest case - block found, no allocation needed */
if (!partial) {
got_it:
map_bh(bh, inode->i_sb, block_to_cpu(chain[depth-1].key));
/* Clean up and exit */
partial = chain+depth-1; /* the whole chain */
goto cleanup;
}
/* Next simple case - plain lookup or failed read of indirect block */
if (!create || err == -EIO) {
cleanup:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
out:
return err;
}
/*
* Indirect block might be removed by truncate while we were
* reading it. Handling of that case (forget what we've got and
* reread) is taken out of the main path.
*/
if (err == -EAGAIN)
goto changed;
left = (chain + depth) - partial;
err = alloc_branch(inode, left, offsets+(partial-chain), partial);
if (err)
goto cleanup;
if (splice_branch(inode, chain, partial, left) < 0)
goto changed;
set_buffer_new(bh);
goto got_it;
changed:
while (partial > chain) {
brelse(partial->bh);
partial--;
}
goto reread;
}