206  *	ext2_get_branch - read the chain of indirect blocks leading to data
208  *	@depth: depth of the chain (1 - direct pointer, etc.)
210  *	@chain: place to store the result
215  *	(incomplete one) otherwise. Upon the return chain[i].key contains
216  *	the number of (i+1)-th block in the chain (as it is stored in memory,
217  *	i.e. little-endian 32-bit), chain[i].p contains the address of that
219  *	for i>0) and chain[i].bh points to the buffer_head of i-th indirect
221  *	numbers of the chain, addresses they were taken from (and where we can
222  *	verify that chain did not change) and buffer_heads hosting these
229  *	or when it notices that chain had been changed while it was reading
232  *	the whole chain, all way to the data (returns %NULL, *err == 0).
237 				 Indirect chain[4],  in ext2_get_branch()
241 	Indirect *p = chain;  in ext2_get_branch()
246 	add_chain (chain, NULL, EXT2_I(inode)->i_data + *offsets);  in ext2_get_branch()
254 		if (!verify_chain(chain, p))  in ext2_get_branch()
325  *	@partial: pointer to the last triple within a chain
353  * 	@branch: chain of indirect blocks
453  *	ext2_alloc_branch - allocate and set up a chain of blocks.
455  *	@indirect_blks: depth of the chain (number of blocks to allocate)
459  *	@branch: place to store the chain in.
462  *	links them into chain and (if we are synchronous) writes them to disk.
464  *	inode. It stores the information about that chain in the branch[], in
466  *	we had read the existing part of chain and partial points to the last
469  *	place chain is disconnected - *branch->p is still zero (we did not
475  *	ext2_alloc_block() (normally -ENOSPC). Otherwise we set the chain
520 			 * End of chain, update the last new metablock of  in ext2_alloc_branch()
521 			 * the chain to point to the new allocated  in ext2_alloc_branch()
559  * chain to new block and return 0.
631 	Indirect chain[4];  in ext2_get_blocks()  local
648 	partial = ext2_get_branch(inode, depth, offsets, chain, &err);  in ext2_get_blocks()
651 		first_block = le32_to_cpu(chain[depth - 1].key);  in ext2_get_blocks()
657 			if (!verify_chain(chain, chain + depth - 1)) {  in ext2_get_blocks()
666 				partial = chain + depth - 1;  in ext2_get_blocks()
669 			blk = le32_to_cpu(*(chain[depth-1].p + count));  in ext2_get_blocks()
686 	 * the chain(ext2_get_branch() returns -EAGAIN err), or  in ext2_get_blocks()
687 	 * if the chain has been changed after we grab the semaphore,  in ext2_get_blocks()
689 	 * another get_block allocated this branch) re-grab the chain to see if  in ext2_get_blocks()
693 	 * at this point, we will have the current copy of the chain when we  in ext2_get_blocks()
696 	if (err == -EAGAIN || !verify_chain(chain, partial)) {  in ext2_get_blocks()
697 		while (partial > chain) {  in ext2_get_blocks()
701 		partial = ext2_get_branch(inode, depth, offsets, chain, &err);  in ext2_get_blocks()
724 	indirect_blks = (chain + depth) - partial - 1;  in ext2_get_blocks()
735 				offsets + (partial - chain), partial);  in ext2_get_blocks()
748 				   le32_to_cpu(chain[depth-1].key),  in ext2_get_blocks()
756 				le32_to_cpu(chain[depth-1].key), count,  in ext2_get_blocks()
772 	partial = chain + depth - 1;	/* the whole chain */  in ext2_get_blocks()
774 	while (partial > chain) {  in ext2_get_blocks()
779 		*bno = le32_to_cpu(chain[depth-1].key);  in ext2_get_blocks()
1008  *	@chain:	  place to store the pointers to partial indirect blocks
1025  *	truncated blocks - in @chain[].bh and pointers to their last elements
1026  *	that should not be removed - in @chain[].p. Return value is the pointer
1027  *	to last filled element of @chain.
1032  *			(@chain[i].p+1 .. end of @chain[i].bh->b_data)
1033  *		c) free the subtrees growing from the inode past the @chain[0].p
1040 				Indirect chain[4],  in ext2_find_shared()
1049 	partial = ext2_get_branch(inode, k, offsets, chain, &err);  in ext2_find_shared()
1051 		partial = chain + k-1;  in ext2_find_shared()
1061 	for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)  in ext2_find_shared()
1069 	if (p == chain + k - 1 && p > chain) {  in ext2_find_shared()
1178 	Indirect chain[4];  in __ext2_truncate_blocks()  local
1207 	partial = ext2_find_shared(inode, n, offsets, chain, &nr);  in __ext2_truncate_blocks()
1210 		if (partial == chain)  in __ext2_truncate_blocks()
1214 		ext2_free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);  in __ext2_truncate_blocks()
1217 	while (partial > chain) {  in __ext2_truncate_blocks()
1221 				   (chain+n-1) - partial);  in __ext2_truncate_blocks()