1474 строки
43 KiB
C
1474 строки
43 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* linux/fs/ext4/indirect.c
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*
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* from
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*
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* linux/fs/ext4/inode.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/inode.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* Goal-directed block allocation by Stephen Tweedie
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* (sct@redhat.com), 1993, 1998
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*/
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#include "ext4_jbd2.h"
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#include "truncate.h"
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#include <linux/dax.h>
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#include <linux/uio.h>
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#include <trace/events/ext4.h>
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typedef struct {
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__le32 *p;
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__le32 key;
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struct buffer_head *bh;
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} Indirect;
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static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
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{
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p->key = *(p->p = v);
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p->bh = bh;
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}
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/**
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* ext4_block_to_path - parse the block number into array of offsets
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* @inode: inode in question (we are only interested in its superblock)
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* @i_block: block number to be parsed
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* @offsets: array to store the offsets in
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* @boundary: set this non-zero if the referred-to block is likely to be
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* followed (on disk) by an indirect block.
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*
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* To store the locations of file's data ext4 uses a data structure common
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* for UNIX filesystems - tree of pointers anchored in the inode, with
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* data blocks at leaves and indirect blocks in intermediate nodes.
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* This function translates the block number into path in that tree -
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* return value is the path length and @offsets[n] is the offset of
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* pointer to (n+1)th node in the nth one. If @block is out of range
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* (negative or too large) warning is printed and zero returned.
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*
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* Note: function doesn't find node addresses, so no IO is needed. All
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* we need to know is the capacity of indirect blocks (taken from the
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* inode->i_sb).
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*/
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/*
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* Portability note: the last comparison (check that we fit into triple
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* indirect block) is spelled differently, because otherwise on an
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* architecture with 32-bit longs and 8Kb pages we might get into trouble
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* if our filesystem had 8Kb blocks. We might use long long, but that would
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* kill us on x86. Oh, well, at least the sign propagation does not matter -
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* i_block would have to be negative in the very beginning, so we would not
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* get there at all.
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*/
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static int ext4_block_to_path(struct inode *inode,
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ext4_lblk_t i_block,
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ext4_lblk_t offsets[4], int *boundary)
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{
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int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
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int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
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const long direct_blocks = EXT4_NDIR_BLOCKS,
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indirect_blocks = ptrs,
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double_blocks = (1 << (ptrs_bits * 2));
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int n = 0;
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int final = 0;
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if (i_block < direct_blocks) {
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offsets[n++] = i_block;
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final = direct_blocks;
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} else if ((i_block -= direct_blocks) < indirect_blocks) {
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offsets[n++] = EXT4_IND_BLOCK;
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offsets[n++] = i_block;
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final = ptrs;
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} else if ((i_block -= indirect_blocks) < double_blocks) {
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offsets[n++] = EXT4_DIND_BLOCK;
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offsets[n++] = i_block >> ptrs_bits;
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offsets[n++] = i_block & (ptrs - 1);
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final = ptrs;
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} else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
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offsets[n++] = EXT4_TIND_BLOCK;
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offsets[n++] = i_block >> (ptrs_bits * 2);
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offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
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offsets[n++] = i_block & (ptrs - 1);
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final = ptrs;
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} else {
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ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
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i_block + direct_blocks +
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indirect_blocks + double_blocks, inode->i_ino);
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}
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if (boundary)
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*boundary = final - 1 - (i_block & (ptrs - 1));
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return n;
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}
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/**
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* ext4_get_branch - read the chain of indirect blocks leading to data
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* @inode: inode in question
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* @depth: depth of the chain (1 - direct pointer, etc.)
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* @offsets: offsets of pointers in inode/indirect blocks
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* @chain: place to store the result
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* @err: here we store the error value
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*
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* Function fills the array of triples <key, p, bh> and returns %NULL
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* if everything went OK or the pointer to the last filled triple
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* (incomplete one) otherwise. Upon the return chain[i].key contains
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* the number of (i+1)-th block in the chain (as it is stored in memory,
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* i.e. little-endian 32-bit), chain[i].p contains the address of that
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* number (it points into struct inode for i==0 and into the bh->b_data
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* for i>0) and chain[i].bh points to the buffer_head of i-th indirect
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* block for i>0 and NULL for i==0. In other words, it holds the block
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* numbers of the chain, addresses they were taken from (and where we can
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* verify that chain did not change) and buffer_heads hosting these
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* numbers.
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*
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* Function stops when it stumbles upon zero pointer (absent block)
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* (pointer to last triple returned, *@err == 0)
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* or when it gets an IO error reading an indirect block
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* (ditto, *@err == -EIO)
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* or when it reads all @depth-1 indirect blocks successfully and finds
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* the whole chain, all way to the data (returns %NULL, *err == 0).
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*
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* Need to be called with
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* down_read(&EXT4_I(inode)->i_data_sem)
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*/
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static Indirect *ext4_get_branch(struct inode *inode, int depth,
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ext4_lblk_t *offsets,
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Indirect chain[4], int *err)
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{
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struct super_block *sb = inode->i_sb;
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Indirect *p = chain;
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struct buffer_head *bh;
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unsigned int key;
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int ret = -EIO;
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*err = 0;
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/* i_data is not going away, no lock needed */
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add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
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if (!p->key)
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goto no_block;
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while (--depth) {
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key = le32_to_cpu(p->key);
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if (key > ext4_blocks_count(EXT4_SB(sb)->s_es)) {
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/* the block was out of range */
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ret = -EFSCORRUPTED;
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goto failure;
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}
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bh = sb_getblk(sb, key);
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if (unlikely(!bh)) {
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ret = -ENOMEM;
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goto failure;
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}
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if (!bh_uptodate_or_lock(bh)) {
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if (ext4_read_bh(bh, 0, NULL) < 0) {
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put_bh(bh);
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goto failure;
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}
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/* validate block references */
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if (ext4_check_indirect_blockref(inode, bh)) {
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put_bh(bh);
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goto failure;
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}
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}
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add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
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/* Reader: end */
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if (!p->key)
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goto no_block;
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}
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return NULL;
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failure:
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*err = ret;
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no_block:
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return p;
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}
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/**
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* ext4_find_near - find a place for allocation with sufficient locality
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* @inode: owner
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* @ind: descriptor of indirect block.
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*
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* This function returns the preferred place for block allocation.
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* It is used when heuristic for sequential allocation fails.
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* Rules are:
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* + if there is a block to the left of our position - allocate near it.
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* + if pointer will live in indirect block - allocate near that block.
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* + if pointer will live in inode - allocate in the same
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* cylinder group.
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*
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* In the latter case we colour the starting block by the callers PID to
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* prevent it from clashing with concurrent allocations for a different inode
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* in the same block group. The PID is used here so that functionally related
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* files will be close-by on-disk.
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*
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* Caller must make sure that @ind is valid and will stay that way.
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*/
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static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
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{
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struct ext4_inode_info *ei = EXT4_I(inode);
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__le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
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__le32 *p;
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/* Try to find previous block */
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for (p = ind->p - 1; p >= start; p--) {
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if (*p)
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return le32_to_cpu(*p);
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}
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/* No such thing, so let's try location of indirect block */
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if (ind->bh)
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return ind->bh->b_blocknr;
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/*
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* It is going to be referred to from the inode itself? OK, just put it
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* into the same cylinder group then.
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*/
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return ext4_inode_to_goal_block(inode);
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}
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/**
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* ext4_find_goal - find a preferred place for allocation.
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* @inode: owner
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* @block: block we want
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* @partial: pointer to the last triple within a chain
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*
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* Normally this function find the preferred place for block allocation,
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* returns it.
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* Because this is only used for non-extent files, we limit the block nr
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* to 32 bits.
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*/
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static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
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Indirect *partial)
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{
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ext4_fsblk_t goal;
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/*
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* XXX need to get goal block from mballoc's data structures
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*/
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goal = ext4_find_near(inode, partial);
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goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
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return goal;
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}
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/**
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* ext4_blks_to_allocate - Look up the block map and count the number
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* of direct blocks need to be allocated for the given branch.
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*
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* @branch: chain of indirect blocks
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* @k: number of blocks need for indirect blocks
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* @blks: number of data blocks to be mapped.
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* @blocks_to_boundary: the offset in the indirect block
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*
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* return the total number of blocks to be allocate, including the
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* direct and indirect blocks.
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*/
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static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
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int blocks_to_boundary)
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{
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unsigned int count = 0;
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/*
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* Simple case, [t,d]Indirect block(s) has not allocated yet
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* then it's clear blocks on that path have not allocated
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*/
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if (k > 0) {
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/* right now we don't handle cross boundary allocation */
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if (blks < blocks_to_boundary + 1)
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count += blks;
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else
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count += blocks_to_boundary + 1;
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return count;
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}
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count++;
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while (count < blks && count <= blocks_to_boundary &&
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le32_to_cpu(*(branch[0].p + count)) == 0) {
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count++;
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}
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return count;
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}
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/**
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* ext4_alloc_branch() - allocate and set up a chain of blocks
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* @handle: handle for this transaction
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* @ar: structure describing the allocation request
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* @indirect_blks: number of allocated indirect blocks
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* @offsets: offsets (in the blocks) to store the pointers to next.
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* @branch: place to store the chain in.
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*
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* This function allocates blocks, zeroes out all but the last one,
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* links them into chain and (if we are synchronous) writes them to disk.
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* In other words, it prepares a branch that can be spliced onto the
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* inode. It stores the information about that chain in the branch[], in
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* the same format as ext4_get_branch() would do. We are calling it after
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* we had read the existing part of chain and partial points to the last
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* triple of that (one with zero ->key). Upon the exit we have the same
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* picture as after the successful ext4_get_block(), except that in one
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* place chain is disconnected - *branch->p is still zero (we did not
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* set the last link), but branch->key contains the number that should
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* be placed into *branch->p to fill that gap.
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*
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* If allocation fails we free all blocks we've allocated (and forget
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* their buffer_heads) and return the error value the from failed
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* ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
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* as described above and return 0.
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*/
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static int ext4_alloc_branch(handle_t *handle,
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struct ext4_allocation_request *ar,
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int indirect_blks, ext4_lblk_t *offsets,
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Indirect *branch)
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{
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struct buffer_head * bh;
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ext4_fsblk_t b, new_blocks[4];
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__le32 *p;
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int i, j, err, len = 1;
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for (i = 0; i <= indirect_blks; i++) {
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if (i == indirect_blks) {
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new_blocks[i] = ext4_mb_new_blocks(handle, ar, &err);
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} else {
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ar->goal = new_blocks[i] = ext4_new_meta_blocks(handle,
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ar->inode, ar->goal,
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ar->flags & EXT4_MB_DELALLOC_RESERVED,
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NULL, &err);
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/* Simplify error cleanup... */
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branch[i+1].bh = NULL;
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}
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if (err) {
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i--;
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goto failed;
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}
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branch[i].key = cpu_to_le32(new_blocks[i]);
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if (i == 0)
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continue;
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bh = branch[i].bh = sb_getblk(ar->inode->i_sb, new_blocks[i-1]);
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if (unlikely(!bh)) {
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err = -ENOMEM;
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goto failed;
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}
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lock_buffer(bh);
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BUFFER_TRACE(bh, "call get_create_access");
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err = ext4_journal_get_create_access(handle, ar->inode->i_sb,
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bh, EXT4_JTR_NONE);
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if (err) {
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unlock_buffer(bh);
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goto failed;
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}
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memset(bh->b_data, 0, bh->b_size);
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p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
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b = new_blocks[i];
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if (i == indirect_blks)
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len = ar->len;
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for (j = 0; j < len; j++)
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*p++ = cpu_to_le32(b++);
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BUFFER_TRACE(bh, "marking uptodate");
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set_buffer_uptodate(bh);
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unlock_buffer(bh);
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BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
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err = ext4_handle_dirty_metadata(handle, ar->inode, bh);
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if (err)
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goto failed;
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}
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return 0;
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failed:
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if (i == indirect_blks) {
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/* Free data blocks */
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ext4_free_blocks(handle, ar->inode, NULL, new_blocks[i],
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ar->len, 0);
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i--;
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}
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for (; i >= 0; i--) {
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/*
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* We want to ext4_forget() only freshly allocated indirect
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* blocks. Buffer for new_blocks[i] is at branch[i+1].bh
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* (buffer at branch[0].bh is indirect block / inode already
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* existing before ext4_alloc_branch() was called). Also
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* because blocks are freshly allocated, we don't need to
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* revoke them which is why we don't set
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* EXT4_FREE_BLOCKS_METADATA.
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*/
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ext4_free_blocks(handle, ar->inode, branch[i+1].bh,
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new_blocks[i], 1,
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branch[i+1].bh ? EXT4_FREE_BLOCKS_FORGET : 0);
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}
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return err;
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}
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/**
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* ext4_splice_branch() - splice the allocated branch onto inode.
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* @handle: handle for this transaction
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* @ar: structure describing the allocation request
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* @where: location of missing link
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* @num: number of indirect blocks we are adding
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*
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* This function fills the missing link and does all housekeeping needed in
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* inode (->i_blocks, etc.). In case of success we end up with the full
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* chain to new block and return 0.
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*/
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static int ext4_splice_branch(handle_t *handle,
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struct ext4_allocation_request *ar,
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Indirect *where, int num)
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{
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int i;
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int err = 0;
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ext4_fsblk_t current_block;
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/*
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* If we're splicing into a [td]indirect block (as opposed to the
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* inode) then we need to get write access to the [td]indirect block
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* before the splice.
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*/
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if (where->bh) {
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BUFFER_TRACE(where->bh, "get_write_access");
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err = ext4_journal_get_write_access(handle, ar->inode->i_sb,
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where->bh, EXT4_JTR_NONE);
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if (err)
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goto err_out;
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}
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/* That's it */
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*where->p = where->key;
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/*
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* Update the host buffer_head or inode to point to more just allocated
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* direct blocks blocks
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*/
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if (num == 0 && ar->len > 1) {
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current_block = le32_to_cpu(where->key) + 1;
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for (i = 1; i < ar->len; i++)
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*(where->p + i) = cpu_to_le32(current_block++);
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}
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/* We are done with atomic stuff, now do the rest of housekeeping */
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/* had we spliced it onto indirect block? */
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if (where->bh) {
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/*
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* If we spliced it onto an indirect block, we haven't
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* altered the inode. Note however that if it is being spliced
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* onto an indirect block at the very end of the file (the
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* file is growing) then we *will* alter the inode to reflect
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* the new i_size. But that is not done here - it is done in
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* generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
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*/
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ext4_debug("splicing indirect only\n");
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BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
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err = ext4_handle_dirty_metadata(handle, ar->inode, where->bh);
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if (err)
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goto err_out;
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} else {
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/*
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* OK, we spliced it into the inode itself on a direct block.
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*/
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err = ext4_mark_inode_dirty(handle, ar->inode);
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if (unlikely(err))
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goto err_out;
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ext4_debug("splicing direct\n");
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}
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return err;
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err_out:
|
|
for (i = 1; i <= num; i++) {
|
|
/*
|
|
* branch[i].bh is newly allocated, so there is no
|
|
* need to revoke the block, which is why we don't
|
|
* need to set EXT4_FREE_BLOCKS_METADATA.
|
|
*/
|
|
ext4_free_blocks(handle, ar->inode, where[i].bh, 0, 1,
|
|
EXT4_FREE_BLOCKS_FORGET);
|
|
}
|
|
ext4_free_blocks(handle, ar->inode, NULL, le32_to_cpu(where[num].key),
|
|
ar->len, 0);
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* The ext4_ind_map_blocks() function handles non-extents inodes
|
|
* (i.e., using the traditional indirect/double-indirect i_blocks
|
|
* scheme) for ext4_map_blocks().
|
|
*
|
|
* Allocation strategy is simple: if we have to allocate something, we will
|
|
* have to go the whole way to leaf. So let's do it before attaching anything
|
|
* to tree, set linkage between the newborn blocks, write them if sync is
|
|
* required, recheck the path, free and repeat if check fails, otherwise
|
|
* set the last missing link (that will protect us from any truncate-generated
|
|
* removals - all blocks on the path are immune now) and possibly force the
|
|
* write on the parent block.
|
|
* That has a nice additional property: no special recovery from the failed
|
|
* allocations is needed - we simply release blocks and do not touch anything
|
|
* reachable from inode.
|
|
*
|
|
* `handle' can be NULL if create == 0.
|
|
*
|
|
* return > 0, # of blocks mapped or allocated.
|
|
* return = 0, if plain lookup failed.
|
|
* return < 0, error case.
|
|
*
|
|
* The ext4_ind_get_blocks() function should be called with
|
|
* down_write(&EXT4_I(inode)->i_data_sem) if allocating filesystem
|
|
* blocks (i.e., flags has EXT4_GET_BLOCKS_CREATE set) or
|
|
* down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system
|
|
* blocks.
|
|
*/
|
|
int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
|
|
struct ext4_map_blocks *map,
|
|
int flags)
|
|
{
|
|
struct ext4_allocation_request ar;
|
|
int err = -EIO;
|
|
ext4_lblk_t offsets[4];
|
|
Indirect chain[4];
|
|
Indirect *partial;
|
|
int indirect_blks;
|
|
int blocks_to_boundary = 0;
|
|
int depth;
|
|
int count = 0;
|
|
ext4_fsblk_t first_block = 0;
|
|
|
|
trace_ext4_ind_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
|
|
ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
|
|
ASSERT(handle != NULL || (flags & EXT4_GET_BLOCKS_CREATE) == 0);
|
|
depth = ext4_block_to_path(inode, map->m_lblk, offsets,
|
|
&blocks_to_boundary);
|
|
|
|
if (depth == 0)
|
|
goto out;
|
|
|
|
partial = ext4_get_branch(inode, depth, offsets, chain, &err);
|
|
|
|
/* Simplest case - block found, no allocation needed */
|
|
if (!partial) {
|
|
first_block = le32_to_cpu(chain[depth - 1].key);
|
|
count++;
|
|
/*map more blocks*/
|
|
while (count < map->m_len && count <= blocks_to_boundary) {
|
|
ext4_fsblk_t blk;
|
|
|
|
blk = le32_to_cpu(*(chain[depth-1].p + count));
|
|
|
|
if (blk == first_block + count)
|
|
count++;
|
|
else
|
|
break;
|
|
}
|
|
goto got_it;
|
|
}
|
|
|
|
/* Next simple case - plain lookup failed */
|
|
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
|
|
unsigned epb = inode->i_sb->s_blocksize / sizeof(u32);
|
|
int i;
|
|
|
|
/*
|
|
* Count number blocks in a subtree under 'partial'. At each
|
|
* level we count number of complete empty subtrees beyond
|
|
* current offset and then descend into the subtree only
|
|
* partially beyond current offset.
|
|
*/
|
|
count = 0;
|
|
for (i = partial - chain + 1; i < depth; i++)
|
|
count = count * epb + (epb - offsets[i] - 1);
|
|
count++;
|
|
/* Fill in size of a hole we found */
|
|
map->m_pblk = 0;
|
|
map->m_len = min_t(unsigned int, map->m_len, count);
|
|
goto cleanup;
|
|
}
|
|
|
|
/* Failed read of indirect block */
|
|
if (err == -EIO)
|
|
goto cleanup;
|
|
|
|
/*
|
|
* Okay, we need to do block allocation.
|
|
*/
|
|
if (ext4_has_feature_bigalloc(inode->i_sb)) {
|
|
EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
|
|
"non-extent mapped inodes with bigalloc");
|
|
err = -EFSCORRUPTED;
|
|
goto out;
|
|
}
|
|
|
|
/* Set up for the direct block allocation */
|
|
memset(&ar, 0, sizeof(ar));
|
|
ar.inode = inode;
|
|
ar.logical = map->m_lblk;
|
|
if (S_ISREG(inode->i_mode))
|
|
ar.flags = EXT4_MB_HINT_DATA;
|
|
if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
|
|
ar.flags |= EXT4_MB_DELALLOC_RESERVED;
|
|
if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
|
|
ar.flags |= EXT4_MB_USE_RESERVED;
|
|
|
|
ar.goal = ext4_find_goal(inode, map->m_lblk, partial);
|
|
|
|
/* the number of blocks need to allocate for [d,t]indirect blocks */
|
|
indirect_blks = (chain + depth) - partial - 1;
|
|
|
|
/*
|
|
* Next look up the indirect map to count the totoal number of
|
|
* direct blocks to allocate for this branch.
|
|
*/
|
|
ar.len = ext4_blks_to_allocate(partial, indirect_blks,
|
|
map->m_len, blocks_to_boundary);
|
|
|
|
/*
|
|
* Block out ext4_truncate while we alter the tree
|
|
*/
|
|
err = ext4_alloc_branch(handle, &ar, indirect_blks,
|
|
offsets + (partial - chain), partial);
|
|
|
|
/*
|
|
* The ext4_splice_branch call will free and forget any buffers
|
|
* on the new chain if there is a failure, but that risks using
|
|
* up transaction credits, especially for bitmaps where the
|
|
* credits cannot be returned. Can we handle this somehow? We
|
|
* may need to return -EAGAIN upwards in the worst case. --sct
|
|
*/
|
|
if (!err)
|
|
err = ext4_splice_branch(handle, &ar, partial, indirect_blks);
|
|
if (err)
|
|
goto cleanup;
|
|
|
|
map->m_flags |= EXT4_MAP_NEW;
|
|
|
|
ext4_update_inode_fsync_trans(handle, inode, 1);
|
|
count = ar.len;
|
|
got_it:
|
|
map->m_flags |= EXT4_MAP_MAPPED;
|
|
map->m_pblk = le32_to_cpu(chain[depth-1].key);
|
|
map->m_len = count;
|
|
if (count > blocks_to_boundary)
|
|
map->m_flags |= EXT4_MAP_BOUNDARY;
|
|
err = count;
|
|
/* Clean up and exit */
|
|
partial = chain + depth - 1; /* the whole chain */
|
|
cleanup:
|
|
while (partial > chain) {
|
|
BUFFER_TRACE(partial->bh, "call brelse");
|
|
brelse(partial->bh);
|
|
partial--;
|
|
}
|
|
out:
|
|
trace_ext4_ind_map_blocks_exit(inode, flags, map, err);
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* Calculate number of indirect blocks touched by mapping @nrblocks logically
|
|
* contiguous blocks
|
|
*/
|
|
int ext4_ind_trans_blocks(struct inode *inode, int nrblocks)
|
|
{
|
|
/*
|
|
* With N contiguous data blocks, we need at most
|
|
* N/EXT4_ADDR_PER_BLOCK(inode->i_sb) + 1 indirect blocks,
|
|
* 2 dindirect blocks, and 1 tindirect block
|
|
*/
|
|
return DIV_ROUND_UP(nrblocks, EXT4_ADDR_PER_BLOCK(inode->i_sb)) + 4;
|
|
}
|
|
|
|
static int ext4_ind_trunc_restart_fn(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *bh, int *dropped)
|
|
{
|
|
int err;
|
|
|
|
if (bh) {
|
|
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
|
|
err = ext4_handle_dirty_metadata(handle, inode, bh);
|
|
if (unlikely(err))
|
|
return err;
|
|
}
|
|
err = ext4_mark_inode_dirty(handle, inode);
|
|
if (unlikely(err))
|
|
return err;
|
|
/*
|
|
* Drop i_data_sem to avoid deadlock with ext4_map_blocks. At this
|
|
* moment, get_block can be called only for blocks inside i_size since
|
|
* page cache has been already dropped and writes are blocked by
|
|
* i_rwsem. So we can safely drop the i_data_sem here.
|
|
*/
|
|
BUG_ON(EXT4_JOURNAL(inode) == NULL);
|
|
ext4_discard_preallocations(inode, 0);
|
|
up_write(&EXT4_I(inode)->i_data_sem);
|
|
*dropped = 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Truncate transactions can be complex and absolutely huge. So we need to
|
|
* be able to restart the transaction at a convenient checkpoint to make
|
|
* sure we don't overflow the journal.
|
|
*
|
|
* Try to extend this transaction for the purposes of truncation. If
|
|
* extend fails, we restart transaction.
|
|
*/
|
|
static int ext4_ind_truncate_ensure_credits(handle_t *handle,
|
|
struct inode *inode,
|
|
struct buffer_head *bh,
|
|
int revoke_creds)
|
|
{
|
|
int ret;
|
|
int dropped = 0;
|
|
|
|
ret = ext4_journal_ensure_credits_fn(handle, EXT4_RESERVE_TRANS_BLOCKS,
|
|
ext4_blocks_for_truncate(inode), revoke_creds,
|
|
ext4_ind_trunc_restart_fn(handle, inode, bh, &dropped));
|
|
if (dropped)
|
|
down_write(&EXT4_I(inode)->i_data_sem);
|
|
if (ret <= 0)
|
|
return ret;
|
|
if (bh) {
|
|
BUFFER_TRACE(bh, "retaking write access");
|
|
ret = ext4_journal_get_write_access(handle, inode->i_sb, bh,
|
|
EXT4_JTR_NONE);
|
|
if (unlikely(ret))
|
|
return ret;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Probably it should be a library function... search for first non-zero word
|
|
* or memcmp with zero_page, whatever is better for particular architecture.
|
|
* Linus?
|
|
*/
|
|
static inline int all_zeroes(__le32 *p, __le32 *q)
|
|
{
|
|
while (p < q)
|
|
if (*p++)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* ext4_find_shared - find the indirect blocks for partial truncation.
|
|
* @inode: inode in question
|
|
* @depth: depth of the affected branch
|
|
* @offsets: offsets of pointers in that branch (see ext4_block_to_path)
|
|
* @chain: place to store the pointers to partial indirect blocks
|
|
* @top: place to the (detached) top of branch
|
|
*
|
|
* This is a helper function used by ext4_truncate().
|
|
*
|
|
* When we do truncate() we may have to clean the ends of several
|
|
* indirect blocks but leave the blocks themselves alive. Block is
|
|
* partially truncated if some data below the new i_size is referred
|
|
* from it (and it is on the path to the first completely truncated
|
|
* data block, indeed). We have to free the top of that path along
|
|
* with everything to the right of the path. Since no allocation
|
|
* past the truncation point is possible until ext4_truncate()
|
|
* finishes, we may safely do the latter, but top of branch may
|
|
* require special attention - pageout below the truncation point
|
|
* might try to populate it.
|
|
*
|
|
* We atomically detach the top of branch from the tree, store the
|
|
* block number of its root in *@top, pointers to buffer_heads of
|
|
* partially truncated blocks - in @chain[].bh and pointers to
|
|
* their last elements that should not be removed - in
|
|
* @chain[].p. Return value is the pointer to last filled element
|
|
* of @chain.
|
|
*
|
|
* The work left to caller to do the actual freeing of subtrees:
|
|
* a) free the subtree starting from *@top
|
|
* b) free the subtrees whose roots are stored in
|
|
* (@chain[i].p+1 .. end of @chain[i].bh->b_data)
|
|
* c) free the subtrees growing from the inode past the @chain[0].
|
|
* (no partially truncated stuff there). */
|
|
|
|
static Indirect *ext4_find_shared(struct inode *inode, int depth,
|
|
ext4_lblk_t offsets[4], Indirect chain[4],
|
|
__le32 *top)
|
|
{
|
|
Indirect *partial, *p;
|
|
int k, err;
|
|
|
|
*top = 0;
|
|
/* Make k index the deepest non-null offset + 1 */
|
|
for (k = depth; k > 1 && !offsets[k-1]; k--)
|
|
;
|
|
partial = ext4_get_branch(inode, k, offsets, chain, &err);
|
|
/* Writer: pointers */
|
|
if (!partial)
|
|
partial = chain + k-1;
|
|
/*
|
|
* If the branch acquired continuation since we've looked at it -
|
|
* fine, it should all survive and (new) top doesn't belong to us.
|
|
*/
|
|
if (!partial->key && *partial->p)
|
|
/* Writer: end */
|
|
goto no_top;
|
|
for (p = partial; (p > chain) && all_zeroes((__le32 *) p->bh->b_data, p->p); p--)
|
|
;
|
|
/*
|
|
* OK, we've found the last block that must survive. The rest of our
|
|
* branch should be detached before unlocking. However, if that rest
|
|
* of branch is all ours and does not grow immediately from the inode
|
|
* it's easier to cheat and just decrement partial->p.
|
|
*/
|
|
if (p == chain + k - 1 && p > chain) {
|
|
p->p--;
|
|
} else {
|
|
*top = *p->p;
|
|
/* Nope, don't do this in ext4. Must leave the tree intact */
|
|
#if 0
|
|
*p->p = 0;
|
|
#endif
|
|
}
|
|
/* Writer: end */
|
|
|
|
while (partial > p) {
|
|
brelse(partial->bh);
|
|
partial--;
|
|
}
|
|
no_top:
|
|
return partial;
|
|
}
|
|
|
|
/*
|
|
* Zero a number of block pointers in either an inode or an indirect block.
|
|
* If we restart the transaction we must again get write access to the
|
|
* indirect block for further modification.
|
|
*
|
|
* We release `count' blocks on disk, but (last - first) may be greater
|
|
* than `count' because there can be holes in there.
|
|
*
|
|
* Return 0 on success, 1 on invalid block range
|
|
* and < 0 on fatal error.
|
|
*/
|
|
static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *bh,
|
|
ext4_fsblk_t block_to_free,
|
|
unsigned long count, __le32 *first,
|
|
__le32 *last)
|
|
{
|
|
__le32 *p;
|
|
int flags = EXT4_FREE_BLOCKS_VALIDATED;
|
|
int err;
|
|
|
|
if (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode) ||
|
|
ext4_test_inode_flag(inode, EXT4_INODE_EA_INODE))
|
|
flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
|
|
else if (ext4_should_journal_data(inode))
|
|
flags |= EXT4_FREE_BLOCKS_FORGET;
|
|
|
|
if (!ext4_inode_block_valid(inode, block_to_free, count)) {
|
|
EXT4_ERROR_INODE(inode, "attempt to clear invalid "
|
|
"blocks %llu len %lu",
|
|
(unsigned long long) block_to_free, count);
|
|
return 1;
|
|
}
|
|
|
|
err = ext4_ind_truncate_ensure_credits(handle, inode, bh,
|
|
ext4_free_data_revoke_credits(inode, count));
|
|
if (err < 0)
|
|
goto out_err;
|
|
|
|
for (p = first; p < last; p++)
|
|
*p = 0;
|
|
|
|
ext4_free_blocks(handle, inode, NULL, block_to_free, count, flags);
|
|
return 0;
|
|
out_err:
|
|
ext4_std_error(inode->i_sb, err);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* ext4_free_data - free a list of data blocks
|
|
* @handle: handle for this transaction
|
|
* @inode: inode we are dealing with
|
|
* @this_bh: indirect buffer_head which contains *@first and *@last
|
|
* @first: array of block numbers
|
|
* @last: points immediately past the end of array
|
|
*
|
|
* We are freeing all blocks referred from that array (numbers are stored as
|
|
* little-endian 32-bit) and updating @inode->i_blocks appropriately.
|
|
*
|
|
* We accumulate contiguous runs of blocks to free. Conveniently, if these
|
|
* blocks are contiguous then releasing them at one time will only affect one
|
|
* or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
|
|
* actually use a lot of journal space.
|
|
*
|
|
* @this_bh will be %NULL if @first and @last point into the inode's direct
|
|
* block pointers.
|
|
*/
|
|
static void ext4_free_data(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *this_bh,
|
|
__le32 *first, __le32 *last)
|
|
{
|
|
ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
|
|
unsigned long count = 0; /* Number of blocks in the run */
|
|
__le32 *block_to_free_p = NULL; /* Pointer into inode/ind
|
|
corresponding to
|
|
block_to_free */
|
|
ext4_fsblk_t nr; /* Current block # */
|
|
__le32 *p; /* Pointer into inode/ind
|
|
for current block */
|
|
int err = 0;
|
|
|
|
if (this_bh) { /* For indirect block */
|
|
BUFFER_TRACE(this_bh, "get_write_access");
|
|
err = ext4_journal_get_write_access(handle, inode->i_sb,
|
|
this_bh, EXT4_JTR_NONE);
|
|
/* Important: if we can't update the indirect pointers
|
|
* to the blocks, we can't free them. */
|
|
if (err)
|
|
return;
|
|
}
|
|
|
|
for (p = first; p < last; p++) {
|
|
nr = le32_to_cpu(*p);
|
|
if (nr) {
|
|
/* accumulate blocks to free if they're contiguous */
|
|
if (count == 0) {
|
|
block_to_free = nr;
|
|
block_to_free_p = p;
|
|
count = 1;
|
|
} else if (nr == block_to_free + count) {
|
|
count++;
|
|
} else {
|
|
err = ext4_clear_blocks(handle, inode, this_bh,
|
|
block_to_free, count,
|
|
block_to_free_p, p);
|
|
if (err)
|
|
break;
|
|
block_to_free = nr;
|
|
block_to_free_p = p;
|
|
count = 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!err && count > 0)
|
|
err = ext4_clear_blocks(handle, inode, this_bh, block_to_free,
|
|
count, block_to_free_p, p);
|
|
if (err < 0)
|
|
/* fatal error */
|
|
return;
|
|
|
|
if (this_bh) {
|
|
BUFFER_TRACE(this_bh, "call ext4_handle_dirty_metadata");
|
|
|
|
/*
|
|
* The buffer head should have an attached journal head at this
|
|
* point. However, if the data is corrupted and an indirect
|
|
* block pointed to itself, it would have been detached when
|
|
* the block was cleared. Check for this instead of OOPSing.
|
|
*/
|
|
if ((EXT4_JOURNAL(inode) == NULL) || bh2jh(this_bh))
|
|
ext4_handle_dirty_metadata(handle, inode, this_bh);
|
|
else
|
|
EXT4_ERROR_INODE(inode,
|
|
"circular indirect block detected at "
|
|
"block %llu",
|
|
(unsigned long long) this_bh->b_blocknr);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* ext4_free_branches - free an array of branches
|
|
* @handle: JBD handle for this transaction
|
|
* @inode: inode we are dealing with
|
|
* @parent_bh: the buffer_head which contains *@first and *@last
|
|
* @first: array of block numbers
|
|
* @last: pointer immediately past the end of array
|
|
* @depth: depth of the branches to free
|
|
*
|
|
* We are freeing all blocks referred from these branches (numbers are
|
|
* stored as little-endian 32-bit) and updating @inode->i_blocks
|
|
* appropriately.
|
|
*/
|
|
static void ext4_free_branches(handle_t *handle, struct inode *inode,
|
|
struct buffer_head *parent_bh,
|
|
__le32 *first, __le32 *last, int depth)
|
|
{
|
|
ext4_fsblk_t nr;
|
|
__le32 *p;
|
|
|
|
if (ext4_handle_is_aborted(handle))
|
|
return;
|
|
|
|
if (depth--) {
|
|
struct buffer_head *bh;
|
|
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
p = last;
|
|
while (--p >= first) {
|
|
nr = le32_to_cpu(*p);
|
|
if (!nr)
|
|
continue; /* A hole */
|
|
|
|
if (!ext4_inode_block_valid(inode, nr, 1)) {
|
|
EXT4_ERROR_INODE(inode,
|
|
"invalid indirect mapped "
|
|
"block %lu (level %d)",
|
|
(unsigned long) nr, depth);
|
|
break;
|
|
}
|
|
|
|
/* Go read the buffer for the next level down */
|
|
bh = ext4_sb_bread(inode->i_sb, nr, 0);
|
|
|
|
/*
|
|
* A read failure? Report error and clear slot
|
|
* (should be rare).
|
|
*/
|
|
if (IS_ERR(bh)) {
|
|
ext4_error_inode_block(inode, nr, -PTR_ERR(bh),
|
|
"Read failure");
|
|
continue;
|
|
}
|
|
|
|
/* This zaps the entire block. Bottom up. */
|
|
BUFFER_TRACE(bh, "free child branches");
|
|
ext4_free_branches(handle, inode, bh,
|
|
(__le32 *) bh->b_data,
|
|
(__le32 *) bh->b_data + addr_per_block,
|
|
depth);
|
|
brelse(bh);
|
|
|
|
/*
|
|
* Everything below this pointer has been
|
|
* released. Now let this top-of-subtree go.
|
|
*
|
|
* We want the freeing of this indirect block to be
|
|
* atomic in the journal with the updating of the
|
|
* bitmap block which owns it. So make some room in
|
|
* the journal.
|
|
*
|
|
* We zero the parent pointer *after* freeing its
|
|
* pointee in the bitmaps, so if extend_transaction()
|
|
* for some reason fails to put the bitmap changes and
|
|
* the release into the same transaction, recovery
|
|
* will merely complain about releasing a free block,
|
|
* rather than leaking blocks.
|
|
*/
|
|
if (ext4_handle_is_aborted(handle))
|
|
return;
|
|
if (ext4_ind_truncate_ensure_credits(handle, inode,
|
|
NULL,
|
|
ext4_free_metadata_revoke_credits(
|
|
inode->i_sb, 1)) < 0)
|
|
return;
|
|
|
|
/*
|
|
* The forget flag here is critical because if
|
|
* we are journaling (and not doing data
|
|
* journaling), we have to make sure a revoke
|
|
* record is written to prevent the journal
|
|
* replay from overwriting the (former)
|
|
* indirect block if it gets reallocated as a
|
|
* data block. This must happen in the same
|
|
* transaction where the data blocks are
|
|
* actually freed.
|
|
*/
|
|
ext4_free_blocks(handle, inode, NULL, nr, 1,
|
|
EXT4_FREE_BLOCKS_METADATA|
|
|
EXT4_FREE_BLOCKS_FORGET);
|
|
|
|
if (parent_bh) {
|
|
/*
|
|
* The block which we have just freed is
|
|
* pointed to by an indirect block: journal it
|
|
*/
|
|
BUFFER_TRACE(parent_bh, "get_write_access");
|
|
if (!ext4_journal_get_write_access(handle,
|
|
inode->i_sb, parent_bh,
|
|
EXT4_JTR_NONE)) {
|
|
*p = 0;
|
|
BUFFER_TRACE(parent_bh,
|
|
"call ext4_handle_dirty_metadata");
|
|
ext4_handle_dirty_metadata(handle,
|
|
inode,
|
|
parent_bh);
|
|
}
|
|
}
|
|
}
|
|
} else {
|
|
/* We have reached the bottom of the tree. */
|
|
BUFFER_TRACE(parent_bh, "free data blocks");
|
|
ext4_free_data(handle, inode, parent_bh, first, last);
|
|
}
|
|
}
|
|
|
|
void ext4_ind_truncate(handle_t *handle, struct inode *inode)
|
|
{
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
__le32 *i_data = ei->i_data;
|
|
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
ext4_lblk_t offsets[4];
|
|
Indirect chain[4];
|
|
Indirect *partial;
|
|
__le32 nr = 0;
|
|
int n = 0;
|
|
ext4_lblk_t last_block, max_block;
|
|
unsigned blocksize = inode->i_sb->s_blocksize;
|
|
|
|
last_block = (inode->i_size + blocksize-1)
|
|
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
|
max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
|
|
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
|
|
|
if (last_block != max_block) {
|
|
n = ext4_block_to_path(inode, last_block, offsets, NULL);
|
|
if (n == 0)
|
|
return;
|
|
}
|
|
|
|
ext4_es_remove_extent(inode, last_block, EXT_MAX_BLOCKS - last_block);
|
|
|
|
/*
|
|
* The orphan list entry will now protect us from any crash which
|
|
* occurs before the truncate completes, so it is now safe to propagate
|
|
* the new, shorter inode size (held for now in i_size) into the
|
|
* on-disk inode. We do this via i_disksize, which is the value which
|
|
* ext4 *really* writes onto the disk inode.
|
|
*/
|
|
ei->i_disksize = inode->i_size;
|
|
|
|
if (last_block == max_block) {
|
|
/*
|
|
* It is unnecessary to free any data blocks if last_block is
|
|
* equal to the indirect block limit.
|
|
*/
|
|
return;
|
|
} else if (n == 1) { /* direct blocks */
|
|
ext4_free_data(handle, inode, NULL, i_data+offsets[0],
|
|
i_data + EXT4_NDIR_BLOCKS);
|
|
goto do_indirects;
|
|
}
|
|
|
|
partial = ext4_find_shared(inode, n, offsets, chain, &nr);
|
|
/* Kill the top of shared branch (not detached) */
|
|
if (nr) {
|
|
if (partial == chain) {
|
|
/* Shared branch grows from the inode */
|
|
ext4_free_branches(handle, inode, NULL,
|
|
&nr, &nr+1, (chain+n-1) - partial);
|
|
*partial->p = 0;
|
|
/*
|
|
* We mark the inode dirty prior to restart,
|
|
* and prior to stop. No need for it here.
|
|
*/
|
|
} else {
|
|
/* Shared branch grows from an indirect block */
|
|
BUFFER_TRACE(partial->bh, "get_write_access");
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p,
|
|
partial->p+1, (chain+n-1) - partial);
|
|
}
|
|
}
|
|
/* Clear the ends of indirect blocks on the shared branch */
|
|
while (partial > chain) {
|
|
ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
|
|
(__le32*)partial->bh->b_data+addr_per_block,
|
|
(chain+n-1) - partial);
|
|
BUFFER_TRACE(partial->bh, "call brelse");
|
|
brelse(partial->bh);
|
|
partial--;
|
|
}
|
|
do_indirects:
|
|
/* Kill the remaining (whole) subtrees */
|
|
switch (offsets[0]) {
|
|
default:
|
|
nr = i_data[EXT4_IND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
|
|
i_data[EXT4_IND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_IND_BLOCK:
|
|
nr = i_data[EXT4_DIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
|
|
i_data[EXT4_DIND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_DIND_BLOCK:
|
|
nr = i_data[EXT4_TIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
|
|
i_data[EXT4_TIND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_TIND_BLOCK:
|
|
;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* ext4_ind_remove_space - remove space from the range
|
|
* @handle: JBD handle for this transaction
|
|
* @inode: inode we are dealing with
|
|
* @start: First block to remove
|
|
* @end: One block after the last block to remove (exclusive)
|
|
*
|
|
* Free the blocks in the defined range (end is exclusive endpoint of
|
|
* range). This is used by ext4_punch_hole().
|
|
*/
|
|
int ext4_ind_remove_space(handle_t *handle, struct inode *inode,
|
|
ext4_lblk_t start, ext4_lblk_t end)
|
|
{
|
|
struct ext4_inode_info *ei = EXT4_I(inode);
|
|
__le32 *i_data = ei->i_data;
|
|
int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
|
|
ext4_lblk_t offsets[4], offsets2[4];
|
|
Indirect chain[4], chain2[4];
|
|
Indirect *partial, *partial2;
|
|
Indirect *p = NULL, *p2 = NULL;
|
|
ext4_lblk_t max_block;
|
|
__le32 nr = 0, nr2 = 0;
|
|
int n = 0, n2 = 0;
|
|
unsigned blocksize = inode->i_sb->s_blocksize;
|
|
|
|
max_block = (EXT4_SB(inode->i_sb)->s_bitmap_maxbytes + blocksize-1)
|
|
>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
|
|
if (end >= max_block)
|
|
end = max_block;
|
|
if ((start >= end) || (start > max_block))
|
|
return 0;
|
|
|
|
n = ext4_block_to_path(inode, start, offsets, NULL);
|
|
n2 = ext4_block_to_path(inode, end, offsets2, NULL);
|
|
|
|
BUG_ON(n > n2);
|
|
|
|
if ((n == 1) && (n == n2)) {
|
|
/* We're punching only within direct block range */
|
|
ext4_free_data(handle, inode, NULL, i_data + offsets[0],
|
|
i_data + offsets2[0]);
|
|
return 0;
|
|
} else if (n2 > n) {
|
|
/*
|
|
* Start and end are on a different levels so we're going to
|
|
* free partial block at start, and partial block at end of
|
|
* the range. If there are some levels in between then
|
|
* do_indirects label will take care of that.
|
|
*/
|
|
|
|
if (n == 1) {
|
|
/*
|
|
* Start is at the direct block level, free
|
|
* everything to the end of the level.
|
|
*/
|
|
ext4_free_data(handle, inode, NULL, i_data + offsets[0],
|
|
i_data + EXT4_NDIR_BLOCKS);
|
|
goto end_range;
|
|
}
|
|
|
|
|
|
partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
|
|
if (nr) {
|
|
if (partial == chain) {
|
|
/* Shared branch grows from the inode */
|
|
ext4_free_branches(handle, inode, NULL,
|
|
&nr, &nr+1, (chain+n-1) - partial);
|
|
*partial->p = 0;
|
|
} else {
|
|
/* Shared branch grows from an indirect block */
|
|
BUFFER_TRACE(partial->bh, "get_write_access");
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p,
|
|
partial->p+1, (chain+n-1) - partial);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Clear the ends of indirect blocks on the shared branch
|
|
* at the start of the range
|
|
*/
|
|
while (partial > chain) {
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p + 1,
|
|
(__le32 *)partial->bh->b_data+addr_per_block,
|
|
(chain+n-1) - partial);
|
|
partial--;
|
|
}
|
|
|
|
end_range:
|
|
partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
|
|
if (nr2) {
|
|
if (partial2 == chain2) {
|
|
/*
|
|
* Remember, end is exclusive so here we're at
|
|
* the start of the next level we're not going
|
|
* to free. Everything was covered by the start
|
|
* of the range.
|
|
*/
|
|
goto do_indirects;
|
|
}
|
|
} else {
|
|
/*
|
|
* ext4_find_shared returns Indirect structure which
|
|
* points to the last element which should not be
|
|
* removed by truncate. But this is end of the range
|
|
* in punch_hole so we need to point to the next element
|
|
*/
|
|
partial2->p++;
|
|
}
|
|
|
|
/*
|
|
* Clear the ends of indirect blocks on the shared branch
|
|
* at the end of the range
|
|
*/
|
|
while (partial2 > chain2) {
|
|
ext4_free_branches(handle, inode, partial2->bh,
|
|
(__le32 *)partial2->bh->b_data,
|
|
partial2->p,
|
|
(chain2+n2-1) - partial2);
|
|
partial2--;
|
|
}
|
|
goto do_indirects;
|
|
}
|
|
|
|
/* Punch happened within the same level (n == n2) */
|
|
partial = p = ext4_find_shared(inode, n, offsets, chain, &nr);
|
|
partial2 = p2 = ext4_find_shared(inode, n2, offsets2, chain2, &nr2);
|
|
|
|
/* Free top, but only if partial2 isn't its subtree. */
|
|
if (nr) {
|
|
int level = min(partial - chain, partial2 - chain2);
|
|
int i;
|
|
int subtree = 1;
|
|
|
|
for (i = 0; i <= level; i++) {
|
|
if (offsets[i] != offsets2[i]) {
|
|
subtree = 0;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (!subtree) {
|
|
if (partial == chain) {
|
|
/* Shared branch grows from the inode */
|
|
ext4_free_branches(handle, inode, NULL,
|
|
&nr, &nr+1,
|
|
(chain+n-1) - partial);
|
|
*partial->p = 0;
|
|
} else {
|
|
/* Shared branch grows from an indirect block */
|
|
BUFFER_TRACE(partial->bh, "get_write_access");
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p,
|
|
partial->p+1,
|
|
(chain+n-1) - partial);
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!nr2) {
|
|
/*
|
|
* ext4_find_shared returns Indirect structure which
|
|
* points to the last element which should not be
|
|
* removed by truncate. But this is end of the range
|
|
* in punch_hole so we need to point to the next element
|
|
*/
|
|
partial2->p++;
|
|
}
|
|
|
|
while (partial > chain || partial2 > chain2) {
|
|
int depth = (chain+n-1) - partial;
|
|
int depth2 = (chain2+n2-1) - partial2;
|
|
|
|
if (partial > chain && partial2 > chain2 &&
|
|
partial->bh->b_blocknr == partial2->bh->b_blocknr) {
|
|
/*
|
|
* We've converged on the same block. Clear the range,
|
|
* then we're done.
|
|
*/
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p + 1,
|
|
partial2->p,
|
|
(chain+n-1) - partial);
|
|
goto cleanup;
|
|
}
|
|
|
|
/*
|
|
* The start and end partial branches may not be at the same
|
|
* level even though the punch happened within one level. So, we
|
|
* give them a chance to arrive at the same level, then walk
|
|
* them in step with each other until we converge on the same
|
|
* block.
|
|
*/
|
|
if (partial > chain && depth <= depth2) {
|
|
ext4_free_branches(handle, inode, partial->bh,
|
|
partial->p + 1,
|
|
(__le32 *)partial->bh->b_data+addr_per_block,
|
|
(chain+n-1) - partial);
|
|
partial--;
|
|
}
|
|
if (partial2 > chain2 && depth2 <= depth) {
|
|
ext4_free_branches(handle, inode, partial2->bh,
|
|
(__le32 *)partial2->bh->b_data,
|
|
partial2->p,
|
|
(chain2+n2-1) - partial2);
|
|
partial2--;
|
|
}
|
|
}
|
|
|
|
cleanup:
|
|
while (p && p > chain) {
|
|
BUFFER_TRACE(p->bh, "call brelse");
|
|
brelse(p->bh);
|
|
p--;
|
|
}
|
|
while (p2 && p2 > chain2) {
|
|
BUFFER_TRACE(p2->bh, "call brelse");
|
|
brelse(p2->bh);
|
|
p2--;
|
|
}
|
|
return 0;
|
|
|
|
do_indirects:
|
|
/* Kill the remaining (whole) subtrees */
|
|
switch (offsets[0]) {
|
|
default:
|
|
if (++n >= n2)
|
|
break;
|
|
nr = i_data[EXT4_IND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
|
|
i_data[EXT4_IND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_IND_BLOCK:
|
|
if (++n >= n2)
|
|
break;
|
|
nr = i_data[EXT4_DIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
|
|
i_data[EXT4_DIND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_DIND_BLOCK:
|
|
if (++n >= n2)
|
|
break;
|
|
nr = i_data[EXT4_TIND_BLOCK];
|
|
if (nr) {
|
|
ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
|
|
i_data[EXT4_TIND_BLOCK] = 0;
|
|
}
|
|
fallthrough;
|
|
case EXT4_TIND_BLOCK:
|
|
;
|
|
}
|
|
goto cleanup;
|
|
}
|