--- /dev/null
+/*
+ * linux/fs/ext4/indirect.c
+ *
+ * from
+ *
+ * linux/fs/ext4/inode.c
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * from
+ *
+ * linux/fs/minix/inode.c
+ *
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ *
+ * Goal-directed block allocation by Stephen Tweedie
+ * (sct@redhat.com), 1993, 1998
+ */
+
+#include "ext4_jbd2.h"
+#include "truncate.h"
+#include <linux/uio.h>
+
+#include <trace/events/ext4.h>
+
+typedef struct {
+ __le32 *p;
+ __le32 key;
+ struct buffer_head *bh;
+} Indirect;
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
+{
+ p->key = *(p->p = v);
+ p->bh = bh;
+}
+
+/**
+ * ext4_block_to_path - parse the block number into array of offsets
+ * @inode: inode in question (we are only interested in its superblock)
+ * @i_block: block number to be parsed
+ * @offsets: array to store the offsets in
+ * @boundary: set this non-zero if the referred-to block is likely to be
+ * followed (on disk) by an indirect block.
+ *
+ * To store the locations of file's data ext4 uses a data structure common
+ * for UNIX filesystems - tree of pointers anchored in the inode, with
+ * data blocks at leaves and indirect blocks in intermediate nodes.
+ * This function translates the block number into path in that tree -
+ * return value is the path length and @offsets[n] is the offset of
+ * pointer to (n+1)th node in the nth one. If @block is out of range
+ * (negative or too large) warning is printed and zero returned.
+ *
+ * Note: function doesn't find node addresses, so no IO is needed. All
+ * we need to know is the capacity of indirect blocks (taken from the
+ * inode->i_sb).
+ */
+
+/*
+ * Portability note: the last comparison (check that we fit into triple
+ * indirect block) is spelled differently, because otherwise on an
+ * architecture with 32-bit longs and 8Kb pages we might get into trouble
+ * if our filesystem had 8Kb blocks. We might use long long, but that would
+ * kill us on x86. Oh, well, at least the sign propagation does not matter -
+ * i_block would have to be negative in the very beginning, so we would not
+ * get there at all.
+ */
+
+static int ext4_block_to_path(struct inode *inode,
+ ext4_lblk_t i_block,
+ ext4_lblk_t offsets[4], int *boundary)
+{
+ int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+ int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
+ const long direct_blocks = EXT4_NDIR_BLOCKS,
+ indirect_blocks = ptrs,
+ double_blocks = (1 << (ptrs_bits * 2));
+ int n = 0;
+ int final = 0;
+
+ if (i_block < direct_blocks) {
+ offsets[n++] = i_block;
+ final = direct_blocks;
+ } else if ((i_block -= direct_blocks) < indirect_blocks) {
+ offsets[n++] = EXT4_IND_BLOCK;
+ offsets[n++] = i_block;
+ final = ptrs;
+ } else if ((i_block -= indirect_blocks) < double_blocks) {
+ offsets[n++] = EXT4_DIND_BLOCK;
+ offsets[n++] = i_block >> ptrs_bits;
+ offsets[n++] = i_block & (ptrs - 1);
+ final = ptrs;
+ } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
+ offsets[n++] = EXT4_TIND_BLOCK;
+ offsets[n++] = i_block >> (ptrs_bits * 2);
+ offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
+ offsets[n++] = i_block & (ptrs - 1);
+ final = ptrs;
+ } else {
+ ext4_warning(inode->i_sb, "block %lu > max in inode %lu",
+ i_block + direct_blocks +
+ indirect_blocks + double_blocks, inode->i_ino);
+ }
+ if (boundary)
+ *boundary = final - 1 - (i_block & (ptrs - 1));
+ return n;
+}
+
+/**
+ * ext4_get_branch - read the chain of indirect blocks leading to data
+ * @inode: inode in question
+ * @depth: depth of the chain (1 - direct pointer, etc.)
+ * @offsets: offsets of pointers in inode/indirect blocks
+ * @chain: place to store the result
+ * @err: here we store the error value
+ *
+ * Function fills the array of triples <key, p, bh> and returns %NULL
+ * if everything went OK or the pointer to the last filled triple
+ * (incomplete one) otherwise. Upon the return chain[i].key contains
+ * the number of (i+1)-th block in the chain (as it is stored in memory,
+ * i.e. little-endian 32-bit), chain[i].p contains the address of that
+ * number (it points into struct inode for i==0 and into the bh->b_data
+ * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
+ * block for i>0 and NULL for i==0. In other words, it holds the block
+ * numbers of the chain, addresses they were taken from (and where we can
+ * verify that chain did not change) and buffer_heads hosting these
+ * numbers.
+ *
+ * Function stops when it stumbles upon zero pointer (absent block)
+ * (pointer to last triple returned, *@err == 0)
+ * or when it gets an IO error reading an indirect block
+ * (ditto, *@err == -EIO)
+ * or when it reads all @depth-1 indirect blocks successfully and finds
+ * the whole chain, all way to the data (returns %NULL, *err == 0).
+ *
+ * Need to be called with
+ * down_read(&EXT4_I(inode)->i_data_sem)
+ */
+static Indirect *ext4_get_branch(struct inode *inode, int depth,
+ ext4_lblk_t *offsets,
+ Indirect chain[4], int *err)
+{
+ struct super_block *sb = inode->i_sb;
+ Indirect *p = chain;
+ struct buffer_head *bh;
+ int ret = -EIO;
+
+ *err = 0;
+ /* i_data is not going away, no lock needed */
+ add_chain(chain, NULL, EXT4_I(inode)->i_data + *offsets);
+ if (!p->key)
+ goto no_block;
+ while (--depth) {
+ bh = sb_getblk(sb, le32_to_cpu(p->key));
+ if (unlikely(!bh)) {
+ ret = -ENOMEM;
+ goto failure;
+ }
+
+ if (!bh_uptodate_or_lock(bh)) {
+ if (bh_submit_read(bh) < 0) {
+ put_bh(bh);
+ goto failure;
+ }
+ /* validate block references */
+ if (ext4_check_indirect_blockref(inode, bh)) {
+ put_bh(bh);
+ goto failure;
+ }
+ }
+
+ add_chain(++p, bh, (__le32 *)bh->b_data + *++offsets);
+ /* Reader: end */
+ if (!p->key)
+ goto no_block;
+ }
+ return NULL;
+
+failure:
+ *err = ret;
+no_block:
+ return p;
+}
+
+/**
+ * ext4_find_near - find a place for allocation with sufficient locality
+ * @inode: owner
+ * @ind: descriptor of indirect block.
+ *
+ * This function returns the preferred place for block allocation.
+ * It is used when heuristic for sequential allocation fails.
+ * Rules are:
+ * + if there is a block to the left of our position - allocate near it.
+ * + if pointer will live in indirect block - allocate near that block.
+ * + if pointer will live in inode - allocate in the same
+ * cylinder group.
+ *
+ * In the latter case we colour the starting block by the callers PID to
+ * prevent it from clashing with concurrent allocations for a different inode
+ * in the same block group. The PID is used here so that functionally related
+ * files will be close-by on-disk.
+ *
+ * Caller must make sure that @ind is valid and will stay that way.
+ */
+static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ __le32 *start = ind->bh ? (__le32 *) ind->bh->b_data : ei->i_data;
+ __le32 *p;
+
+ /* Try to find previous block */
+ for (p = ind->p - 1; p >= start; p--) {
+ if (*p)
+ return le32_to_cpu(*p);
+ }
+
+ /* No such thing, so let's try location of indirect block */
+ if (ind->bh)
+ return ind->bh->b_blocknr;
+
+ /*
+ * It is going to be referred to from the inode itself? OK, just put it
+ * into the same cylinder group then.
+ */
+ return ext4_inode_to_goal_block(inode);
+}
+
+/**
+ * ext4_find_goal - find a preferred place for allocation.
+ * @inode: owner
+ * @block: block we want
+ * @partial: pointer to the last triple within a chain
+ *
+ * Normally this function find the preferred place for block allocation,
+ * returns it.
+ * Because this is only used for non-extent files, we limit the block nr
+ * to 32 bits.
+ */
+static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block,
+ Indirect *partial)
+{
+ ext4_fsblk_t goal;
+
+ /*
+ * XXX need to get goal block from mballoc's data structures
+ */
+
+ goal = ext4_find_near(inode, partial);
+ goal = goal & EXT4_MAX_BLOCK_FILE_PHYS;
+ return goal;
+}
+
+/**
+ * ext4_blks_to_allocate - Look up the block map and count the number
+ * of direct blocks need to be allocated for the given branch.
+ *
+ * @branch: chain of indirect blocks
+ * @k: number of blocks need for indirect blocks
+ * @blks: number of data blocks to be mapped.
+ * @blocks_to_boundary: the offset in the indirect block
+ *
+ * return the total number of blocks to be allocate, including the
+ * direct and indirect blocks.
+ */
+static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned int blks,
+ int blocks_to_boundary)
+{
+ unsigned int count = 0;
+
+ /*
+ * Simple case, [t,d]Indirect block(s) has not allocated yet
+ * then it's clear blocks on that path have not allocated
+ */
+ if (k > 0) {
+ /* right now we don't handle cross boundary allocation */
+ if (blks < blocks_to_boundary + 1)
+ count += blks;
+ else
+ count += blocks_to_boundary + 1;
+ return count;
+ }
+
+ count++;
+ while (count < blks && count <= blocks_to_boundary &&
+ le32_to_cpu(*(branch[0].p + count)) == 0) {
+ count++;
+ }
+ return count;
+}
+
+/**
+ * ext4_alloc_branch - allocate and set up a chain of blocks.
+ * @handle: handle for this transaction
+ * @inode: owner
+ * @indirect_blks: number of allocated indirect blocks
+ * @blks: number of allocated direct blocks
+ * @goal: preferred place for allocation
+ * @offsets: offsets (in the blocks) to store the pointers to next.
+ * @branch: place to store the chain in.
+ *
+ * This function allocates blocks, zeroes out all but the last one,
+ * links them into chain and (if we are synchronous) writes them to disk.
+ * In other words, it prepares a branch that can be spliced onto the
+ * inode. It stores the information about that chain in the branch[], in
+ * the same format as ext4_get_branch() would do. We are calling it after
+ * we had read the existing part of chain and partial points to the last
+ * triple of that (one with zero ->key). Upon the exit we have the same
+ * picture as after the successful ext4_get_block(), except that in one
+ * place chain is disconnected - *branch->p is still zero (we did not
+ * set the last link), but branch->key contains the number that should
+ * be placed into *branch->p to fill that gap.
+ *
+ * If allocation fails we free all blocks we've allocated (and forget
+ * their buffer_heads) and return the error value the from failed
+ * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
+ * as described above and return 0.
+ */
+static int ext4_alloc_branch(handle_t *handle,
+ struct ext4_allocation_request *ar,
+ int indirect_blks, ext4_lblk_t *offsets,
+ Indirect *branch)
+{
+ struct buffer_head * bh;
+ ext4_fsblk_t b, new_blocks[4];
+ __le32 *p;
+ int i, j, err, len = 1;
+
+ for (i = 0; i <= indirect_blks; i++) {
+ if (i == indirect_blks) {
+ new_blocks[i] = ext4_mb_new_blocks(handle, ar, &err);
+ } else
+ ar->goal = new_blocks[i] = ext4_new_meta_blocks(handle,
+ ar->inode, ar->goal,
+ ar->flags & EXT4_MB_DELALLOC_RESERVED,
+ NULL, &err);
+ if (err) {
+ i--;
+ goto failed;
+ }
+ branch[i].key = cpu_to_le32(new_blocks[i]);
+ if (i == 0)
+ continue;
+
+ bh = branch[i].bh = sb_getblk(ar->inode->i_sb, new_blocks[i-1]);
+ if (unlikely(!bh)) {
+ err = -ENOMEM;
+ goto failed;
+ }
+ lock_buffer(bh);
+ BUFFER_TRACE(bh, "call get_create_access");
+ err = ext4_journal_get_create_access(handle, bh);
+ if (err) {
+ unlock_buffer(bh);
+ goto failed;
+ }
+
+ memset(bh->b_data, 0, bh->b_size);
+ p = branch[i].p = (__le32 *) bh->b_data + offsets[i];
+ b = new_blocks[i];
+
+ if (i == indirect_blks)
+ len = ar->len;
+ for (j = 0; j < len; j++)
+ *p++ = cpu_to_le32(b++);
+
+ BUFFER_TRACE(bh, "marking uptodate");
+ set_buffer_uptodate(bh);
+ unlock_buffer(bh);
+
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, ar->inode, bh);
+ if (err)
+ goto failed;
+ }
+ return 0;
+failed:
+ for (; i >= 0; i--) {
+ /*
+ * We want to ext4_forget() only freshly allocated indirect
+ * blocks. Buffer for new_blocks[i-1] is at branch[i].bh and
+ * buffer at branch[0].bh is indirect block / inode already
+ * existing before ext4_alloc_branch() was called.
+ */
+ if (i > 0 && i != indirect_blks && branch[i].bh)
+ ext4_forget(handle, 1, ar->inode, branch[i].bh,
+ branch[i].bh->b_blocknr);
+ ext4_free_blocks(handle, ar->inode, NULL, new_blocks[i],
+ (i == indirect_blks) ? ar->len : 1, 0);
+ }
+ return err;
+}
+
+/**
+ * ext4_splice_branch - splice the allocated branch onto inode.
+ * @handle: handle for this transaction
+ * @inode: owner
+ * @block: (logical) number of block we are adding
+ * @chain: chain of indirect blocks (with a missing link - see
+ * ext4_alloc_branch)
+ * @where: location of missing link
+ * @num: number of indirect blocks we are adding
+ * @blks: number of direct blocks we are adding
+ *
+ * This function fills the missing link and does all housekeeping needed in
+ * inode (->i_blocks, etc.). In case of success we end up with the full
+ * chain to new block and return 0.
+ */
+static int ext4_splice_branch(handle_t *handle,
+ struct ext4_allocation_request *ar,
+ Indirect *where, int num)
+{
+ int i;
+ int err = 0;
+ ext4_fsblk_t current_block;
+
+ /*
+ * If we're splicing into a [td]indirect block (as opposed to the
+ * inode) then we need to get write access to the [td]indirect block
+ * before the splice.
+ */
+ if (where->bh) {
+ BUFFER_TRACE(where->bh, "get_write_access");
+ err = ext4_journal_get_write_access(handle, where->bh);
+ if (err)
+ goto err_out;
+ }
+ /* That's it */
+
+ *where->p = where->key;
+
+ /*
+ * Update the host buffer_head or inode to point to more just allocated
+ * direct blocks blocks
+ */
+ if (num == 0 && ar->len > 1) {
+ current_block = le32_to_cpu(where->key) + 1;
+ for (i = 1; i < ar->len; i++)
+ *(where->p + i) = cpu_to_le32(current_block++);
+ }
+
+ /* We are done with atomic stuff, now do the rest of housekeeping */
+ /* had we spliced it onto indirect block? */
+ if (where->bh) {
+ /*
+ * If we spliced it onto an indirect block, we haven't
+ * altered the inode. Note however that if it is being spliced
+ * onto an indirect block at the very end of the file (the
+ * file is growing) then we *will* alter the inode to reflect
+ * the new i_size. But that is not done here - it is done in
+ * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
+ */
+ jbd_debug(5, "splicing indirect only\n");
+ BUFFER_TRACE(where->bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, ar->inode, where->bh);
+ if (err)
+ goto err_out;
+ } else {
+ /*
+ * OK, we spliced it into the inode itself on a direct block.
+ */
+ ext4_mark_inode_dirty(handle, ar->inode);
+ jbd_debug(5, "splicing direct\n");
+ }
+ return err;
+
+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);
+ J_ASSERT(!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)));
+ J_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 or failed read of indirect block */
+ if ((flags & EXT4_GET_BLOCKS_CREATE) == 0 || err == -EIO)
+ goto cleanup;
+
+ /*
+ * Okay, we need to do block allocation.
+ */
+ if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_RO_COMPAT_BIGALLOC)) {
+ EXT4_ERROR_INODE(inode, "Can't allocate blocks for "
+ "non-extent mapped inodes with bigalloc");
+ return -ENOSPC;
+ }
+
+ /* 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;
+
+ 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;
+}
+
+/*
+ * O_DIRECT for ext3 (or indirect map) based files
+ *
+ * If the O_DIRECT write will extend the file then add this inode to the
+ * orphan list. So recovery will truncate it back to the original size
+ * if the machine crashes during the write.
+ *
+ * If the O_DIRECT write is intantiating holes inside i_size and the machine
+ * crashes then stale disk data _may_ be exposed inside the file. But current
+ * VFS code falls back into buffered path in that case so we are safe.
+ */
+ssize_t ext4_ind_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
+ loff_t offset)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file->f_mapping->host;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ handle_t *handle;
+ ssize_t ret;
+ int orphan = 0;
+ size_t count = iov_iter_count(iter);
+ int retries = 0;
+
+ if (iov_iter_rw(iter) == WRITE) {
+ loff_t final_size = offset + count;
+
+ if (final_size > inode->i_size) {
+ /* Credits for sb + inode write */
+ handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+ if (IS_ERR(handle)) {
+ ret = PTR_ERR(handle);
+ goto out;
+ }
+ ret = ext4_orphan_add(handle, inode);
+ if (ret) {
+ ext4_journal_stop(handle);
+ goto out;
+ }
+ orphan = 1;
+ ei->i_disksize = inode->i_size;
+ ext4_journal_stop(handle);
+ }
+ }
+
+retry:
+ if (iov_iter_rw(iter) == READ && ext4_should_dioread_nolock(inode)) {
+ /*
+ * Nolock dioread optimization may be dynamically disabled
+ * via ext4_inode_block_unlocked_dio(). Check inode's state
+ * while holding extra i_dio_count ref.
+ */
+ inode_dio_begin(inode);
+ smp_mb();
+ if (unlikely(ext4_test_inode_state(inode,
+ EXT4_STATE_DIOREAD_LOCK))) {
+ inode_dio_end(inode);
+ goto locked;
+ }
+ if (IS_DAX(inode))
+ ret = dax_do_io(iocb, inode, iter, offset,
+ ext4_get_block, NULL, 0);
+ else
+ ret = __blockdev_direct_IO(iocb, inode,
+ inode->i_sb->s_bdev, iter,
+ offset, ext4_get_block, NULL,
+ NULL, 0);
+ inode_dio_end(inode);
+ } else {
+locked:
+ if (IS_DAX(inode))
+ ret = dax_do_io(iocb, inode, iter, offset,
+ ext4_get_block, NULL, DIO_LOCKING);
+ else
+ ret = blockdev_direct_IO(iocb, inode, iter, offset,
+ ext4_get_block);
+
+ if (unlikely(iov_iter_rw(iter) == WRITE && ret < 0)) {
+ loff_t isize = i_size_read(inode);
+ loff_t end = offset + count;
+
+ if (end > isize)
+ ext4_truncate_failed_write(inode);
+ }
+ }
+ if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+
+ if (orphan) {
+ int err;
+
+ /* Credits for sb + inode write */
+ handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
+ if (IS_ERR(handle)) {
+ /* This is really bad luck. We've written the data
+ * but cannot extend i_size. Bail out and pretend
+ * the write failed... */
+ ret = PTR_ERR(handle);
+ if (inode->i_nlink)
+ ext4_orphan_del(NULL, inode);
+
+ goto out;
+ }
+ if (inode->i_nlink)
+ ext4_orphan_del(handle, inode);
+ if (ret > 0) {
+ loff_t end = offset + ret;
+ if (end > inode->i_size) {
+ ei->i_disksize = end;
+ i_size_write(inode, end);
+ /*
+ * We're going to return a positive `ret'
+ * here due to non-zero-length I/O, so there's
+ * no way of reporting error returns from
+ * ext4_mark_inode_dirty() to userspace. So
+ * ignore it.
+ */
+ ext4_mark_inode_dirty(handle, inode);
+ }
+ }
+ err = ext4_journal_stop(handle);
+ if (ret == 0)
+ ret = err;
+ }
+out:
+ return ret;
+}
+
+/*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate a new block at @lblocks for non extent file based file
+ */
+int ext4_ind_calc_metadata_amount(struct inode *inode, sector_t lblock)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ sector_t dind_mask = ~((sector_t)EXT4_ADDR_PER_BLOCK(inode->i_sb) - 1);
+ int blk_bits;
+
+ if (lblock < EXT4_NDIR_BLOCKS)
+ return 0;
+
+ lblock -= EXT4_NDIR_BLOCKS;
+
+ if (ei->i_da_metadata_calc_len &&
+ (lblock & dind_mask) == ei->i_da_metadata_calc_last_lblock) {
+ ei->i_da_metadata_calc_len++;
+ return 0;
+ }
+ ei->i_da_metadata_calc_last_lblock = lblock & dind_mask;
+ ei->i_da_metadata_calc_len = 1;
+ blk_bits = order_base_2(lblock);
+ return (blk_bits / EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb)) + 1;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Truncate transactions can be complex and absolutely huge. So we need to
+ * be able to restart the transaction at a conventient checkpoint to make
+ * sure we don't overflow the journal.
+ *
+ * Try to extend this transaction for the purposes of truncation. If
+ * extend fails, we need to propagate the failure up and restart the
+ * transaction in the top-level truncate loop. --sct
+ *
+ * Returns 0 if we managed to create more room. If we can't create more
+ * room, and the transaction must be restarted we return 1.
+ */
+static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
+{
+ if (!ext4_handle_valid(handle))
+ return 0;
+ if (ext4_handle_has_enough_credits(handle, EXT4_RESERVE_TRANS_BLOCKS+1))
+ return 0;
+ if (!ext4_journal_extend(handle, ext4_blocks_for_truncate(inode)))
+ return 0;
+ return 1;
+}
+
+/*
+ * 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))
+ flags |= EXT4_FREE_BLOCKS_FORGET | EXT4_FREE_BLOCKS_METADATA;
+ else if (ext4_should_journal_data(inode))
+ flags |= EXT4_FREE_BLOCKS_FORGET;
+
+ if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), 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;
+ }
+
+ if (try_to_extend_transaction(handle, inode)) {
+ if (bh) {
+ BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
+ err = ext4_handle_dirty_metadata(handle, inode, bh);
+ if (unlikely(err))
+ goto out_err;
+ }
+ err = ext4_mark_inode_dirty(handle, inode);
+ if (unlikely(err))
+ goto out_err;
+ err = ext4_truncate_restart_trans(handle, inode,
+ ext4_blocks_for_truncate(inode));
+ if (unlikely(err))
+ goto out_err;
+ if (bh) {
+ BUFFER_TRACE(bh, "retaking write access");
+ err = ext4_journal_get_write_access(handle, bh);
+ if (unlikely(err))
+ 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, this_bh);
+ /* 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_data_block_valid(EXT4_SB(inode->i_sb),
+ 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 = sb_bread(inode->i_sb, nr);
+
+ /*
+ * A read failure? Report error and clear slot
+ * (should be rare).
+ */
+ if (!bh) {
+ EXT4_ERROR_INODE_BLOCK(inode, nr,
+ "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 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 (try_to_extend_transaction(handle, inode)) {
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_truncate_restart_trans(handle, inode,
+ ext4_blocks_for_truncate(inode));
+ }
+
+ /*
+ * 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,
+ parent_bh)){
+ *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;
+ }
+ 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;
+ }
+ 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;
+ }
+ 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;
+ 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 = 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);
+ BUFFER_TRACE(partial->bh, "call brelse");
+ brelse(partial->bh);
+ partial--;
+ }
+
+end_range:
+ partial2 = 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);
+ BUFFER_TRACE(partial2->bh, "call brelse");
+ brelse(partial2->bh);
+ partial2--;
+ }
+ goto do_indirects;
+ }
+
+ /* Punch happened within the same level (n == n2) */
+ partial = ext4_find_shared(inode, n, offsets, chain, &nr);
+ partial2 = 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);
+ BUFFER_TRACE(partial->bh, "call brelse");
+ brelse(partial->bh);
+ BUFFER_TRACE(partial2->bh, "call brelse");
+ brelse(partial2->bh);
+ return 0;
+ }
+
+ /*
+ * 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);
+ BUFFER_TRACE(partial->bh, "call brelse");
+ brelse(partial->bh);
+ partial--;
+ }
+ if (partial2 > chain2 && depth2 <= depth) {
+ ext4_free_branches(handle, inode, partial2->bh,
+ (__le32 *)partial2->bh->b_data,
+ partial2->p,
+ (chain2+n2-1) - partial2);
+ BUFFER_TRACE(partial2->bh, "call brelse");
+ brelse(partial2->bh);
+ partial2--;
+ }
+ }
+ return 0;
+
+do_indirects:
+ /* Kill the remaining (whole) subtrees */
+ switch (offsets[0]) {
+ default:
+ if (++n >= n2)
+ return 0;
+ nr = i_data[EXT4_IND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
+ i_data[EXT4_IND_BLOCK] = 0;
+ }
+ case EXT4_IND_BLOCK:
+ if (++n >= n2)
+ return 0;
+ nr = i_data[EXT4_DIND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
+ i_data[EXT4_DIND_BLOCK] = 0;
+ }
+ case EXT4_DIND_BLOCK:
+ if (++n >= n2)
+ return 0;
+ nr = i_data[EXT4_TIND_BLOCK];
+ if (nr) {
+ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
+ i_data[EXT4_TIND_BLOCK] = 0;
+ }
+ case EXT4_TIND_BLOCK:
+ ;
+ }
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff