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 // SPDX-License-Identifier: GPL-2.0
 /*
  *  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/dax.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 (ext4_read_bh(bh, 0, NULL) < 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
  * @ar: structure describing the allocation request
  * @indirect_blks: number of allocated indirect blocks
  * @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);
             /* Simplify error cleanup... */
             branch[i+1].bh = NULL;
         }
         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, ar->inode->i_sb,
                              bh, EXT4_JTR_NONE);
         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:
     if (i == indirect_blks) {
         /* Free data blocks */
         ext4_free_blocks(handle, ar->inode, NULL, new_blocks[i],
                  ar->len, 0);
         i--;
     }
     for (; i >= 0; i--) {
         /*
          * We want to ext4_forget() only freshly allocated indirect
          * blocks. Buffer for new_blocks[i] is at branch[i+1].bh
          * (buffer at branch[0].bh is indirect block / inode already
          * existing before ext4_alloc_branch() was called). Also
          * because blocks are freshly allocated, we don't need to
          * revoke them which is why we don't set
          * EXT4_FREE_BLOCKS_METADATA.
          */
         ext4_free_blocks(handle, ar->inode, branch[i+1].bh,
                  new_blocks[i], 1,
                  branch[i+1].bh ? EXT4_FREE_BLOCKS_FORGET : 0);
     }
     return err;
 }
 
 /**
  * ext4_splice_branch() - splice the allocated branch onto inode.
  * @handle: handle for this transaction
  * @ar: structure describing the allocation request
  * @where: location of missing link
  * @num:   number of indirect 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, ar->inode->i_sb,
                             where->bh, EXT4_JTR_NONE);
         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.
          */
         ext4_debug("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.
          */
         err = ext4_mark_inode_dirty(handle, ar->inode);
         if (unlikely(err))
             goto err_out;
         ext4_debug("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);
     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;
 }

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