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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (C) 2002, 2004 Oracle.  All rights reserved.
  */
 
 #include <linux/fs.h>
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
 #include <asm/byteorder.h>
 #include <linux/swap.h>
 #include <linux/mpage.h>
 #include <linux/quotaops.h>
 #include <linux/blkdev.h>
 #include <linux/uio.h>
 #include <linux/mm.h>
 
 #include <cluster/masklog.h>
 
 #include "ocfs2.h"
 
 #include "alloc.h"
 #include "aops.h"
 #include "dlmglue.h"
 #include "extent_map.h"
 #include "file.h"
 #include "inode.h"
 #include "journal.h"
 #include "suballoc.h"
 #include "super.h"
 #include "symlink.h"
 #include "refcounttree.h"
 #include "ocfs2_trace.h"
 
 #include "buffer_head_io.h"
 #include "dir.h"
 #include "namei.h"
 #include "sysfile.h"
 
 static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
                    struct buffer_head *bh_result, int create)
 {
     int err = -EIO;
     int status;
     struct ocfs2_dinode *fe = NULL;
     struct buffer_head *bh = NULL;
     struct buffer_head *buffer_cache_bh = NULL;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     void *kaddr;
 
     trace_ocfs2_symlink_get_block(
             (unsigned long long)OCFS2_I(inode)->ip_blkno,
             (unsigned long long)iblock, bh_result, create);
 
     BUG_ON(ocfs2_inode_is_fast_symlink(inode));
 
     if ((iblock << inode->i_sb->s_blocksize_bits) > PATH_MAX + 1) {
         mlog(ML_ERROR, "block offset > PATH_MAX: %llu",
              (unsigned long long)iblock);
         goto bail;
     }
 
     status = ocfs2_read_inode_block(inode, &bh);
     if (status < 0) {
         mlog_errno(status);
         goto bail;
     }
     fe = (struct ocfs2_dinode *) bh->b_data;
 
     if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
                             le32_to_cpu(fe->i_clusters))) {
         err = -ENOMEM;
         mlog(ML_ERROR, "block offset is outside the allocated size: "
              "%llu\n", (unsigned long long)iblock);
         goto bail;
     }
 
     /* We don't use the page cache to create symlink data, so if
      * need be, copy it over from the buffer cache. */
     if (!buffer_uptodate(bh_result) && ocfs2_inode_is_new(inode)) {
         u64 blkno = le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) +
                 iblock;
         buffer_cache_bh = sb_getblk(osb->sb, blkno);
         if (!buffer_cache_bh) {
             err = -ENOMEM;
             mlog(ML_ERROR, "couldn't getblock for symlink!\n");
             goto bail;
         }
 
         /* we haven't locked out transactions, so a commit
          * could've happened. Since we've got a reference on
          * the bh, even if it commits while we're doing the
          * copy, the data is still good. */
         if (buffer_jbd(buffer_cache_bh)
             && ocfs2_inode_is_new(inode)) {
             kaddr = kmap_atomic(bh_result->b_page);
             if (!kaddr) {
                 mlog(ML_ERROR, "couldn't kmap!\n");
                 goto bail;
             }
             memcpy(kaddr + (bh_result->b_size * iblock),
                    buffer_cache_bh->b_data,
                    bh_result->b_size);
             kunmap_atomic(kaddr);
             set_buffer_uptodate(bh_result);
         }
         brelse(buffer_cache_bh);
     }
 
     map_bh(bh_result, inode->i_sb,
            le64_to_cpu(fe->id2.i_list.l_recs[0].e_blkno) + iblock);
 
     err = 0;
 
 bail:
     brelse(bh);
 
     return err;
 }
 
 static int ocfs2_lock_get_block(struct inode *inode, sector_t iblock,
             struct buffer_head *bh_result, int create)
 {
     int ret = 0;
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
 
     down_read(&oi->ip_alloc_sem);
     ret = ocfs2_get_block(inode, iblock, bh_result, create);
     up_read(&oi->ip_alloc_sem);
 
     return ret;
 }
 
 int ocfs2_get_block(struct inode *inode, sector_t iblock,
             struct buffer_head *bh_result, int create)
 {
     int err = 0;
     unsigned int ext_flags;
     u64 max_blocks = bh_result->b_size >> inode->i_blkbits;
     u64 p_blkno, count, past_eof;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
 
     trace_ocfs2_get_block((unsigned long long)OCFS2_I(inode)->ip_blkno,
                   (unsigned long long)iblock, bh_result, create);
 
     if (OCFS2_I(inode)->ip_flags & OCFS2_INODE_SYSTEM_FILE)
         mlog(ML_NOTICE, "get_block on system inode 0x%p (%lu)\n",
              inode, inode->i_ino);
 
     if (S_ISLNK(inode->i_mode)) {
         /* this always does I/O for some reason. */
         err = ocfs2_symlink_get_block(inode, iblock, bh_result, create);
         goto bail;
     }
 
     err = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno, &count,
                       &ext_flags);
     if (err) {
         mlog(ML_ERROR, "Error %d from get_blocks(0x%p, %llu, 1, "
              "%llu, NULL)\n", err, inode, (unsigned long long)iblock,
              (unsigned long long)p_blkno);
         goto bail;
     }
 
     if (max_blocks < count)
         count = max_blocks;
 
     /*
      * ocfs2 never allocates in this function - the only time we
      * need to use BH_New is when we're extending i_size on a file
      * system which doesn't support holes, in which case BH_New
      * allows __block_write_begin() to zero.
      *
      * If we see this on a sparse file system, then a truncate has
      * raced us and removed the cluster. In this case, we clear
      * the buffers dirty and uptodate bits and let the buffer code
      * ignore it as a hole.
      */
     if (create && p_blkno == 0 && ocfs2_sparse_alloc(osb)) {
         clear_buffer_dirty(bh_result);
         clear_buffer_uptodate(bh_result);
         goto bail;
     }
 
     /* Treat the unwritten extent as a hole for zeroing purposes. */
     if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
         map_bh(bh_result, inode->i_sb, p_blkno);
 
     bh_result->b_size = count << inode->i_blkbits;
 
     if (!ocfs2_sparse_alloc(osb)) {
         if (p_blkno == 0) {
             err = -EIO;
             mlog(ML_ERROR,
                  "iblock = %llu p_blkno = %llu blkno=(%llu)\n",
                  (unsigned long long)iblock,
                  (unsigned long long)p_blkno,
                  (unsigned long long)OCFS2_I(inode)->ip_blkno);
             mlog(ML_ERROR, "Size %llu, clusters %u\n", (unsigned long long)i_size_read(inode), OCFS2_I(inode)->ip_clusters);
             dump_stack();
             goto bail;
         }
     }
 
     past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
 
     trace_ocfs2_get_block_end((unsigned long long)OCFS2_I(inode)->ip_blkno,
                   (unsigned long long)past_eof);
     if (create && (iblock >= past_eof))
         set_buffer_new(bh_result);
 
 bail:
     if (err < 0)
         err = -EIO;
 
     return err;
 }
 
 int ocfs2_read_inline_data(struct inode *inode, struct page *page,
                struct buffer_head *di_bh)
 {
     void *kaddr;
     loff_t size;
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 
     if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
         ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno);
         return -EROFS;
     }
 
     size = i_size_read(inode);
 
     if (size > PAGE_SIZE ||
         size > ocfs2_max_inline_data_with_xattr(inode->i_sb, di)) {
         ocfs2_error(inode->i_sb,
                 "Inode %llu has with inline data has bad size: %Lu\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno,
                 (unsigned long long)size);
         return -EROFS;
     }
 
     kaddr = kmap_atomic(page);
     if (size)
         memcpy(kaddr, di->id2.i_data.id_data, size);
     /* Clear the remaining part of the page */
     memset(kaddr + size, 0, PAGE_SIZE - size);
     flush_dcache_page(page);
     kunmap_atomic(kaddr);
 
     SetPageUptodate(page);
 
     return 0;
 }
 
 static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
 {
     int ret;
     struct buffer_head *di_bh = NULL;
 
     BUG_ON(!PageLocked(page));
     BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));
 
     ret = ocfs2_read_inode_block(inode, &di_bh);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     ret = ocfs2_read_inline_data(inode, page, di_bh);
 out:
     unlock_page(page);
 
     brelse(di_bh);
     return ret;
 }
 
 static int ocfs2_read_folio(struct file *file, struct folio *folio)
 {
     struct inode *inode = folio->mapping->host;
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     loff_t start = folio_pos(folio);
     int ret, unlock = 1;
 
     trace_ocfs2_readpage((unsigned long long)oi->ip_blkno, folio->index);
 
     ret = ocfs2_inode_lock_with_page(inode, NULL, 0, &folio->page);
     if (ret != 0) {
         if (ret == AOP_TRUNCATED_PAGE)
             unlock = 0;
         mlog_errno(ret);
         goto out;
     }
 
     if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
         /*
          * Unlock the folio and cycle ip_alloc_sem so that we don't
          * busyloop waiting for ip_alloc_sem to unlock
          */
         ret = AOP_TRUNCATED_PAGE;
         folio_unlock(folio);
         unlock = 0;
         down_read(&oi->ip_alloc_sem);
         up_read(&oi->ip_alloc_sem);
         goto out_inode_unlock;
     }
 
     /*
      * i_size might have just been updated as we grabed the meta lock.  We
      * might now be discovering a truncate that hit on another node.
      * block_read_full_folio->get_block freaks out if it is asked to read
      * beyond the end of a file, so we check here.  Callers
      * (generic_file_read, vm_ops->fault) are clever enough to check i_size
      * and notice that the folio they just read isn't needed.
      *
      * XXX sys_readahead() seems to get that wrong?
      */
     if (start >= i_size_read(inode)) {
         folio_zero_segment(folio, 0, folio_size(folio));
         folio_mark_uptodate(folio);
         ret = 0;
         goto out_alloc;
     }
 
     if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
         ret = ocfs2_readpage_inline(inode, &folio->page);
     else
         ret = block_read_full_folio(folio, ocfs2_get_block);
     unlock = 0;
 
 out_alloc:
     up_read(&oi->ip_alloc_sem);
 out_inode_unlock:
     ocfs2_inode_unlock(inode, 0);
 out:
     if (unlock)
         folio_unlock(folio);
     return ret;
 }
 
 /*
  * This is used only for read-ahead. Failures or difficult to handle
  * situations are safe to ignore.
  *
  * Right now, we don't bother with BH_Boundary - in-inode extent lists
  * are quite large (243 extents on 4k blocks), so most inodes don't
  * grow out to a tree. If need be, detecting boundary extents could
  * trivially be added in a future version of ocfs2_get_block().
  */
 static void ocfs2_readahead(struct readahead_control *rac)
 {
     int ret;
     struct inode *inode = rac->mapping->host;
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
 
     /*
      * Use the nonblocking flag for the dlm code to avoid page
      * lock inversion, but don't bother with retrying.
      */
     ret = ocfs2_inode_lock_full(inode, NULL, 0, OCFS2_LOCK_NONBLOCK);
     if (ret)
         return;
 
     if (down_read_trylock(&oi->ip_alloc_sem) == 0)
         goto out_unlock;
 
     /*
      * Don't bother with inline-data. There isn't anything
      * to read-ahead in that case anyway...
      */
     if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
         goto out_up;
 
     /*
      * Check whether a remote node truncated this file - we just
      * drop out in that case as it's not worth handling here.
      */
     if (readahead_pos(rac) >= i_size_read(inode))
         goto out_up;
 
     mpage_readahead(rac, ocfs2_get_block);
 
 out_up:
     up_read(&oi->ip_alloc_sem);
 out_unlock:
     ocfs2_inode_unlock(inode, 0);
 }
 
 /* Note: Because we don't support holes, our allocation has
  * already happened (allocation writes zeros to the file data)
  * so we don't have to worry about ordered writes in
  * ocfs2_writepage.
  *
  * ->writepage is called during the process of invalidating the page cache
  * during blocked lock processing.  It can't block on any cluster locks
  * to during block mapping.  It's relying on the fact that the block
  * mapping can't have disappeared under the dirty pages that it is
  * being asked to write back.
  */
 static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
 {
     trace_ocfs2_writepage(
         (unsigned long long)OCFS2_I(page->mapping->host)->ip_blkno,
         page->index);
 
     return block_write_full_page(page, ocfs2_get_block, wbc);
 }
 
 /* Taken from ext3. We don't necessarily need the full blown
  * functionality yet, but IMHO it's better to cut and paste the whole
  * thing so we can avoid introducing our own bugs (and easily pick up
  * their fixes when they happen) --Mark */
 int walk_page_buffers(  handle_t *handle,
             struct buffer_head *head,
             unsigned from,
             unsigned to,
             int *partial,
             int (*fn)(  handle_t *handle,
                     struct buffer_head *bh))
 {
     struct buffer_head *bh;
     unsigned block_start, block_end;
     unsigned blocksize = head->b_size;
     int err, ret = 0;
     struct buffer_head *next;
 
     for (   bh = head, block_start = 0;
         ret == 0 && (bh != head || !block_start);
             block_start = block_end, bh = next)
     {
         next = bh->b_this_page;
         block_end = block_start + blocksize;
         if (block_end <= from || block_start >= to) {
             if (partial && !buffer_uptodate(bh))
                 *partial = 1;
             continue;
         }
         err = (*fn)(handle, bh);
         if (!ret)
             ret = err;
     }
     return ret;
 }
 
 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
 {
     sector_t status;
     u64 p_blkno = 0;
     int err = 0;
     struct inode *inode = mapping->host;
 
     trace_ocfs2_bmap((unsigned long long)OCFS2_I(inode)->ip_blkno,
              (unsigned long long)block);
 
     /*
      * The swap code (ab-)uses ->bmap to get a block mapping and then
      * bypasseѕ the file system for actual I/O.  We really can't allow
      * that on refcounted inodes, so we have to skip out here.  And yes,
      * 0 is the magic code for a bmap error..
      */
     if (ocfs2_is_refcount_inode(inode))
         return 0;
 
     /* We don't need to lock journal system files, since they aren't
      * accessed concurrently from multiple nodes.
      */
     if (!INODE_JOURNAL(inode)) {
         err = ocfs2_inode_lock(inode, NULL, 0);
         if (err) {
             if (err != -ENOENT)
                 mlog_errno(err);
             goto bail;
         }
         down_read(&OCFS2_I(inode)->ip_alloc_sem);
     }
 
     if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
         err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
                           NULL);
 
     if (!INODE_JOURNAL(inode)) {
         up_read(&OCFS2_I(inode)->ip_alloc_sem);
         ocfs2_inode_unlock(inode, 0);
     }
 
     if (err) {
         mlog(ML_ERROR, "get_blocks() failed, block = %llu\n",
              (unsigned long long)block);
         mlog_errno(err);
         goto bail;
     }
 
 bail:
     status = err ? 0 : p_blkno;
 
     return status;
 }
 
 static bool ocfs2_release_folio(struct folio *folio, gfp_t wait)
 {
     if (!folio_buffers(folio))
         return false;
     return try_to_free_buffers(folio);
 }
 
 static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
                         u32 cpos,
                         unsigned int *start,
                         unsigned int *end)
 {
     unsigned int cluster_start = 0, cluster_end = PAGE_SIZE;
 
     if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits)) {
         unsigned int cpp;
 
         cpp = 1 << (PAGE_SHIFT - osb->s_clustersize_bits);
 
         cluster_start = cpos % cpp;
         cluster_start = cluster_start << osb->s_clustersize_bits;
 
         cluster_end = cluster_start + osb->s_clustersize;
     }
 
     BUG_ON(cluster_start > PAGE_SIZE);
     BUG_ON(cluster_end > PAGE_SIZE);
 
     if (start)
         *start = cluster_start;
     if (end)
         *end = cluster_end;
 }
 
 /*
  * 'from' and 'to' are the region in the page to avoid zeroing.
  *
  * If pagesize > clustersize, this function will avoid zeroing outside
  * of the cluster boundary.
  *
  * from == to == 0 is code for "zero the entire cluster region"
  */
 static void ocfs2_clear_page_regions(struct page *page,
                      struct ocfs2_super *osb, u32 cpos,
                      unsigned from, unsigned to)
 {
     void *kaddr;
     unsigned int cluster_start, cluster_end;
 
     ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);
 
     kaddr = kmap_atomic(page);
 
     if (from || to) {
         if (from > cluster_start)
             memset(kaddr + cluster_start, 0, from - cluster_start);
         if (to < cluster_end)
             memset(kaddr + to, 0, cluster_end - to);
     } else {
         memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
     }
 
     kunmap_atomic(kaddr);
 }
 
 /*
  * Nonsparse file systems fully allocate before we get to the write
  * code. This prevents ocfs2_write() from tagging the write as an
  * allocating one, which means ocfs2_map_page_blocks() might try to
  * read-in the blocks at the tail of our file. Avoid reading them by
  * testing i_size against each block offset.
  */
 static int ocfs2_should_read_blk(struct inode *inode, struct page *page,
                  unsigned int block_start)
 {
     u64 offset = page_offset(page) + block_start;
 
     if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)))
         return 1;
 
     if (i_size_read(inode) > offset)
         return 1;
 
     return 0;
 }
 
 /*
  * Some of this taken from __block_write_begin(). We already have our
  * mapping by now though, and the entire write will be allocating or
  * it won't, so not much need to use BH_New.
  *
  * This will also skip zeroing, which is handled externally.
  */
 int ocfs2_map_page_blocks(struct page *page, u64 *p_blkno,
               struct inode *inode, unsigned int from,
               unsigned int to, int new)
 {
     int ret = 0;
     struct buffer_head *head, *bh, *wait[2], **wait_bh = wait;
     unsigned int block_end, block_start;
     unsigned int bsize = i_blocksize(inode);
 
     if (!page_has_buffers(page))
         create_empty_buffers(page, bsize, 0);
 
     head = page_buffers(page);
     for (bh = head, block_start = 0; bh != head || !block_start;
          bh = bh->b_this_page, block_start += bsize) {
         block_end = block_start + bsize;
 
         clear_buffer_new(bh);
 
         /*
          * Ignore blocks outside of our i/o range -
          * they may belong to unallocated clusters.
          */
         if (block_start >= to || block_end <= from) {
             if (PageUptodate(page))
                 set_buffer_uptodate(bh);
             continue;
         }
 
         /*
          * For an allocating write with cluster size >= page
          * size, we always write the entire page.
          */
         if (new)
             set_buffer_new(bh);
 
         if (!buffer_mapped(bh)) {
             map_bh(bh, inode->i_sb, *p_blkno);
             clean_bdev_bh_alias(bh);
         }
 
         if (PageUptodate(page)) {
             set_buffer_uptodate(bh);
         } else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
                !buffer_new(bh) &&
                ocfs2_should_read_blk(inode, page, block_start) &&
                (block_start < from || block_end > to)) {
             ll_rw_block(REQ_OP_READ, 1, &bh);
             *wait_bh++=bh;
         }
 
         *p_blkno = *p_blkno + 1;
     }
 
     /*
      * If we issued read requests - let them complete.
      */
     while(wait_bh > wait) {
         wait_on_buffer(*--wait_bh);
         if (!buffer_uptodate(*wait_bh))
             ret = -EIO;
     }
 
     if (ret == 0 || !new)
         return ret;
 
     /*
      * If we get -EIO above, zero out any newly allocated blocks
      * to avoid exposing stale data.
      */
     bh = head;
     block_start = 0;
     do {
         block_end = block_start + bsize;
         if (block_end <= from)
             goto next_bh;
         if (block_start >= to)
             break;
 
         zero_user(page, block_start, bh->b_size);
         set_buffer_uptodate(bh);
         mark_buffer_dirty(bh);
 
 next_bh:
         block_start = block_end;
         bh = bh->b_this_page;
     } while (bh != head);
 
     return ret;
 }
 
 #if (PAGE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
 #define OCFS2_MAX_CTXT_PAGES    1
 #else
 #define OCFS2_MAX_CTXT_PAGES    (OCFS2_MAX_CLUSTERSIZE / PAGE_SIZE)
 #endif
 
 #define OCFS2_MAX_CLUSTERS_PER_PAGE (PAGE_SIZE / OCFS2_MIN_CLUSTERSIZE)
 
 struct ocfs2_unwritten_extent {
     struct list_head    ue_node;
     struct list_head    ue_ip_node;
     u32         ue_cpos;
     u32         ue_phys;
 };
 
 /*
  * Describe the state of a single cluster to be written to.
  */
 struct ocfs2_write_cluster_desc {
     u32     c_cpos;
     u32     c_phys;
     /*
      * Give this a unique field because c_phys eventually gets
      * filled.
      */
     unsigned    c_new;
     unsigned    c_clear_unwritten;
     unsigned    c_needs_zero;
 };
 
 struct ocfs2_write_ctxt {
     /* Logical cluster position / len of write */
     u32             w_cpos;
     u32             w_clen;
 
     /* First cluster allocated in a nonsparse extend */
     u32             w_first_new_cpos;
 
     /* Type of caller. Must be one of buffer, mmap, direct.  */
     ocfs2_write_type_t      w_type;
 
     struct ocfs2_write_cluster_desc w_desc[OCFS2_MAX_CLUSTERS_PER_PAGE];
 
     /*
      * This is true if page_size > cluster_size.
      *
      * It triggers a set of special cases during write which might
      * have to deal with allocating writes to partial pages.
      */
     unsigned int            w_large_pages;
 
     /*
      * Pages involved in this write.
      *
      * w_target_page is the page being written to by the user.
      *
      * w_pages is an array of pages which always contains
      * w_target_page, and in the case of an allocating write with
      * page_size < cluster size, it will contain zero'd and mapped
      * pages adjacent to w_target_page which need to be written
      * out in so that future reads from that region will get
      * zero's.
      */
     unsigned int            w_num_pages;
     struct page         *w_pages[OCFS2_MAX_CTXT_PAGES];
     struct page         *w_target_page;
 
     /*
      * w_target_locked is used for page_mkwrite path indicating no unlocking
      * against w_target_page in ocfs2_write_end_nolock.
      */
     unsigned int            w_target_locked:1;
 
     /*
      * ocfs2_write_end() uses this to know what the real range to
      * write in the target should be.
      */
     unsigned int            w_target_from;
     unsigned int            w_target_to;
 
     /*
      * We could use journal_current_handle() but this is cleaner,
      * IMHO -Mark
      */
     handle_t            *w_handle;
 
     struct buffer_head      *w_di_bh;
 
     struct ocfs2_cached_dealloc_ctxt w_dealloc;
 
     struct list_head        w_unwritten_list;
     unsigned int            w_unwritten_count;
 };
 
 void ocfs2_unlock_and_free_pages(struct page **pages, int num_pages)
 {
     int i;
 
     for(i = 0; i < num_pages; i++) {
         if (pages[i]) {
             unlock_page(pages[i]);
             mark_page_accessed(pages[i]);
             put_page(pages[i]);
         }
     }
 }
 
 static void ocfs2_unlock_pages(struct ocfs2_write_ctxt *wc)
 {
     int i;
 
     /*
      * w_target_locked is only set to true in the page_mkwrite() case.
      * The intent is to allow us to lock the target page from write_begin()
      * to write_end(). The caller must hold a ref on w_target_page.
      */
     if (wc->w_target_locked) {
         BUG_ON(!wc->w_target_page);
         for (i = 0; i < wc->w_num_pages; i++) {
             if (wc->w_target_page == wc->w_pages[i]) {
                 wc->w_pages[i] = NULL;
                 break;
             }
         }
         mark_page_accessed(wc->w_target_page);
         put_page(wc->w_target_page);
     }
     ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
 }
 
 static void ocfs2_free_unwritten_list(struct inode *inode,
                  struct list_head *head)
 {
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_unwritten_extent *ue = NULL, *tmp = NULL;
 
     list_for_each_entry_safe(ue, tmp, head, ue_node) {
         list_del(&ue->ue_node);
         spin_lock(&oi->ip_lock);
         list_del(&ue->ue_ip_node);
         spin_unlock(&oi->ip_lock);
         kfree(ue);
     }
 }
 
 static void ocfs2_free_write_ctxt(struct inode *inode,
                   struct ocfs2_write_ctxt *wc)
 {
     ocfs2_free_unwritten_list(inode, &wc->w_unwritten_list);
     ocfs2_unlock_pages(wc);
     brelse(wc->w_di_bh);
     kfree(wc);
 }
 
 static int ocfs2_alloc_write_ctxt(struct ocfs2_write_ctxt **wcp,
                   struct ocfs2_super *osb, loff_t pos,
                   unsigned len, ocfs2_write_type_t type,
                   struct buffer_head *di_bh)
 {
     u32 cend;
     struct ocfs2_write_ctxt *wc;
 
     wc = kzalloc(sizeof(struct ocfs2_write_ctxt), GFP_NOFS);
     if (!wc)
         return -ENOMEM;
 
     wc->w_cpos = pos >> osb->s_clustersize_bits;
     wc->w_first_new_cpos = UINT_MAX;
     cend = (pos + len - 1) >> osb->s_clustersize_bits;
     wc->w_clen = cend - wc->w_cpos + 1;
     get_bh(di_bh);
     wc->w_di_bh = di_bh;
     wc->w_type = type;
 
     if (unlikely(PAGE_SHIFT > osb->s_clustersize_bits))
         wc->w_large_pages = 1;
     else
         wc->w_large_pages = 0;
 
     ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
     INIT_LIST_HEAD(&wc->w_unwritten_list);
 
     *wcp = wc;
 
     return 0;
 }
 
 /*
  * If a page has any new buffers, zero them out here, and mark them uptodate
  * and dirty so they'll be written out (in order to prevent uninitialised
  * block data from leaking). And clear the new bit.
  */
 static void ocfs2_zero_new_buffers(struct page *page, unsigned from, unsigned to)
 {
     unsigned int block_start, block_end;
     struct buffer_head *head, *bh;
 
     BUG_ON(!PageLocked(page));
     if (!page_has_buffers(page))
         return;
 
     bh = head = page_buffers(page);
     block_start = 0;
     do {
         block_end = block_start + bh->b_size;
 
         if (buffer_new(bh)) {
             if (block_end > from && block_start < to) {
                 if (!PageUptodate(page)) {
                     unsigned start, end;
 
                     start = max(from, block_start);
                     end = min(to, block_end);
 
                     zero_user_segment(page, start, end);
                     set_buffer_uptodate(bh);
                 }
 
                 clear_buffer_new(bh);
                 mark_buffer_dirty(bh);
             }
         }
 
         block_start = block_end;
         bh = bh->b_this_page;
     } while (bh != head);
 }
 
 /*
  * Only called when we have a failure during allocating write to write
  * zero's to the newly allocated region.
  */
 static void ocfs2_write_failure(struct inode *inode,
                 struct ocfs2_write_ctxt *wc,
                 loff_t user_pos, unsigned user_len)
 {
     int i;
     unsigned from = user_pos & (PAGE_SIZE - 1),
         to = user_pos + user_len;
     struct page *tmppage;
 
     if (wc->w_target_page)
         ocfs2_zero_new_buffers(wc->w_target_page, from, to);
 
     for(i = 0; i < wc->w_num_pages; i++) {
         tmppage = wc->w_pages[i];
 
         if (tmppage && page_has_buffers(tmppage)) {
             if (ocfs2_should_order_data(inode))
                 ocfs2_jbd2_inode_add_write(wc->w_handle, inode,
                                user_pos, user_len);
 
             block_commit_write(tmppage, from, to);
         }
     }
 }
 
 static int ocfs2_prepare_page_for_write(struct inode *inode, u64 *p_blkno,
                     struct ocfs2_write_ctxt *wc,
                     struct page *page, u32 cpos,
                     loff_t user_pos, unsigned user_len,
                     int new)
 {
     int ret;
     unsigned int map_from = 0, map_to = 0;
     unsigned int cluster_start, cluster_end;
     unsigned int user_data_from = 0, user_data_to = 0;
 
     ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), cpos,
                     &cluster_start, &cluster_end);
 
     /* treat the write as new if the a hole/lseek spanned across
      * the page boundary.
      */
     new = new | ((i_size_read(inode) <= page_offset(page)) &&
             (page_offset(page) <= user_pos));
 
     if (page == wc->w_target_page) {
         map_from = user_pos & (PAGE_SIZE - 1);
         map_to = map_from + user_len;
 
         if (new)
             ret = ocfs2_map_page_blocks(page, p_blkno, inode,
                             cluster_start, cluster_end,
                             new);
         else
             ret = ocfs2_map_page_blocks(page, p_blkno, inode,
                             map_from, map_to, new);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         user_data_from = map_from;
         user_data_to = map_to;
         if (new) {
             map_from = cluster_start;
             map_to = cluster_end;
         }
     } else {
         /*
          * If we haven't allocated the new page yet, we
          * shouldn't be writing it out without copying user
          * data. This is likely a math error from the caller.
          */
         BUG_ON(!new);
 
         map_from = cluster_start;
         map_to = cluster_end;
 
         ret = ocfs2_map_page_blocks(page, p_blkno, inode,
                         cluster_start, cluster_end, new);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     /*
      * Parts of newly allocated pages need to be zero'd.
      *
      * Above, we have also rewritten 'to' and 'from' - as far as
      * the rest of the function is concerned, the entire cluster
      * range inside of a page needs to be written.
      *
      * We can skip this if the page is up to date - it's already
      * been zero'd from being read in as a hole.
      */
     if (new && !PageUptodate(page))
         ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
                      cpos, user_data_from, user_data_to);
 
     flush_dcache_page(page);
 
 out:
     return ret;
 }
 
 /*
  * This function will only grab one clusters worth of pages.
  */
 static int ocfs2_grab_pages_for_write(struct address_space *mapping,
                       struct ocfs2_write_ctxt *wc,
                       u32 cpos, loff_t user_pos,
                       unsigned user_len, int new,
                       struct page *mmap_page)
 {
     int ret = 0, i;
     unsigned long start, target_index, end_index, index;
     struct inode *inode = mapping->host;
     loff_t last_byte;
 
     target_index = user_pos >> PAGE_SHIFT;
 
     /*
      * Figure out how many pages we'll be manipulating here. For
      * non allocating write, we just change the one
      * page. Otherwise, we'll need a whole clusters worth.  If we're
      * writing past i_size, we only need enough pages to cover the
      * last page of the write.
      */
     if (new) {
         wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
         start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
         /*
          * We need the index *past* the last page we could possibly
          * touch.  This is the page past the end of the write or
          * i_size, whichever is greater.
          */
         last_byte = max(user_pos + user_len, i_size_read(inode));
         BUG_ON(last_byte < 1);
         end_index = ((last_byte - 1) >> PAGE_SHIFT) + 1;
         if ((start + wc->w_num_pages) > end_index)
             wc->w_num_pages = end_index - start;
     } else {
         wc->w_num_pages = 1;
         start = target_index;
     }
     end_index = (user_pos + user_len - 1) >> PAGE_SHIFT;
 
     for(i = 0; i < wc->w_num_pages; i++) {
         index = start + i;
 
         if (index >= target_index && index <= end_index &&
             wc->w_type == OCFS2_WRITE_MMAP) {
             /*
              * ocfs2_pagemkwrite() is a little different
              * and wants us to directly use the page
              * passed in.
              */
             lock_page(mmap_page);
 
             /* Exit and let the caller retry */
             if (mmap_page->mapping != mapping) {
                 WARN_ON(mmap_page->mapping);
                 unlock_page(mmap_page);
                 ret = -EAGAIN;
                 goto out;
             }
 
             get_page(mmap_page);
             wc->w_pages[i] = mmap_page;
             wc->w_target_locked = true;
         } else if (index >= target_index && index <= end_index &&
                wc->w_type == OCFS2_WRITE_DIRECT) {
             /* Direct write has no mapping page. */
             wc->w_pages[i] = NULL;
             continue;
         } else {
             wc->w_pages[i] = find_or_create_page(mapping, index,
                                  GFP_NOFS);
             if (!wc->w_pages[i]) {
                 ret = -ENOMEM;
                 mlog_errno(ret);
                 goto out;
             }
         }
         wait_for_stable_page(wc->w_pages[i]);
 
         if (index == target_index)
             wc->w_target_page = wc->w_pages[i];
     }
 out:
     if (ret)
         wc->w_target_locked = false;
     return ret;
 }
 
 /*
  * Prepare a single cluster for write one cluster into the file.
  */
 static int ocfs2_write_cluster(struct address_space *mapping,
                    u32 *phys, unsigned int new,
                    unsigned int clear_unwritten,
                    unsigned int should_zero,
                    struct ocfs2_alloc_context *data_ac,
                    struct ocfs2_alloc_context *meta_ac,
                    struct ocfs2_write_ctxt *wc, u32 cpos,
                    loff_t user_pos, unsigned user_len)
 {
     int ret, i;
     u64 p_blkno;
     struct inode *inode = mapping->host;
     struct ocfs2_extent_tree et;
     int bpc = ocfs2_clusters_to_blocks(inode->i_sb, 1);
 
     if (new) {
         u32 tmp_pos;
 
         /*
          * This is safe to call with the page locks - it won't take
          * any additional semaphores or cluster locks.
          */
         tmp_pos = cpos;
         ret = ocfs2_add_inode_data(OCFS2_SB(inode->i_sb), inode,
                        &tmp_pos, 1, !clear_unwritten,
                        wc->w_di_bh, wc->w_handle,
                        data_ac, meta_ac, NULL);
         /*
          * This shouldn't happen because we must have already
          * calculated the correct meta data allocation required. The
          * internal tree allocation code should know how to increase
          * transaction credits itself.
          *
          * If need be, we could handle -EAGAIN for a
          * RESTART_TRANS here.
          */
         mlog_bug_on_msg(ret == -EAGAIN,
                 "Inode %llu: EAGAIN return during allocation.\n",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     } else if (clear_unwritten) {
         ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
                           wc->w_di_bh);
         ret = ocfs2_mark_extent_written(inode, &et,
                         wc->w_handle, cpos, 1, *phys,
                         meta_ac, &wc->w_dealloc);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     /*
      * The only reason this should fail is due to an inability to
      * find the extent added.
      */
     ret = ocfs2_get_clusters(inode, cpos, phys, NULL, NULL);
     if (ret < 0) {
         mlog(ML_ERROR, "Get physical blkno failed for inode %llu, "
                 "at logical cluster %u",
                 (unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
         goto out;
     }
 
     BUG_ON(*phys == 0);
 
     p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, *phys);
     if (!should_zero)
         p_blkno += (user_pos >> inode->i_sb->s_blocksize_bits) & (u64)(bpc - 1);
 
     for(i = 0; i < wc->w_num_pages; i++) {
         int tmpret;
 
         /* This is the direct io target page. */
         if (wc->w_pages[i] == NULL) {
             p_blkno++;
             continue;
         }
 
         tmpret = ocfs2_prepare_page_for_write(inode, &p_blkno, wc,
                               wc->w_pages[i], cpos,
                               user_pos, user_len,
                               should_zero);
         if (tmpret) {
             mlog_errno(tmpret);
             if (ret == 0)
                 ret = tmpret;
         }
     }
 
     /*
      * We only have cleanup to do in case of allocating write.
      */
     if (ret && new)
         ocfs2_write_failure(inode, wc, user_pos, user_len);
 
 out:
 
     return ret;
 }
 
 static int ocfs2_write_cluster_by_desc(struct address_space *mapping,
                        struct ocfs2_alloc_context *data_ac,
                        struct ocfs2_alloc_context *meta_ac,
                        struct ocfs2_write_ctxt *wc,
                        loff_t pos, unsigned len)
 {
     int ret, i;
     loff_t cluster_off;
     unsigned int local_len = len;
     struct ocfs2_write_cluster_desc *desc;
     struct ocfs2_super *osb = OCFS2_SB(mapping->host->i_sb);
 
     for (i = 0; i < wc->w_clen; i++) {
         desc = &wc->w_desc[i];
 
         /*
          * We have to make sure that the total write passed in
          * doesn't extend past a single cluster.
          */
         local_len = len;
         cluster_off = pos & (osb->s_clustersize - 1);
         if ((cluster_off + local_len) > osb->s_clustersize)
             local_len = osb->s_clustersize - cluster_off;
 
         ret = ocfs2_write_cluster(mapping, &desc->c_phys,
                       desc->c_new,
                       desc->c_clear_unwritten,
                       desc->c_needs_zero,
                       data_ac, meta_ac,
                       wc, desc->c_cpos, pos, local_len);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         len -= local_len;
         pos += local_len;
     }
 
     ret = 0;
 out:
     return ret;
 }
 
 /*
  * ocfs2_write_end() wants to know which parts of the target page it
  * should complete the write on. It's easiest to compute them ahead of
  * time when a more complete view of the write is available.
  */
 static void ocfs2_set_target_boundaries(struct ocfs2_super *osb,
                     struct ocfs2_write_ctxt *wc,
                     loff_t pos, unsigned len, int alloc)
 {
     struct ocfs2_write_cluster_desc *desc;
 
     wc->w_target_from = pos & (PAGE_SIZE - 1);
     wc->w_target_to = wc->w_target_from + len;
 
     if (alloc == 0)
         return;
 
     /*
      * Allocating write - we may have different boundaries based
      * on page size and cluster size.
      *
      * NOTE: We can no longer compute one value from the other as
      * the actual write length and user provided length may be
      * different.
      */
 
     if (wc->w_large_pages) {
         /*
          * We only care about the 1st and last cluster within
          * our range and whether they should be zero'd or not. Either
          * value may be extended out to the start/end of a
          * newly allocated cluster.
          */
         desc = &wc->w_desc[0];
         if (desc->c_needs_zero)
             ocfs2_figure_cluster_boundaries(osb,
                             desc->c_cpos,
                             &wc->w_target_from,
                             NULL);
 
         desc = &wc->w_desc[wc->w_clen - 1];
         if (desc->c_needs_zero)
             ocfs2_figure_cluster_boundaries(osb,
                             desc->c_cpos,
                             NULL,
                             &wc->w_target_to);
     } else {
         wc->w_target_from = 0;
         wc->w_target_to = PAGE_SIZE;
     }
 }
 
 /*
  * Check if this extent is marked UNWRITTEN by direct io. If so, we need not to
  * do the zero work. And should not to clear UNWRITTEN since it will be cleared
  * by the direct io procedure.
  * If this is a new extent that allocated by direct io, we should mark it in
  * the ip_unwritten_list.
  */
 static int ocfs2_unwritten_check(struct inode *inode,
                  struct ocfs2_write_ctxt *wc,
                  struct ocfs2_write_cluster_desc *desc)
 {
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_unwritten_extent *ue = NULL, *new = NULL;
     int ret = 0;
 
     if (!desc->c_needs_zero)
         return 0;
 
 retry:
     spin_lock(&oi->ip_lock);
     /* Needs not to zero no metter buffer or direct. The one who is zero
      * the cluster is doing zero. And he will clear unwritten after all
      * cluster io finished. */
     list_for_each_entry(ue, &oi->ip_unwritten_list, ue_ip_node) {
         if (desc->c_cpos == ue->ue_cpos) {
             BUG_ON(desc->c_new);
             desc->c_needs_zero = 0;
             desc->c_clear_unwritten = 0;
             goto unlock;
         }
     }
 
     if (wc->w_type != OCFS2_WRITE_DIRECT)
         goto unlock;
 
     if (new == NULL) {
         spin_unlock(&oi->ip_lock);
         new = kmalloc(sizeof(struct ocfs2_unwritten_extent),
                  GFP_NOFS);
         if (new == NULL) {
             ret = -ENOMEM;
             goto out;
         }
         goto retry;
     }
     /* This direct write will doing zero. */
     new->ue_cpos = desc->c_cpos;
     new->ue_phys = desc->c_phys;
     desc->c_clear_unwritten = 0;
     list_add_tail(&new->ue_ip_node, &oi->ip_unwritten_list);
     list_add_tail(&new->ue_node, &wc->w_unwritten_list);
     wc->w_unwritten_count++;
     new = NULL;
 unlock:
     spin_unlock(&oi->ip_lock);
 out:
     kfree(new);
     return ret;
 }
 
 /*
  * Populate each single-cluster write descriptor in the write context
  * with information about the i/o to be done.
  *
  * Returns the number of clusters that will have to be allocated, as
  * well as a worst case estimate of the number of extent records that
  * would have to be created during a write to an unwritten region.
  */
 static int ocfs2_populate_write_desc(struct inode *inode,
                      struct ocfs2_write_ctxt *wc,
                      unsigned int *clusters_to_alloc,
                      unsigned int *extents_to_split)
 {
     int ret;
     struct ocfs2_write_cluster_desc *desc;
     unsigned int num_clusters = 0;
     unsigned int ext_flags = 0;
     u32 phys = 0;
     int i;
 
     *clusters_to_alloc = 0;
     *extents_to_split = 0;
 
     for (i = 0; i < wc->w_clen; i++) {
         desc = &wc->w_desc[i];
         desc->c_cpos = wc->w_cpos + i;
 
         if (num_clusters == 0) {
             /*
              * Need to look up the next extent record.
              */
             ret = ocfs2_get_clusters(inode, desc->c_cpos, &phys,
                          &num_clusters, &ext_flags);
             if (ret) {
                 mlog_errno(ret);
                 goto out;
             }
 
             /* We should already CoW the refcountd extent. */
             BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
 
             /*
              * Assume worst case - that we're writing in
              * the middle of the extent.
              *
              * We can assume that the write proceeds from
              * left to right, in which case the extent
              * insert code is smart enough to coalesce the
              * next splits into the previous records created.
              */
             if (ext_flags & OCFS2_EXT_UNWRITTEN)
                 *extents_to_split = *extents_to_split + 2;
         } else if (phys) {
             /*
              * Only increment phys if it doesn't describe
              * a hole.
              */
             phys++;
         }
 
         /*
          * If w_first_new_cpos is < UINT_MAX, we have a non-sparse
          * file that got extended.  w_first_new_cpos tells us
          * where the newly allocated clusters are so we can
          * zero them.
          */
         if (desc->c_cpos >= wc->w_first_new_cpos) {
             BUG_ON(phys == 0);
             desc->c_needs_zero = 1;
         }
 
         desc->c_phys = phys;
         if (phys == 0) {
             desc->c_new = 1;
             desc->c_needs_zero = 1;
             desc->c_clear_unwritten = 1;
             *clusters_to_alloc = *clusters_to_alloc + 1;
         }
 
         if (ext_flags & OCFS2_EXT_UNWRITTEN) {
             desc->c_clear_unwritten = 1;
             desc->c_needs_zero = 1;
         }
 
         ret = ocfs2_unwritten_check(inode, wc, desc);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         num_clusters--;
     }
 
     ret = 0;
 out:
     return ret;
 }
 
 static int ocfs2_write_begin_inline(struct address_space *mapping,
                     struct inode *inode,
                     struct ocfs2_write_ctxt *wc)
 {
     int ret;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct page *page;
     handle_t *handle;
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
 
     handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto out;
     }
 
     page = find_or_create_page(mapping, 0, GFP_NOFS);
     if (!page) {
         ocfs2_commit_trans(osb, handle);
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
     /*
      * If we don't set w_num_pages then this page won't get unlocked
      * and freed on cleanup of the write context.
      */
     wc->w_pages[0] = wc->w_target_page = page;
     wc->w_num_pages = 1;
 
     ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
                       OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         ocfs2_commit_trans(osb, handle);
 
         mlog_errno(ret);
         goto out;
     }
 
     if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
         ocfs2_set_inode_data_inline(inode, di);
 
     if (!PageUptodate(page)) {
         ret = ocfs2_read_inline_data(inode, page, wc->w_di_bh);
         if (ret) {
             ocfs2_commit_trans(osb, handle);
 
             goto out;
         }
     }
 
     wc->w_handle = handle;
 out:
     return ret;
 }
 
 int ocfs2_size_fits_inline_data(struct buffer_head *di_bh, u64 new_size)
 {
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
 
     if (new_size <= le16_to_cpu(di->id2.i_data.id_count))
         return 1;
     return 0;
 }
 
 static int ocfs2_try_to_write_inline_data(struct address_space *mapping,
                       struct inode *inode, loff_t pos,
                       unsigned len, struct page *mmap_page,
                       struct ocfs2_write_ctxt *wc)
 {
     int ret, written = 0;
     loff_t end = pos + len;
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_dinode *di = NULL;
 
     trace_ocfs2_try_to_write_inline_data((unsigned long long)oi->ip_blkno,
                          len, (unsigned long long)pos,
                          oi->ip_dyn_features);
 
     /*
      * Handle inodes which already have inline data 1st.
      */
     if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
         if (mmap_page == NULL &&
             ocfs2_size_fits_inline_data(wc->w_di_bh, end))
             goto do_inline_write;
 
         /*
          * The write won't fit - we have to give this inode an
          * inline extent list now.
          */
         ret = ocfs2_convert_inline_data_to_extents(inode, wc->w_di_bh);
         if (ret)
             mlog_errno(ret);
         goto out;
     }
 
     /*
      * Check whether the inode can accept inline data.
      */
     if (oi->ip_clusters != 0 || i_size_read(inode) != 0)
         return 0;
 
     /*
      * Check whether the write can fit.
      */
     di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
     if (mmap_page ||
         end > ocfs2_max_inline_data_with_xattr(inode->i_sb, di))
         return 0;
 
 do_inline_write:
     ret = ocfs2_write_begin_inline(mapping, inode, wc);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     /*
      * This signals to the caller that the data can be written
      * inline.
      */
     written = 1;
 out:
     return written ? written : ret;
 }
 
 /*
  * This function only does anything for file systems which can't
  * handle sparse files.
  *
  * What we want to do here is fill in any hole between the current end
  * of allocation and the end of our write. That way the rest of the
  * write path can treat it as an non-allocating write, which has no
  * special case code for sparse/nonsparse files.
  */
 static int ocfs2_expand_nonsparse_inode(struct inode *inode,
                     struct buffer_head *di_bh,
                     loff_t pos, unsigned len,
                     struct ocfs2_write_ctxt *wc)
 {
     int ret;
     loff_t newsize = pos + len;
 
     BUG_ON(ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
 
     if (newsize <= i_size_read(inode))
         return 0;
 
     ret = ocfs2_extend_no_holes(inode, di_bh, newsize, pos);
     if (ret)
         mlog_errno(ret);
 
     /* There is no wc if this is call from direct. */
     if (wc)
         wc->w_first_new_cpos =
             ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
 
     return ret;
 }
 
 static int ocfs2_zero_tail(struct inode *inode, struct buffer_head *di_bh,
                loff_t pos)
 {
     int ret = 0;
 
     BUG_ON(!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)));
     if (pos > i_size_read(inode))
         ret = ocfs2_zero_extend(inode, di_bh, pos);
 
     return ret;
 }
 
 int ocfs2_write_begin_nolock(struct address_space *mapping,
                  loff_t pos, unsigned len, ocfs2_write_type_t type,
                  struct page **pagep, void **fsdata,
                  struct buffer_head *di_bh, struct page *mmap_page)
 {
     int ret, cluster_of_pages, credits = OCFS2_INODE_UPDATE_CREDITS;
     unsigned int clusters_to_alloc, extents_to_split, clusters_need = 0;
     struct ocfs2_write_ctxt *wc;
     struct inode *inode = mapping->host;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_dinode *di;
     struct ocfs2_alloc_context *data_ac = NULL;
     struct ocfs2_alloc_context *meta_ac = NULL;
     handle_t *handle;
     struct ocfs2_extent_tree et;
     int try_free = 1, ret1;
 
 try_again:
     ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, type, di_bh);
     if (ret) {
         mlog_errno(ret);
         return ret;
     }
 
     if (ocfs2_supports_inline_data(osb)) {
         ret = ocfs2_try_to_write_inline_data(mapping, inode, pos, len,
                              mmap_page, wc);
         if (ret == 1) {
             ret = 0;
             goto success;
         }
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     /* Direct io change i_size late, should not zero tail here. */
     if (type != OCFS2_WRITE_DIRECT) {
         if (ocfs2_sparse_alloc(osb))
             ret = ocfs2_zero_tail(inode, di_bh, pos);
         else
             ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
                                len, wc);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     ret = ocfs2_check_range_for_refcount(inode, pos, len);
     if (ret < 0) {
         mlog_errno(ret);
         goto out;
     } else if (ret == 1) {
         clusters_need = wc->w_clen;
         ret = ocfs2_refcount_cow(inode, di_bh,
                      wc->w_cpos, wc->w_clen, UINT_MAX);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
     }
 
     ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc,
                     &extents_to_split);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
     clusters_need += clusters_to_alloc;
 
     di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
 
     trace_ocfs2_write_begin_nolock(
             (unsigned long long)OCFS2_I(inode)->ip_blkno,
             (long long)i_size_read(inode),
             le32_to_cpu(di->i_clusters),
             pos, len, type, mmap_page,
             clusters_to_alloc, extents_to_split);
 
     /*
      * We set w_target_from, w_target_to here so that
      * ocfs2_write_end() knows which range in the target page to
      * write out. An allocation requires that we write the entire
      * cluster range.
      */
     if (clusters_to_alloc || extents_to_split) {
         /*
          * XXX: We are stretching the limits of
          * ocfs2_lock_allocators(). It greatly over-estimates
          * the work to be done.
          */
         ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode),
                           wc->w_di_bh);
         ret = ocfs2_lock_allocators(inode, &et,
                         clusters_to_alloc, extents_to_split,
                         &data_ac, &meta_ac);
         if (ret) {
             mlog_errno(ret);
             goto out;
         }
 
         if (data_ac)
             data_ac->ac_resv = &OCFS2_I(inode)->ip_la_data_resv;
 
         credits = ocfs2_calc_extend_credits(inode->i_sb,
                             &di->id2.i_list);
     } else if (type == OCFS2_WRITE_DIRECT)
         /* direct write needs not to start trans if no extents alloc. */
         goto success;
 
     /*
      * We have to zero sparse allocated clusters, unwritten extent clusters,
      * and non-sparse clusters we just extended.  For non-sparse writes,
      * we know zeros will only be needed in the first and/or last cluster.
      */
     if (wc->w_clen && (wc->w_desc[0].c_needs_zero ||
                wc->w_desc[wc->w_clen - 1].c_needs_zero))
         cluster_of_pages = 1;
     else
         cluster_of_pages = 0;
 
     ocfs2_set_target_boundaries(osb, wc, pos, len, cluster_of_pages);
 
     handle = ocfs2_start_trans(osb, credits);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto out;
     }
 
     wc->w_handle = handle;
 
     if (clusters_to_alloc) {
         ret = dquot_alloc_space_nodirty(inode,
             ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
         if (ret)
             goto out_commit;
     }
 
     ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), wc->w_di_bh,
                       OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto out_quota;
     }
 
     /*
      * Fill our page array first. That way we've grabbed enough so
      * that we can zero and flush if we error after adding the
      * extent.
      */
     ret = ocfs2_grab_pages_for_write(mapping, wc, wc->w_cpos, pos, len,
                      cluster_of_pages, mmap_page);
     if (ret) {
         /*
          * ocfs2_grab_pages_for_write() returns -EAGAIN if it could not lock
          * the target page. In this case, we exit with no error and no target
          * page. This will trigger the caller, page_mkwrite(), to re-try
          * the operation.
          */
         if (type == OCFS2_WRITE_MMAP && ret == -EAGAIN) {
             BUG_ON(wc->w_target_page);
             ret = 0;
             goto out_quota;
         }
 
         mlog_errno(ret);
         goto out_quota;
     }
 
     ret = ocfs2_write_cluster_by_desc(mapping, data_ac, meta_ac, wc, pos,
                       len);
     if (ret) {
         mlog_errno(ret);
         goto out_quota;
     }
 
     if (data_ac)
         ocfs2_free_alloc_context(data_ac);
     if (meta_ac)
         ocfs2_free_alloc_context(meta_ac);
 
 success:
     if (pagep)
         *pagep = wc->w_target_page;
     *fsdata = wc;
     return 0;
 out_quota:
     if (clusters_to_alloc)
         dquot_free_space(inode,
               ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
 out_commit:
     ocfs2_commit_trans(osb, handle);
 
 out:
     /*
      * The mmapped page won't be unlocked in ocfs2_free_write_ctxt(),
      * even in case of error here like ENOSPC and ENOMEM. So, we need
      * to unlock the target page manually to prevent deadlocks when
      * retrying again on ENOSPC, or when returning non-VM_FAULT_LOCKED
      * to VM code.
      */
     if (wc->w_target_locked)
         unlock_page(mmap_page);
 
     ocfs2_free_write_ctxt(inode, wc);
 
     if (data_ac) {
         ocfs2_free_alloc_context(data_ac);
         data_ac = NULL;
     }
     if (meta_ac) {
         ocfs2_free_alloc_context(meta_ac);
         meta_ac = NULL;
     }
 
     if (ret == -ENOSPC && try_free) {
         /*
          * Try to free some truncate log so that we can have enough
          * clusters to allocate.
          */
         try_free = 0;
 
         ret1 = ocfs2_try_to_free_truncate_log(osb, clusters_need);
         if (ret1 == 1)
             goto try_again;
 
         if (ret1 < 0)
             mlog_errno(ret1);
     }
 
     return ret;
 }
 
 static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
                  loff_t pos, unsigned len,
                  struct page **pagep, void **fsdata)
 {
     int ret;
     struct buffer_head *di_bh = NULL;
     struct inode *inode = mapping->host;
 
     ret = ocfs2_inode_lock(inode, &di_bh, 1);
     if (ret) {
         mlog_errno(ret);
         return ret;
     }
 
     /*
      * Take alloc sem here to prevent concurrent lookups. That way
      * the mapping, zeroing and tree manipulation within
      * ocfs2_write() will be safe against ->read_folio(). This
      * should also serve to lock out allocation from a shared
      * writeable region.
      */
     down_write(&OCFS2_I(inode)->ip_alloc_sem);
 
     ret = ocfs2_write_begin_nolock(mapping, pos, len, OCFS2_WRITE_BUFFER,
                        pagep, fsdata, di_bh, NULL);
     if (ret) {
         mlog_errno(ret);
         goto out_fail;
     }
 
     brelse(di_bh);
 
     return 0;
 
 out_fail:
     up_write(&OCFS2_I(inode)->ip_alloc_sem);
 
     brelse(di_bh);
     ocfs2_inode_unlock(inode, 1);
 
     return ret;
 }
 
 static void ocfs2_write_end_inline(struct inode *inode, loff_t pos,
                    unsigned len, unsigned *copied,
                    struct ocfs2_dinode *di,
                    struct ocfs2_write_ctxt *wc)
 {
     void *kaddr;
 
     if (unlikely(*copied < len)) {
         if (!PageUptodate(wc->w_target_page)) {
             *copied = 0;
             return;
         }
     }
 
     kaddr = kmap_atomic(wc->w_target_page);
     memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
     kunmap_atomic(kaddr);
 
     trace_ocfs2_write_end_inline(
          (unsigned long long)OCFS2_I(inode)->ip_blkno,
          (unsigned long long)pos, *copied,
          le16_to_cpu(di->id2.i_data.id_count),
          le16_to_cpu(di->i_dyn_features));
 }
 
 int ocfs2_write_end_nolock(struct address_space *mapping,
                loff_t pos, unsigned len, unsigned copied, void *fsdata)
 {
     int i, ret;
     unsigned from, to, start = pos & (PAGE_SIZE - 1);
     struct inode *inode = mapping->host;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_write_ctxt *wc = fsdata;
     struct ocfs2_dinode *di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
     handle_t *handle = wc->w_handle;
     struct page *tmppage;
 
     BUG_ON(!list_empty(&wc->w_unwritten_list));
 
     if (handle) {
         ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode),
                 wc->w_di_bh, OCFS2_JOURNAL_ACCESS_WRITE);
         if (ret) {
             copied = ret;
             mlog_errno(ret);
             goto out;
         }
     }
 
     if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
         ocfs2_write_end_inline(inode, pos, len, &copied, di, wc);
         goto out_write_size;
     }
 
     if (unlikely(copied < len) && wc->w_target_page) {
         if (!PageUptodate(wc->w_target_page))
             copied = 0;
 
         ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
                        start+len);
     }
     if (wc->w_target_page)
         flush_dcache_page(wc->w_target_page);
 
     for(i = 0; i < wc->w_num_pages; i++) {
         tmppage = wc->w_pages[i];
 
         /* This is the direct io target page. */
         if (tmppage == NULL)
             continue;
 
         if (tmppage == wc->w_target_page) {
             from = wc->w_target_from;
             to = wc->w_target_to;
 
             BUG_ON(from > PAGE_SIZE ||
                    to > PAGE_SIZE ||
                    to < from);
         } else {
             /*
              * Pages adjacent to the target (if any) imply
              * a hole-filling write in which case we want
              * to flush their entire range.
              */
             from = 0;
             to = PAGE_SIZE;
         }
 
         if (page_has_buffers(tmppage)) {
             if (handle && ocfs2_should_order_data(inode)) {
                 loff_t start_byte =
                     ((loff_t)tmppage->index << PAGE_SHIFT) +
                     from;
                 loff_t length = to - from;
                 ocfs2_jbd2_inode_add_write(handle, inode,
                                start_byte, length);
             }
             block_commit_write(tmppage, from, to);
         }
     }
 
 out_write_size:
     /* Direct io do not update i_size here. */
     if (wc->w_type != OCFS2_WRITE_DIRECT) {
         pos += copied;
         if (pos > i_size_read(inode)) {
             i_size_write(inode, pos);
             mark_inode_dirty(inode);
         }
         inode->i_blocks = ocfs2_inode_sector_count(inode);
         di->i_size = cpu_to_le64((u64)i_size_read(inode));
         inode->i_mtime = inode->i_ctime = current_time(inode);
         di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
         di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
         if (handle)
             ocfs2_update_inode_fsync_trans(handle, inode, 1);
     }
     if (handle)
         ocfs2_journal_dirty(handle, wc->w_di_bh);
 
 out:
     /* unlock pages before dealloc since it needs acquiring j_trans_barrier
      * lock, or it will cause a deadlock since journal commit threads holds
      * this lock and will ask for the page lock when flushing the data.
      * put it here to preserve the unlock order.
      */
     ocfs2_unlock_pages(wc);
 
     if (handle)
         ocfs2_commit_trans(osb, handle);
 
     ocfs2_run_deallocs(osb, &wc->w_dealloc);
 
     brelse(wc->w_di_bh);
     kfree(wc);
 
     return copied;
 }
 
 static int ocfs2_write_end(struct file *file, struct address_space *mapping,
                loff_t pos, unsigned len, unsigned copied,
                struct page *page, void *fsdata)
 {
     int ret;
     struct inode *inode = mapping->host;
 
     ret = ocfs2_write_end_nolock(mapping, pos, len, copied, fsdata);
 
     up_write(&OCFS2_I(inode)->ip_alloc_sem);
     ocfs2_inode_unlock(inode, 1);
 
     return ret;
 }
 
 struct ocfs2_dio_write_ctxt {
     struct list_head    dw_zero_list;
     unsigned        dw_zero_count;
     int         dw_orphaned;
     pid_t           dw_writer_pid;
 };
 
 static struct ocfs2_dio_write_ctxt *
 ocfs2_dio_alloc_write_ctx(struct buffer_head *bh, int *alloc)
 {
     struct ocfs2_dio_write_ctxt *dwc = NULL;
 
     if (bh->b_private)
         return bh->b_private;
 
     dwc = kmalloc(sizeof(struct ocfs2_dio_write_ctxt), GFP_NOFS);
     if (dwc == NULL)
         return NULL;
     INIT_LIST_HEAD(&dwc->dw_zero_list);
     dwc->dw_zero_count = 0;
     dwc->dw_orphaned = 0;
     dwc->dw_writer_pid = task_pid_nr(current);
     bh->b_private = dwc;
     *alloc = 1;
 
     return dwc;
 }
 
 static void ocfs2_dio_free_write_ctx(struct inode *inode,
                      struct ocfs2_dio_write_ctxt *dwc)
 {
     ocfs2_free_unwritten_list(inode, &dwc->dw_zero_list);
     kfree(dwc);
 }
 
 /*
  * TODO: Make this into a generic get_blocks function.
  *
  * From do_direct_io in direct-io.c:
  *  "So what we do is to permit the ->get_blocks function to populate
  *   bh.b_size with the size of IO which is permitted at this offset and
  *   this i_blkbits."
  *
  * This function is called directly from get_more_blocks in direct-io.c.
  *
  * called like this: dio->get_blocks(dio->inode, fs_startblk,
  *                  fs_count, map_bh, dio->rw == WRITE);
  */
 static int ocfs2_dio_wr_get_block(struct inode *inode, sector_t iblock,
                    struct buffer_head *bh_result, int create)
 {
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_write_ctxt *wc;
     struct ocfs2_write_cluster_desc *desc = NULL;
     struct ocfs2_dio_write_ctxt *dwc = NULL;
     struct buffer_head *di_bh = NULL;
     u64 p_blkno;
     unsigned int i_blkbits = inode->i_sb->s_blocksize_bits;
     loff_t pos = iblock << i_blkbits;
     sector_t endblk = (i_size_read(inode) - 1) >> i_blkbits;
     unsigned len, total_len = bh_result->b_size;
     int ret = 0, first_get_block = 0;
 
     len = osb->s_clustersize - (pos & (osb->s_clustersize - 1));
     len = min(total_len, len);
 
     /*
      * bh_result->b_size is count in get_more_blocks according to write
      * "pos" and "end", we need map twice to return different buffer state:
      * 1. area in file size, not set NEW;
      * 2. area out file size, set  NEW.
      *
      *         iblock    endblk
      * |--------|---------|---------|---------
      * |<-------area in file------->|
      */
 
     if ((iblock <= endblk) &&
         ((iblock + ((len - 1) >> i_blkbits)) > endblk))
         len = (endblk - iblock + 1) << i_blkbits;
 
     mlog(0, "get block of %lu at %llu:%u req %u\n",
             inode->i_ino, pos, len, total_len);
 
     /*
      * Because we need to change file size in ocfs2_dio_end_io_write(), or
      * we may need to add it to orphan dir. So can not fall to fast path
      * while file size will be changed.
      */
     if (pos + total_len <= i_size_read(inode)) {
 
         /* This is the fast path for re-write. */
         ret = ocfs2_lock_get_block(inode, iblock, bh_result, create);
         if (buffer_mapped(bh_result) &&
             !buffer_new(bh_result) &&
             ret == 0)
             goto out;
 
         /* Clear state set by ocfs2_get_block. */
         bh_result->b_state = 0;
     }
 
     dwc = ocfs2_dio_alloc_write_ctx(bh_result, &first_get_block);
     if (unlikely(dwc == NULL)) {
         ret = -ENOMEM;
         mlog_errno(ret);
         goto out;
     }
 
     if (ocfs2_clusters_for_bytes(inode->i_sb, pos + total_len) >
         ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode)) &&
         !dwc->dw_orphaned) {
         /*
          * when we are going to alloc extents beyond file size, add the
          * inode to orphan dir, so we can recall those spaces when
          * system crashed during write.
          */
         ret = ocfs2_add_inode_to_orphan(osb, inode);
         if (ret < 0) {
             mlog_errno(ret);
             goto out;
         }
         dwc->dw_orphaned = 1;
     }
 
     ret = ocfs2_inode_lock(inode, &di_bh, 1);
     if (ret) {
         mlog_errno(ret);
         goto out;
     }
 
     down_write(&oi->ip_alloc_sem);
 
     if (first_get_block) {
         if (ocfs2_sparse_alloc(osb))
             ret = ocfs2_zero_tail(inode, di_bh, pos);
         else
             ret = ocfs2_expand_nonsparse_inode(inode, di_bh, pos,
                                total_len, NULL);
         if (ret < 0) {
             mlog_errno(ret);
             goto unlock;
         }
     }
 
     ret = ocfs2_write_begin_nolock(inode->i_mapping, pos, len,
                        OCFS2_WRITE_DIRECT, NULL,
                        (void **)&wc, di_bh, NULL);
     if (ret) {
         mlog_errno(ret);
         goto unlock;
     }
 
     desc = &wc->w_desc[0];
 
     p_blkno = ocfs2_clusters_to_blocks(inode->i_sb, desc->c_phys);
     BUG_ON(p_blkno == 0);
     p_blkno += iblock & (u64)(ocfs2_clusters_to_blocks(inode->i_sb, 1) - 1);
 
     map_bh(bh_result, inode->i_sb, p_blkno);
     bh_result->b_size = len;
     if (desc->c_needs_zero)
         set_buffer_new(bh_result);
 
     if (iblock > endblk)
         set_buffer_new(bh_result);
 
     /* May sleep in end_io. It should not happen in a irq context. So defer
      * it to dio work queue. */
     set_buffer_defer_completion(bh_result);
 
     if (!list_empty(&wc->w_unwritten_list)) {
         struct ocfs2_unwritten_extent *ue = NULL;
 
         ue = list_first_entry(&wc->w_unwritten_list,
                       struct ocfs2_unwritten_extent,
                       ue_node);
         BUG_ON(ue->ue_cpos != desc->c_cpos);
         /* The physical address may be 0, fill it. */
         ue->ue_phys = desc->c_phys;
 
         list_splice_tail_init(&wc->w_unwritten_list, &dwc->dw_zero_list);
         dwc->dw_zero_count += wc->w_unwritten_count;
     }
 
     ret = ocfs2_write_end_nolock(inode->i_mapping, pos, len, len, wc);
     BUG_ON(ret != len);
     ret = 0;
 unlock:
     up_write(&oi->ip_alloc_sem);
     ocfs2_inode_unlock(inode, 1);
     brelse(di_bh);
 out:
     if (ret < 0)
         ret = -EIO;
     return ret;
 }
 
 static int ocfs2_dio_end_io_write(struct inode *inode,
                   struct ocfs2_dio_write_ctxt *dwc,
                   loff_t offset,
                   ssize_t bytes)
 {
     struct ocfs2_cached_dealloc_ctxt dealloc;
     struct ocfs2_extent_tree et;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     struct ocfs2_inode_info *oi = OCFS2_I(inode);
     struct ocfs2_unwritten_extent *ue = NULL;
     struct buffer_head *di_bh = NULL;
     struct ocfs2_dinode *di;
     struct ocfs2_alloc_context *data_ac = NULL;
     struct ocfs2_alloc_context *meta_ac = NULL;
     handle_t *handle = NULL;
     loff_t end = offset + bytes;
     int ret = 0, credits = 0;
 
     ocfs2_init_dealloc_ctxt(&dealloc);
 
     /* We do clear unwritten, delete orphan, change i_size here. If neither
      * of these happen, we can skip all this. */
     if (list_empty(&dwc->dw_zero_list) &&
         end <= i_size_read(inode) &&
         !dwc->dw_orphaned)
         goto out;
 
     ret = ocfs2_inode_lock(inode, &di_bh, 1);
     if (ret < 0) {
         mlog_errno(ret);
         goto out;
     }
 
     down_write(&oi->ip_alloc_sem);
 
     /* Delete orphan before acquire i_rwsem. */
     if (dwc->dw_orphaned) {
         BUG_ON(dwc->dw_writer_pid != task_pid_nr(current));
 
         end = end > i_size_read(inode) ? end : 0;
 
         ret = ocfs2_del_inode_from_orphan(osb, inode, di_bh,
                 !!end, end);
         if (ret < 0)
             mlog_errno(ret);
     }
 
     di = (struct ocfs2_dinode *)di_bh->b_data;
 
     ocfs2_init_dinode_extent_tree(&et, INODE_CACHE(inode), di_bh);
 
     /* Attach dealloc with extent tree in case that we may reuse extents
      * which are already unlinked from current extent tree due to extent
      * rotation and merging.
      */
     et.et_dealloc = &dealloc;
 
     ret = ocfs2_lock_allocators(inode, &et, 0, dwc->dw_zero_count*2,
                     &data_ac, &meta_ac);
     if (ret) {
         mlog_errno(ret);
         goto unlock;
     }
 
     credits = ocfs2_calc_extend_credits(inode->i_sb, &di->id2.i_list);
 
     handle = ocfs2_start_trans(osb, credits);
     if (IS_ERR(handle)) {
         ret = PTR_ERR(handle);
         mlog_errno(ret);
         goto unlock;
     }
     ret = ocfs2_journal_access_di(handle, INODE_CACHE(inode), di_bh,
                       OCFS2_JOURNAL_ACCESS_WRITE);
     if (ret) {
         mlog_errno(ret);
         goto commit;
     }
 
     list_for_each_entry(ue, &dwc->dw_zero_list, ue_node) {
         ret = ocfs2_mark_extent_written(inode, &et, handle,
                         ue->ue_cpos, 1,
                         ue->ue_phys,
                         meta_ac, &dealloc);
         if (ret < 0) {
             mlog_errno(ret);
             break;
         }
     }
 
     if (end > i_size_read(inode)) {
         ret = ocfs2_set_inode_size(handle, inode, di_bh, end);
         if (ret < 0)
             mlog_errno(ret);
     }
 commit:
     ocfs2_commit_trans(osb, handle);
 unlock:
     up_write(&oi->ip_alloc_sem);
     ocfs2_inode_unlock(inode, 1);
     brelse(di_bh);
 out:
     if (data_ac)
         ocfs2_free_alloc_context(data_ac);
     if (meta_ac)
         ocfs2_free_alloc_context(meta_ac);
     ocfs2_run_deallocs(osb, &dealloc);
     ocfs2_dio_free_write_ctx(inode, dwc);
 
     return ret;
 }
 
 /*
  * ocfs2_dio_end_io is called by the dio core when a dio is finished.  We're
  * particularly interested in the aio/dio case.  We use the rw_lock DLM lock
  * to protect io on one node from truncation on another.
  */
 static int ocfs2_dio_end_io(struct kiocb *iocb,
                 loff_t offset,
                 ssize_t bytes,
                 void *private)
 {
     struct inode *inode = file_inode(iocb->ki_filp);
     int level;
     int ret = 0;
 
     /* this io's submitter should not have unlocked this before we could */
     BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
 
     if (bytes <= 0)
         mlog_ratelimited(ML_ERROR, "Direct IO failed, bytes = %lld",
                  (long long)bytes);
     if (private) {
         if (bytes > 0)
             ret = ocfs2_dio_end_io_write(inode, private, offset,
                              bytes);
         else
             ocfs2_dio_free_write_ctx(inode, private);
     }
 
     ocfs2_iocb_clear_rw_locked(iocb);
 
     level = ocfs2_iocb_rw_locked_level(iocb);
     ocfs2_rw_unlock(inode, level);
     return ret;
 }
 
 static ssize_t ocfs2_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 {
     struct file *file = iocb->ki_filp;
     struct inode *inode = file->f_mapping->host;
     struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
     get_block_t *get_block;
 
     /*
      * Fallback to buffered I/O if we see an inode without
      * extents.
      */
     if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
         return 0;
 
     /* Fallback to buffered I/O if we do not support append dio. */
     if (iocb->ki_pos + iter->count > i_size_read(inode) &&
         !ocfs2_supports_append_dio(osb))
         return 0;
 
     if (iov_iter_rw(iter) == READ)
         get_block = ocfs2_lock_get_block;
     else
         get_block = ocfs2_dio_wr_get_block;
 
     return __blockdev_direct_IO(iocb, inode, inode->i_sb->s_bdev,
                     iter, get_block,
                     ocfs2_dio_end_io, NULL, 0);
 }
 
 const struct address_space_operations ocfs2_aops = {
     .dirty_folio        = block_dirty_folio,
     .read_folio     = ocfs2_read_folio,
     .readahead      = ocfs2_readahead,
     .writepage      = ocfs2_writepage,
     .write_begin        = ocfs2_write_begin,
     .write_end      = ocfs2_write_end,
     .bmap           = ocfs2_bmap,
     .direct_IO      = ocfs2_direct_IO,
     .invalidate_folio   = block_invalidate_folio,
     .release_folio      = ocfs2_release_folio,
     .migrate_folio      = buffer_migrate_folio,
     .is_partially_uptodate  = block_is_partially_uptodate,
     .error_remove_page  = generic_error_remove_page,
 };

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