Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux...
[safe/jmp/linux-2.6] / fs / ocfs2 / aops.c
index 0d858d0..deb2b13 100644 (file)
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
 #include <asm/byteorder.h>
+#include <linux/swap.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/mpage.h>
+#include <linux/quotaops.h>
 
 #define MLOG_MASK_PREFIX ML_FILE_IO
 #include <cluster/masklog.h>
 #include "file.h"
 #include "inode.h"
 #include "journal.h"
+#include "suballoc.h"
 #include "super.h"
 #include "symlink.h"
+#include "refcounttree.h"
 
 #include "buffer_head_io.h"
 
@@ -64,21 +70,13 @@ static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
                goto bail;
        }
 
-       status = ocfs2_read_block(OCFS2_SB(inode->i_sb),
-                                 OCFS2_I(inode)->ip_blkno,
-                                 &bh, OCFS2_BH_CACHED, inode);
+       status = ocfs2_read_inode_block(inode, &bh);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }
        fe = (struct ocfs2_dinode *) bh->b_data;
 
-       if (!OCFS2_IS_VALID_DINODE(fe)) {
-               mlog(ML_ERROR, "Invalid dinode #%llu: signature = %.*s\n",
-                    (unsigned long long)fe->i_blkno, 7, fe->i_signature);
-               goto bail;
-       }
-
        if ((u64)iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
                                                    le32_to_cpu(fe->i_clusters))) {
                mlog(ML_ERROR, "block offset is outside the allocated size: "
@@ -123,18 +121,20 @@ static int ocfs2_symlink_get_block(struct inode *inode, sector_t iblock,
        err = 0;
 
 bail:
-       if (bh)
-               brelse(bh);
+       brelse(bh);
 
        mlog_exit(err);
        return err;
 }
 
-static int ocfs2_get_block(struct inode *inode, sector_t iblock,
-                          struct buffer_head *bh_result, int create)
+int ocfs2_get_block(struct inode *inode, sector_t iblock,
+                   struct buffer_head *bh_result, int create)
 {
        int err = 0;
-       u64 p_blkno, past_eof;
+       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);
 
        mlog_entry("(0x%p, %llu, 0x%p, %d)\n", inode,
                   (unsigned long long)iblock, bh_result, create);
@@ -149,17 +149,8 @@ static int ocfs2_get_block(struct inode *inode, sector_t iblock,
                goto bail;
        }
 
-       /* this can happen if another node truncs after our extend! */
-       spin_lock(&OCFS2_I(inode)->ip_lock);
-       if (iblock >= ocfs2_clusters_to_blocks(inode->i_sb,
-                                              OCFS2_I(inode)->ip_clusters))
-               err = -EIO;
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
-       if (err)
-               goto bail;
-
-       err = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
-                                         NULL);
+       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,
@@ -167,22 +158,52 @@ static int ocfs2_get_block(struct inode *inode, sector_t iblock,
                goto bail;
        }
 
-       map_bh(bh_result, inode->i_sb, p_blkno);
+       if (max_blocks < count)
+               count = max_blocks;
 
-       if (bh_result->b_blocknr == 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);
+       /*
+        * 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_prepare_write() 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;
        }
 
-       past_eof = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
-       mlog(0, "Inode %lu, past_eof = %llu\n", inode->i_ino,
-            (unsigned long long)past_eof);
+       /* 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));
+               mlog(0, "Inode %lu, past_eof = %llu\n", inode->i_ino,
+                    (unsigned long long)past_eof);
 
-       if (create && (iblock >= past_eof))
-               set_buffer_new(bh_result);
+               if (create && (iblock >= past_eof))
+                       set_buffer_new(bh_result);
+       }
 
 bail:
        if (err < 0)
@@ -192,15 +213,75 @@ bail:
        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",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno);
+               return -EROFS;
+       }
+
+       size = i_size_read(inode);
+
+       if (size > PAGE_CACHE_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",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                           (unsigned long long)size);
+               return -EROFS;
+       }
+
+       kaddr = kmap_atomic(page, KM_USER0);
+       if (size)
+               memcpy(kaddr, di->id2.i_data.id_data, size);
+       /* Clear the remaining part of the page */
+       memset(kaddr + size, 0, PAGE_CACHE_SIZE - size);
+       flush_dcache_page(page);
+       kunmap_atomic(kaddr, KM_USER0);
+
+       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_readpage(struct file *file, struct page *page)
 {
        struct inode *inode = page->mapping->host;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
        loff_t start = (loff_t)page->index << PAGE_CACHE_SHIFT;
        int ret, unlock = 1;
 
        mlog_entry("(0x%p, %lu)\n", file, (page ? page->index : 0));
 
-       ret = ocfs2_meta_lock_with_page(inode, NULL, NULL, 0, page);
+       ret = ocfs2_inode_lock_with_page(inode, NULL, 0, page);
        if (ret != 0) {
                if (ret == AOP_TRUNCATED_PAGE)
                        unlock = 0;
@@ -208,43 +289,38 @@ static int ocfs2_readpage(struct file *file, struct page *page)
                goto out;
        }
 
-       down_read(&OCFS2_I(inode)->ip_alloc_sem);
+       if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
+               ret = AOP_TRUNCATED_PAGE;
+               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_page->get_block freaks out if it is asked to read
         * beyond the end of a file, so we check here.  Callers
-        * (generic_file_read, fault->nopage) are clever enough to check i_size
+        * (generic_file_read, vm_ops->fault) are clever enough to check i_size
         * and notice that the page they just read isn't needed.
         *
         * XXX sys_readahead() seems to get that wrong?
         */
        if (start >= i_size_read(inode)) {
-               char *addr = kmap(page);
-               memset(addr, 0, PAGE_SIZE);
-               flush_dcache_page(page);
-               kunmap(page);
+               zero_user(page, 0, PAGE_SIZE);
                SetPageUptodate(page);
                ret = 0;
                goto out_alloc;
        }
 
-       ret = ocfs2_data_lock_with_page(inode, 0, page);
-       if (ret != 0) {
-               if (ret == AOP_TRUNCATED_PAGE)
-                       unlock = 0;
-               mlog_errno(ret);
-               goto out_alloc;
-       }
-
-       ret = block_read_full_page(page, ocfs2_get_block);
+       if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+               ret = ocfs2_readpage_inline(inode, page);
+       else
+               ret = block_read_full_page(page, ocfs2_get_block);
        unlock = 0;
 
-       ocfs2_data_unlock(inode, 0);
 out_alloc:
        up_read(&OCFS2_I(inode)->ip_alloc_sem);
-       ocfs2_meta_unlock(inode, 0);
+out_inode_unlock:
+       ocfs2_inode_unlock(inode, 0);
 out:
        if (unlock)
                unlock_page(page);
@@ -252,6 +328,62 @@ out:
        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 int ocfs2_readpages(struct file *filp, struct address_space *mapping,
+                          struct list_head *pages, unsigned nr_pages)
+{
+       int ret, err = -EIO;
+       struct inode *inode = mapping->host;
+       struct ocfs2_inode_info *oi = OCFS2_I(inode);
+       loff_t start;
+       struct page *last;
+
+       /*
+        * 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 err;
+
+       if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
+               ocfs2_inode_unlock(inode, 0);
+               return err;
+       }
+
+       /*
+        * 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_unlock;
+
+       /*
+        * Check whether a remote node truncated this file - we just
+        * drop out in that case as it's not worth handling here.
+        */
+       last = list_entry(pages->prev, struct page, lru);
+       start = (loff_t)last->index << PAGE_CACHE_SHIFT;
+       if (start >= i_size_read(inode))
+               goto out_unlock;
+
+       err = mpage_readpages(mapping, pages, nr_pages, ocfs2_get_block);
+
+out_unlock:
+       up_read(&oi->ip_alloc_sem);
+       ocfs2_inode_unlock(inode, 0);
+
+       return err;
+}
+
 /* 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
@@ -277,33 +409,17 @@ static int ocfs2_writepage(struct page *page, struct writeback_control *wbc)
 }
 
 /*
- * ocfs2_prepare_write() can be an outer-most ocfs2 call when it is called
- * from loopback.  It must be able to perform its own locking around
- * ocfs2_get_block().
+ * This is called from ocfs2_write_zero_page() which has handled it's
+ * own cluster locking and has ensured allocation exists for those
+ * blocks to be written.
  */
-int ocfs2_prepare_write(struct file *file, struct page *page,
-                       unsigned from, unsigned to)
+int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page,
+                              unsigned from, unsigned to)
 {
-       struct inode *inode = page->mapping->host;
        int ret;
 
-       mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
-
-       ret = ocfs2_meta_lock_with_page(inode, NULL, NULL, 0, page);
-       if (ret != 0) {
-               mlog_errno(ret);
-               goto out;
-       }
-
-       down_read(&OCFS2_I(inode)->ip_alloc_sem);
-
        ret = block_prepare_write(page, from, to, ocfs2_get_block);
 
-       up_read(&OCFS2_I(inode)->ip_alloc_sem);
-
-       ocfs2_meta_unlock(inode, 0);
-out:
-       mlog_exit(ret);
        return ret;
 }
 
@@ -311,13 +427,13 @@ out:
  * 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 */
-static 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))
+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;
@@ -343,143 +459,36 @@ static int walk_page_buffers(    handle_t *handle,
        return ret;
 }
 
-struct ocfs2_journal_handle *ocfs2_start_walk_page_trans(struct inode *inode,
+handle_t *ocfs2_start_walk_page_trans(struct inode *inode,
                                                         struct page *page,
                                                         unsigned from,
                                                         unsigned to)
 {
        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
-       struct ocfs2_journal_handle *handle = NULL;
+       handle_t *handle;
        int ret = 0;
 
-       handle = ocfs2_start_trans(osb, NULL, OCFS2_INODE_UPDATE_CREDITS);
-       if (!handle) {
+       handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+       if (IS_ERR(handle)) {
                ret = -ENOMEM;
                mlog_errno(ret);
                goto out;
        }
 
        if (ocfs2_should_order_data(inode)) {
-               ret = walk_page_buffers(handle->k_handle,
-                                       page_buffers(page),
-                                       from, to, NULL,
-                                       ocfs2_journal_dirty_data);
-               if (ret < 0) 
+               ret = ocfs2_jbd2_file_inode(handle, inode);
+               if (ret < 0)
                        mlog_errno(ret);
        }
 out:
        if (ret) {
-               if (handle)
-                       ocfs2_commit_trans(handle);
+               if (!IS_ERR(handle))
+                       ocfs2_commit_trans(osb, handle);
                handle = ERR_PTR(ret);
        }
        return handle;
 }
 
-static int ocfs2_commit_write(struct file *file, struct page *page,
-                             unsigned from, unsigned to)
-{
-       int ret, extending = 0, locklevel = 0;
-       loff_t new_i_size;
-       struct buffer_head *di_bh = NULL;
-       struct inode *inode = page->mapping->host;
-       struct ocfs2_journal_handle *handle = NULL;
-
-       mlog_entry("(0x%p, 0x%p, %u, %u)\n", file, page, from, to);
-
-       /* NOTE: ocfs2_file_aio_write has ensured that it's safe for
-        * us to sample inode->i_size here without the metadata lock:
-        *
-        * 1) We're currently holding the inode alloc lock, so no
-        *    nodes can change it underneath us.
-        *
-        * 2) We've had to take the metadata lock at least once
-        *    already to check for extending writes, hence insuring
-        *    that our current copy is also up to date.
-        */
-       new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
-       if (new_i_size > i_size_read(inode)) {
-               extending = 1;
-               locklevel = 1;
-       }
-
-       ret = ocfs2_meta_lock_with_page(inode, NULL, &di_bh, locklevel, page);
-       if (ret != 0) {
-               mlog_errno(ret);
-               goto out;
-       }
-
-       ret = ocfs2_data_lock_with_page(inode, 1, page);
-       if (ret != 0) {
-               mlog_errno(ret);
-               goto out_unlock_meta;
-       }
-
-       if (extending) {
-               handle = ocfs2_start_walk_page_trans(inode, page, from, to);
-               if (IS_ERR(handle)) {
-                       ret = PTR_ERR(handle);
-                       handle = NULL;
-                       goto out_unlock_data;
-               }
-
-               /* Mark our buffer early. We'd rather catch this error up here
-                * as opposed to after a successful commit_write which would
-                * require us to set back inode->i_size. */
-               ret = ocfs2_journal_access(handle, inode, di_bh,
-                                          OCFS2_JOURNAL_ACCESS_WRITE);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto out_commit;
-               }
-       }
-
-       /* might update i_size */
-       ret = generic_commit_write(file, page, from, to);
-       if (ret < 0) {
-               mlog_errno(ret);
-               goto out_commit;
-       }
-
-       if (extending) {
-               loff_t size = (u64) i_size_read(inode);
-               struct ocfs2_dinode *di =
-                       (struct ocfs2_dinode *)di_bh->b_data;
-
-               /* ocfs2_mark_inode_dirty is too heavy to use here. */
-               inode->i_blocks = ocfs2_align_bytes_to_sectors(size);
-               inode->i_ctime = inode->i_mtime = CURRENT_TIME;
-
-               di->i_size = cpu_to_le64(size);
-               di->i_ctime = di->i_mtime = 
-                               cpu_to_le64(inode->i_mtime.tv_sec);
-               di->i_ctime_nsec = di->i_mtime_nsec = 
-                               cpu_to_le32(inode->i_mtime.tv_nsec);
-
-               ret = ocfs2_journal_dirty(handle, di_bh);
-               if (ret < 0) {
-                       mlog_errno(ret);
-                       goto out_commit;
-               }
-       }
-
-       BUG_ON(extending && (i_size_read(inode) != new_i_size));
-
-out_commit:
-       if (handle)
-               ocfs2_commit_trans(handle);
-out_unlock_data:
-       ocfs2_data_unlock(inode, 1);
-out_unlock_meta:
-       ocfs2_meta_unlock(inode, locklevel);
-out:
-       if (di_bh)
-               brelse(di_bh);
-
-       mlog_exit(ret);
-       return ret;
-}
-
 static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
 {
        sector_t status;
@@ -493,7 +502,7 @@ static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
         * accessed concurrently from multiple nodes.
         */
        if (!INODE_JOURNAL(inode)) {
-               err = ocfs2_meta_lock(inode, NULL, NULL, 0);
+               err = ocfs2_inode_lock(inode, NULL, 0);
                if (err) {
                        if (err != -ENOENT)
                                mlog_errno(err);
@@ -502,12 +511,13 @@ static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
                down_read(&OCFS2_I(inode)->ip_alloc_sem);
        }
 
-       err = ocfs2_extent_map_get_blocks(inode, block, 1, &p_blkno,
-                                         NULL);
+       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_meta_unlock(inode, 0);
+               ocfs2_inode_unlock(inode, 0);
        }
 
        if (err) {
@@ -517,7 +527,6 @@ static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
                goto bail;
        }
 
-
 bail:
        status = err ? 0 : p_blkno;
 
@@ -543,39 +552,29 @@ static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
                                     struct buffer_head *bh_result, int create)
 {
        int ret;
-       u64 vbo_max; /* file offset, max_blocks from iblock */
-       u64 p_blkno;
-       int contig_blocks;
-       unsigned char blocksize_bits;
+       u64 p_blkno, inode_blocks, contig_blocks;
+       unsigned int ext_flags;
+       unsigned char blocksize_bits = inode->i_sb->s_blocksize_bits;
        unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
 
-       if (!inode || !bh_result) {
-               mlog(ML_ERROR, "inode or bh_result is null\n");
-               return -EIO;
-       }
-
-       blocksize_bits = inode->i_sb->s_blocksize_bits;
-
        /* This function won't even be called if the request isn't all
         * nicely aligned and of the right size, so there's no need
         * for us to check any of that. */
 
-       vbo_max = ((u64)iblock + max_blocks) << blocksize_bits;
+       inode_blocks = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
 
-       spin_lock(&OCFS2_I(inode)->ip_lock);
-       if ((iblock + max_blocks) >
-           ocfs2_clusters_to_blocks(inode->i_sb,
-                                    OCFS2_I(inode)->ip_clusters)) {
-               spin_unlock(&OCFS2_I(inode)->ip_lock);
+       /*
+        * Any write past EOF is not allowed because we'd be extending.
+        */
+       if (create && (iblock + max_blocks) > inode_blocks) {
                ret = -EIO;
                goto bail;
        }
-       spin_unlock(&OCFS2_I(inode)->ip_lock);
 
        /* This figures out the size of the next contiguous block, and
         * our logical offset */
-       ret = ocfs2_extent_map_get_blocks(inode, iblock, 1, &p_blkno,
-                                         &contig_blocks);
+       ret = ocfs2_extent_map_get_blocks(inode, iblock, &p_blkno,
+                                         &contig_blocks, &ext_flags);
        if (ret) {
                mlog(ML_ERROR, "get_blocks() failed iblock=%llu\n",
                     (unsigned long long)iblock);
@@ -583,7 +582,39 @@ static int ocfs2_direct_IO_get_blocks(struct inode *inode, sector_t iblock,
                goto bail;
        }
 
-       map_bh(bh_result, inode->i_sb, p_blkno);
+       if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb)) && !p_blkno && create) {
+               ocfs2_error(inode->i_sb,
+                           "Inode %llu has a hole at block %llu\n",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                           (unsigned long long)iblock);
+               ret = -EROFS;
+               goto bail;
+       }
+
+       /* We should already CoW the refcounted extent. */
+       BUG_ON(ext_flags & OCFS2_EXT_REFCOUNTED);
+       /*
+        * get_more_blocks() expects us to describe a hole by clearing
+        * the mapped bit on bh_result().
+        *
+        * Consider an unwritten extent as a hole.
+        */
+       if (p_blkno && !(ext_flags & OCFS2_EXT_UNWRITTEN))
+               map_bh(bh_result, inode->i_sb, p_blkno);
+       else {
+               /*
+                * ocfs2_prepare_inode_for_write() should have caught
+                * the case where we'd be filling a hole and triggered
+                * a buffered write instead.
+                */
+               if (create) {
+                       ret = -EIO;
+                       mlog_errno(ret);
+                       goto bail;
+               }
+
+               clear_buffer_mapped(bh_result);
+       }
 
        /* make sure we don't map more than max_blocks blocks here as
           that's all the kernel will handle at this point. */
@@ -605,13 +636,39 @@ static void ocfs2_dio_end_io(struct kiocb *iocb,
                             ssize_t bytes,
                             void *private)
 {
-       struct inode *inode = iocb->ki_filp->f_dentry->d_inode;
+       struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
+       int level;
 
        /* this io's submitter should not have unlocked this before we could */
        BUG_ON(!ocfs2_iocb_is_rw_locked(iocb));
+
        ocfs2_iocb_clear_rw_locked(iocb);
-       up_read(&inode->i_alloc_sem);
-       ocfs2_rw_unlock(inode, 0);
+
+       level = ocfs2_iocb_rw_locked_level(iocb);
+       if (!level)
+               up_read(&inode->i_alloc_sem);
+       ocfs2_rw_unlock(inode, level);
+}
+
+/*
+ * ocfs2_invalidatepage() and ocfs2_releasepage() are shamelessly stolen
+ * from ext3.  PageChecked() bits have been removed as OCFS2 does not
+ * do journalled data.
+ */
+static void ocfs2_invalidatepage(struct page *page, unsigned long offset)
+{
+       journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
+
+       jbd2_journal_invalidatepage(journal, page, offset);
+}
+
+static int ocfs2_releasepage(struct page *page, gfp_t wait)
+{
+       journal_t *journal = OCFS2_SB(page->mapping->host->i_sb)->journal->j_journal;
+
+       if (!page_has_buffers(page))
+               return 0;
+       return jbd2_journal_try_to_free_buffers(journal, page, wait);
 }
 
 static ssize_t ocfs2_direct_IO(int rw,
@@ -621,25 +678,1349 @@ static ssize_t ocfs2_direct_IO(int rw,
                               unsigned long nr_segs)
 {
        struct file *file = iocb->ki_filp;
-       struct inode *inode = file->f_dentry->d_inode->i_mapping->host;
+       struct inode *inode = file->f_path.dentry->d_inode->i_mapping->host;
        int ret;
 
        mlog_entry_void();
+
+       /*
+        * 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 are appending. */
+       if (i_size_read(inode) <= offset)
+               return 0;
+
        ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
                                            inode->i_sb->s_bdev, iov, offset,
                                            nr_segs, 
                                            ocfs2_direct_IO_get_blocks,
                                            ocfs2_dio_end_io);
+
        mlog_exit(ret);
        return ret;
 }
 
-struct address_space_operations ocfs2_aops = {
-       .readpage       = ocfs2_readpage,
-       .writepage      = ocfs2_writepage,
-       .prepare_write  = ocfs2_prepare_write,
-       .commit_write   = ocfs2_commit_write,
-       .bmap           = ocfs2_bmap,
-       .sync_page      = block_sync_page,
-       .direct_IO      = ocfs2_direct_IO
+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_CACHE_SIZE;
+
+       if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits)) {
+               unsigned int cpp;
+
+               cpp = 1 << (PAGE_CACHE_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, KM_USER0);
+
+       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, KM_USER0);
+}
+
+/*
+ * 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_prepare_write(). 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 = 1 << inode->i_blkbits;
+
+       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);
+                       unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
+               }
+
+               if (PageUptodate(page)) {
+                       if (!buffer_uptodate(bh))
+                               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(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_CACHE_SIZE >= OCFS2_MAX_CLUSTERSIZE)
+#define OCFS2_MAX_CTXT_PAGES   1
+#else
+#define OCFS2_MAX_CTXT_PAGES   (OCFS2_MAX_CLUSTERSIZE / PAGE_CACHE_SIZE)
+#endif
+
+#define OCFS2_MAX_CLUSTERS_PER_PAGE    (PAGE_CACHE_SIZE / OCFS2_MIN_CLUSTERSIZE)
+
+/*
+ * 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_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;
+
+       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.
+        */
+       struct page                     *w_pages[OCFS2_MAX_CTXT_PAGES];
+       unsigned int                    w_num_pages;
+       struct page                     *w_target_page;
+
+       /*
+        * 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;
+};
+
+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]);
+                       page_cache_release(pages[i]);
+               }
+       }
+}
+
+static void ocfs2_free_write_ctxt(struct ocfs2_write_ctxt *wc)
+{
+       ocfs2_unlock_and_free_pages(wc->w_pages, wc->w_num_pages);
+
+       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, 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;
+
+       if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
+               wc->w_large_pages = 1;
+       else
+               wc->w_large_pages = 0;
+
+       ocfs2_init_dealloc_ctxt(&wc->w_dealloc);
+
+       *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_CACHE_SIZE - 1),
+               to = user_pos + user_len;
+       struct page *tmppage;
+
+       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 (page_has_buffers(tmppage)) {
+                       if (ocfs2_should_order_data(inode))
+                               ocfs2_jbd2_file_inode(wc->w_handle, inode);
+
+                       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);
+
+       if (page == wc->w_target_page) {
+               map_from = user_pos & (PAGE_CACHE_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, int new,
+                                     struct page *mmap_page)
+{
+       int ret = 0, i;
+       unsigned long start, target_index, index;
+       struct inode *inode = mapping->host;
+
+       target_index = user_pos >> PAGE_CACHE_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 (new) {
+               wc->w_num_pages = ocfs2_pages_per_cluster(inode->i_sb);
+               start = ocfs2_align_clusters_to_page_index(inode->i_sb, cpos);
+       } else {
+               wc->w_num_pages = 1;
+               start = target_index;
+       }
+
+       for(i = 0; i < wc->w_num_pages; i++) {
+               index = start + i;
+
+               if (index == target_index && mmap_page) {
+                       /*
+                        * ocfs2_pagemkwrite() is a little different
+                        * and wants us to directly use the page
+                        * passed in.
+                        */
+                       lock_page(mmap_page);
+
+                       if (mmap_page->mapping != mapping) {
+                               unlock_page(mmap_page);
+                               /*
+                                * Sanity check - the locking in
+                                * ocfs2_pagemkwrite() should ensure
+                                * that this code doesn't trigger.
+                                */
+                               ret = -EINVAL;
+                               mlog_errno(ret);
+                               goto out;
+                       }
+
+                       page_cache_get(mmap_page);
+                       wc->w_pages[i] = mmap_page;
+               } 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;
+                       }
+               }
+
+               if (index == target_index)
+                       wc->w_target_page = wc->w_pages[i];
+       }
+out:
+       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 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, new;
+       u64 v_blkno, p_blkno;
+       struct inode *inode = mapping->host;
+       struct ocfs2_extent_tree et;
+
+       new = phys == 0 ? 1 : 0;
+       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, 0, 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 (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;
+               }
+       }
+
+       if (should_zero)
+               v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, cpos);
+       else
+               v_blkno = user_pos >> inode->i_sb->s_blocksize_bits;
+
+       /*
+        * The only reason this should fail is due to an inability to
+        * find the extent added.
+        */
+       ret = ocfs2_extent_map_get_blocks(inode, v_blkno, &p_blkno, NULL,
+                                         NULL);
+       if (ret < 0) {
+               ocfs2_error(inode->i_sb, "Corrupting extend for inode %llu, "
+                           "at logical block %llu",
+                           (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                           (unsigned long long)v_blkno);
+               goto out;
+       }
+
+       BUG_ON(p_blkno == 0);
+
+       for(i = 0; i < wc->w_num_pages; i++) {
+               int tmpret;
+
+               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_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_CACHE_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_CACHE_SIZE;
+       }
+}
+
+/*
+ * 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;
+                       *clusters_to_alloc = *clusters_to_alloc + 1;
+               }
+
+               if (ext_flags & OCFS2_EXT_UNWRITTEN) {
+                       desc->c_unwritten = 1;
+                       desc->c_needs_zero = 1;
+               }
+
+               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;
+
+       page = find_or_create_page(mapping, 0, GFP_NOFS);
+       if (!page) {
+               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;
+
+       handle = ocfs2_start_trans(osb, OCFS2_INODE_UPDATE_CREDITS);
+       if (IS_ERR(handle)) {
+               ret = PTR_ERR(handle);
+               mlog_errno(ret);
+               goto out;
+       }
+
+       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;
+
+       mlog(0, "Inode %llu, write of %u bytes at off %llu. features: 0x%x\n",
+            (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, loff_t pos,
+                                       unsigned len,
+                                       struct ocfs2_write_ctxt *wc)
+{
+       int ret;
+       struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+       loff_t newsize = pos + len;
+
+       if (ocfs2_sparse_alloc(osb))
+               return 0;
+
+       if (newsize <= i_size_read(inode))
+               return 0;
+
+       ret = ocfs2_extend_no_holes(inode, newsize, pos);
+       if (ret)
+               mlog_errno(ret);
+
+       wc->w_first_new_cpos =
+               ocfs2_clusters_for_bytes(inode->i_sb, i_size_read(inode));
+
+       return ret;
+}
+
+int ocfs2_write_begin_nolock(struct address_space *mapping,
+                            loff_t pos, unsigned len, unsigned flags,
+                            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;
+       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;
+
+       ret = ocfs2_alloc_write_ctxt(&wc, osb, pos, len, 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;
+               }
+       }
+
+       ret = ocfs2_expand_nonsparse_inode(inode, 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) {
+               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;
+       }
+
+       di = (struct ocfs2_dinode *)wc->w_di_bh->b_data;
+
+       /*
+        * 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.
+                */
+               mlog(0, "extend inode %llu, i_size = %lld, di->i_clusters = %u,"
+                    " clusters_to_add = %u, extents_to_split = %u\n",
+                    (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                    (long long)i_size_read(inode), le32_to_cpu(di->i_clusters),
+                    clusters_to_alloc, extents_to_split);
+
+               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;
+               }
+
+               credits = ocfs2_calc_extend_credits(inode->i_sb,
+                                                   &di->id2.i_list,
+                                                   clusters_to_alloc);
+
+       }
+
+       /*
+        * 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 (clusters_to_alloc || extents_to_split ||
+           (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 && vfs_dq_alloc_space_nodirty(inode,
+                       ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc))) {
+               ret = -EDQUOT;
+               goto out_commit;
+       }
+       /*
+        * We don't want this to fail in ocfs2_write_end(), so do it
+        * here.
+        */
+       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,
+                                        cluster_of_pages, mmap_page);
+       if (ret) {
+               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:
+       *pagep = wc->w_target_page;
+       *fsdata = wc;
+       return 0;
+out_quota:
+       if (clusters_to_alloc)
+               vfs_dq_free_space(inode,
+                         ocfs2_clusters_to_bytes(osb->sb, clusters_to_alloc));
+out_commit:
+       ocfs2_commit_trans(osb, handle);
+
+out:
+       ocfs2_free_write_ctxt(wc);
+
+       if (data_ac)
+               ocfs2_free_alloc_context(data_ac);
+       if (meta_ac)
+               ocfs2_free_alloc_context(meta_ac);
+       return ret;
+}
+
+static int ocfs2_write_begin(struct file *file, struct address_space *mapping,
+                            loff_t pos, unsigned len, unsigned flags,
+                            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 ->readpage(). 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, flags, 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, KM_USER0);
+       memcpy(di->id2.i_data.id_data + pos, kaddr + pos, *copied);
+       kunmap_atomic(kaddr, KM_USER0);
+
+       mlog(0, "Data written to inode at offset %llu. "
+            "id_count = %u, copied = %u, i_dyn_features = 0x%x\n",
+            (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,
+                          struct page *page, void *fsdata)
+{
+       int i;
+       unsigned from, to, start = pos & (PAGE_CACHE_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;
+
+       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)) {
+               if (!PageUptodate(wc->w_target_page))
+                       copied = 0;
+
+               ocfs2_zero_new_buffers(wc->w_target_page, start+copied,
+                                      start+len);
+       }
+       flush_dcache_page(wc->w_target_page);
+
+       for(i = 0; i < wc->w_num_pages; i++) {
+               tmppage = wc->w_pages[i];
+
+               if (tmppage == wc->w_target_page) {
+                       from = wc->w_target_from;
+                       to = wc->w_target_to;
+
+                       BUG_ON(from > PAGE_CACHE_SIZE ||
+                              to > PAGE_CACHE_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_CACHE_SIZE;
+               }
+
+               if (page_has_buffers(tmppage)) {
+                       if (ocfs2_should_order_data(inode))
+                               ocfs2_jbd2_file_inode(wc->w_handle, inode);
+                       block_commit_write(tmppage, from, to);
+               }
+       }
+
+out_write_size:
+       pos += copied;
+       if (pos > inode->i_size) {
+               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;
+       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);
+       ocfs2_journal_dirty(handle, wc->w_di_bh);
+
+       ocfs2_commit_trans(osb, handle);
+
+       ocfs2_run_deallocs(osb, &wc->w_dealloc);
+
+       ocfs2_free_write_ctxt(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, page, fsdata);
+
+       up_write(&OCFS2_I(inode)->ip_alloc_sem);
+       ocfs2_inode_unlock(inode, 1);
+
+       return ret;
+}
+
+const struct address_space_operations ocfs2_aops = {
+       .readpage               = ocfs2_readpage,
+       .readpages              = ocfs2_readpages,
+       .writepage              = ocfs2_writepage,
+       .write_begin            = ocfs2_write_begin,
+       .write_end              = ocfs2_write_end,
+       .bmap                   = ocfs2_bmap,
+       .sync_page              = block_sync_page,
+       .direct_IO              = ocfs2_direct_IO,
+       .invalidatepage         = ocfs2_invalidatepage,
+       .releasepage            = ocfs2_releasepage,
+       .migratepage            = buffer_migrate_page,
+       .is_partially_uptodate  = block_is_partially_uptodate,
+       .error_remove_page      = generic_error_remove_page,
 };