Merge Btrfs into fs/btrfs

1 files changed, 1133 insertions, 0 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
new file mode 100644
index 000000000000..48a702d41c8c
--- /dev/null
+++ b/fs/btrfs/file.c
@@ -0,0 +1,1133 @@
+/*
+ * Copyright (C) 2007 Oracle.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/smp_lock.h>
+#include <linux/backing-dev.h>
+#include <linux/mpage.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/statfs.h>
+#include <linux/compat.h>
+#include <linux/version.h>
+#include "ctree.h"
+#include "disk-io.h"
+#include "transaction.h"
+#include "btrfs_inode.h"
+#include "ioctl.h"
+#include "print-tree.h"
+#include "tree-log.h"
+#include "locking.h"
+#include "compat.h"
+
+
+static int noinline btrfs_copy_from_user(loff_t pos, int num_pages,
+                                         int write_bytes,
+                                         struct page **prepared_pages,
+                                         const char __user * buf)
+{
+        long page_fault = 0;
+        int i;
+        int offset = pos & (PAGE_CACHE_SIZE - 1);
+
+        for (i = 0; i < num_pages && write_bytes > 0; i++, offset = 0) {
+                size_t count = min_t(size_t,
+                                     PAGE_CACHE_SIZE - offset, write_bytes);
+                struct page *page = prepared_pages[i];
+                fault_in_pages_readable(buf, count);
+
+                /* Copy data from userspace to the current page */
+                kmap(page);
+                page_fault = __copy_from_user(page_address(page) + offset,
+                                              buf, count);
+                /* Flush processor's dcache for this page */
+                flush_dcache_page(page);
+                kunmap(page);
+                buf += count;
+                write_bytes -= count;
+
+                if (page_fault)
+                        break;
+        }
+        return page_fault ? -EFAULT : 0;
+}
+
+static void noinline btrfs_drop_pages(struct page **pages, size_t num_pages)
+{
+        size_t i;
+        for (i = 0; i < num_pages; i++) {
+                if (!pages[i])
+                        break;
+                ClearPageChecked(pages[i]);
+                unlock_page(pages[i]);
+                mark_page_accessed(pages[i]);
+                page_cache_release(pages[i]);
+        }
+}
+
+static int noinline insert_inline_extent(struct btrfs_trans_handle *trans,
+                                struct btrfs_root *root, struct inode *inode,
+                                u64 offset, size_t size,
+                                struct page **pages, size_t page_offset,
+                                int num_pages)
+{
+        struct btrfs_key key;
+        struct btrfs_path *path;
+        struct extent_buffer *leaf;
+        char *kaddr;
+        unsigned long ptr;
+        struct btrfs_file_extent_item *ei;
+        struct page *page;
+        u32 datasize;
+        int err = 0;
+        int ret;
+        int i;
+        ssize_t cur_size;
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+
+        btrfs_set_trans_block_group(trans, inode);
+
+        key.objectid = inode->i_ino;
+        key.offset = offset;
+        btrfs_set_key_type(&key, BTRFS_EXTENT_DATA_KEY);
+
+        ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
+        if (ret < 0) {
+                err = ret;
+                goto fail;
+        }
+        if (ret == 1) {
+                struct btrfs_key found_key;
+
+                if (path->slots[0] == 0)
+                        goto insert;
+
+                path->slots[0]--;
+                leaf = path->nodes[0];
+                btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+
+                if (found_key.objectid != inode->i_ino)
+                        goto insert;
+
+                if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+                        goto insert;
+                ei = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_file_extent_item);
+
+                if (btrfs_file_extent_type(leaf, ei) !=
+                    BTRFS_FILE_EXTENT_INLINE) {
+                        goto insert;
+                }
+                btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+                ret = 0;
+        }
+        if (ret == 0) {
+                u32 found_size;
+                u64 found_end;
+
+                leaf = path->nodes[0];
+                ei = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_file_extent_item);
+
+                if (btrfs_file_extent_type(leaf, ei) !=
+                    BTRFS_FILE_EXTENT_INLINE) {
+                        err = ret;
+                        btrfs_print_leaf(root, leaf);
+                        printk("found wasn't inline offset %Lu inode %lu\n",
+                               offset, inode->i_ino);
+                        goto fail;
+                }
+                found_size = btrfs_file_extent_inline_len(leaf,
+                                          btrfs_item_nr(leaf, path->slots[0]));
+                found_end = key.offset + found_size;
+
+                if (found_end < offset + size) {
+                        btrfs_release_path(root, path);
+                        ret = btrfs_search_slot(trans, root, &key, path,
+                                                offset + size - found_end, 1);
+                        BUG_ON(ret != 0);
+
+                        ret = btrfs_extend_item(trans, root, path,
+                                                offset + size - found_end);
+                        if (ret) {
+                                err = ret;
+                                goto fail;
+                        }
+                        leaf = path->nodes[0];
+                        ei = btrfs_item_ptr(leaf, path->slots[0],
+                                            struct btrfs_file_extent_item);
+                        inode->i_blocks += (offset + size - found_end) >> 9;
+                }
+                if (found_end < offset) {
+                        ptr = btrfs_file_extent_inline_start(ei) + found_size;
+                        memset_extent_buffer(leaf, 0, ptr, offset - found_end);
+                }
+        } else {
+insert:
+                btrfs_release_path(root, path);
+                datasize = offset + size - key.offset;
+                inode->i_blocks += datasize >> 9;
+                datasize = btrfs_file_extent_calc_inline_size(datasize);
+                ret = btrfs_insert_empty_item(trans, root, path, &key,
+                                              datasize);
+                if (ret) {
+                        err = ret;
+                        printk("got bad ret %d\n", ret);
+                        goto fail;
+                }
+                leaf = path->nodes[0];
+                ei = btrfs_item_ptr(leaf, path->slots[0],
+                                    struct btrfs_file_extent_item);
+                btrfs_set_file_extent_generation(leaf, ei, trans->transid);
+                btrfs_set_file_extent_type(leaf, ei, BTRFS_FILE_EXTENT_INLINE);
+        }
+        ptr = btrfs_file_extent_inline_start(ei) + offset - key.offset;
+
+        cur_size = size;
+        i = 0;
+        while (size > 0) {
+                page = pages[i];
+                kaddr = kmap_atomic(page, KM_USER0);
+                cur_size = min_t(size_t, PAGE_CACHE_SIZE - page_offset, size);
+                write_extent_buffer(leaf, kaddr + page_offset, ptr, cur_size);
+                kunmap_atomic(kaddr, KM_USER0);
+                page_offset = 0;
+                ptr += cur_size;
+                size -= cur_size;
+                if (i >= num_pages) {
+                        printk("i %d num_pages %d\n", i, num_pages);
+                }
+                i++;
+        }
+        btrfs_mark_buffer_dirty(leaf);
+fail:
+        btrfs_free_path(path);
+        return err;
+}
+
+static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
+                                   struct btrfs_root *root,
+                                   struct file *file,
+                                   struct page **pages,
+                                   size_t num_pages,
+                                   loff_t pos,
+                                   size_t write_bytes)
+{
+        int err = 0;
+        int i;
+        struct inode *inode = fdentry(file)->d_inode;
+        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+        u64 hint_byte;
+        u64 num_bytes;
+        u64 start_pos;
+        u64 end_of_last_block;
+        u64 end_pos = pos + write_bytes;
+        u64 inline_size;
+        int did_inline = 0;
+        loff_t isize = i_size_read(inode);
+
+        start_pos = pos & ~((u64)root->sectorsize - 1);
+        num_bytes = (write_bytes + pos - start_pos +
+                    root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
+
+        end_of_last_block = start_pos + num_bytes - 1;
+
+        lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+        trans = btrfs_join_transaction(root, 1);
+        if (!trans) {
+                err = -ENOMEM;
+                goto out_unlock;
+        }
+        btrfs_set_trans_block_group(trans, inode);
+        hint_byte = 0;
+
+        if ((end_of_last_block & 4095) == 0) {
+                printk("strange end of last %Lu %zu %Lu\n", start_pos, write_bytes, end_of_last_block);
+        }
+        set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+
+        /* FIXME...EIEIO, ENOSPC and more */
+        /* insert any holes we need to create */
+        if (isize < start_pos) {
+                u64 last_pos_in_file;
+                u64 hole_size;
+                u64 mask = root->sectorsize - 1;
+                last_pos_in_file = (isize + mask) & ~mask;
+                hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
+                if (hole_size > 0) {
+                        btrfs_wait_ordered_range(inode, last_pos_in_file,
+                                                 last_pos_in_file + hole_size);
+                        mutex_lock(&BTRFS_I(inode)->extent_mutex);
+                        err = btrfs_drop_extents(trans, root, inode,
+                                                 last_pos_in_file,
+                                                 last_pos_in_file + hole_size,
+                                                 last_pos_in_file,
+                                                 &hint_byte);
+                        if (err)
+                                goto failed;
+
+                        err = btrfs_insert_file_extent(trans, root,
+                                                       inode->i_ino,
+                                                       last_pos_in_file,
+                                                       0, 0, hole_size, 0);
+                        btrfs_drop_extent_cache(inode, last_pos_in_file,
+                                        last_pos_in_file + hole_size -1);
+                        mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+                        btrfs_check_file(root, inode);
+                }
+                if (err)
+                        goto failed;
+        }
+
+        /*
+         * either allocate an extent for the new bytes or setup the key
+         * to show we are doing inline data in the extent
+         */
+        inline_size = end_pos;
+        if (isize >= BTRFS_MAX_INLINE_DATA_SIZE(root) ||
+            inline_size > root->fs_info->max_inline ||
+            (inline_size & (root->sectorsize -1)) == 0 ||
+            inline_size >= BTRFS_MAX_INLINE_DATA_SIZE(root)) {
+                /* check for reserved extents on each page, we don't want
+                 * to reset the delalloc bit on things that already have
+                 * extents reserved.
+                 */
+                btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+                for (i = 0; i < num_pages; i++) {
+                        struct page *p = pages[i];
+                        SetPageUptodate(p);
+                        ClearPageChecked(p);
+                        set_page_dirty(p);
+                }
+        } else {
+                u64 aligned_end;
+                /* step one, delete the existing extents in this range */
+                aligned_end = (pos + write_bytes + root->sectorsize - 1) &
+                        ~((u64)root->sectorsize - 1);
+                mutex_lock(&BTRFS_I(inode)->extent_mutex);
+                err = btrfs_drop_extents(trans, root, inode, start_pos,
+                                         aligned_end, aligned_end, &hint_byte);
+                if (err)
+                        goto failed;
+                if (isize > inline_size)
+                        inline_size = min_t(u64, isize, aligned_end);
+                inline_size -= start_pos;
+                err = insert_inline_extent(trans, root, inode, start_pos,
+                                           inline_size, pages, 0, num_pages);
+                btrfs_drop_extent_cache(inode, start_pos, aligned_end - 1);
+                BUG_ON(err);
+                mutex_unlock(&BTRFS_I(inode)->extent_mutex);
+
+                /*
+                 * an ugly way to do all the prop accounting around
+                 * the page bits and mapping tags
+                 */
+                set_page_writeback(pages[0]);
+                end_page_writeback(pages[0]);
+                did_inline = 1;
+        }
+        if (end_pos > isize) {
+                i_size_write(inode, end_pos);
+                if (did_inline)
+                        BTRFS_I(inode)->disk_i_size = end_pos;
+                btrfs_update_inode(trans, root, inode);
+        }
+failed:
+        err = btrfs_end_transaction(trans, root);
+out_unlock:
+        unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
+        return err;
+}
+
+int noinline btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
+{
+        struct extent_map *em;
+        struct extent_map *split = NULL;
+        struct extent_map *split2 = NULL;
+        struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+        u64 len = end - start + 1;
+        int ret;
+        int testend = 1;
+
+        WARN_ON(end < start);
+        if (end == (u64)-1) {
+                len = (u64)-1;
+                testend = 0;
+        }
+        while(1) {
+                if (!split)
+                        split = alloc_extent_map(GFP_NOFS);
+                if (!split2)
+                        split2 = alloc_extent_map(GFP_NOFS);
+
+                spin_lock(&em_tree->lock);
+                em = lookup_extent_mapping(em_tree, start, len);
+                if (!em) {
+                        spin_unlock(&em_tree->lock);
+                        break;
+                }
+                clear_bit(EXTENT_FLAG_PINNED, &em->flags);
+                remove_extent_mapping(em_tree, em);
+
+                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+                    em->start < start) {
+                        split->start = em->start;
+                        split->len = start - em->start;
+                        split->block_start = em->block_start;
+                        split->bdev = em->bdev;
+                        split->flags = em->flags;
+                        ret = add_extent_mapping(em_tree, split);
+                        BUG_ON(ret);
+                        free_extent_map(split);
+                        split = split2;
+                        split2 = NULL;
+                }
+                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
+                    testend && em->start + em->len > start + len) {
+                        u64 diff = start + len - em->start;
+
+                        split->start = start + len;
+                        split->len = em->start + em->len - (start + len);
+                        split->bdev = em->bdev;
+                        split->flags = em->flags;
+
+                        split->block_start = em->block_start + diff;
+
+                        ret = add_extent_mapping(em_tree, split);
+                        BUG_ON(ret);
+                        free_extent_map(split);
+                        split = NULL;
+                }
+                spin_unlock(&em_tree->lock);
+
+                /* once for us */
+                free_extent_map(em);
+                /* once for the tree*/
+                free_extent_map(em);
+        }
+        if (split)
+                free_extent_map(split);
+        if (split2)
+                free_extent_map(split2);
+        return 0;
+}
+
+int btrfs_check_file(struct btrfs_root *root, struct inode *inode)
+{
+        return 0;
+#if 0
+        struct btrfs_path *path;
+        struct btrfs_key found_key;
+        struct extent_buffer *leaf;
+        struct btrfs_file_extent_item *extent;
+        u64 last_offset = 0;
+        int nritems;
+        int slot;
+        int found_type;
+        int ret;
+        int err = 0;
+        u64 extent_end = 0;
+
+        path = btrfs_alloc_path();
+        ret = btrfs_lookup_file_extent(NULL, root, path, inode->i_ino,
+                                       last_offset, 0);
+        while(1) {
+                nritems = btrfs_header_nritems(path->nodes[0]);
+                if (path->slots[0] >= nritems) {
+                        ret = btrfs_next_leaf(root, path);
+                        if (ret)
+                                goto out;
+                        nritems = btrfs_header_nritems(path->nodes[0]);
+                }
+                slot = path->slots[0];
+                leaf = path->nodes[0];
+                btrfs_item_key_to_cpu(leaf, &found_key, slot);
+                if (found_key.objectid != inode->i_ino)
+                        break;
+                if (found_key.type != BTRFS_EXTENT_DATA_KEY)
+                        goto out;
+
+                if (found_key.offset < last_offset) {
+                        WARN_ON(1);
+                        btrfs_print_leaf(root, leaf);
+                        printk("inode %lu found offset %Lu expected %Lu\n",
+                               inode->i_ino, found_key.offset, last_offset);
+                        err = 1;
+                        goto out;
+                }
+                extent = btrfs_item_ptr(leaf, slot,
+                                        struct btrfs_file_extent_item);
+                found_type = btrfs_file_extent_type(leaf, extent);
+                if (found_type == BTRFS_FILE_EXTENT_REG) {
+                        extent_end = found_key.offset +
+                             btrfs_file_extent_num_bytes(leaf, extent);
+                } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+                        struct btrfs_item *item;
+                        item = btrfs_item_nr(leaf, slot);
+                        extent_end = found_key.offset +
+                             btrfs_file_extent_inline_len(leaf, item);
+                        extent_end = (extent_end + root->sectorsize - 1) &
+                                ~((u64)root->sectorsize -1 );
+                }
+                last_offset = extent_end;
+                path->slots[0]++;
+        }
+        if (0 && last_offset < inode->i_size) {
+                WARN_ON(1);
+                btrfs_print_leaf(root, leaf);
+                printk("inode %lu found offset %Lu size %Lu\n", inode->i_ino,
+                       last_offset, inode->i_size);
+                err = 1;
+
+        }
+out:
+        btrfs_free_path(path);
+        return err;
+#endif
+}
+
+/*
+ * this is very complex, but the basic idea is to drop all extents
+ * in the range start - end.  hint_block is filled in with a block number
+ * that would be a good hint to the block allocator for this file.
+ *
+ * If an extent intersects the range but is not entirely inside the range
+ * it is either truncated or split.  Anything entirely inside the range
+ * is deleted from the tree.
+ */
+int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans,
+                       struct btrfs_root *root, struct inode *inode,
+                       u64 start, u64 end, u64 inline_limit, u64 *hint_byte)
+{
+        u64 extent_end = 0;
+        u64 search_start = start;
+        u64 leaf_start;
+        u64 root_gen;
+        u64 root_owner;
+        struct extent_buffer *leaf;
+        struct btrfs_file_extent_item *extent;
+        struct btrfs_path *path;
+        struct btrfs_key key;
+        struct btrfs_file_extent_item old;
+        int keep;
+        int slot;
+        int bookend;
+        int found_type;
+        int found_extent;
+        int found_inline;
+        int recow;
+        int ret;
+
+        btrfs_drop_extent_cache(inode, start, end - 1);
+
+        path = btrfs_alloc_path();
+        if (!path)
+                return -ENOMEM;
+        while(1) {
+                recow = 0;
+                btrfs_release_path(root, path);
+                ret = btrfs_lookup_file_extent(trans, root, path, inode->i_ino,
+                                               search_start, -1);
+                if (ret < 0)
+                        goto out;
+                if (ret > 0) {
+                        if (path->slots[0] == 0) {
+                                ret = 0;
+                                goto out;
+                        }
+                        path->slots[0]--;
+                }
+next_slot:
+                keep = 0;
+                bookend = 0;
+                found_extent = 0;
+                found_inline = 0;
+                leaf_start = 0;
+                root_gen = 0;
+                root_owner = 0;
+                extent = NULL;
+                leaf = path->nodes[0];
+                slot = path->slots[0];
+                ret = 0;
+                btrfs_item_key_to_cpu(leaf, &key, slot);
+                if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY &&
+                    key.offset >= end) {
+                        goto out;
+                }
+                if (btrfs_key_type(&key) > BTRFS_EXTENT_DATA_KEY ||
+                    key.objectid != inode->i_ino) {
+                        goto out;
+                }
+                if (recow) {
+                        search_start = key.offset;
+                        continue;
+                }
+                if (btrfs_key_type(&key) == BTRFS_EXTENT_DATA_KEY) {
+                        extent = btrfs_item_ptr(leaf, slot,
+                                                struct btrfs_file_extent_item);
+                        found_type = btrfs_file_extent_type(leaf, extent);
+                        if (found_type == BTRFS_FILE_EXTENT_REG) {
+                                extent_end =
+                                     btrfs_file_extent_disk_bytenr(leaf,
+                                                                   extent);
+                                if (extent_end)
+                                        *hint_byte = extent_end;
+
+                                extent_end = key.offset +
+                                     btrfs_file_extent_num_bytes(leaf, extent);
+                                found_extent = 1;
+                        } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+                                struct btrfs_item *item;
+                                item = btrfs_item_nr(leaf, slot);
+                                found_inline = 1;
+                                extent_end = key.offset +
+                                     btrfs_file_extent_inline_len(leaf, item);
+                        }
+                } else {
+                        extent_end = search_start;
+                }
+
+                /* we found nothing we can drop */
+                if ((!found_extent && !found_inline) ||
+                    search_start >= extent_end) {
+                        int nextret;
+                        u32 nritems;
+                        nritems = btrfs_header_nritems(leaf);
+                        if (slot >= nritems - 1) {
+                                nextret = btrfs_next_leaf(root, path);
+                                if (nextret)
+                                        goto out;
+                                recow = 1;
+                        } else {
+                                path->slots[0]++;
+                        }
+                        goto next_slot;
+                }
+
+                if (found_inline) {
+                        u64 mask = root->sectorsize - 1;
+                        search_start = (extent_end + mask) & ~mask;
+                } else
+                        search_start = extent_end;
+                if (end <= extent_end && start >= key.offset && found_inline) {
+                        *hint_byte = EXTENT_MAP_INLINE;
+                        goto out;
+                }
+
+                if (found_extent) {
+                        read_extent_buffer(leaf, &old, (unsigned long)extent,
+                                           sizeof(old));
+                        root_gen = btrfs_header_generation(leaf);
+                        root_owner = btrfs_header_owner(leaf);
+                        leaf_start = leaf->start;
+                }
+
+                if (end < extent_end && end >= key.offset) {
+                        bookend = 1;
+                        if (found_inline && start <= key.offset)
+                                keep = 1;
+                }
+                /* truncate existing extent */
+                if (start > key.offset) {
+                        u64 new_num;
+                        u64 old_num;
+                        keep = 1;
+                        WARN_ON(start & (root->sectorsize - 1));
+                        if (found_extent) {
+                                new_num = start - key.offset;
+                                old_num = btrfs_file_extent_num_bytes(leaf,
+                                                                      extent);
+                                *hint_byte =
+                                        btrfs_file_extent_disk_bytenr(leaf,
+                                                                      extent);
+                                if (btrfs_file_extent_disk_bytenr(leaf,
+                                                                  extent)) {
+                                        dec_i_blocks(inode, old_num - new_num);
+                                }
+                                btrfs_set_file_extent_num_bytes(leaf, extent,
+                                                                new_num);
+                                btrfs_mark_buffer_dirty(leaf);
+                        } else if (key.offset < inline_limit &&
+                                   (end > extent_end) &&
+                                   (inline_limit < extent_end)) {
+                                u32 new_size;
+                                new_size = btrfs_file_extent_calc_inline_size(
+                                                   inline_limit - key.offset);
+                                dec_i_blocks(inode, (extent_end - key.offset) -
+                                        (inline_limit - key.offset));
+                                btrfs_truncate_item(trans, root, path,
+                                                    new_size, 1);
+                        }
+                }
+                /* delete the entire extent */
+                if (!keep) {
+                        ret = btrfs_del_item(trans, root, path);
+                        /* TODO update progress marker and return */
+                        BUG_ON(ret);
+                        extent = NULL;
+                        btrfs_release_path(root, path);
+                        /* the extent will be freed later */
+                }
+                if (bookend && found_inline && start <= key.offset) {
+                        u32 new_size;
+                        new_size = btrfs_file_extent_calc_inline_size(
+                                                   extent_end - end);
+                        dec_i_blocks(inode, (extent_end - key.offset) -
+                                        (extent_end - end));
+                        ret = btrfs_truncate_item(trans, root, path,
+                                                  new_size, 0);
+                        BUG_ON(ret);
+                }
+                /* create bookend, splitting the extent in two */
+                if (bookend && found_extent) {
+                        u64 disk_bytenr;
+                        struct btrfs_key ins;
+                        ins.objectid = inode->i_ino;
+                        ins.offset = end;
+                        btrfs_set_key_type(&ins, BTRFS_EXTENT_DATA_KEY);
+                        btrfs_release_path(root, path);
+                        ret = btrfs_insert_empty_item(trans, root, path, &ins,
+                                                      sizeof(*extent));
+                        BUG_ON(ret);
+
+                        leaf = path->nodes[0];
+                        extent = btrfs_item_ptr(leaf, path->slots[0],
+                                                struct btrfs_file_extent_item);
+                        write_extent_buffer(leaf, &old,
+                                            (unsigned long)extent, sizeof(old));
+
+                        btrfs_set_file_extent_offset(leaf, extent,
+                                    le64_to_cpu(old.offset) + end - key.offset);
+                        WARN_ON(le64_to_cpu(old.num_bytes) <
+                                (extent_end - end));
+                        btrfs_set_file_extent_num_bytes(leaf, extent,
+                                                        extent_end - end);
+                        btrfs_set_file_extent_type(leaf, extent,
+                                                   BTRFS_FILE_EXTENT_REG);
+
+                        btrfs_mark_buffer_dirty(path->nodes[0]);
+
+                        disk_bytenr = le64_to_cpu(old.disk_bytenr);
+                        if (disk_bytenr != 0) {
+                                ret = btrfs_inc_extent_ref(trans, root,
+                                                disk_bytenr,
+                                                le64_to_cpu(old.disk_num_bytes),
+                                                leaf->start,
+                                                root->root_key.objectid,
+                                                trans->transid,
+                                                ins.objectid, ins.offset);
+                                BUG_ON(ret);
+                        }
+                        btrfs_release_path(root, path);
+                        if (disk_bytenr != 0) {
+                                inode->i_blocks +=
+                                      btrfs_file_extent_num_bytes(leaf,
+                                                                  extent) >> 9;
+                        }
+                }
+
+                if (found_extent && !keep) {
+                        u64 disk_bytenr = le64_to_cpu(old.disk_bytenr);
+
+                        if (disk_bytenr != 0) {
+                                dec_i_blocks(inode, le64_to_cpu(old.num_bytes));
+                                ret = btrfs_free_extent(trans, root,
+                                                disk_bytenr,
+                                                le64_to_cpu(old.disk_num_bytes),
+                                                leaf_start, root_owner,
+                                                root_gen, key.objectid,
+                                                key.offset, 0);
+                                BUG_ON(ret);
+                                *hint_byte = disk_bytenr;
+                        }
+                }
+
+                if (search_start >= end) {
+                        ret = 0;
+                        goto out;
+                }
+        }
+out:
+        btrfs_free_path(path);
+        btrfs_check_file(root, inode);
+        return ret;
+}
+
+/*
+ * this gets pages into the page cache and locks them down
+ */
+static int noinline prepare_pages(struct btrfs_root *root, struct file *file,
+                         struct page **pages, size_t num_pages,
+                         loff_t pos, unsigned long first_index,
+                         unsigned long last_index, size_t write_bytes)
+{
+        int i;
+        unsigned long index = pos >> PAGE_CACHE_SHIFT;
+        struct inode *inode = fdentry(file)->d_inode;
+        int err = 0;
+        u64 start_pos;
+        u64 last_pos;
+
+        start_pos = pos & ~((u64)root->sectorsize - 1);
+        last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
+
+        memset(pages, 0, num_pages * sizeof(struct page *));
+again:
+        for (i = 0; i < num_pages; i++) {
+                pages[i] = grab_cache_page(inode->i_mapping, index + i);
+                if (!pages[i]) {
+                        err = -ENOMEM;
+                        BUG_ON(1);
+                }
+                wait_on_page_writeback(pages[i]);
+        }
+        if (start_pos < inode->i_size) {
+                struct btrfs_ordered_extent *ordered;
+                lock_extent(&BTRFS_I(inode)->io_tree,
+                            start_pos, last_pos - 1, GFP_NOFS);
+                ordered = btrfs_lookup_first_ordered_extent(inode, last_pos -1);
+                if (ordered &&
+                    ordered->file_offset + ordered->len > start_pos &&
+                    ordered->file_offset < last_pos) {
+                        btrfs_put_ordered_extent(ordered);
+                        unlock_extent(&BTRFS_I(inode)->io_tree,
+                                      start_pos, last_pos - 1, GFP_NOFS);
+                        for (i = 0; i < num_pages; i++) {
+                                unlock_page(pages[i]);
+                                page_cache_release(pages[i]);
+                        }
+                        btrfs_wait_ordered_range(inode, start_pos,
+                                                 last_pos - start_pos);
+                        goto again;
+                }
+                if (ordered)
+                        btrfs_put_ordered_extent(ordered);
+
+                clear_extent_bits(&BTRFS_I(inode)->io_tree, start_pos,
+                                  last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC,
+                                  GFP_NOFS);
+                unlock_extent(&BTRFS_I(inode)->io_tree,
+                              start_pos, last_pos - 1, GFP_NOFS);
+        }
+        for (i = 0; i < num_pages; i++) {
+                clear_page_dirty_for_io(pages[i]);
+                set_page_extent_mapped(pages[i]);
+                WARN_ON(!PageLocked(pages[i]));
+        }
+        return 0;
+}
+
+static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
+                                size_t count, loff_t *ppos)
+{
+        loff_t pos;
+        loff_t start_pos;
+        ssize_t num_written = 0;
+        ssize_t err = 0;
+        int ret = 0;
+        struct inode *inode = fdentry(file)->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct page **pages = NULL;
+        int nrptrs;
+        struct page *pinned[2];
+        unsigned long first_index;
+        unsigned long last_index;
+
+        nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
+                     PAGE_CACHE_SIZE / (sizeof(struct page *)));
+        pinned[0] = NULL;
+        pinned[1] = NULL;
+
+        pos = *ppos;
+        start_pos = pos;
+
+        vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+        current->backing_dev_info = inode->i_mapping->backing_dev_info;
+        err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
+        if (err)
+                goto out_nolock;
+        if (count == 0)
+                goto out_nolock;
+#ifdef REMOVE_SUID_PATH
+        err = remove_suid(&file->f_path);
+#else
+# if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,26)
+        err = file_remove_suid(file);
+# else
+        err = remove_suid(fdentry(file));
+# endif
+#endif
+        if (err)
+                goto out_nolock;
+        file_update_time(file);
+
+        pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
+
+        mutex_lock(&inode->i_mutex);
+        first_index = pos >> PAGE_CACHE_SHIFT;
+        last_index = (pos + count) >> PAGE_CACHE_SHIFT;
+
+        /*
+         * if this is a nodatasum mount, force summing off for the inode
+         * all the time.  That way a later mount with summing on won't
+         * get confused
+         */
+        if (btrfs_test_opt(root, NODATASUM))
+                btrfs_set_flag(inode, NODATASUM);
+
+        /*
+         * there are lots of better ways to do this, but this code
+         * makes sure the first and last page in the file range are
+         * up to date and ready for cow
+         */
+        if ((pos & (PAGE_CACHE_SIZE - 1))) {
+                pinned[0] = grab_cache_page(inode->i_mapping, first_index);
+                if (!PageUptodate(pinned[0])) {
+                        ret = btrfs_readpage(NULL, pinned[0]);
+                        BUG_ON(ret);
+                        wait_on_page_locked(pinned[0]);
+                } else {
+                        unlock_page(pinned[0]);
+                }
+        }
+        if ((pos + count) & (PAGE_CACHE_SIZE - 1)) {
+                pinned[1] = grab_cache_page(inode->i_mapping, last_index);
+                if (!PageUptodate(pinned[1])) {
+                        ret = btrfs_readpage(NULL, pinned[1]);
+                        BUG_ON(ret);
+                        wait_on_page_locked(pinned[1]);
+                } else {
+                        unlock_page(pinned[1]);
+                }
+        }
+
+        while(count > 0) {
+                size_t offset = pos & (PAGE_CACHE_SIZE - 1);
+                size_t write_bytes = min(count, nrptrs *
+                                        (size_t)PAGE_CACHE_SIZE -
+                                         offset);
+                size_t num_pages = (write_bytes + PAGE_CACHE_SIZE - 1) >>
+                                        PAGE_CACHE_SHIFT;
+
+                WARN_ON(num_pages > nrptrs);
+                memset(pages, 0, sizeof(pages));
+
+                ret = btrfs_check_free_space(root, write_bytes, 0);
+                if (ret)
+                        goto out;
+
+                ret = prepare_pages(root, file, pages, num_pages,
+                                    pos, first_index, last_index,
+                                    write_bytes);
+                if (ret)
+                        goto out;
+
+                ret = btrfs_copy_from_user(pos, num_pages,
+                                           write_bytes, pages, buf);
+                if (ret) {
+                        btrfs_drop_pages(pages, num_pages);
+                        goto out;
+                }
+
+                ret = dirty_and_release_pages(NULL, root, file, pages,
+                                              num_pages, pos, write_bytes);
+                btrfs_drop_pages(pages, num_pages);
+                if (ret)
+                        goto out;
+
+                buf += write_bytes;
+                count -= write_bytes;
+                pos += write_bytes;
+                num_written += write_bytes;
+
+                balance_dirty_pages_ratelimited_nr(inode->i_mapping, num_pages);
+                if (num_pages < (root->leafsize >> PAGE_CACHE_SHIFT) + 1)
+                        btrfs_btree_balance_dirty(root, 1);
+                btrfs_throttle(root);
+                cond_resched();
+        }
+out:
+        mutex_unlock(&inode->i_mutex);
+
+out_nolock:
+        kfree(pages);
+        if (pinned[0])
+                page_cache_release(pinned[0]);
+        if (pinned[1])
+                page_cache_release(pinned[1]);
+        *ppos = pos;
+
+        if (num_written > 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+                struct btrfs_trans_handle *trans;
+
+                err = btrfs_fdatawrite_range(inode->i_mapping, start_pos,
+                                             start_pos + num_written -1,
+                                             WB_SYNC_NONE);
+                if (err < 0)
+                        num_written = err;
+
+                err = btrfs_wait_on_page_writeback_range(inode->i_mapping,
+                                 start_pos, start_pos + num_written - 1);
+                if (err < 0)
+                        num_written = err;
+
+                trans = btrfs_start_transaction(root, 1);
+                ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
+                if (ret == 0) {
+                        btrfs_sync_log(trans, root);
+                        btrfs_end_transaction(trans, root);
+                } else {
+                        btrfs_commit_transaction(trans, root);
+                }
+        } else if (num_written > 0 && (file->f_flags & O_DIRECT)) {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
+                do_sync_file_range(file, start_pos,
+                                      start_pos + num_written - 1,
+                                      SYNC_FILE_RANGE_WRITE |
+                                      SYNC_FILE_RANGE_WAIT_AFTER);
+#else
+                do_sync_mapping_range(inode->i_mapping, start_pos,
+                                      start_pos + num_written - 1,
+                                      SYNC_FILE_RANGE_WRITE |
+                                      SYNC_FILE_RANGE_WAIT_AFTER);
+#endif
+                invalidate_mapping_pages(inode->i_mapping,
+                      start_pos >> PAGE_CACHE_SHIFT,
+                     (start_pos + num_written - 1) >> PAGE_CACHE_SHIFT);
+        }
+        current->backing_dev_info = NULL;
+        return num_written ? num_written : err;
+}
+
+int btrfs_release_file(struct inode * inode, struct file * filp)
+{
+        if (filp->private_data)
+                btrfs_ioctl_trans_end(filp);
+        return 0;
+}
+
+int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
+{
+        struct inode *inode = dentry->d_inode;
+        struct btrfs_root *root = BTRFS_I(inode)->root;
+        int ret = 0;
+        struct btrfs_trans_handle *trans;
+
+        /*
+         * check the transaction that last modified this inode
+         * and see if its already been committed
+         */
+        if (!BTRFS_I(inode)->last_trans)
+                goto out;
+
+        mutex_lock(&root->fs_info->trans_mutex);
+        if (BTRFS_I(inode)->last_trans <=
+            root->fs_info->last_trans_committed) {
+                BTRFS_I(inode)->last_trans = 0;
+                mutex_unlock(&root->fs_info->trans_mutex);
+                goto out;
+        }
+        mutex_unlock(&root->fs_info->trans_mutex);
+
+        root->fs_info->tree_log_batch++;
+        filemap_fdatawait(inode->i_mapping);
+        root->fs_info->tree_log_batch++;
+
+        /*
+         * ok we haven't committed the transaction yet, lets do a commit
+         */
+        if (file->private_data)
+                btrfs_ioctl_trans_end(file);
+
+        trans = btrfs_start_transaction(root, 1);
+        if (!trans) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        ret = btrfs_log_dentry_safe(trans, root, file->f_dentry);
+        if (ret < 0) {
+                goto out;
+        }
+
+        /* we've logged all the items and now have a consistent
+         * version of the file in the log.  It is possible that
+         * someone will come in and modify the file, but that's
+         * fine because the log is consistent on disk, and we
+         * have references to all of the file's extents
+         *
+         * It is possible that someone will come in and log the
+         * file again, but that will end up using the synchronization
+         * inside btrfs_sync_log to keep things safe.
+         */
+        mutex_unlock(&file->f_dentry->d_inode->i_mutex);
+
+        if (ret > 0) {
+                ret = btrfs_commit_transaction(trans, root);
+        } else {
+                btrfs_sync_log(trans, root);
+                ret = btrfs_end_transaction(trans, root);
+        }
+        mutex_lock(&file->f_dentry->d_inode->i_mutex);
+out:
+        return ret > 0 ? EIO : ret;
+}
+
+static struct vm_operations_struct btrfs_file_vm_ops = {
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
+        .nopage         = filemap_nopage,
+        .populate       = filemap_populate,
+#else
+        .fault          = filemap_fault,
+#endif
+        .page_mkwrite   = btrfs_page_mkwrite,
+};
+
+static int btrfs_file_mmap(struct file  *filp, struct vm_area_struct *vma)
+{
+        vma->vm_ops = &btrfs_file_vm_ops;
+        file_accessed(filp);
+        return 0;
+}
+
+struct file_operations btrfs_file_operations = {
+        .llseek         = generic_file_llseek,
+        .read           = do_sync_read,
+        .aio_read       = generic_file_aio_read,
+        .splice_read    = generic_file_splice_read,
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
+        .sendfile       = generic_file_sendfile,
+#endif
+        .write          = btrfs_file_write,
+        .mmap           = btrfs_file_mmap,
+        .open           = generic_file_open,
+        .release        = btrfs_release_file,
+        .fsync          = btrfs_sync_file,
+        .unlocked_ioctl = btrfs_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl   = btrfs_ioctl,
+#endif
+};