NFS: Cleanup file handle allocations in fs/nfs/super.c
[safe/jmp/linux-2.6] / fs / btrfs / file.c
index ef66c3d..29ff749 100644 (file)
 #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/slab.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"
@@ -124,7 +124,11 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                    root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 
        end_of_last_block = start_pos + num_bytes - 1;
-       btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+       err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block,
+                                       NULL);
+       if (err)
+               return err;
+
        for (i = 0; i < num_pages; i++) {
                struct page *p = pages[i];
                SetPageUptodate(p);
@@ -177,19 +181,16 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                }
                flags = em->flags;
                if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
-                       write_unlock(&em_tree->lock);
-                       if (em->start <= start &&
-                           (!testend || em->start + em->len >= start + len)) {
+                       if (testend && em->start + em->len >= start + len) {
                                free_extent_map(em);
+                               write_unlock(&em_tree->lock);
                                break;
                        }
-                       if (start < em->start) {
-                               len = em->start - start;
-                       } else {
+                       start = em->start + em->len;
+                       if (testend)
                                len = start + len - (em->start + em->len);
-                               start = em->start + em->len;
-                       }
                        free_extent_map(em);
+                       write_unlock(&em_tree->lock);
                        continue;
                }
                compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
@@ -262,323 +263,253 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
  * 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.
- *
- * inline_limit is used to tell this code which offsets in the file to keep
- * if they contain inline extents.
  */
-noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
-                      struct btrfs_root *root, struct inode *inode,
-                      u64 start, u64 end, u64 locked_end,
-                      u64 inline_limit, u64 *hint_byte)
+int btrfs_drop_extents(struct btrfs_trans_handle *trans, struct inode *inode,
+                      u64 start, u64 end, u64 *hint_byte, int drop_cache)
 {
-       u64 extent_end = 0;
-       u64 search_start = start;
-       u64 ram_bytes = 0;
-       u64 disk_bytenr = 0;
-       u64 orig_locked_end = locked_end;
-       u8 compression;
-       u8 encryption;
-       u16 other_encoding = 0;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
        struct extent_buffer *leaf;
-       struct btrfs_file_extent_item *extent;
+       struct btrfs_file_extent_item *fi;
        struct btrfs_path *path;
        struct btrfs_key key;
-       struct btrfs_file_extent_item old;
-       int keep;
-       int slot;
-       int bookend;
-       int found_type = 0;
-       int found_extent;
-       int found_inline;
+       struct btrfs_key new_key;
+       u64 search_start = start;
+       u64 disk_bytenr = 0;
+       u64 num_bytes = 0;
+       u64 extent_offset = 0;
+       u64 extent_end = 0;
+       int del_nr = 0;
+       int del_slot = 0;
+       int extent_type;
        int recow;
        int ret;
 
-       inline_limit = 0;
-       btrfs_drop_extent_cache(inode, start, end - 1, 0);
+       if (drop_cache)
+               btrfs_drop_extent_cache(inode, start, end - 1, 0);
 
        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]--;
+                       break;
+               if (ret > 0 && path->slots[0] > 0 && search_start == start) {
+                       leaf = path->nodes[0];
+                       btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1);
+                       if (key.objectid == inode->i_ino &&
+                           key.type == BTRFS_EXTENT_DATA_KEY)
+                               path->slots[0]--;
                }
+               ret = 0;
 next_slot:
-               keep = 0;
-               bookend = 0;
-               found_extent = 0;
-               found_inline = 0;
-               compression = 0;
-               encryption = 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 = max(key.offset, start);
-                       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);
-                       compression = btrfs_file_extent_compression(leaf,
-                                                                   extent);
-                       encryption = btrfs_file_extent_encryption(leaf,
-                                                                 extent);
-                       other_encoding = btrfs_file_extent_other_encoding(leaf,
-                                                                 extent);
-                       if (found_type == BTRFS_FILE_EXTENT_REG ||
-                           found_type == BTRFS_FILE_EXTENT_PREALLOC) {
-                               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);
-                               ram_bytes = btrfs_file_extent_ram_bytes(leaf,
-                                                               extent);
-                               found_extent = 1;
-                       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
-                               found_inline = 1;
-                               extent_end = key.offset +
-                                    btrfs_file_extent_inline_len(leaf, extent);
+               if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+                       BUG_ON(del_nr > 0);
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret < 0)
+                               break;
+                       if (ret > 0) {
+                               ret = 0;
+                               break;
                        }
+                       leaf = path->nodes[0];
+                       recow = 1;
+               }
+
+               btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+               if (key.objectid > inode->i_ino ||
+                   key.type > BTRFS_EXTENT_DATA_KEY || key.offset >= end)
+                       break;
+
+               fi = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+               extent_type = btrfs_file_extent_type(leaf, fi);
+
+               if (extent_type == BTRFS_FILE_EXTENT_REG ||
+                   extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
+                       disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
+                       num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
+                       extent_offset = btrfs_file_extent_offset(leaf, fi);
+                       extent_end = key.offset +
+                               btrfs_file_extent_num_bytes(leaf, fi);
+               } else if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+                       extent_end = key.offset +
+                               btrfs_file_extent_inline_len(leaf, fi);
                } else {
+                       WARN_ON(1);
                        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]++;
-                       }
+               if (extent_end <= search_start) {
+                       path->slots[0]++;
                        goto next_slot;
                }
 
-               if (end <= extent_end && start >= key.offset && found_inline)
-                       *hint_byte = EXTENT_MAP_INLINE;
-
-               if (found_extent) {
-                       read_extent_buffer(leaf, &old, (unsigned long)extent,
-                                          sizeof(old));
-               }
-
-               if (end < extent_end && end >= key.offset) {
-                       bookend = 1;
-                       if (found_inline && start <= key.offset)
-                               keep = 1;
+               search_start = max(key.offset, start);
+               if (recow) {
+                       btrfs_release_path(root, path);
+                       continue;
                }
 
-               if (bookend && found_extent) {
-                       if (locked_end < extent_end) {
-                               ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
-                                               locked_end, extent_end - 1,
-                                               GFP_NOFS);
-                               if (!ret) {
-                                       btrfs_release_path(root, path);
-                                       lock_extent(&BTRFS_I(inode)->io_tree,
-                                               locked_end, extent_end - 1,
-                                               GFP_NOFS);
-                                       locked_end = extent_end;
-                                       continue;
-                               }
-                               locked_end = extent_end;
+               /*
+                *     | - range to drop - |
+                *  | -------- extent -------- |
+                */
+               if (start > key.offset && end < extent_end) {
+                       BUG_ON(del_nr > 0);
+                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+
+                       memcpy(&new_key, &key, sizeof(new_key));
+                       new_key.offset = start;
+                       ret = btrfs_duplicate_item(trans, root, path,
+                                                  &new_key);
+                       if (ret == -EAGAIN) {
+                               btrfs_release_path(root, path);
+                               continue;
                        }
-                       disk_bytenr = le64_to_cpu(old.disk_bytenr);
-                       if (disk_bytenr != 0) {
+                       if (ret < 0)
+                               break;
+
+                       leaf = path->nodes[0];
+                       fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+                                           struct btrfs_file_extent_item);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       start - key.offset);
+
+                       fi = btrfs_item_ptr(leaf, path->slots[0],
+                                           struct btrfs_file_extent_item);
+
+                       extent_offset += start - key.offset;
+                       btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       extent_end - start);
+                       btrfs_mark_buffer_dirty(leaf);
+
+                       if (disk_bytenr > 0) {
                                ret = btrfs_inc_extent_ref(trans, root,
-                                          disk_bytenr,
-                                          le64_to_cpu(old.disk_num_bytes), 0,
-                                          root->root_key.objectid,
-                                          key.objectid, key.offset -
-                                          le64_to_cpu(old.offset));
+                                               disk_bytenr, num_bytes, 0,
+                                               root->root_key.objectid,
+                                               new_key.objectid,
+                                               start - extent_offset);
                                BUG_ON(ret);
+                               *hint_byte = disk_bytenr;
                        }
+                       key.offset = start;
                }
+               /*
+                *  | ---- range to drop ----- |
+                *      | -------- extent -------- |
+                */
+               if (start <= key.offset && end < extent_end) {
+                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+
+                       memcpy(&new_key, &key, sizeof(new_key));
+                       new_key.offset = end;
+                       btrfs_set_item_key_safe(trans, root, path, &new_key);
 
-               if (found_inline) {
-                       u64 mask = root->sectorsize - 1;
-                       search_start = (extent_end + mask) & ~mask;
-               } else
-                       search_start = extent_end;
-
-               /* 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)) {
-                                       inode_sub_bytes(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);
-                               inode_sub_bytes(inode, extent_end -
-                                               inline_limit);
-                               btrfs_set_file_extent_ram_bytes(leaf, extent,
-                                                       new_size);
-                               if (!compression && !encryption) {
-                                       btrfs_truncate_item(trans, root, path,
-                                                           new_size, 1);
-                               }
+                       extent_offset += end - key.offset;
+                       btrfs_set_file_extent_offset(leaf, fi, extent_offset);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       extent_end - end);
+                       btrfs_mark_buffer_dirty(leaf);
+                       if (disk_bytenr > 0) {
+                               inode_sub_bytes(inode, end - key.offset);
+                               *hint_byte = disk_bytenr;
                        }
+                       break;
                }
-               /* delete the entire extent */
-               if (!keep) {
-                       if (found_inline)
-                               inode_sub_bytes(inode, extent_end -
-                                               key.offset);
-                       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);
-                       inode_sub_bytes(inode, end - key.offset);
-                       btrfs_set_file_extent_ram_bytes(leaf, extent,
-                                                       new_size);
-                       if (!compression && !encryption)
-                               ret = btrfs_truncate_item(trans, root, path,
-                                                         new_size, 0);
-                       BUG_ON(ret);
-               }
-               /* create bookend, splitting the extent in two */
-               if (bookend && found_extent) {
-                       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);
-                       path->leave_spinning = 1;
-                       ret = btrfs_insert_empty_item(trans, root, path, &ins,
-                                                     sizeof(*extent));
-                       BUG_ON(ret);
+               search_start = extent_end;
+               /*
+                *       | ---- range to drop ----- |
+                *  | -------- extent -------- |
+                */
+               if (start > key.offset && end >= extent_end) {
+                       BUG_ON(del_nr > 0);
+                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
 
-                       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_compression(leaf, extent,
-                                                         compression);
-                       btrfs_set_file_extent_encryption(leaf, extent,
-                                                        encryption);
-                       btrfs_set_file_extent_other_encoding(leaf, extent,
-                                                            other_encoding);
-                       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_num_bytes(leaf, fi,
+                                                       start - key.offset);
+                       btrfs_mark_buffer_dirty(leaf);
+                       if (disk_bytenr > 0) {
+                               inode_sub_bytes(inode, extent_end - start);
+                               *hint_byte = disk_bytenr;
+                       }
+                       if (end == extent_end)
+                               break;
 
-                       /*
-                        * set the ram bytes to the size of the full extent
-                        * before splitting.  This is a worst case flag,
-                        * but its the best we can do because we don't know
-                        * how splitting affects compression
-                        */
-                       btrfs_set_file_extent_ram_bytes(leaf, extent,
-                                                       ram_bytes);
-                       btrfs_set_file_extent_type(leaf, extent, found_type);
-
-                       btrfs_unlock_up_safe(path, 1);
-                       btrfs_mark_buffer_dirty(path->nodes[0]);
-                       btrfs_set_lock_blocking(path->nodes[0]);
-
-                       path->leave_spinning = 0;
-                       btrfs_release_path(root, path);
-                       if (disk_bytenr != 0)
-                               inode_add_bytes(inode, extent_end - end);
+                       path->slots[0]++;
+                       goto next_slot;
                }
 
-               if (found_extent && !keep) {
-                       u64 old_disk_bytenr = le64_to_cpu(old.disk_bytenr);
+               /*
+                *  | ---- range to drop ----- |
+                *    | ------ extent ------ |
+                */
+               if (start <= key.offset && end >= extent_end) {
+                       if (del_nr == 0) {
+                               del_slot = path->slots[0];
+                               del_nr = 1;
+                       } else {
+                               BUG_ON(del_slot + del_nr != path->slots[0]);
+                               del_nr++;
+                       }
 
-                       if (old_disk_bytenr != 0) {
+                       if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
                                inode_sub_bytes(inode,
-                                               le64_to_cpu(old.num_bytes));
+                                               extent_end - key.offset);
+                               extent_end = ALIGN(extent_end,
+                                                  root->sectorsize);
+                       } else if (disk_bytenr > 0) {
                                ret = btrfs_free_extent(trans, root,
-                                               old_disk_bytenr,
-                                               le64_to_cpu(old.disk_num_bytes),
-                                               0, root->root_key.objectid,
+                                               disk_bytenr, num_bytes, 0,
+                                               root->root_key.objectid,
                                                key.objectid, key.offset -
-                                               le64_to_cpu(old.offset));
+                                               extent_offset);
                                BUG_ON(ret);
-                               *hint_byte = old_disk_bytenr;
+                               inode_sub_bytes(inode,
+                                               extent_end - key.offset);
+                               *hint_byte = disk_bytenr;
                        }
-               }
 
-               if (search_start >= end) {
-                       ret = 0;
-                       goto out;
+                       if (end == extent_end)
+                               break;
+
+                       if (path->slots[0] + 1 < btrfs_header_nritems(leaf)) {
+                               path->slots[0]++;
+                               goto next_slot;
+                       }
+
+                       ret = btrfs_del_items(trans, root, path, del_slot,
+                                             del_nr);
+                       BUG_ON(ret);
+
+                       del_nr = 0;
+                       del_slot = 0;
+
+                       btrfs_release_path(root, path);
+                       continue;
                }
+
+               BUG_ON(1);
        }
-out:
-       btrfs_free_path(path);
-       if (locked_end > orig_locked_end) {
-               unlock_extent(&BTRFS_I(inode)->io_tree, orig_locked_end,
-                             locked_end - 1, GFP_NOFS);
+
+       if (del_nr > 0) {
+               ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+               BUG_ON(ret);
        }
+
+       btrfs_free_path(path);
        return ret;
 }
 
 static int extent_mergeable(struct extent_buffer *leaf, int slot,
-                           u64 objectid, u64 bytenr, u64 *start, u64 *end)
+                           u64 objectid, u64 bytenr, u64 orig_offset,
+                           u64 *start, u64 *end)
 {
        struct btrfs_file_extent_item *fi;
        struct btrfs_key key;
@@ -594,6 +525,7 @@ static int extent_mergeable(struct extent_buffer *leaf, int slot,
        fi = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item);
        if (btrfs_file_extent_type(leaf, fi) != BTRFS_FILE_EXTENT_REG ||
            btrfs_file_extent_disk_bytenr(leaf, fi) != bytenr ||
+           btrfs_file_extent_offset(leaf, fi) != key.offset - orig_offset ||
            btrfs_file_extent_compression(leaf, fi) ||
            btrfs_file_extent_encryption(leaf, fi) ||
            btrfs_file_extent_other_encoding(leaf, fi))
@@ -616,23 +548,24 @@ static int extent_mergeable(struct extent_buffer *leaf, int slot,
  * two or three.
  */
 int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
-                             struct btrfs_root *root,
                              struct inode *inode, u64 start, u64 end)
 {
+       struct btrfs_root *root = BTRFS_I(inode)->root;
        struct extent_buffer *leaf;
        struct btrfs_path *path;
        struct btrfs_file_extent_item *fi;
        struct btrfs_key key;
+       struct btrfs_key new_key;
        u64 bytenr;
        u64 num_bytes;
        u64 extent_end;
        u64 orig_offset;
        u64 other_start;
        u64 other_end;
-       u64 split = start;
-       u64 locked_end = end;
-       int extent_type;
-       int split_end = 1;
+       u64 split;
+       int del_nr = 0;
+       int del_slot = 0;
+       int recow;
        int ret;
 
        btrfs_drop_extent_cache(inode, start, end - 1, 0);
@@ -640,12 +573,11 @@ int btrfs_mark_extent_written(struct btrfs_trans_handle *trans,
        path = btrfs_alloc_path();
        BUG_ON(!path);
 again:
+       recow = 0;
+       split = start;
        key.objectid = inode->i_ino;
        key.type = BTRFS_EXTENT_DATA_KEY;
-       if (split == start)
-               key.offset = split;
-       else
-               key.offset = split - 1;
+       key.offset = split;
 
        ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
        if (ret > 0 && path->slots[0] > 0)
@@ -657,159 +589,158 @@ again:
               key.type != BTRFS_EXTENT_DATA_KEY);
        fi = btrfs_item_ptr(leaf, path->slots[0],
                            struct btrfs_file_extent_item);
-       extent_type = btrfs_file_extent_type(leaf, fi);
-       BUG_ON(extent_type != BTRFS_FILE_EXTENT_PREALLOC);
+       BUG_ON(btrfs_file_extent_type(leaf, fi) !=
+              BTRFS_FILE_EXTENT_PREALLOC);
        extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
        BUG_ON(key.offset > start || extent_end < end);
 
        bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
        num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
        orig_offset = key.offset - btrfs_file_extent_offset(leaf, fi);
+       memcpy(&new_key, &key, sizeof(new_key));
 
-       if (key.offset == start)
-               split = end;
-
-       if (key.offset == start && extent_end == end) {
-               int del_nr = 0;
-               int del_slot = 0;
-               other_start = end;
-               other_end = 0;
-               if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
-                                    bytenr, &other_start, &other_end)) {
-                       extent_end = other_end;
-                       del_slot = path->slots[0] + 1;
-                       del_nr++;
-                       ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
-                                               0, root->root_key.objectid,
-                                               inode->i_ino, orig_offset);
-                       BUG_ON(ret);
-               }
+       if (start == key.offset && end < extent_end) {
                other_start = 0;
                other_end = start;
-               if (extent_mergeable(leaf, path->slots[0] - 1, inode->i_ino,
-                                    bytenr, &other_start, &other_end)) {
-                       key.offset = other_start;
-                       del_slot = path->slots[0];
-                       del_nr++;
-                       ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
-                                               0, root->root_key.objectid,
-                                               inode->i_ino, orig_offset);
-                       BUG_ON(ret);
-               }
-               split_end = 0;
-               if (del_nr == 0) {
-                       btrfs_set_file_extent_type(leaf, fi,
-                                                  BTRFS_FILE_EXTENT_REG);
-                       goto done;
-               }
-
-               fi = btrfs_item_ptr(leaf, del_slot - 1,
-                                   struct btrfs_file_extent_item);
-               btrfs_set_file_extent_type(leaf, fi, BTRFS_FILE_EXTENT_REG);
-               btrfs_set_file_extent_num_bytes(leaf, fi,
-                                               extent_end - key.offset);
-               btrfs_mark_buffer_dirty(leaf);
-
-               ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
-               BUG_ON(ret);
-               goto release;
-       } else if (split == start) {
-               if (locked_end < extent_end) {
-                       ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
-                                       locked_end, extent_end - 1, GFP_NOFS);
-                       if (!ret) {
-                               btrfs_release_path(root, path);
-                               lock_extent(&BTRFS_I(inode)->io_tree,
-                                       locked_end, extent_end - 1, GFP_NOFS);
-                               locked_end = extent_end;
-                               goto again;
-                       }
-                       locked_end = extent_end;
+               if (extent_mergeable(leaf, path->slots[0] - 1,
+                                    inode->i_ino, bytenr, orig_offset,
+                                    &other_start, &other_end)) {
+                       new_key.offset = end;
+                       btrfs_set_item_key_safe(trans, root, path, &new_key);
+                       fi = btrfs_item_ptr(leaf, path->slots[0],
+                                           struct btrfs_file_extent_item);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       extent_end - end);
+                       btrfs_set_file_extent_offset(leaf, fi,
+                                                    end - orig_offset);
+                       fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+                                           struct btrfs_file_extent_item);
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       end - other_start);
+                       btrfs_mark_buffer_dirty(leaf);
+                       goto out;
                }
-               btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
-       } else  {
-               BUG_ON(key.offset != start);
-               key.offset = split;
-               btrfs_set_file_extent_offset(leaf, fi, key.offset -
-                                            orig_offset);
-               btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
-               btrfs_set_item_key_safe(trans, root, path, &key);
-               extent_end = split;
        }
 
-       if (extent_end == end) {
-               split_end = 0;
-               extent_type = BTRFS_FILE_EXTENT_REG;
-       }
-       if (extent_end == end && split == start) {
+       if (start > key.offset && end == extent_end) {
                other_start = end;
                other_end = 0;
-               if (extent_mergeable(leaf, path->slots[0] + 1, inode->i_ino,
-                                    bytenr, &other_start, &other_end)) {
-                       path->slots[0]++;
+               if (extent_mergeable(leaf, path->slots[0] + 1,
+                                    inode->i_ino, bytenr, orig_offset,
+                                    &other_start, &other_end)) {
                        fi = btrfs_item_ptr(leaf, path->slots[0],
                                            struct btrfs_file_extent_item);
-                       key.offset = split;
-                       btrfs_set_item_key_safe(trans, root, path, &key);
-                       btrfs_set_file_extent_offset(leaf, fi, key.offset -
-                                                    orig_offset);
                        btrfs_set_file_extent_num_bytes(leaf, fi,
-                                                       other_end - split);
-                       goto done;
-               }
-       }
-       if (extent_end == end && split == end) {
-               other_start = 0;
-               other_end = start;
-               if (extent_mergeable(leaf, path->slots[0] - 1 , inode->i_ino,
-                                    bytenr, &other_start, &other_end)) {
-                       path->slots[0]--;
+                                                       start - key.offset);
+                       path->slots[0]++;
+                       new_key.offset = start;
+                       btrfs_set_item_key_safe(trans, root, path, &new_key);
+
                        fi = btrfs_item_ptr(leaf, path->slots[0],
                                            struct btrfs_file_extent_item);
-                       btrfs_set_file_extent_num_bytes(leaf, fi, extent_end -
-                                                       other_start);
-                       goto done;
+                       btrfs_set_file_extent_num_bytes(leaf, fi,
+                                                       other_end - start);
+                       btrfs_set_file_extent_offset(leaf, fi,
+                                                    start - orig_offset);
+                       btrfs_mark_buffer_dirty(leaf);
+                       goto out;
                }
        }
 
-       btrfs_mark_buffer_dirty(leaf);
+       while (start > key.offset || end < extent_end) {
+               if (key.offset == start)
+                       split = end;
 
-       ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
-                                  root->root_key.objectid,
-                                  inode->i_ino, orig_offset);
-       BUG_ON(ret);
-       btrfs_release_path(root, path);
+               new_key.offset = split;
+               ret = btrfs_duplicate_item(trans, root, path, &new_key);
+               if (ret == -EAGAIN) {
+                       btrfs_release_path(root, path);
+                       goto again;
+               }
+               BUG_ON(ret < 0);
 
-       key.offset = start;
-       ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*fi));
-       BUG_ON(ret);
+               leaf = path->nodes[0];
+               fi = btrfs_item_ptr(leaf, path->slots[0] - 1,
+                                   struct btrfs_file_extent_item);
+               btrfs_set_file_extent_num_bytes(leaf, fi,
+                                               split - key.offset);
 
-       leaf = path->nodes[0];
-       fi = btrfs_item_ptr(leaf, path->slots[0],
-                           struct btrfs_file_extent_item);
-       btrfs_set_file_extent_generation(leaf, fi, trans->transid);
-       btrfs_set_file_extent_type(leaf, fi, extent_type);
-       btrfs_set_file_extent_disk_bytenr(leaf, fi, bytenr);
-       btrfs_set_file_extent_disk_num_bytes(leaf, fi, num_bytes);
-       btrfs_set_file_extent_offset(leaf, fi, key.offset - orig_offset);
-       btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - key.offset);
-       btrfs_set_file_extent_ram_bytes(leaf, fi, num_bytes);
-       btrfs_set_file_extent_compression(leaf, fi, 0);
-       btrfs_set_file_extent_encryption(leaf, fi, 0);
-       btrfs_set_file_extent_other_encoding(leaf, fi, 0);
-done:
-       btrfs_mark_buffer_dirty(leaf);
-
-release:
-       btrfs_release_path(root, path);
-       if (split_end && split == start) {
-               split = end;
-               goto again;
+               fi = btrfs_item_ptr(leaf, path->slots[0],
+                                   struct btrfs_file_extent_item);
+
+               btrfs_set_file_extent_offset(leaf, fi, split - orig_offset);
+               btrfs_set_file_extent_num_bytes(leaf, fi,
+                                               extent_end - split);
+               btrfs_mark_buffer_dirty(leaf);
+
+               ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes, 0,
+                                          root->root_key.objectid,
+                                          inode->i_ino, orig_offset);
+               BUG_ON(ret);
+
+               if (split == start) {
+                       key.offset = start;
+               } else {
+                       BUG_ON(start != key.offset);
+                       path->slots[0]--;
+                       extent_end = end;
+               }
+               recow = 1;
        }
-       if (locked_end > end) {
-               unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
-                             GFP_NOFS);
+
+       other_start = end;
+       other_end = 0;
+       if (extent_mergeable(leaf, path->slots[0] + 1,
+                            inode->i_ino, bytenr, orig_offset,
+                            &other_start, &other_end)) {
+               if (recow) {
+                       btrfs_release_path(root, path);
+                       goto again;
+               }
+               extent_end = other_end;
+               del_slot = path->slots[0] + 1;
+               del_nr++;
+               ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+                                       0, root->root_key.objectid,
+                                       inode->i_ino, orig_offset);
+               BUG_ON(ret);
        }
+       other_start = 0;
+       other_end = start;
+       if (extent_mergeable(leaf, path->slots[0] - 1,
+                            inode->i_ino, bytenr, orig_offset,
+                            &other_start, &other_end)) {
+               if (recow) {
+                       btrfs_release_path(root, path);
+                       goto again;
+               }
+               key.offset = other_start;
+               del_slot = path->slots[0];
+               del_nr++;
+               ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
+                                       0, root->root_key.objectid,
+                                       inode->i_ino, orig_offset);
+               BUG_ON(ret);
+       }
+       if (del_nr == 0) {
+               fi = btrfs_item_ptr(leaf, path->slots[0],
+                          struct btrfs_file_extent_item);
+               btrfs_set_file_extent_type(leaf, fi,
+                                          BTRFS_FILE_EXTENT_REG);
+               btrfs_mark_buffer_dirty(leaf);
+       } else {
+               fi = btrfs_item_ptr(leaf, del_slot - 1,
+                          struct btrfs_file_extent_item);
+               btrfs_set_file_extent_type(leaf, fi,
+                                          BTRFS_FILE_EXTENT_REG);
+               btrfs_set_file_extent_num_bytes(leaf, fi,
+                                               extent_end - key.offset);
+               btrfs_mark_buffer_dirty(leaf);
+
+               ret = btrfs_del_items(trans, root, path, del_slot, del_nr);
+               BUG_ON(ret);
+       }
+out:
        btrfs_free_path(path);
        return 0;
 }
@@ -824,6 +755,7 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file,
                         loff_t pos, unsigned long first_index,
                         unsigned long last_index, size_t write_bytes)
 {
+       struct extent_state *cached_state = NULL;
        int i;
        unsigned long index = pos >> PAGE_CACHE_SHIFT;
        struct inode *inode = fdentry(file)->d_inode;
@@ -852,16 +784,18 @@ again:
        }
        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);
+               lock_extent_bits(&BTRFS_I(inode)->io_tree,
+                                start_pos, last_pos - 1, 0, &cached_state,
+                                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);
+                       unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+                                            start_pos, last_pos - 1,
+                                            &cached_state, GFP_NOFS);
                        for (i = 0; i < num_pages; i++) {
                                unlock_page(pages[i]);
                                page_cache_release(pages[i]);
@@ -873,11 +807,13 @@ 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,
+               clear_extent_bit(&BTRFS_I(inode)->io_tree, start_pos,
+                                 last_pos - 1, EXTENT_DIRTY | EXTENT_DELALLOC |
+                                 EXTENT_DO_ACCOUNTING, 0, 0, &cached_state,
                                  GFP_NOFS);
-               unlock_extent(&BTRFS_I(inode)->io_tree,
-                             start_pos, last_pos - 1, GFP_NOFS);
+               unlock_extent_cached(&BTRFS_I(inode)->io_tree,
+                                    start_pos, last_pos - 1, &cached_state,
+                                    GFP_NOFS);
        }
        for (i = 0; i < num_pages; i++) {
                clear_page_dirty_for_io(pages[i]);
@@ -904,7 +840,7 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
        unsigned long last_index;
        int will_write;
 
-       will_write = ((file->f_flags & O_SYNC) || IS_SYNC(inode) ||
+       will_write = ((file->f_flags & O_DSYNC) || IS_SYNC(inode) ||
                      (file->f_flags & O_DIRECT));
 
        nrptrs = min((count + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE,
@@ -916,21 +852,35 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
        start_pos = pos;
 
        vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+       /* do the reserve before the mutex lock in case we have to do some
+        * flushing.  We wouldn't deadlock, but this is more polite.
+        */
+       err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+       if (err)
+               goto out_nolock;
+
+       mutex_lock(&inode->i_mutex);
+
        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;
+               goto out;
+
        if (count == 0)
-               goto out_nolock;
+               goto out;
 
        err = file_remove_suid(file);
        if (err)
-               goto out_nolock;
+               goto out;
+
        file_update_time(file);
 
        pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 
-       mutex_lock(&inode->i_mutex);
+       /* generic_write_checks can change our pos */
+       start_pos = pos;
+
        BTRFS_I(inode)->sequence++;
        first_index = pos >> PAGE_CACHE_SHIFT;
        last_index = (pos + count) >> PAGE_CACHE_SHIFT;
@@ -1004,9 +954,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                }
 
                if (will_write) {
-                       btrfs_fdatawrite_range(inode->i_mapping, pos,
-                                              pos + write_bytes - 1,
-                                              WB_SYNC_ALL);
+                       filemap_fdatawrite_range(inode->i_mapping, pos,
+                                                pos + write_bytes - 1);
                } else {
                        balance_dirty_pages_ratelimited_nr(inode->i_mapping,
                                                           num_pages);
@@ -1027,6 +976,7 @@ out:
        mutex_unlock(&inode->i_mutex);
        if (ret)
                err = ret;
+       btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 
 out_nolock:
        kfree(pages);
@@ -1057,7 +1007,7 @@ out_nolock:
                if (err)
                        num_written = err;
 
-               if ((file->f_flags & O_SYNC) || IS_SYNC(inode)) {
+               if ((file->f_flags & O_DSYNC) || IS_SYNC(inode)) {
                        trans = btrfs_start_transaction(root, 1);
                        ret = btrfs_log_dentry_safe(trans, root,
                                                    file->f_dentry);
@@ -1067,8 +1017,10 @@ out_nolock:
                                        btrfs_end_transaction(trans, root);
                                else
                                        btrfs_commit_transaction(trans, root);
-                       } else {
+                       } else if (ret != BTRFS_NO_LOG_SYNC) {
                                btrfs_commit_transaction(trans, root);
+                       } else {
+                               btrfs_end_transaction(trans, root);
                        }
                }
                if (file->f_flags & O_DIRECT) {
@@ -1118,6 +1070,13 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
        int ret = 0;
        struct btrfs_trans_handle *trans;
 
+
+       /* we wait first, since the writeback may change the inode */
+       root->log_batch++;
+       /* the VFS called filemap_fdatawrite for us */
+       btrfs_wait_ordered_range(inode, 0, (u64)-1);
+       root->log_batch++;
+
        /*
         * check the transaction that last modified this inode
         * and see if its already been committed
@@ -1125,6 +1084,11 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
        if (!BTRFS_I(inode)->last_trans)
                goto out;
 
+       /*
+        * if the last transaction that changed this file was before
+        * the current transaction, we can bail out now without any
+        * syncing
+        */
        mutex_lock(&root->fs_info->trans_mutex);
        if (BTRFS_I(inode)->last_trans <=
            root->fs_info->last_trans_committed) {
@@ -1134,13 +1098,6 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
        }
        mutex_unlock(&root->fs_info->trans_mutex);
 
-       root->log_batch++;
-       filemap_fdatawrite(inode->i_mapping);
-       btrfs_wait_ordered_range(inode, 0, (u64)-1);
-       root->log_batch++;
-
-       if (datasync && !(inode->i_state & I_DIRTY_PAGES))
-               goto out;
        /*
         * ok we haven't committed the transaction yet, lets do a commit
         */
@@ -1169,21 +1126,25 @@ int btrfs_sync_file(struct file *file, struct dentry *dentry, int datasync)
         */
        mutex_unlock(&dentry->d_inode->i_mutex);
 
-       if (ret > 0) {
-               ret = btrfs_commit_transaction(trans, root);
-       } else {
-               ret = btrfs_sync_log(trans, root);
-               if (ret == 0)
-                       ret = btrfs_end_transaction(trans, root);
-               else
+       if (ret != BTRFS_NO_LOG_SYNC) {
+               if (ret > 0) {
                        ret = btrfs_commit_transaction(trans, root);
+               } else {
+                       ret = btrfs_sync_log(trans, root);
+                       if (ret == 0)
+                               ret = btrfs_end_transaction(trans, root);
+                       else
+                               ret = btrfs_commit_transaction(trans, root);
+               }
+       } else {
+               ret = btrfs_end_transaction(trans, root);
        }
        mutex_lock(&dentry->d_inode->i_mutex);
 out:
-       return ret > 0 ? EIO : ret;
+       return ret > 0 ? -EIO : ret;
 }
 
-static struct vm_operations_struct btrfs_file_vm_ops = {
+static const struct vm_operations_struct btrfs_file_vm_ops = {
        .fault          = filemap_fault,
        .page_mkwrite   = btrfs_page_mkwrite,
 };
@@ -1195,7 +1156,7 @@ static int btrfs_file_mmap(struct file    *filp, struct vm_area_struct *vma)
        return 0;
 }
 
-struct file_operations btrfs_file_operations = {
+const struct file_operations btrfs_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = do_sync_read,
        .aio_read       = generic_file_aio_read,