Btrfs: Extent based page cache code. This uses an rbtree of extents and tests
[linux-2.6-block.git] / fs / btrfs / file.c
index 6933ab11a5cdde67e081cd4e42df3915bcb76e0d..71a481894ab6ce74e5f784c80f20a780c9b0d3dd 100644 (file)
@@ -81,14 +81,14 @@ static void btrfs_drop_pages(struct page **pages, size_t num_pages)
        }
 }
 
-static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
+static int insert_inline_extent(struct btrfs_trans_handle *trans,
+                               struct btrfs_root *root, struct inode *inode,
                                u64 offset, ssize_t size,
-                               struct buffer_head *bh)
+                               struct page *page, size_t page_offset)
 {
        struct btrfs_key key;
        struct btrfs_path *path;
        char *ptr, *kaddr;
-       struct btrfs_trans_handle *trans;
        struct btrfs_file_extent_item *ei;
        u32 datasize;
        int err = 0;
@@ -98,8 +98,6 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
        if (!path)
                return -ENOMEM;
 
-       mutex_lock(&root->fs_info->fs_mutex);
-       trans = btrfs_start_transaction(root, 1);
        btrfs_set_trans_block_group(trans, inode);
 
        key.objectid = inode->i_ino;
@@ -122,18 +120,13 @@ static int insert_inline_extent(struct btrfs_root *root, struct inode *inode,
                                   BTRFS_FILE_EXTENT_INLINE);
        ptr = btrfs_file_extent_inline_start(ei);
 
-       kaddr = kmap_atomic(bh->b_page, KM_USER0);
+       kaddr = kmap_atomic(page, KM_USER0);
        btrfs_memcpy(root, path->nodes[0]->b_data,
-                    ptr, kaddr + bh_offset(bh),
-                    size);
+                    ptr, kaddr + page_offset, size);
        kunmap_atomic(kaddr, KM_USER0);
        btrfs_mark_buffer_dirty(path->nodes[0]);
 fail:
        btrfs_free_path(path);
-       ret = btrfs_end_transaction(trans, root);
-       if (ret && !err)
-               err = ret;
-       mutex_unlock(&root->fs_info->fs_mutex);
        return err;
 }
 
@@ -145,45 +138,143 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                                   loff_t pos,
                                   size_t write_bytes)
 {
-       int i;
-       int offset;
        int err = 0;
-       int ret;
-       int this_write;
+       int i;
        struct inode *inode = file->f_path.dentry->d_inode;
-       struct buffer_head *bh;
+       struct extent_map *em;
+       struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+       struct btrfs_key ins;
+       u64 hint_block;
+       u64 num_blocks;
+       u64 start_pos;
+       u64 end_of_last_block;
+       u64 end_pos = pos + write_bytes;
+       loff_t isize = i_size_read(inode);
 
-       for (i = 0; i < num_pages; i++) {
-               offset = pos & (PAGE_CACHE_SIZE -1);
-               this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
+       em = alloc_extent_map(GFP_NOFS);
+       if (!em)
+               return -ENOMEM;
 
-               /* FIXME, one block at a time */
-               bh = page_buffers(pages[i]);
+       em->bdev = inode->i_sb->s_bdev;
 
-               if (buffer_mapped(bh) && bh->b_blocknr == 0) {
-                       ret = insert_inline_extent(root, inode,
-                                       pages[i]->index << PAGE_CACHE_SHIFT,
-                                       offset + this_write, bh);
-                       if (ret) {
-                               err = ret;
-                               goto failed;
-                       }
-               }
+       start_pos = pos & ~((u64)root->blocksize - 1);
+       num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
+                       inode->i_blkbits;
 
-               ret = btrfs_commit_write(file, pages[i], offset,
-                                        offset + this_write);
-               pos += this_write;
-               if (ret) {
-                       err = ret;
+       end_of_last_block = start_pos + (num_blocks << inode->i_blkbits) - 1;
+       mutex_lock(&root->fs_info->fs_mutex);
+       trans = btrfs_start_transaction(root, 1);
+       if (!trans) {
+               err = -ENOMEM;
+               goto out_unlock;
+       }
+       btrfs_set_trans_block_group(trans, inode);
+       inode->i_blocks += num_blocks << 3;
+       hint_block = 0;
+
+       if ((end_of_last_block & 4095) == 0) {
+               printk("strange end of last %Lu %lu %Lu\n", start_pos, write_bytes, end_of_last_block);
+       }
+       set_extent_uptodate(em_tree, start_pos, end_of_last_block, GFP_NOFS);
+
+       /* FIXME...EIEIO, ENOSPC and more */
+
+       /* step one, delete the existing extents in this range */
+       /* FIXME blocksize != pagesize */
+       if (start_pos < inode->i_size) {
+               err = btrfs_drop_extents(trans, root, inode,
+                        start_pos, (pos + write_bytes + root->blocksize -1) &
+                        ~((u64)root->blocksize - 1), &hint_block);
+               if (err)
+                       goto failed;
+       }
+
+       /* insert any holes we need to create */
+       if (inode->i_size < start_pos) {
+               u64 last_pos_in_file;
+               u64 hole_size;
+               u64 mask = root->blocksize - 1;
+               last_pos_in_file = (isize + mask) & ~mask;
+               hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
+               hole_size >>= inode->i_blkbits;
+               if (last_pos_in_file < start_pos) {
+                       err = btrfs_insert_file_extent(trans, root,
+                                                      inode->i_ino,
+                                                      last_pos_in_file,
+                                                      0, 0, hole_size);
+               }
+               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
+        */
+       if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
+           pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
+               err = btrfs_alloc_extent(trans, root, inode->i_ino,
+                                        num_blocks, 0, hint_block, (u64)-1,
+                                        &ins, 1);
+               BUG_ON(err);
+               err = btrfs_insert_file_extent(trans, root, inode->i_ino,
+                                      start_pos, ins.objectid, ins.offset,
+                                      ins.offset);
+               BUG_ON(err);
+               em->start = start_pos;
+               em->end = end_of_last_block;
+               em->block_start = ins.objectid << inode->i_blkbits;
+               em->block_end = em->block_start +
+                       (ins.offset << inode->i_blkbits) - 1;
+               set_extent_dirty(em_tree, start_pos, end_of_last_block,
+                                GFP_NOFS);
+               err = add_extent_mapping(em_tree, em);
+               for (i = 0; i < num_pages; i++) {
+                       struct page *p = pages[i];
+                       SetPageUptodate(p);
+                       __set_page_dirty_nobuffers(p);
                }
-               WARN_ON(this_write > write_bytes);
-               write_bytes -= this_write;
+       } else {
+               struct page *p = pages[0];
+               err = insert_inline_extent(trans, root, inode, start_pos,
+                                          end_pos - start_pos, p, 0);
+               BUG_ON(err);
+               em->start = start_pos;
+               em->end = end_pos;
+               em->block_start = EXTENT_MAP_INLINE;
+               em->block_end = EXTENT_MAP_INLINE;
+               add_extent_mapping(em_tree, em);
+       }
+       if (end_pos > isize) {
+               i_size_write(inode, end_pos);
+               btrfs_update_inode(trans, root, inode);
        }
 failed:
+       err = btrfs_end_transaction(trans, root);
+out_unlock:
+       mutex_unlock(&root->fs_info->fs_mutex);
+       free_extent_map(em);
        return err;
 }
 
+int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end)
+{
+       struct extent_map *em;
+       struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
+
+       while(1) {
+               em = lookup_extent_mapping(em_tree, start, end);
+               if (!em)
+                       break;
+               remove_extent_mapping(em_tree, em);
+               /* once for us */
+               free_extent_map(em);
+               /* once for the tree*/
+               free_extent_map(em);
+       }
+       return 0;
+}
+
 /*
  * 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
@@ -213,6 +304,8 @@ int btrfs_drop_extents(struct btrfs_trans_handle *trans,
        int found_inline;
        int recow;
 
+       btrfs_drop_extent_cache(inode, start, end - 1);
+
        path = btrfs_alloc_path();
        if (!path)
                return -ENOMEM;
@@ -434,18 +527,9 @@ static int prepare_pages(struct btrfs_root *root,
        int i;
        unsigned long index = pos >> PAGE_CACHE_SHIFT;
        struct inode *inode = file->f_path.dentry->d_inode;
-       int offset;
        int err = 0;
-       int this_write;
-       struct buffer_head *bh;
-       struct buffer_head *head;
-       loff_t isize = i_size_read(inode);
-       struct btrfs_trans_handle *trans;
-       u64 hint_block;
        u64 num_blocks;
-       u64 alloc_extent_start;
        u64 start_pos;
-       struct btrfs_key ins;
 
        start_pos = pos & ~((u64)PAGE_CACHE_SIZE - 1);
        num_blocks = (write_bytes + pos - start_pos + root->blocksize - 1) >>
@@ -457,119 +541,17 @@ static int prepare_pages(struct btrfs_root *root,
                pages[i] = grab_cache_page(inode->i_mapping, index + i);
                if (!pages[i]) {
                        err = -ENOMEM;
-                       goto failed_release;
+                       BUG_ON(1);
                }
                cancel_dirty_page(pages[i], PAGE_CACHE_SIZE);
                wait_on_page_writeback(pages[i]);
-       }
-
-       mutex_lock(&root->fs_info->fs_mutex);
-       trans = btrfs_start_transaction(root, 1);
-       if (!trans) {
-               err = -ENOMEM;
-               mutex_unlock(&root->fs_info->fs_mutex);
-               goto out_unlock;
-       }
-       btrfs_set_trans_block_group(trans, inode);
-       /* FIXME blocksize != 4096 */
-       inode->i_blocks += num_blocks << 3;
-       hint_block = 0;
-
-       /* FIXME...EIEIO, ENOSPC and more */
-
-       /* step one, delete the existing extents in this range */
-       /* FIXME blocksize != pagesize */
-       if (start_pos < inode->i_size) {
-               err = btrfs_drop_extents(trans, root, inode,
-                        start_pos, (pos + write_bytes + root->blocksize -1) &
-                        ~((u64)root->blocksize - 1), &hint_block);
-               if (err)
-                       goto failed_release;
-       }
-
-       /* insert any holes we need to create */
-       if (inode->i_size < start_pos) {
-               u64 last_pos_in_file;
-               u64 hole_size;
-               u64 mask = root->blocksize - 1;
-               last_pos_in_file = (isize + mask) & ~mask;
-               hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
-               hole_size >>= inode->i_blkbits;
-               if (last_pos_in_file < start_pos) {
-                       err = btrfs_insert_file_extent(trans, root,
-                                                      inode->i_ino,
-                                                      last_pos_in_file,
-                                                      0, 0, hole_size);
-               }
-               if (err)
-                       goto failed_release;
-       }
-
-       /*
-        * either allocate an extent for the new bytes or setup the key
-        * to show we are doing inline data in the extent
-        */
-       if (isize >= PAGE_CACHE_SIZE || pos + write_bytes < inode->i_size ||
-           pos + write_bytes - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
-               err = btrfs_alloc_extent(trans, root, inode->i_ino,
-                                        num_blocks, 0, hint_block, (u64)-1,
-                                        &ins, 1);
-               if (err)
-                       goto failed_truncate;
-               err = btrfs_insert_file_extent(trans, root, inode->i_ino,
-                                      start_pos, ins.objectid, ins.offset,
-                                      ins.offset);
-               if (err)
-                       goto failed_truncate;
-       } else {
-               ins.offset = 0;
-               ins.objectid = 0;
-       }
-       BUG_ON(err);
-       alloc_extent_start = ins.objectid;
-       err = btrfs_end_transaction(trans, root);
-       mutex_unlock(&root->fs_info->fs_mutex);
-
-       for (i = 0; i < num_pages; i++) {
-               offset = pos & (PAGE_CACHE_SIZE -1);
-               this_write = min((size_t)PAGE_CACHE_SIZE - offset, write_bytes);
-               if (!page_has_buffers(pages[i])) {
-                       create_empty_buffers(pages[i],
-                                            root->fs_info->sb->s_blocksize,
-                                            (1 << BH_Uptodate));
+               if (!PagePrivate(pages[i])) {
+                       SetPagePrivate(pages[i]);
+                       set_page_private(pages[i], 1);
+                       page_cache_get(pages[i]);
                }
-               head = page_buffers(pages[i]);
-               bh = head;
-               do {
-                       err = btrfs_map_bh_to_logical(root, bh,
-                                                     alloc_extent_start);
-                       BUG_ON(err);
-                       if (err)
-                               goto failed_truncate;
-                       bh = bh->b_this_page;
-                       if (alloc_extent_start)
-                               alloc_extent_start++;
-               } while (bh != head);
-               pos += this_write;
-               WARN_ON(this_write > write_bytes);
-               write_bytes -= this_write;
        }
        return 0;
-
-failed_release:
-       btrfs_drop_pages(pages, num_pages);
-       return err;
-
-failed_truncate:
-       btrfs_drop_pages(pages, num_pages);
-       if (pos > isize)
-               vmtruncate(inode, isize);
-       return err;
-
-out_unlock:
-       mutex_unlock(&root->fs_info->fs_mutex);
-       goto failed_release;
-
 }
 
 static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
@@ -685,7 +667,6 @@ out:
                page_cache_release(pinned[1]);
        *ppos = pos;
        current->backing_dev_info = NULL;
-       mark_inode_dirty(inode);
        return num_written ? num_written : err;
 }
 
@@ -714,8 +695,8 @@ static int btrfs_sync_file(struct file *file,
        mutex_unlock(&root->fs_info->trans_mutex);
 
        /*
-        * ok we haven't committed the transaction yet, lets do a commit
-        */
+        * ok we haven't committed the transaction yet, lets do a commit
+        */
        trans = btrfs_start_transaction(root, 1);
        if (!trans) {
                ret = -ENOMEM;