Btrfs: sparse files!

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 99 insertions, 22 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index c1a0adde9b1c..5b87c4e9d491 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -17,6 +17,7 @@
 #include "transaction.h"
 #include "btrfs_inode.h"
 #include "ioctl.h"
+#include "print-tree.h"
 
 struct btrfs_iget_args {
         u64 ino;
@@ -421,14 +422,17 @@ static int btrfs_truncate_in_trans(struct btrfs_trans_handle *trans,
                                             struct btrfs_file_extent_item);
                         if (btrfs_file_extent_type(fi) !=
                             BTRFS_FILE_EXTENT_INLINE) {
+                                u64 num_dec;
                                 extent_start =
                                         btrfs_file_extent_disk_blocknr(fi);
                                 extent_num_blocks =
                                         btrfs_file_extent_disk_num_blocks(fi);
                                 /* FIXME blocksize != 4096 */
-                                inode->i_blocks -=
-                                        btrfs_file_extent_num_blocks(fi) << 3;
-                                found_extent = 1;
+                                num_dec = btrfs_file_extent_num_blocks(fi) << 3;
+                                if (extent_start != 0) {
+                                        found_extent = 1;
+                                        inode->i_blocks -= num_dec;
+                                }
                         }
                 }
                 ret = btrfs_del_item(trans, root, path);
@@ -448,6 +452,43 @@ error:
         return ret;
 }
 
+static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+        struct inode *inode = dentry->d_inode;
+        int err;
+
+        err = inode_change_ok(inode, attr);
+        if (err)
+                return err;
+
+        if (S_ISREG(inode->i_mode) &&
+            attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
+                struct btrfs_trans_handle *trans;
+                struct btrfs_root *root = BTRFS_I(inode)->root;
+                u64 mask = root->blocksize - 1;
+                u64 pos = (inode->i_size + mask) & ~mask;
+                u64 hole_size;
+
+                if (attr->ia_size < pos)
+                        goto out;
+                hole_size = (attr->ia_size - pos + mask) & ~mask;
+                hole_size >>= inode->i_blkbits;
+
+                mutex_lock(&root->fs_info->fs_mutex);
+                trans = btrfs_start_transaction(root, 1);
+                btrfs_set_trans_block_group(trans, inode);
+                err = btrfs_insert_file_extent(trans, root, inode->i_ino,
+                                               pos, 0, 0, hole_size);
+                BUG_ON(err);
+                btrfs_end_transaction(trans, root);
+                mutex_unlock(&root->fs_info->fs_mutex);
+        }
+
+        err = inode_setattr(inode, attr);
+
+out:
+        return err;
+}
 static void btrfs_delete_inode(struct inode *inode)
 {
         struct btrfs_trans_handle *trans;
@@ -1169,8 +1210,10 @@ static int btrfs_get_block_lock(struct inode *inode, sector_t iblock,
         if (found_type == BTRFS_FILE_EXTENT_REG) {
                 extent_start = extent_start >> inode->i_blkbits;
                 extent_end = extent_start + btrfs_file_extent_num_blocks(item);
+                err = 0;
+                if (blocknr == 0)
+                        goto out;
                 if (iblock >= extent_start && iblock < extent_end) {
-                        err = 0;
                         btrfs_map_bh_to_logical(root, result, blocknr +
                                                 iblock - extent_start);
                         goto out;
@@ -1591,7 +1634,7 @@ static int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                                      ptr, bh->b_data, offset + write_bytes);
                         mark_buffer_dirty(path->nodes[0]);
                         btrfs_free_path(path);
-                } else {
+                } else if (buffer_mapped(bh)) {
                         btrfs_csum_file_block(trans, root, inode->i_ino,
                                       pages[i]->index << PAGE_CACHE_SHIFT,
                                       kmap(pages[i]), PAGE_CACHE_SIZE);
@@ -1693,15 +1736,24 @@ static int drop_extents(struct btrfs_trans_handle *trans,
                         goto out;
                 }
 
-                search_start = extent_end;
+                if (found_inline) {
+                        u64 mask = root->blocksize - 1;
+                        search_start = (extent_end + mask) & ~mask;
+                } else
+                        search_start = extent_end;
 
                 if (end < extent_end && end >= key.offset) {
                         if (found_extent) {
+                                u64 disk_blocknr =
+                                        btrfs_file_extent_disk_blocknr(extent);
+                                u64 disk_num_blocks =
+                                      btrfs_file_extent_disk_num_blocks(extent);
                                 memcpy(&old, extent, sizeof(old));
-                                ret = btrfs_inc_extent_ref(trans, root,
-                                      btrfs_file_extent_disk_blocknr(&old),
-                                      btrfs_file_extent_disk_num_blocks(&old));
-                                BUG_ON(ret);
+                                if (disk_blocknr != 0) {
+                                        ret = btrfs_inc_extent_ref(trans, root,
+                                                 disk_blocknr, disk_num_blocks);
+                                        BUG_ON(ret);
+                                }
                         }
                         WARN_ON(found_inline);
                         bookend = 1;
@@ -1719,7 +1771,10 @@ static int drop_extents(struct btrfs_trans_handle *trans,
                                 old_num = btrfs_file_extent_num_blocks(extent);
                                 *hint_block =
                                         btrfs_file_extent_disk_blocknr(extent);
-                                inode->i_blocks -= (old_num - new_num) << 3;
+                                if (btrfs_file_extent_disk_blocknr(extent)) {
+                                        inode->i_blocks -=
+                                                (old_num - new_num) << 3;
+                                }
                                 btrfs_set_file_extent_num_blocks(extent,
                                                                  new_num);
                                 mark_buffer_dirty(path->nodes[0]);
@@ -1745,7 +1800,7 @@ static int drop_extents(struct btrfs_trans_handle *trans,
                         BUG_ON(ret);
                         btrfs_release_path(root, path);
                         extent = NULL;
-                        if (found_extent) {
+                        if (found_extent && disk_blocknr != 0) {
                                 inode->i_blocks -= extent_num_blocks << 3;
                                 ret = btrfs_free_extent(trans, root,
                                                         disk_blocknr,
@@ -1785,18 +1840,19 @@ static int drop_extents(struct btrfs_trans_handle *trans,
                                     btrfs_file_extent_offset(&old) +
                                     ((end - key.offset) >> inode->i_blkbits));
                         WARN_ON(btrfs_file_extent_num_blocks(&old) <
-                                (end - key.offset) >> inode->i_blkbits);
+                                (extent_end - end) >> inode->i_blkbits);
                         btrfs_set_file_extent_num_blocks(extent,
-                                    btrfs_file_extent_num_blocks(&old) -
-                                    ((end - key.offset) >> inode->i_blkbits));
+                                    (extent_end - end) >> inode->i_blkbits);
 
                         btrfs_set_file_extent_type(extent,
                                                    BTRFS_FILE_EXTENT_REG);
                         btrfs_set_file_extent_generation(extent,
                                     btrfs_file_extent_generation(&old));
                         btrfs_mark_buffer_dirty(path->nodes[0]);
-                        inode->i_blocks +=
-                                btrfs_file_extent_num_blocks(extent) << 3;
+                        if (btrfs_file_extent_disk_blocknr(&old) != 0) {
+                                inode->i_blocks +=
+                                      btrfs_file_extent_num_blocks(extent) << 3;
+                        }
                         ret = 0;
                         goto out;
                 }
@@ -1960,6 +2016,21 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                                    ~((u64)root->blocksize - 1), &hint_block);
                 BUG_ON(ret);
         }
+        if (inode->i_size < start_pos) {
+                u64 last_pos_in_file;
+                u64 hole_size;
+                u64 mask = root->blocksize - 1;
+                last_pos_in_file = (inode->i_size + mask) & ~mask;
+                hole_size = (start_pos - last_pos_in_file + mask) & ~mask;
+                hole_size >>= inode->i_blkbits;
+                if (last_pos_in_file < start_pos) {
+                        ret = btrfs_insert_file_extent(trans, root,
+                                                       inode->i_ino,
+                                                       last_pos_in_file,
+                                                       0, 0, hole_size);
+                }
+                BUG_ON(ret);
+        }
         if (inode->i_size >= PAGE_CACHE_SIZE || pos + count < inode->i_size ||
             pos + count - start_pos > BTRFS_MAX_INLINE_DATA_SIZE(root)) {
                 ret = btrfs_alloc_extent(trans, root, inode->i_ino,
@@ -1967,7 +2038,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                                          &ins, 1);
                 BUG_ON(ret);
                 ret = btrfs_insert_file_extent(trans, root, inode->i_ino,
-                                       start_pos, ins.objectid, ins.offset);
+                                       start_pos, ins.objectid, ins.offset,
+                                       ins.offset);
                 BUG_ON(ret);
         } else {
                 ins.offset = 0;
@@ -2044,10 +2116,13 @@ static int btrfs_read_actor(read_descriptor_t *desc, struct page *page,
                                   page->index << PAGE_CACHE_SHIFT,
                                   kmap(page), PAGE_CACHE_SIZE);
                 if (ret) {
-                        printk("failed to verify ino %lu page %lu\n",
-                               page->mapping->host->i_ino,
-                               page->index);
-                        memset(page_address(page), 0, PAGE_CACHE_SIZE);
+                        if (ret != -ENOENT) {
+                                printk("failed to verify ino %lu page %lu\n",
+                                       page->mapping->host->i_ino,
+                                       page->index);
+                                memset(page_address(page), 0, PAGE_CACHE_SIZE);
+                                flush_dcache_page(page);
+                        }
                 }
                 SetPageChecked(page);
                 kunmap(page);
@@ -2759,6 +2834,7 @@ static struct inode_operations btrfs_dir_inode_operations = {
         .rmdir          = btrfs_rmdir,
         .rename         = btrfs_rename,
         .symlink        = btrfs_symlink,
+        .setattr        = btrfs_setattr,
 };
 
 static struct inode_operations btrfs_dir_ro_inode_operations = {
@@ -2788,6 +2864,7 @@ static struct address_space_operations btrfs_symlink_aops = {
 static struct inode_operations btrfs_file_inode_operations = {
         .truncate       = btrfs_truncate,
         .getattr        = btrfs_getattr,
+        .setattr        = btrfs_setattr,
 };
 
 static struct file_operations btrfs_file_operations = {