Btrfs: update hole handling v2

This patch splits the hole insertion code out of btrfs_setattr
into btrfs_cont_expand and updates btrfs_get_extent to properly
handle the case that file extent items are not continuous.

Signed-off-by: Yan Zheng <zheng.yan@oracle.com>

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index abb2733..ca5547a 100644 (file)
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -1908,6 +1908,7 @@ int btrfs_update_inode(struct btrfs_trans_handle *trans,
 int btrfs_orphan_add(struct btrfs_trans_handle *trans, struct inode *inode);
 int btrfs_orphan_del(struct btrfs_trans_handle *trans, struct inode *inode);
 void btrfs_orphan_cleanup(struct btrfs_root *root);
+int btrfs_cont_expand(struct inode *inode, loff_t size);
 
 /* ioctl.c */
 long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);

diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h
index abbcbeb..e693e1b 100644 (file)
--- a/fs/btrfs/extent_map.h
+++ b/fs/btrfs/extent_map.h
@@ -11,6 +11,7 @@
 /* bits for the flags field */
 #define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
 #define EXTENT_FLAG_COMPRESSED 1
+#define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
 
 struct extent_map {
        struct rb_node rb_node;

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 0aa1543..b8a7637 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -142,40 +142,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
        }
        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,
-                                                      hole_size, 0, 0, 0);
-                       btrfs_drop_extent_cache(inode, last_pos_in_file,
-                                       last_pos_in_file + hole_size - 1, 0);
-                       mutex_unlock(&BTRFS_I(inode)->extent_mutex);
-                       btrfs_check_file(root, inode);
-               }
-               if (err)
-                       goto failed;
-       }
-
        /* check for reserved extents on each page, we don't want
         * to reset the delalloc bit on things that already have
         * extents reserved.
@@ -191,7 +157,6 @@ static int noinline dirty_and_release_pages(struct btrfs_trans_handle *trans,
                i_size_write(inode, 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);
@@ -697,6 +662,12 @@ static int noinline prepare_pages(struct btrfs_root *root, struct file *file,
        start_pos = pos & ~((u64)root->sectorsize - 1);
        last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT;
 
+       if (start_pos > inode->i_size) {
+               err = btrfs_cont_expand(inode, start_pos);
+               if (err)
+                       return err;
+       }
+
        memset(pages, 0, num_pages * sizeof(struct page *));
 again:
        for (i = 0; i < num_pages; i++) {

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dd9cd01..8254d6f 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2296,81 +2296,91 @@ out:
        return ret;
 }
 
-static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+int btrfs_cont_expand(struct inode *inode, loff_t size)
 {
-       struct inode *inode = dentry->d_inode;
+       struct btrfs_trans_handle *trans;
+       struct btrfs_root *root = BTRFS_I(inode)->root;
+       struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+       struct extent_map *em;
+       u64 mask = root->sectorsize - 1;
+       u64 hole_start = (inode->i_size + mask) & ~mask;
+       u64 block_end = (size + mask) & ~mask;
+       u64 last_byte;
+       u64 cur_offset;
+       u64 hole_size;
        int err;
 
-       err = inode_change_ok(inode, attr);
+       if (size <= hole_start)
+               return 0;
+
+       err = btrfs_check_free_space(root, 1, 0);
        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;
-               struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+       btrfs_truncate_page(inode->i_mapping, inode->i_size);
 
-               u64 mask = root->sectorsize - 1;
-               u64 hole_start = (inode->i_size + mask) & ~mask;
-               u64 block_end = (attr->ia_size + mask) & ~mask;
-               u64 hole_size;
-               u64 alloc_hint = 0;
+       while (1) {
+               struct btrfs_ordered_extent *ordered;
+               btrfs_wait_ordered_range(inode, hole_start,
+                                        block_end - hole_start);
+               lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+               ordered = btrfs_lookup_ordered_extent(inode, hole_start);
+               if (!ordered)
+                       break;
+               unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+               btrfs_put_ordered_extent(ordered);
+       }
 
-               if (attr->ia_size <= hole_start)
-                       goto out;
+       trans = btrfs_start_transaction(root, 1);
+       btrfs_set_trans_block_group(trans, inode);
 
-               err = btrfs_check_free_space(root, 1, 0);
-               if (err)
-                       goto fail;
+       cur_offset = hole_start;
+       while (1) {
+               em = btrfs_get_extent(inode, NULL, 0, cur_offset,
+                               block_end - cur_offset, 0);
+               BUG_ON(IS_ERR(em) || !em);
+               last_byte = min(extent_map_end(em), block_end);
+               last_byte = (last_byte + mask) & ~mask;
+               if (test_bit(EXTENT_FLAG_VACANCY, &em->flags)) {
+                       hole_size = last_byte - cur_offset;
+                       err = btrfs_insert_file_extent(trans, root,
+                                       inode->i_ino, cur_offset, 0,
+                                       0, hole_size, 0, hole_size,
+                                       0, 0, 0);
+                       btrfs_drop_extent_cache(inode, hole_start,
+                                       last_byte - 1, 0);
+               }
+               free_extent_map(em);
+               cur_offset = last_byte;
+               if (err || cur_offset >= block_end)
+                       break;
+       }
 
-               btrfs_truncate_page(inode->i_mapping, inode->i_size);
+       btrfs_end_transaction(trans, root);
+       unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+       return err;
+}
 
-               hole_size = block_end - hole_start;
-               while(1) {
-                       struct btrfs_ordered_extent *ordered;
-                       btrfs_wait_ordered_range(inode, hole_start, hole_size);
-
-                       lock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
-                       ordered = btrfs_lookup_ordered_extent(inode, hole_start);
-                       if (ordered) {
-                               unlock_extent(io_tree, hole_start,
-                                             block_end - 1, GFP_NOFS);
-                               btrfs_put_ordered_extent(ordered);
-                       } else {
-                               break;
-                       }
-               }
+static int btrfs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+       struct inode *inode = dentry->d_inode;
+       int err;
 
-               trans = btrfs_start_transaction(root, 1);
-               btrfs_set_trans_block_group(trans, inode);
-               mutex_lock(&BTRFS_I(inode)->extent_mutex);
-               err = btrfs_drop_extents(trans, root, inode,
-                                        hole_start, block_end, hole_start,
-                                        &alloc_hint);
+       err = inode_change_ok(inode, attr);
+       if (err)
+               return err;
 
-               if (alloc_hint != EXTENT_MAP_INLINE) {
-                       err = btrfs_insert_file_extent(trans, root,
-                                                      inode->i_ino,
-                                                      hole_start, 0, 0,
-                                                      hole_size, 0, hole_size,
-                                                      0, 0, 0);
-                       btrfs_drop_extent_cache(inode, hole_start,
-                                               (u64)-1, 0);
-                       btrfs_check_file(root, inode);
-               }
-               mutex_unlock(&BTRFS_I(inode)->extent_mutex);
-               btrfs_end_transaction(trans, root);
-               unlock_extent(io_tree, hole_start, block_end - 1, GFP_NOFS);
+       if (S_ISREG(inode->i_mode) &&
+           attr->ia_valid & ATTR_SIZE && attr->ia_size > inode->i_size) {
+               err = btrfs_cont_expand(inode, attr->ia_size);
                if (err)
                        return err;
        }
-out:
+
        err = inode_setattr(inode, attr);
 
        if (!err && ((attr->ia_valid & ATTR_MODE)))
                err = btrfs_acl_chmod(inode);
-fail:
        return err;
 }
 
@@ -3456,27 +3466,44 @@ again:
        if (found_type == BTRFS_FILE_EXTENT_REG) {
                extent_end = extent_start +
                       btrfs_file_extent_num_bytes(leaf, item);
-               err = 0;
-               if (start < extent_start || start >= extent_end) {
-                       em->start = start;
-                       if (start < extent_start) {
-                               if (start + len <= extent_start)
-                                       goto not_found;
-                               em->len = extent_end - extent_start;
-                       } else {
-                               em->len = len;
+       } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
+               size_t size;
+               size = btrfs_file_extent_inline_len(leaf, item);
+               extent_end = (extent_start + size + root->sectorsize - 1) &
+                       ~((u64)root->sectorsize - 1);
+       }
+
+       if (start >= extent_end) {
+               path->slots[0]++;
+               if (path->slots[0] >= btrfs_header_nritems(leaf)) {
+                       ret = btrfs_next_leaf(root, path);
+                       if (ret < 0) {
+                               err = ret;
+                               goto out;
                        }
-                       goto not_found_em;
+                       if (ret > 0)
+                               goto not_found;
+                       leaf = path->nodes[0];
                }
+               btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
+               if (found_key.objectid != objectid ||
+                   found_key.type != BTRFS_EXTENT_DATA_KEY)
+                       goto not_found;
+               if (start + len <= found_key.offset)
+                       goto not_found;
+               em->start = start;
+               em->len = found_key.offset - start;
+               goto not_found_em;
+       }
+
+       if (found_type == BTRFS_FILE_EXTENT_REG) {
+               em->start = extent_start;
+               em->len = extent_end - extent_start;
                bytenr = btrfs_file_extent_disk_bytenr(leaf, item);
                if (bytenr == 0) {
-                       em->start = extent_start;
-                       em->len = extent_end - extent_start;
                        em->block_start = EXTENT_MAP_HOLE;
                        goto insert;
                }
-               em->start = extent_start;
-               em->len = extent_end - extent_start;
                if (compressed) {
                        set_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
                        em->block_start = bytenr;
@@ -3489,38 +3516,21 @@ again:
                }
                goto insert;
        } else if (found_type == BTRFS_FILE_EXTENT_INLINE) {
-               u64 page_start;
                unsigned long ptr;
                char *map;
                size_t size;
                size_t extent_offset;
                size_t copy_size;
 
-               size = btrfs_file_extent_inline_len(leaf, item);
-               extent_end = (extent_start + size + root->sectorsize - 1) &
-                       ~((u64)root->sectorsize - 1);
-               if (start < extent_start || start >= extent_end) {
-                       em->start = start;
-                       if (start < extent_start) {
-                               if (start + len <= extent_start)
-                                       goto not_found;
-                               em->len = extent_end - extent_start;
-                       } else {
-                               em->len = len;
-                       }
-                       goto not_found_em;
-               }
                em->block_start = EXTENT_MAP_INLINE;
-
                if (!page || create) {
                        em->start = extent_start;
-                       em->len = (size + root->sectorsize - 1) &
-                       ~((u64)root->sectorsize - 1);
+                       em->len = extent_end - extent_start;
                        goto out;
                }
 
-               page_start = page_offset(page) + pg_offset;
-               extent_offset = page_start - extent_start;
+               size = btrfs_file_extent_inline_len(leaf, item);
+               extent_offset = page_offset(page) + pg_offset - extent_start;
                copy_size = min_t(u64, PAGE_CACHE_SIZE - pg_offset,
                                size - extent_offset);
                em->start = extent_start + extent_offset;
@@ -3570,6 +3580,7 @@ not_found:
        em->len = len;
 not_found_em:
        em->block_start = EXTENT_MAP_HOLE;
+       set_bit(EXTENT_FLAG_VACANCY, &em->flags);
 insert:
        btrfs_release_path(root, path);
        if (em->start > start || extent_map_end(em) <= start) {