Btrfs: Add fallocate support v2
This patch updates btrfs-progs for fallocate support.
fallocate is a little different in Btrfs because we need to tell the
COW system that a given preallocated extent doesn't need to be
cow'd as long as there are no snapshots of it. This leverages the
-o nodatacow checks.
Signed-off-by: Yan Zheng <zheng.yan@oracle.com>
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 1a0510a..238a8e2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -381,7 +381,7 @@
int keep;
int slot;
int bookend;
- int found_type;
+ int found_type = 0;
int found_extent;
int found_inline;
int recow;
@@ -442,7 +442,8 @@
extent);
other_encoding = btrfs_file_extent_other_encoding(leaf,
extent);
- if (found_type == BTRFS_FILE_EXTENT_REG) {
+ if (found_type == BTRFS_FILE_EXTENT_REG ||
+ found_type == BTRFS_FILE_EXTENT_PREALLOC) {
extent_end =
btrfs_file_extent_disk_bytenr(leaf,
extent);
@@ -609,8 +610,7 @@
*/
btrfs_set_file_extent_ram_bytes(leaf, extent,
ram_bytes);
- btrfs_set_file_extent_type(leaf, extent,
- BTRFS_FILE_EXTENT_REG);
+ btrfs_set_file_extent_type(leaf, extent, found_type);
btrfs_mark_buffer_dirty(path->nodes[0]);
@@ -661,6 +661,243 @@
return ret;
}
+static int extent_mergeable(struct extent_buffer *leaf, int slot,
+ u64 objectid, u64 bytenr, u64 *start, u64 *end)
+{
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ u64 extent_end;
+
+ if (slot < 0 || slot >= btrfs_header_nritems(leaf))
+ return 0;
+
+ btrfs_item_key_to_cpu(leaf, &key, slot);
+ if (key.objectid != objectid || key.type != BTRFS_EXTENT_DATA_KEY)
+ return 0;
+
+ 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_compression(leaf, fi) ||
+ btrfs_file_extent_encryption(leaf, fi) ||
+ btrfs_file_extent_other_encoding(leaf, fi))
+ return 0;
+
+ extent_end = key.offset + btrfs_file_extent_num_bytes(leaf, fi);
+ if ((*start && *start != key.offset) || (*end && *end != extent_end))
+ return 0;
+
+ *start = key.offset;
+ *end = extent_end;
+ return 1;
+}
+
+/*
+ * Mark extent in the range start - end as written.
+ *
+ * This changes extent type from 'pre-allocated' to 'regular'. If only
+ * part of extent is marked as written, the extent will be split into
+ * 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 extent_buffer *leaf;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *fi;
+ struct btrfs_key key;
+ u64 bytenr;
+ u64 num_bytes;
+ u64 extent_end;
+ u64 extent_offset;
+ u64 other_start;
+ u64 other_end;
+ u64 split = start;
+ u64 locked_end = end;
+ int extent_type;
+ int split_end = 1;
+ int ret;
+
+ btrfs_drop_extent_cache(inode, start, end - 1, 0);
+
+ path = btrfs_alloc_path();
+ BUG_ON(!path);
+again:
+ key.objectid = inode->i_ino;
+ key.type = BTRFS_EXTENT_DATA_KEY;
+ if (split == start)
+ key.offset = split;
+ else
+ key.offset = split - 1;
+
+ ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
+ if (ret > 0 && path->slots[0] > 0)
+ path->slots[0]--;
+
+ leaf = path->nodes[0];
+ btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
+ BUG_ON(key.objectid != inode->i_ino ||
+ 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);
+ 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);
+ extent_offset = btrfs_file_extent_offset(leaf, fi);
+
+ if (key.offset == start)
+ split = end;
+
+ if (key.offset == start && extent_end == end) {
+ int del_nr = 0;
+ int del_slot = 0;
+ u64 leaf_owner = btrfs_header_owner(leaf);
+ u64 leaf_gen = btrfs_header_generation(leaf);
+ 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,
+ leaf->start, leaf_owner,
+ leaf_gen, inode->i_ino, 0);
+ BUG_ON(ret);
+ }
+ 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,
+ leaf->start, leaf_owner,
+ leaf_gen, inode->i_ino, 0);
+ 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 done;
+ } 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;
+ }
+ btrfs_set_file_extent_num_bytes(leaf, fi, split - key.offset);
+ extent_offset += split - key.offset;
+ } else {
+ BUG_ON(key.offset != start);
+ btrfs_set_file_extent_offset(leaf, fi, extent_offset +
+ split - key.offset);
+ btrfs_set_file_extent_num_bytes(leaf, fi, extent_end - split);
+ key.offset = 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) {
+ 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]++;
+ 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, extent_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]--;
+ 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_mark_buffer_dirty(leaf);
+ btrfs_release_path(root, path);
+
+ 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],
+ 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, extent_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);
+
+ ret = btrfs_inc_extent_ref(trans, root, bytenr, num_bytes,
+ leaf->start, root->root_key.objectid,
+ trans->transid, inode->i_ino);
+ BUG_ON(ret);
+done:
+ btrfs_mark_buffer_dirty(leaf);
+ btrfs_release_path(root, path);
+ if (split_end && split == start) {
+ split = end;
+ goto again;
+ }
+ if (locked_end > end) {
+ unlock_extent(&BTRFS_I(inode)->io_tree, end, locked_end - 1,
+ GFP_NOFS);
+ }
+ btrfs_free_path(path);
+ return 0;
+}
+
/*
* this gets pages into the page cache and locks them down, it also properly
* waits for data=ordered extents to finish before allowing the pages to be