diff options
author | Yan Zheng <zheng.yan@oracle.com> | 2008-10-30 14:25:28 -0400 |
---|---|---|
committer | Chris Mason <chris.mason@oracle.com> | 2008-10-30 14:25:28 -0400 |
commit | d899e05215178fed903ad0e7fc1cb4d8e0cc0a88 (patch) | |
tree | 2969e3558f5c50ec0f9ac4201099c0d5d1d6e2c2 /fs/btrfs/file.c | |
parent | 80ff385665b7fca29fefe358a60ab0d09f9b8e87 (diff) |
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>
Diffstat (limited to 'fs/btrfs/file.c')
-rw-r--r-- | fs/btrfs/file.c | 245 |
1 files changed, 241 insertions, 4 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 1a0510ad030..238a8e215eb 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -381,7 +381,7 @@ int noinline btrfs_drop_extents(struct btrfs_trans_handle *trans, 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 @@ next_slot: 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 @@ next_slot: */ 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 @@ out: 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 |