Btrfs: remove unnecessary condition in btrfs_clone() to avoid too much nesting
The bulk of the work done when cloning extents, at ioctl.c:btrfs_clone(), is done inside an if statement that checks if the found key has the type BTRFS_EXTENT_DATA_KEY. That if statement is redundant however, because btrfs_search_slot() always leaves us in a leaf slot that points to a key that is always greater then or equals to the search key, and our search key here has that type, and because we bail out before that if statement if the key at the given leaf slot is greater then BTRFS_EXTENT_DATA_KEY. Therefore just remove that if statement, not only because it is useless but mostly because it increases the nesting/indentation level in this function which is quite big and makes things a bit awkward whenever I need to fix something that requires changing btrfs_clone() (and it has been like that for many years already). Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana
David Sterba
parent
559ca6ea69
commit
b64119b5f0
288
fs/btrfs/ioctl.c
288
fs/btrfs/ioctl.c
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@ -3516,6 +3516,14 @@ static int btrfs_clone(struct inode *src, struct inode *inode,
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while (1) {
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u64 next_key_min_offset = key.offset + 1;
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struct btrfs_file_extent_item *extent;
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int type;
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u32 size;
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struct btrfs_key new_key;
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u64 disko = 0, diskl = 0;
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u64 datao = 0, datal = 0;
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u8 comp;
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u64 drop_start;
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/*
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* note the key will change type as we walk through the
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@ -3556,169 +3564,147 @@ process_slot:
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key.objectid != btrfs_ino(BTRFS_I(src)))
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break;
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if (key.type == BTRFS_EXTENT_DATA_KEY) {
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struct btrfs_file_extent_item *extent;
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int type;
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u32 size;
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struct btrfs_key new_key;
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u64 disko = 0, diskl = 0;
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u64 datao = 0, datal = 0;
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u8 comp;
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u64 drop_start;
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ASSERT(key.type == BTRFS_EXTENT_DATA_KEY);
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extent = btrfs_item_ptr(leaf, slot,
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struct btrfs_file_extent_item);
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comp = btrfs_file_extent_compression(leaf, extent);
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type = btrfs_file_extent_type(leaf, extent);
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if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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disko = btrfs_file_extent_disk_bytenr(leaf,
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extent);
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diskl = btrfs_file_extent_disk_num_bytes(leaf,
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extent);
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datao = btrfs_file_extent_offset(leaf, extent);
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datal = btrfs_file_extent_num_bytes(leaf,
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extent);
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} else if (type == BTRFS_FILE_EXTENT_INLINE) {
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/* take upper bound, may be compressed */
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datal = btrfs_file_extent_ram_bytes(leaf,
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extent);
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}
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extent = btrfs_item_ptr(leaf, slot,
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struct btrfs_file_extent_item);
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comp = btrfs_file_extent_compression(leaf, extent);
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type = btrfs_file_extent_type(leaf, extent);
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if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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disko = btrfs_file_extent_disk_bytenr(leaf, extent);
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diskl = btrfs_file_extent_disk_num_bytes(leaf, extent);
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datao = btrfs_file_extent_offset(leaf, extent);
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datal = btrfs_file_extent_num_bytes(leaf, extent);
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} else if (type == BTRFS_FILE_EXTENT_INLINE) {
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/* Take upper bound, may be compressed */
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datal = btrfs_file_extent_ram_bytes(leaf, extent);
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}
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/*
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* The first search might have left us at an extent item that
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* ends before our target range's start, can happen if we have
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* holes and NO_HOLES feature enabled.
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*/
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if (key.offset + datal <= off) {
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path->slots[0]++;
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goto process_slot;
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} else if (key.offset >= off + len) {
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break;
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}
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next_key_min_offset = key.offset + datal;
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size = btrfs_item_size_nr(leaf, slot);
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read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot),
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size);
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btrfs_release_path(path);
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path->leave_spinning = 0;
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memcpy(&new_key, &key, sizeof(new_key));
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new_key.objectid = btrfs_ino(BTRFS_I(inode));
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if (off <= key.offset)
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new_key.offset = key.offset + destoff - off;
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else
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new_key.offset = destoff;
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/*
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* Deal with a hole that doesn't have an extent item that
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* represents it (NO_HOLES feature enabled).
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* This hole is either in the middle of the cloning range or at
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* the beginning (fully overlaps it or partially overlaps it).
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*/
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if (new_key.offset != last_dest_end)
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drop_start = last_dest_end;
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else
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drop_start = new_key.offset;
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if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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struct btrfs_clone_extent_info clone_info;
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/*
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* The first search might have left us at an extent
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* item that ends before our target range's start, can
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* happen if we have holes and NO_HOLES feature enabled.
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* a | --- range to clone ---| b
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* | ------------- extent ------------- |
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*/
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if (key.offset + datal <= off) {
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path->slots[0]++;
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goto process_slot;
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} else if (key.offset >= off + len) {
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break;
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/* Subtract range b */
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if (key.offset + datal > off + len)
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datal = off + len - key.offset;
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/* Subtract range a */
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if (off > key.offset) {
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datao += off - key.offset;
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datal -= off - key.offset;
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}
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next_key_min_offset = key.offset + datal;
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size = btrfs_item_size_nr(leaf, slot);
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read_extent_buffer(leaf, buf,
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btrfs_item_ptr_offset(leaf, slot),
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size);
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btrfs_release_path(path);
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path->leave_spinning = 0;
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memcpy(&new_key, &key, sizeof(new_key));
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new_key.objectid = btrfs_ino(BTRFS_I(inode));
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if (off <= key.offset)
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new_key.offset = key.offset + destoff - off;
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else
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new_key.offset = destoff;
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/*
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* Deal with a hole that doesn't have an extent item
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* that represents it (NO_HOLES feature enabled).
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* This hole is either in the middle of the cloning
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* range or at the beginning (fully overlaps it or
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* partially overlaps it).
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*/
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if (new_key.offset != last_dest_end)
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drop_start = last_dest_end;
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else
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drop_start = new_key.offset;
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if (type == BTRFS_FILE_EXTENT_REG ||
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type == BTRFS_FILE_EXTENT_PREALLOC) {
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struct btrfs_clone_extent_info clone_info;
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/*
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* a | --- range to clone ---| b
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* | ------------- extent ------------- |
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*/
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/* subtract range b */
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if (key.offset + datal > off + len)
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datal = off + len - key.offset;
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/* subtract range a */
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if (off > key.offset) {
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datao += off - key.offset;
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datal -= off - key.offset;
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}
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clone_info.disk_offset = disko;
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clone_info.disk_len = diskl;
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clone_info.data_offset = datao;
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clone_info.data_len = datal;
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clone_info.file_offset = new_key.offset;
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clone_info.extent_buf = buf;
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clone_info.item_size = size;
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ret = btrfs_punch_hole_range(inode, path,
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clone_info.disk_offset = disko;
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clone_info.disk_len = diskl;
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clone_info.data_offset = datao;
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clone_info.data_len = datal;
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clone_info.file_offset = new_key.offset;
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clone_info.extent_buf = buf;
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clone_info.item_size = size;
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ret = btrfs_punch_hole_range(inode, path,
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drop_start,
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new_key.offset + datal - 1,
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&clone_info, &trans);
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if (ret)
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goto out;
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} else if (type == BTRFS_FILE_EXTENT_INLINE) {
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u64 skip = 0;
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u64 trim = 0;
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if (off > key.offset) {
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skip = off - key.offset;
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new_key.offset += skip;
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}
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if (key.offset + datal > off + len)
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trim = key.offset + datal - (off + len);
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if (comp && (skip || trim)) {
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ret = -EINVAL;
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goto out;
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}
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size -= skip + trim;
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datal -= skip + trim;
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/*
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* If our extent is inline, we know we will drop
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* or adjust at most 1 extent item in the
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* destination root.
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*
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* 1 - adjusting old extent (we may have to
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* split it)
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* 1 - add new extent
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* 1 - inode update
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*/
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trans = btrfs_start_transaction(root, 3);
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if (IS_ERR(trans)) {
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ret = PTR_ERR(trans);
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goto out;
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}
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ret = clone_copy_inline_extent(inode,
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trans, path,
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&new_key,
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drop_start,
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datal,
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skip, size, buf);
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if (ret) {
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if (ret != -EOPNOTSUPP)
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btrfs_abort_transaction(trans,
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ret);
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btrfs_end_transaction(trans);
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goto out;
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}
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}
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btrfs_release_path(path);
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last_dest_end = ALIGN(new_key.offset + datal,
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fs_info->sectorsize);
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ret = clone_finish_inode_update(trans, inode,
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last_dest_end,
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destoff, olen,
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no_time_update);
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if (ret)
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goto out;
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if (new_key.offset + datal >= destoff + len)
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break;
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} else if (type == BTRFS_FILE_EXTENT_INLINE) {
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u64 skip = 0;
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u64 trim = 0;
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if (off > key.offset) {
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skip = off - key.offset;
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new_key.offset += skip;
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}
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if (key.offset + datal > off + len)
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trim = key.offset + datal - (off + len);
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if (comp && (skip || trim)) {
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ret = -EINVAL;
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goto out;
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}
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size -= skip + trim;
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datal -= skip + trim;
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/*
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* If our extent is inline, we know we will drop or
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* adjust at most 1 extent item in the destination root.
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*
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* 1 - adjusting old extent (we may have to split it)
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* 1 - add new extent
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* 1 - inode update
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*/
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trans = btrfs_start_transaction(root, 3);
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if (IS_ERR(trans)) {
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ret = PTR_ERR(trans);
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goto out;
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}
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ret = clone_copy_inline_extent(inode, trans, path,
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&new_key, drop_start,
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datal, skip, size, buf);
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if (ret) {
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if (ret != -EOPNOTSUPP)
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btrfs_abort_transaction(trans, ret);
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btrfs_end_transaction(trans);
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goto out;
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}
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}
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btrfs_release_path(path);
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last_dest_end = ALIGN(new_key.offset + datal,
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fs_info->sectorsize);
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ret = clone_finish_inode_update(trans, inode, last_dest_end,
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destoff, olen, no_time_update);
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if (ret)
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goto out;
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if (new_key.offset + datal >= destoff + len)
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break;
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btrfs_release_path(path);
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key.offset = next_key_min_offset;
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