diff options
| -rw-r--r-- | fs/btrfs/ioctl.c | 195 |
1 files changed, 152 insertions, 43 deletions
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 8b2c82ce36b3..87c720865ebf 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3166,6 +3166,150 @@ static void clone_update_extent_map(struct inode *inode, &BTRFS_I(inode)->runtime_flags); } +/* + * Make sure we do not end up inserting an inline extent into a file that has + * already other (non-inline) extents. If a file has an inline extent it can + * not have any other extents and the (single) inline extent must start at the + * file offset 0. Failing to respect these rules will lead to file corruption, + * resulting in EIO errors on read/write operations, hitting BUG_ON's in mm, etc + * + * We can have extents that have been already written to disk or we can have + * dirty ranges still in delalloc, in which case the extent maps and items are + * created only when we run delalloc, and the delalloc ranges might fall outside + * the range we are currently locking in the inode's io tree. So we check the + * inode's i_size because of that (i_size updates are done while holding the + * i_mutex, which we are holding here). + * We also check to see if the inode has a size not greater than "datal" but has + * extents beyond it, due to an fallocate with FALLOC_FL_KEEP_SIZE (and we are + * protected against such concurrent fallocate calls by the i_mutex). + * + * If the file has no extents but a size greater than datal, do not allow the + * copy because we would need turn the inline extent into a non-inline one (even + * with NO_HOLES enabled). If we find our destination inode only has one inline + * extent, just overwrite it with the source inline extent if its size is less + * than the source extent's size, or we could copy the source inline extent's + * data into the destination inode's inline extent if the later is greater then + * the former. + */ +static int clone_copy_inline_extent(struct inode *src, + struct inode *dst, + struct btrfs_trans_handle *trans, + struct btrfs_path *path, + struct btrfs_key *new_key, + const u64 drop_start, + const u64 datal, + const u64 skip, + const u64 size, + char *inline_data) +{ + struct btrfs_root *root = BTRFS_I(dst)->root; + const u64 aligned_end = ALIGN(new_key->offset + datal, + root->sectorsize); + int ret; + struct btrfs_key key; + + if (new_key->offset > 0) + return -EOPNOTSUPP; + + key.objectid = btrfs_ino(dst); + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + return ret; + } else if (ret > 0) { + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + return ret; + else if (ret > 0) + goto copy_inline_extent; + } + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + if (key.objectid == btrfs_ino(dst) && + key.type == BTRFS_EXTENT_DATA_KEY) { + ASSERT(key.offset > 0); + return -EOPNOTSUPP; + } + } else if (i_size_read(dst) <= datal) { + struct btrfs_file_extent_item *ei; + u64 ext_len; + + /* + * If the file size is <= datal, make sure there are no other + * extents following (can happen do to an fallocate call with + * the flag FALLOC_FL_KEEP_SIZE). + */ + ei = btrfs_item_ptr(path->nodes[0], path->slots[0], + struct btrfs_file_extent_item); + /* + * If it's an inline extent, it can not have other extents + * following it. + */ + if (btrfs_file_extent_type(path->nodes[0], ei) == + BTRFS_FILE_EXTENT_INLINE) + goto copy_inline_extent; + + ext_len = btrfs_file_extent_num_bytes(path->nodes[0], ei); + if (ext_len > aligned_end) + return -EOPNOTSUPP; + + ret = btrfs_next_item(root, path); + if (ret < 0) { + return ret; + } else if (ret == 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0]); + if (key.objectid == btrfs_ino(dst) && + key.type == BTRFS_EXTENT_DATA_KEY) + return -EOPNOTSUPP; + } + } + +copy_inline_extent: + /* + * We have no extent items, or we have an extent at offset 0 which may + * or may not be inlined. All these cases are dealt the same way. + */ + if (i_size_read(dst) > datal) { + /* + * If the destination inode has an inline extent... + * This would require copying the data from the source inline + * extent into the beginning of the destination's inline extent. + * But this is really complex, both extents can be compressed + * or just one of them, which would require decompressing and + * re-compressing data (which could increase the new compressed + * size, not allowing the compressed data to fit anymore in an + * inline extent). + * So just don't support this case for now (it should be rare, + * we are not really saving space when cloning inline extents). + */ + return -EOPNOTSUPP; + } + + btrfs_release_path(path); + ret = btrfs_drop_extents(trans, root, dst, drop_start, aligned_end, 1); + if (ret) + return ret; + ret = btrfs_insert_empty_item(trans, root, path, new_key, size); + if (ret) + return ret; + + if (skip) { + const u32 start = btrfs_file_extent_calc_inline_size(0); + + memmove(inline_data + start, inline_data + start + skip, datal); + } + + write_extent_buffer(path->nodes[0], inline_data, + btrfs_item_ptr_offset(path->nodes[0], + path->slots[0]), + size); + inode_add_bytes(dst, datal); + + return 0; +} + /** * btrfs_clone() - clone a range from inode file to another * @@ -3432,21 +3576,6 @@ process_slot: } else if (type == BTRFS_FILE_EXTENT_INLINE) { u64 skip = 0; u64 trim = 0; - u64 aligned_end = 0; - - /* - * Don't copy an inline extent into an offset - * greater than zero. Having an inline extent - * at such an offset results in chaos as btrfs - * isn't prepared for such cases. Just skip - * this case for the same reasons as commented - * at btrfs_ioctl_clone(). - */ - if (last_dest_end > 0) { - ret = -EOPNOTSUPP; - btrfs_end_transaction(trans, root); - goto out; - } if (off > key.offset) { skip = off - key.offset; @@ -3464,42 +3593,22 @@ process_slot: size -= skip + trim; datal -= skip + trim; - aligned_end = ALIGN(new_key.offset + datal, - root->sectorsize); - ret = btrfs_drop_extents(trans, root, inode, - drop_start, - aligned_end, - 1); + ret = clone_copy_inline_extent(src, inode, + trans, path, + &new_key, + drop_start, + datal, + skip, size, buf); if (ret) { if (ret != -EOPNOTSUPP) btrfs_abort_transaction(trans, - root, ret); - btrfs_end_transaction(trans, root); - goto out; - } - - ret = btrfs_insert_empty_item(trans, root, path, - &new_key, size); - if (ret) { - btrfs_abort_transaction(trans, root, - ret); + root, + ret); btrfs_end_transaction(trans, root); goto out; } - - if (skip) { - u32 start = - btrfs_file_extent_calc_inline_size(0); - memmove(buf+start, buf+start+skip, - datal); - } - leaf = path->nodes[0]; slot = path->slots[0]; - write_extent_buffer(leaf, buf, - btrfs_item_ptr_offset(leaf, slot), - size); - inode_add_bytes(inode, datal); } /* If we have an implicit hole (NO_HOLES feature). */ |