diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index e60b13b27a6d..6e99e5f8d32c 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -56,6 +56,7 @@ #include "uuid-tree.h" #include "ioctl.h" #include "file.h" +#include "file-item.h" #include "scrub.h" #include "super.h" @@ -5060,6 +5061,342 @@ static int btrfs_ioctl_shutdown(struct btrfs_fs_info *fs_info, unsigned long arg return ret; } +#define GET_CSUMS_BUF_MAX SZ_16M + +static int copy_csums_to_user(struct btrfs_fs_info *fs_info, u64 disk_bytenr, + u64 len, u8 __user *buf) +{ + struct btrfs_root *csum_root; + struct btrfs_ordered_sum *sums; + LIST_HEAD(list); + const u32 csum_size = fs_info->csum_size; + int ret; + + csum_root = btrfs_csum_root(fs_info, disk_bytenr); + if (unlikely(!csum_root)) { + btrfs_err(fs_info, "missing csum root for extent at bytenr %llu", disk_bytenr); + return -EUCLEAN; + } + + ret = btrfs_lookup_csums_list(csum_root, disk_bytenr, + disk_bytenr + len - 1, &list, false); + if (ret < 0) + return ret; + + ret = 0; + while (!list_empty(&list)) { + u64 offset; + size_t copy_size; + + sums = list_first_entry(&list, struct btrfs_ordered_sum, list); + list_del(&sums->list); + + offset = ((sums->logical - disk_bytenr) >> fs_info->sectorsize_bits) * csum_size; + copy_size = (sums->len >> fs_info->sectorsize_bits) * csum_size; + + if (copy_to_user(buf + offset, sums->sums, copy_size)) { + kfree(sums); + ret = -EFAULT; + goto out; + } + + kfree(sums); + } + +out: + while (!list_empty(&list)) { + sums = list_first_entry(&list, struct btrfs_ordered_sum, list); + list_del(&sums->list); + kfree(sums); + } + return ret; +} + +static int btrfs_ioctl_get_csums(struct file *file, void __user *argp) +{ + struct inode *vfs_inode = file_inode(file); + struct btrfs_inode *inode = BTRFS_I(vfs_inode); + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct btrfs_root *root = inode->root; + struct btrfs_ioctl_get_csums_args args; + BTRFS_PATH_AUTO_FREE(path); + const u64 ino = btrfs_ino(inode); + const u32 csum_size = fs_info->csum_size; + u8 __user *ubuf; + u64 buf_limit; + u64 buf_used = 0; + u64 cur_offset; + u64 end_offset; + u64 prev_extent_end; + struct btrfs_key key; + int ret; + + if (!(file->f_mode & FMODE_READ)) + return -EBADF; + + if (!S_ISREG(vfs_inode->i_mode)) + return -EINVAL; + + if (copy_from_user(&args, argp, sizeof(args))) + return -EFAULT; + + if (!IS_ALIGNED(args.offset, fs_info->sectorsize) || + !IS_ALIGNED(args.length, fs_info->sectorsize)) + return -EINVAL; + if (args.length == 0) + return -EINVAL; + if (args.offset + args.length < args.offset) + return -EOVERFLOW; + if (args.flags != 0) + return -EINVAL; + if (args.buf_size < sizeof(struct btrfs_ioctl_get_csums_entry)) + return -EINVAL; + + buf_limit = min_t(u64, args.buf_size, GET_CSUMS_BUF_MAX); + ubuf = (u8 __user *)(argp + offsetof(struct btrfs_ioctl_get_csums_args, buf)); + + if (clear_user(ubuf, buf_limit)) + return -EFAULT; + + cur_offset = args.offset; + end_offset = args.offset + args.length; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + ret = btrfs_wait_ordered_range(inode, cur_offset, args.length); + if (ret) + return ret; + + ret = down_read_interruptible(&vfs_inode->i_rwsem); + if (ret) + return ret; + + ret = btrfs_wait_ordered_range(inode, cur_offset, args.length); + if (ret) + goto out_unlock; + + /* NODATASUM early exit. */ + if (inode->flags & BTRFS_INODE_NODATASUM) { + struct btrfs_ioctl_get_csums_entry entry = { + .offset = cur_offset, + .length = end_offset - cur_offset, + .type = BTRFS_GET_CSUMS_NODATASUM, + }; + + if (copy_to_user(ubuf, &entry, sizeof(entry))) { + ret = -EFAULT; + goto out_unlock; + } + + buf_used = sizeof(entry); + cur_offset = end_offset; + goto done; + } + + prev_extent_end = cur_offset; + + while (cur_offset < end_offset) { + struct btrfs_file_extent_item *ei; + struct extent_buffer *leaf; + struct btrfs_ioctl_get_csums_entry entry = { 0 }; + u64 extent_end; + u64 disk_bytenr = 0; + u64 extent_offset = 0; + u64 range_start, range_len; + u64 entry_csum_size; + u64 key_offset; + int extent_type; + u8 compression; + u8 encryption; + + /* Search for the extent at or before cur_offset. */ + key.objectid = ino; + key.type = BTRFS_EXTENT_DATA_KEY; + key.offset = cur_offset; + + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) + goto out_unlock; + + if (ret > 0 && path->slots[0] > 0) { + btrfs_item_key_to_cpu(path->nodes[0], &key, + path->slots[0] - 1); + if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY) { + path->slots[0]--; + if (btrfs_file_extent_end(path) <= cur_offset) + path->slots[0]++; + } + } + + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + goto out_unlock; + if (ret > 0) { + ret = 0; + btrfs_release_path(path); + break; + } + } + + leaf = path->nodes[0]; + + btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); + if (key.objectid != ino || key.type != BTRFS_EXTENT_DATA_KEY) { + btrfs_release_path(path); + break; + } + + extent_end = btrfs_file_extent_end(path); + key_offset = key.offset; + + /* Read extent fields before releasing the path. */ + ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_file_extent_item); + extent_type = btrfs_file_extent_type(leaf, ei); + compression = btrfs_file_extent_compression(leaf, ei); + encryption = btrfs_file_extent_encryption(leaf, ei); + + if (extent_type != BTRFS_FILE_EXTENT_INLINE) { + disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, ei); + if (disk_bytenr && compression == BTRFS_COMPRESS_NONE) + extent_offset = btrfs_file_extent_offset(leaf, ei); + } + + btrfs_release_path(path); + + /* Implicit hole (NO_HOLES feature). */ + if (prev_extent_end < key_offset) { + u64 hole_end = min(key_offset, end_offset); + u64 hole_len = hole_end - prev_extent_end; + + if (prev_extent_end >= cur_offset) { + entry.offset = prev_extent_end; + entry.length = hole_len; + entry.type = BTRFS_GET_CSUMS_ZEROED; + + if (buf_used + sizeof(entry) > buf_limit) + goto done; + if (copy_to_user(ubuf + buf_used, &entry, sizeof(entry))) { + ret = -EFAULT; + goto out_unlock; + } + buf_used += sizeof(entry); + cur_offset = hole_end; + } + + if (key_offset >= end_offset) { + cur_offset = end_offset; + break; + } + } + + /* Clamp to our query range. */ + range_start = max(cur_offset, key_offset); + range_len = min(extent_end, end_offset) - range_start; + + entry.offset = range_start; + entry.length = range_len; + + if (extent_type == BTRFS_FILE_EXTENT_INLINE) { + entry.type = BTRFS_GET_CSUMS_INLINE; + if (compression != BTRFS_COMPRESS_NONE) + entry.type |= BTRFS_GET_CSUMS_COMPRESSED; + if (encryption != 0) + entry.type |= BTRFS_GET_CSUMS_ENCRYPTED; + entry_csum_size = 0; + } else if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) { + entry.type = BTRFS_GET_CSUMS_ZEROED; + entry_csum_size = 0; + } else { + /* BTRFS_FILE_EXTENT_REG */ + if (disk_bytenr == 0) { + /* Explicit hole. */ + entry.type = BTRFS_GET_CSUMS_ZEROED; + entry_csum_size = 0; + } else if (encryption != 0 || compression != BTRFS_COMPRESS_NONE) { + entry.type = 0; + if (encryption != 0) + entry.type |= BTRFS_GET_CSUMS_ENCRYPTED; + if (compression != BTRFS_COMPRESS_NONE) + entry.type |= BTRFS_GET_CSUMS_COMPRESSED; + entry_csum_size = 0; + } else { + entry.type = BTRFS_GET_CSUMS_HAS_CSUMS; + entry_csum_size = (range_len >> fs_info->sectorsize_bits) * csum_size; + } + } + + /* Check if this entry (+ csum data) fits in the buffer. */ + if (buf_used + sizeof(entry) + entry_csum_size > buf_limit) { + if (buf_used == 0) { + ret = -EOVERFLOW; + goto out_unlock; + } + goto done; + } + + if (copy_to_user(ubuf + buf_used, &entry, sizeof(entry))) { + ret = -EFAULT; + goto out_unlock; + } + buf_used += sizeof(entry); + + if (entry.type == BTRFS_GET_CSUMS_HAS_CSUMS) { + ret = copy_csums_to_user(fs_info, + disk_bytenr + extent_offset + (range_start - key_offset), + range_len, ubuf + buf_used); + if (ret) + goto out_unlock; + buf_used += entry_csum_size; + } + + cur_offset = range_start + range_len; + prev_extent_end = extent_end; + + if (fatal_signal_pending(current)) { + if (buf_used == 0) { + ret = -EINTR; + goto out_unlock; + } + goto done; + } + + cond_resched(); + } + + /* Handle trailing implicit hole. */ + if (cur_offset < end_offset) { + struct btrfs_ioctl_get_csums_entry entry = { + .offset = prev_extent_end, + .length = end_offset - prev_extent_end, + .type = BTRFS_GET_CSUMS_ZEROED, + }; + + if (buf_used + sizeof(entry) <= buf_limit) { + if (copy_to_user(ubuf + buf_used, &entry, sizeof(entry))) { + ret = -EFAULT; + goto out_unlock; + } + buf_used += sizeof(entry); + cur_offset = end_offset; + } + } + +done: + args.offset = cur_offset; + args.length = (cur_offset < end_offset) ? end_offset - cur_offset : 0; + args.buf_size = buf_used; + + if (copy_to_user(argp, &args, sizeof(args))) + ret = -EFAULT; + +out_unlock: + up_read(&vfs_inode->i_rwsem); + return ret; +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -5217,6 +5554,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_subvol_sync(fs_info, argp); case BTRFS_IOC_SHUTDOWN: return btrfs_ioctl_shutdown(fs_info, arg); + case BTRFS_IOC_GET_CSUMS: + return btrfs_ioctl_get_csums(file, argp); } return -ENOTTY; diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index 9165154a274d..9b576603b3f1 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -1100,6 +1100,38 @@ enum btrfs_err_code { BTRFS_ERROR_DEV_RAID1C4_MIN_NOT_MET, }; +/* Flags for struct btrfs_ioctl_get_csums_entry::type. */ +#define BTRFS_GET_CSUMS_HAS_CSUMS (1U << 0) +#define BTRFS_GET_CSUMS_ZEROED (1U << 1) +#define BTRFS_GET_CSUMS_NODATASUM (1U << 2) +#define BTRFS_GET_CSUMS_COMPRESSED (1U << 3) +#define BTRFS_GET_CSUMS_ENCRYPTED (1U << 4) +#define BTRFS_GET_CSUMS_INLINE (1U << 5) + +struct btrfs_ioctl_get_csums_entry { + /* File offset of this range. */ + __u64 offset; + /* Length in bytes. */ + __u64 length; + /* One of BTRFS_GET_CSUMS_* types. */ + __u32 type; + /* Padding, must be 0. */ + __u32 reserved; +}; + +struct btrfs_ioctl_get_csums_args { + /* In/out: file offset in bytes. */ + __u64 offset; + /* In/out: range length in bytes. */ + __u64 length; + /* In/out: buffer capacity / bytes written. */ + __u64 buf_size; + /* In: flags, must be 0 for now. */ + __u64 flags; + /* Out: entries of type btrfs_ioctl_get_csums_entry + csum data */ + __u8 buf[]; +}; + /* Flags for IOC_SHUTDOWN, must match XFS_FSOP_GOING_FLAGS_* flags. */ #define BTRFS_SHUTDOWN_FLAGS_DEFAULT 0x0 #define BTRFS_SHUTDOWN_FLAGS_LOGFLUSH 0x1 @@ -1226,6 +1258,8 @@ enum btrfs_err_code { struct btrfs_ioctl_encoded_io_args) #define BTRFS_IOC_SUBVOL_SYNC_WAIT _IOW(BTRFS_IOCTL_MAGIC, 65, \ struct btrfs_ioctl_subvol_wait) +#define BTRFS_IOC_GET_CSUMS _IOWR(BTRFS_IOCTL_MAGIC, 66, \ + struct btrfs_ioctl_get_csums_args) /* Shutdown ioctl should follow XFS's interfaces, thus not using btrfs magic. */ #define BTRFS_IOC_SHUTDOWN _IOR('X', 125, __u32)