| Message ID | 6716dfd581687f8662d3c828ca2f9911ba58c721.1629234193.git.osandov@fb.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: add ioctls and send/receive support for reading/writing compressed data | expand |
On 18.08.21 г. 0:06, Omar Sandoval wrote: > From: Omar Sandoval <osandov@fb.com> > > There are 4 main cases: > > 1. Inline extents: we copy the data straight out of the extent buffer. > 2. Hole/preallocated extents: we fill in zeroes. > 3. Regular, uncompressed extents: we read the sectors we need directly > from disk. > 4. Regular, compressed extents: we read the entire compressed extent > from disk and indicate what subset of the decompressed extent is in > the file. > > This initial implementation simplifies a few things that can be improved > in the future: > > - We hold the inode lock during the operation. > - Cases 1, 3, and 4 allocate temporary memory to read into before > copying out to userspace. > - We don't do read repair, because it turns out that read repair is > currently broken for compressed data. > > Signed-off-by: Omar Sandoval <osandov@fb.com> > --- > fs/btrfs/ctree.h | 4 + > fs/btrfs/inode.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++ > fs/btrfs/ioctl.c | 111 +++++++++++ > 3 files changed, 604 insertions(+) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 973616d80080..b68d8ea42f6e 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page); > void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode, > struct page *page, u64 start, > u64 end, bool uptodate); > +struct btrfs_ioctl_encoded_io_args; > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, > + struct btrfs_ioctl_encoded_io_args *encoded); > + > extern const struct dentry_operations btrfs_dentry_operations; > extern const struct iomap_ops btrfs_dio_iomap_ops; > extern const struct iomap_dio_ops btrfs_dio_ops; > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > index 0b5ff14aa7fd..6d7fae859fb5 100644 > --- a/fs/btrfs/inode.c > +++ b/fs/btrfs/inode.c > @@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end) > } > } > > +static int btrfs_encoded_io_compression_from_extent(int compress_type) > +{ > + switch (compress_type) { > + case BTRFS_COMPRESS_NONE: > + return BTRFS_ENCODED_IO_COMPRESSION_NONE; > + case BTRFS_COMPRESS_ZLIB: > + return BTRFS_ENCODED_IO_COMPRESSION_ZLIB; > + case BTRFS_COMPRESS_LZO: > + /* > + * The LZO format depends on the page size. 64k is the maximum > + * sectorsize (and thus page size) that we support. > + */ > + if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K) > + return -EINVAL; > + return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12); > + case BTRFS_COMPRESS_ZSTD: > + return BTRFS_ENCODED_IO_COMPRESSION_ZSTD; > + default: > + return -EUCLEAN; > + } > +} > + > +static ssize_t btrfs_encoded_read_inline( > + struct kiocb *iocb, > + struct iov_iter *iter, u64 start, > + u64 lockend, > + struct extent_state **cached_state, > + u64 extent_start, size_t count, > + struct btrfs_ioctl_encoded_io_args *encoded, > + bool *unlocked) > +{ > + struct inode *inode = file_inode(iocb->ki_filp); > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > + struct btrfs_path *path; > + struct extent_buffer *leaf; > + struct btrfs_file_extent_item *item; > + u64 ram_bytes; > + unsigned long ptr; > + void *tmp; > + ssize_t ret; > + > + path = btrfs_alloc_path(); > + if (!path) { > + ret = -ENOMEM; > + goto out; > + } > + ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path, > + btrfs_ino(BTRFS_I(inode)), extent_start, > + 0); > + if (ret) { > + if (ret > 0) { > + /* The extent item disappeared? */ > + ret = -EIO; > + } > + goto out; > + } > + leaf = path->nodes[0]; > + item = btrfs_item_ptr(leaf, path->slots[0], > + struct btrfs_file_extent_item); > + > + ram_bytes = btrfs_file_extent_ram_bytes(leaf, item); > + ptr = btrfs_file_extent_inline_start(item); > + > + encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) - > + iocb->ki_pos); > + ret = btrfs_encoded_io_compression_from_extent( > + btrfs_file_extent_compression(leaf, item)); > + if (ret < 0) > + goto out; > + encoded->compression = ret; > + if (encoded->compression) { > + size_t inline_size; > + > + inline_size = btrfs_file_extent_inline_item_len(leaf, > + btrfs_item_nr(path->slots[0])); > + if (inline_size > count) { > + ret = -ENOBUFS; > + goto out; > + } > + count = inline_size; > + encoded->unencoded_len = ram_bytes; > + encoded->unencoded_offset = iocb->ki_pos - extent_start; > + } else { > + encoded->len = encoded->unencoded_len = count = > + min_t(u64, count, encoded->len); > + ptr += iocb->ki_pos - extent_start; > + } > + > + tmp = kmalloc(count, GFP_NOFS); > + if (!tmp) { > + ret = -ENOMEM; > + goto out; > + } > + read_extent_buffer(leaf, tmp, ptr, count); > + btrfs_release_path(path); > + unlock_extent_cached(io_tree, start, lockend, cached_state); > + inode_unlock_shared(inode); > + *unlocked = true; > + > + ret = copy_to_iter(tmp, count, iter); > + if (ret != count) > + ret = -EFAULT; > + kfree(tmp); > +out: > + btrfs_free_path(path); > + return ret; > +} > + > +struct btrfs_encoded_read_private { > + struct inode *inode; > + wait_queue_head_t wait; > + atomic_t pending; > + blk_status_t status; > + bool skip_csum; > +}; > + > +static blk_status_t submit_encoded_read_bio(struct inode *inode, > + struct bio *bio, int mirror_num, > + unsigned long bio_flags) > +{ > + struct btrfs_encoded_read_private *priv = bio->bi_private; > + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + blk_status_t ret; > + > + if (!priv->skip_csum) { > + ret = btrfs_lookup_bio_sums(inode, bio, NULL); > + if (ret) > + return ret; > + } > + > + ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); > + if (ret) { > + btrfs_io_bio_free_csum(io_bio); > + return ret; > + } > + > + atomic_inc(&priv->pending); > + ret = btrfs_map_bio(fs_info, bio, mirror_num); > + if (ret) { > + atomic_dec(&priv->pending); > + btrfs_io_bio_free_csum(io_bio); > + } > + return ret; > +} > + > +static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio) > +{ > + const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK; > + struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private; > + struct inode *inode = priv->inode; > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + u32 sectorsize = fs_info->sectorsize; > + struct bio_vec *bvec; > + struct bvec_iter_all iter_all; > + u64 start = io_bio->logical; > + u32 bio_offset = 0; > + > + if (priv->skip_csum || !uptodate) > + return io_bio->bio.bi_status; > + > + bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) { > + unsigned int i, nr_sectors, pgoff; > + > + nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len); > + pgoff = bvec->bv_offset; > + for (i = 0; i < nr_sectors; i++) { > + ASSERT(pgoff < PAGE_SIZE); > + if (check_data_csum(inode, io_bio, bio_offset, > + bvec->bv_page, pgoff, start)) > + return BLK_STS_IOERR; > + start += sectorsize; > + bio_offset += sectorsize; > + pgoff += sectorsize; > + } > + } > + return BLK_STS_OK; > +} > + > +static void btrfs_encoded_read_endio(struct bio *bio) > +{ > + struct btrfs_encoded_read_private *priv = bio->bi_private; > + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); > + blk_status_t status; > + > + status = btrfs_encoded_read_check_bio(io_bio); > + if (status) { > + /* > + * The memory barrier implied by the atomic_dec_return() here > + * pairs with the memory barrier implied by the > + * atomic_dec_return() or io_wait_event() in > + * btrfs_encoded_read_regular_fill_pages() to ensure that this > + * write is observed before the load of status in > + * btrfs_encoded_read_regular_fill_pages(). > + */ > + WRITE_ONCE(priv->status, status); > + } > + if (!atomic_dec_return(&priv->pending)) > + wake_up(&priv->wait); > + btrfs_io_bio_free_csum(io_bio); > + bio_put(bio); > +} > + > +static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset, > + u64 disk_io_size, struct page **pages) > +{ > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + struct btrfs_encoded_read_private priv = { > + .inode = inode, > + .pending = ATOMIC_INIT(1), > + .skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM, > + }; > + unsigned long i = 0; > + u64 cur = 0; > + int ret; > + > + init_waitqueue_head(&priv.wait); > + /* > + * Submit bios for the extent, splitting due to bio or stripe limits as > + * necessary. > + */ > + while (cur < disk_io_size) { > + struct extent_map *em; > + struct btrfs_io_geometry geom; > + struct bio *bio = NULL; > + u64 remaining; > + > + em = btrfs_get_chunk_map(fs_info, offset + cur, > + disk_io_size - cur); > + if (IS_ERR(em)) { > + ret = PTR_ERR(em); > + } else { > + ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ, > + offset + cur, &geom); > + free_extent_map(em); > + } > + if (ret) { > + WRITE_ONCE(priv.status, errno_to_blk_status(ret)); > + break; > + } > + remaining = min(geom.len, disk_io_size - cur); > + while (bio || remaining) { > + size_t bytes = min_t(u64, remaining, PAGE_SIZE); > + > + if (!bio) { > + bio = btrfs_bio_alloc(offset + cur); > + bio->bi_end_io = btrfs_encoded_read_endio; > + bio->bi_private = &priv; > + bio->bi_opf = REQ_OP_READ; > + } > + > + if (!bytes || > + bio_add_page(bio, pages[i], bytes, 0) < bytes) { > + blk_status_t status; > + > + status = submit_encoded_read_bio(inode, bio, 0, > + 0); > + if (status) { > + WRITE_ONCE(priv.status, status); > + bio_put(bio); > + goto out; > + } > + bio = NULL; > + continue; > + } > + > + i++; > + cur += bytes; > + remaining -= bytes; > + } > + } > + > +out: > + if (atomic_dec_return(&priv.pending)) > + io_wait_event(priv.wait, !atomic_read(&priv.pending)); > + /* See btrfs_encoded_read_endio() for ordering. */ > + return blk_status_to_errno(READ_ONCE(priv.status)); > +} > + > +static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, > + struct iov_iter *iter, > + u64 start, u64 lockend, > + struct extent_state **cached_state, > + u64 offset, u64 disk_io_size, > + size_t count, bool compressed, > + bool *unlocked) > +{ > + struct inode *inode = file_inode(iocb->ki_filp); > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > + struct page **pages; > + unsigned long nr_pages, i; > + u64 cur; > + size_t page_offset; > + ssize_t ret; > + > + nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE); > + pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); > + if (!pages) > + return -ENOMEM; > + for (i = 0; i < nr_pages; i++) { > + pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM); > + if (!pages[i]) { > + ret = -ENOMEM; > + goto out; > + } > + } > + > + ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size, > + pages); > + if (ret) > + goto out; > + > + unlock_extent_cached(io_tree, start, lockend, cached_state); > + inode_unlock_shared(inode); > + *unlocked = true; > + > + if (compressed) { > + i = 0; > + page_offset = 0; > + } else { > + i = (iocb->ki_pos - start) >> PAGE_SHIFT; > + page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1); > + } > + cur = 0; > + while (cur < count) { > + size_t bytes = min_t(size_t, count - cur, > + PAGE_SIZE - page_offset); > + > + if (copy_page_to_iter(pages[i], page_offset, bytes, > + iter) != bytes) { > + ret = -EFAULT; > + goto out; > + } > + i++; > + cur += bytes; > + page_offset = 0; > + } > + ret = count; > +out: > + for (i = 0; i < nr_pages; i++) { > + if (pages[i]) > + __free_page(pages[i]); > + } > + kfree(pages); > + return ret; > +} > + > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, > + struct btrfs_ioctl_encoded_io_args *encoded) > +{ > + struct inode *inode = file_inode(iocb->ki_filp); > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > + ssize_t ret; > + size_t count = iov_iter_count(iter); > + u64 start, lockend, offset, disk_io_size; > + struct extent_state *cached_state = NULL; > + struct extent_map *em; > + bool unlocked = false; > + > + file_accessed(iocb->ki_filp); > + > + inode_lock_shared(inode); > + > + if (iocb->ki_pos >= inode->i_size) { > + inode_unlock_shared(inode); > + return 0; Don't we need to signal beyond EOF reads somehow. As it stands returning 0 means returning zeroed portion of btrfs_ioctl_encoded_io_args to user space? > + } > + start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize); > + /* > + * We don't know how long the extent containing iocb->ki_pos is, but if > + * it's compressed we know that it won't be longer than this. > + */ > + lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; > + > + for (;;) { > + struct btrfs_ordered_extent *ordered; > + > + ret = btrfs_wait_ordered_range(inode, start, > + lockend - start + 1); > + if (ret) > + goto out_unlock_inode; > + lock_extent_bits(io_tree, start, lockend, &cached_state); > + ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start, > + lockend - start + 1); > + if (!ordered) > + break; > + btrfs_put_ordered_extent(ordered); > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > + cond_resched(); > + } Can't you simply use btrfs_lock_and_flush_ordered_range, the major difference is btrfs_wait_ordered_range basically instantiates any pending delalloc, whilst btrfs_lock_and_flush_ordered_range returns with any, already-instantiated OE run to completion and the range locked ? > + > + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, > + lockend - start + 1); > + if (IS_ERR(em)) { > + ret = PTR_ERR(em); > + goto out_unlock_extent; > + } > + > + if (em->block_start == EXTENT_MAP_INLINE) { > + u64 extent_start = em->start; > + > + /* > + * For inline extents we get everything we need out of the > + * extent item. > + */ > + free_extent_map(em); > + em = NULL; > + ret = btrfs_encoded_read_inline(iocb, iter, start, lockend, > + &cached_state, extent_start, > + count, encoded, &unlocked); > + goto out; > + } > + > + /* > + * We only want to return up to EOF even if the extent extends beyond > + * that. > + */ > + encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) - > + iocb->ki_pos); > + if (em->block_start == EXTENT_MAP_HOLE || > + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { > + offset = EXTENT_MAP_HOLE; > + encoded->len = encoded->unencoded_len = count = > + min_t(u64, count, encoded->len); > + } else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) { > + offset = em->block_start; > + /* > + * Bail if the buffer isn't large enough to return the whole > + * compressed extent. > + */ > + if (em->block_len > count) { > + ret = -ENOBUFS; > + goto out_em; > + } > + disk_io_size = count = em->block_len; > + encoded->unencoded_len = em->ram_bytes; > + encoded->unencoded_offset = iocb->ki_pos - em->orig_start; > + ret = btrfs_encoded_io_compression_from_extent( > + em->compress_type); > + if (ret < 0) > + goto out_em; > + encoded->compression = ret; > + } else { > + offset = em->block_start + (start - em->start); > + if (encoded->len > count) > + encoded->len = count; > + /* > + * Don't read beyond what we locked. This also limits the page > + * allocations that we'll do. > + */ > + disk_io_size = min(lockend + 1, > + iocb->ki_pos + encoded->len) - start; > + encoded->len = encoded->unencoded_len = count = > + start + disk_io_size - iocb->ki_pos; > + disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize); > + } > + free_extent_map(em); > + em = NULL; > + > + if (offset == EXTENT_MAP_HOLE) { > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > + inode_unlock_shared(inode); > + unlocked = true; > + ret = iov_iter_zero(count, iter); > + if (ret != count) > + ret = -EFAULT; > + } else { > + ret = btrfs_encoded_read_regular(iocb, iter, start, lockend, > + &cached_state, offset, > + disk_io_size, count, > + encoded->compression, > + &unlocked); > + } > + > +out: > + if (ret >= 0) > + iocb->ki_pos += encoded->len; > +out_em: > + free_extent_map(em); > +out_unlock_extent: > + if (!unlocked) > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > +out_unlock_inode: > + if (!unlocked) > + inode_unlock_shared(inode); > + return ret; > +} > + > #ifdef CONFIG_SWAP > /* > * Add an entry indicating a block group or device which is pinned by a <snip> > /* Mask out flags that are inappropriate for the given type of inode. */ > @@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat) > return ret; > } > > +static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp, > + bool compat) > +{ > + struct btrfs_ioctl_encoded_io_args args; nit: If you make this args = {}; you guarantee it's zeroed out then you can get rid of the ugly memset further down. > + size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, > + flags); > + size_t copy_end; > + struct iovec iovstack[UIO_FASTIOV]; > + struct iovec *iov = iovstack; > + struct iov_iter iter; > + loff_t pos; > + struct kiocb kiocb; > + ssize_t ret; > + > + if (!capable(CAP_SYS_ADMIN)) { > + ret = -EPERM; > + goto out_acct; > + } > + > + if (compat) { > +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) > + struct btrfs_ioctl_encoded_io_args_32 args32; > + > + copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32, > + flags); > + if (copy_from_user(&args32, argp, copy_end)) { > + ret = -EFAULT; > + goto out_acct; > + } > + args.iov = compat_ptr(args32.iov); > + args.iovcnt = args32.iovcnt; > + args.offset = args32.offset; > + args.flags = args32.flags; > +#else > + return -ENOTTY; > +#endif > + } else { > + copy_end = copy_end_kernel; > + if (copy_from_user(&args, argp, copy_end)) { > + ret = -EFAULT; > + goto out_acct; > + } > + } > + if (args.flags != 0) { > + ret = -EINVAL; > + goto out_acct; > + } > + memset((char *)&args + copy_end_kernel, 0, > + sizeof(args) - copy_end_kernel); > + > + ret = import_iovec(READ, args.iov, args.iovcnt, ARRAY_SIZE(iovstack), > + &iov, &iter); > + if (ret < 0) > + goto out_acct; > + > + if (iov_iter_count(&iter) == 0) { > + ret = 0; > + goto out_iov; > + } > + pos = args.offset; > + ret = rw_verify_area(READ, file, &pos, args.len); > + if (ret < 0) > + goto out_iov; > + > + init_sync_kiocb(&kiocb, file); > + ret = kiocb_set_rw_flags(&kiocb, 0); > + if (ret) > + goto out_iov; > + kiocb.ki_pos = pos; > + > + ret = btrfs_encoded_read(&kiocb, &iter, &args); > + if (ret >= 0) { > + fsnotify_access(file); > + if (copy_to_user(argp + copy_end, > + (char *)&args + copy_end_kernel, > + sizeof(args) - copy_end_kernel)) > + ret = -EFAULT; > + } > + > +out_iov: > + kfree(iov); > +out_acct: > + if (ret > 0) > + add_rchar(current, ret); > + inc_syscr(current); > + return ret; > +} > + > long btrfs_ioctl(struct file *file, unsigned int > cmd, unsigned long arg) > {
On Fri, Aug 20, 2021 at 03:30:02PM +0300, Nikolay Borisov wrote: > > > On 18.08.21 г. 0:06, Omar Sandoval wrote: > > From: Omar Sandoval <osandov@fb.com> > > > > There are 4 main cases: > > > > 1. Inline extents: we copy the data straight out of the extent buffer. > > 2. Hole/preallocated extents: we fill in zeroes. > > 3. Regular, uncompressed extents: we read the sectors we need directly > > from disk. > > 4. Regular, compressed extents: we read the entire compressed extent > > from disk and indicate what subset of the decompressed extent is in > > the file. > > > > This initial implementation simplifies a few things that can be improved > > in the future: > > > > - We hold the inode lock during the operation. > > - Cases 1, 3, and 4 allocate temporary memory to read into before > > copying out to userspace. > > - We don't do read repair, because it turns out that read repair is > > currently broken for compressed data. > > > > Signed-off-by: Omar Sandoval <osandov@fb.com> > > --- > > fs/btrfs/ctree.h | 4 + > > fs/btrfs/inode.c | 489 +++++++++++++++++++++++++++++++++++++++++++++++ > > fs/btrfs/ioctl.c | 111 +++++++++++ > > 3 files changed, 604 insertions(+) > > > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > > index 973616d80080..b68d8ea42f6e 100644 > > --- a/fs/btrfs/ctree.h > > +++ b/fs/btrfs/ctree.h > > @@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page); > > void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode, > > struct page *page, u64 start, > > u64 end, bool uptodate); > > +struct btrfs_ioctl_encoded_io_args; > > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, > > + struct btrfs_ioctl_encoded_io_args *encoded); > > + > > extern const struct dentry_operations btrfs_dentry_operations; > > extern const struct iomap_ops btrfs_dio_iomap_ops; > > extern const struct iomap_dio_ops btrfs_dio_ops; > > diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c > > index 0b5ff14aa7fd..6d7fae859fb5 100644 > > --- a/fs/btrfs/inode.c > > +++ b/fs/btrfs/inode.c > > @@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end) > > } > > } > > > > +static int btrfs_encoded_io_compression_from_extent(int compress_type) > > +{ > > + switch (compress_type) { > > + case BTRFS_COMPRESS_NONE: > > + return BTRFS_ENCODED_IO_COMPRESSION_NONE; > > + case BTRFS_COMPRESS_ZLIB: > > + return BTRFS_ENCODED_IO_COMPRESSION_ZLIB; > > + case BTRFS_COMPRESS_LZO: > > + /* > > + * The LZO format depends on the page size. 64k is the maximum > > + * sectorsize (and thus page size) that we support. > > + */ > > + if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K) > > + return -EINVAL; > > + return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12); > > + case BTRFS_COMPRESS_ZSTD: > > + return BTRFS_ENCODED_IO_COMPRESSION_ZSTD; > > + default: > > + return -EUCLEAN; > > + } > > +} > > + > > +static ssize_t btrfs_encoded_read_inline( > > + struct kiocb *iocb, > > + struct iov_iter *iter, u64 start, > > + u64 lockend, > > + struct extent_state **cached_state, > > + u64 extent_start, size_t count, > > + struct btrfs_ioctl_encoded_io_args *encoded, > > + bool *unlocked) > > +{ > > + struct inode *inode = file_inode(iocb->ki_filp); > > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > > + struct btrfs_path *path; > > + struct extent_buffer *leaf; > > + struct btrfs_file_extent_item *item; > > + u64 ram_bytes; > > + unsigned long ptr; > > + void *tmp; > > + ssize_t ret; > > + > > + path = btrfs_alloc_path(); > > + if (!path) { > > + ret = -ENOMEM; > > + goto out; > > + } > > + ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path, > > + btrfs_ino(BTRFS_I(inode)), extent_start, > > + 0); > > + if (ret) { > > + if (ret > 0) { > > + /* The extent item disappeared? */ > > + ret = -EIO; > > + } > > + goto out; > > + } > > + leaf = path->nodes[0]; > > + item = btrfs_item_ptr(leaf, path->slots[0], > > + struct btrfs_file_extent_item); > > + > > + ram_bytes = btrfs_file_extent_ram_bytes(leaf, item); > > + ptr = btrfs_file_extent_inline_start(item); > > + > > + encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) - > > + iocb->ki_pos); > > + ret = btrfs_encoded_io_compression_from_extent( > > + btrfs_file_extent_compression(leaf, item)); > > + if (ret < 0) > > + goto out; > > + encoded->compression = ret; > > + if (encoded->compression) { > > + size_t inline_size; > > + > > + inline_size = btrfs_file_extent_inline_item_len(leaf, > > + btrfs_item_nr(path->slots[0])); > > + if (inline_size > count) { > > + ret = -ENOBUFS; > > + goto out; > > + } > > + count = inline_size; > > + encoded->unencoded_len = ram_bytes; > > + encoded->unencoded_offset = iocb->ki_pos - extent_start; > > + } else { > > + encoded->len = encoded->unencoded_len = count = > > + min_t(u64, count, encoded->len); > > + ptr += iocb->ki_pos - extent_start; > > + } > > + > > + tmp = kmalloc(count, GFP_NOFS); > > + if (!tmp) { > > + ret = -ENOMEM; > > + goto out; > > + } > > + read_extent_buffer(leaf, tmp, ptr, count); > > + btrfs_release_path(path); > > + unlock_extent_cached(io_tree, start, lockend, cached_state); > > + inode_unlock_shared(inode); > > + *unlocked = true; > > + > > + ret = copy_to_iter(tmp, count, iter); > > + if (ret != count) > > + ret = -EFAULT; > > + kfree(tmp); > > +out: > > + btrfs_free_path(path); > > + return ret; > > +} > > + > > +struct btrfs_encoded_read_private { > > + struct inode *inode; > > + wait_queue_head_t wait; > > + atomic_t pending; > > + blk_status_t status; > > + bool skip_csum; > > +}; > > + > > +static blk_status_t submit_encoded_read_bio(struct inode *inode, > > + struct bio *bio, int mirror_num, > > + unsigned long bio_flags) > > +{ > > + struct btrfs_encoded_read_private *priv = bio->bi_private; > > + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); > > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > > + blk_status_t ret; > > + > > + if (!priv->skip_csum) { > > + ret = btrfs_lookup_bio_sums(inode, bio, NULL); > > + if (ret) > > + return ret; > > + } > > + > > + ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); > > + if (ret) { > > + btrfs_io_bio_free_csum(io_bio); > > + return ret; > > + } > > + > > + atomic_inc(&priv->pending); > > + ret = btrfs_map_bio(fs_info, bio, mirror_num); > > + if (ret) { > > + atomic_dec(&priv->pending); > > + btrfs_io_bio_free_csum(io_bio); > > + } > > + return ret; > > +} > > + > > +static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio) > > +{ > > + const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK; > > + struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private; > > + struct inode *inode = priv->inode; > > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > > + u32 sectorsize = fs_info->sectorsize; > > + struct bio_vec *bvec; > > + struct bvec_iter_all iter_all; > > + u64 start = io_bio->logical; > > + u32 bio_offset = 0; > > + > > + if (priv->skip_csum || !uptodate) > > + return io_bio->bio.bi_status; > > + > > + bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) { > > + unsigned int i, nr_sectors, pgoff; > > + > > + nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len); > > + pgoff = bvec->bv_offset; > > + for (i = 0; i < nr_sectors; i++) { > > + ASSERT(pgoff < PAGE_SIZE); > > + if (check_data_csum(inode, io_bio, bio_offset, > > + bvec->bv_page, pgoff, start)) > > + return BLK_STS_IOERR; > > + start += sectorsize; > > + bio_offset += sectorsize; > > + pgoff += sectorsize; > > + } > > + } > > + return BLK_STS_OK; > > +} > > + > > +static void btrfs_encoded_read_endio(struct bio *bio) > > +{ > > + struct btrfs_encoded_read_private *priv = bio->bi_private; > > + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); > > + blk_status_t status; > > + > > + status = btrfs_encoded_read_check_bio(io_bio); > > + if (status) { > > + /* > > + * The memory barrier implied by the atomic_dec_return() here > > + * pairs with the memory barrier implied by the > > + * atomic_dec_return() or io_wait_event() in > > + * btrfs_encoded_read_regular_fill_pages() to ensure that this > > + * write is observed before the load of status in > > + * btrfs_encoded_read_regular_fill_pages(). > > + */ > > + WRITE_ONCE(priv->status, status); > > + } > > + if (!atomic_dec_return(&priv->pending)) > > + wake_up(&priv->wait); > > + btrfs_io_bio_free_csum(io_bio); > > + bio_put(bio); > > +} > > + > > +static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset, > > + u64 disk_io_size, struct page **pages) > > +{ > > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > > + struct btrfs_encoded_read_private priv = { > > + .inode = inode, > > + .pending = ATOMIC_INIT(1), > > + .skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM, > > + }; > > + unsigned long i = 0; > > + u64 cur = 0; > > + int ret; > > + > > + init_waitqueue_head(&priv.wait); > > + /* > > + * Submit bios for the extent, splitting due to bio or stripe limits as > > + * necessary. > > + */ > > + while (cur < disk_io_size) { > > + struct extent_map *em; > > + struct btrfs_io_geometry geom; > > + struct bio *bio = NULL; > > + u64 remaining; > > + > > + em = btrfs_get_chunk_map(fs_info, offset + cur, > > + disk_io_size - cur); > > + if (IS_ERR(em)) { > > + ret = PTR_ERR(em); > > + } else { > > + ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ, > > + offset + cur, &geom); > > + free_extent_map(em); > > + } > > + if (ret) { > > + WRITE_ONCE(priv.status, errno_to_blk_status(ret)); > > + break; > > + } > > + remaining = min(geom.len, disk_io_size - cur); > > + while (bio || remaining) { > > + size_t bytes = min_t(u64, remaining, PAGE_SIZE); > > + > > + if (!bio) { > > + bio = btrfs_bio_alloc(offset + cur); > > + bio->bi_end_io = btrfs_encoded_read_endio; > > + bio->bi_private = &priv; > > + bio->bi_opf = REQ_OP_READ; > > + } > > + > > + if (!bytes || > > + bio_add_page(bio, pages[i], bytes, 0) < bytes) { > > + blk_status_t status; > > + > > + status = submit_encoded_read_bio(inode, bio, 0, > > + 0); > > + if (status) { > > + WRITE_ONCE(priv.status, status); > > + bio_put(bio); > > + goto out; > > + } > > + bio = NULL; > > + continue; > > + } > > + > > + i++; > > + cur += bytes; > > + remaining -= bytes; > > + } > > + } > > + > > +out: > > + if (atomic_dec_return(&priv.pending)) > > + io_wait_event(priv.wait, !atomic_read(&priv.pending)); > > + /* See btrfs_encoded_read_endio() for ordering. */ > > + return blk_status_to_errno(READ_ONCE(priv.status)); > > +} > > + > > +static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, > > + struct iov_iter *iter, > > + u64 start, u64 lockend, > > + struct extent_state **cached_state, > > + u64 offset, u64 disk_io_size, > > + size_t count, bool compressed, > > + bool *unlocked) > > +{ > > + struct inode *inode = file_inode(iocb->ki_filp); > > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > > + struct page **pages; > > + unsigned long nr_pages, i; > > + u64 cur; > > + size_t page_offset; > > + ssize_t ret; > > + > > + nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE); > > + pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); > > + if (!pages) > > + return -ENOMEM; > > + for (i = 0; i < nr_pages; i++) { > > + pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM); > > + if (!pages[i]) { > > + ret = -ENOMEM; > > + goto out; > > + } > > + } > > + > > + ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size, > > + pages); > > + if (ret) > > + goto out; > > + > > + unlock_extent_cached(io_tree, start, lockend, cached_state); > > + inode_unlock_shared(inode); > > + *unlocked = true; > > + > > + if (compressed) { > > + i = 0; > > + page_offset = 0; > > + } else { > > + i = (iocb->ki_pos - start) >> PAGE_SHIFT; > > + page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1); > > + } > > + cur = 0; > > + while (cur < count) { > > + size_t bytes = min_t(size_t, count - cur, > > + PAGE_SIZE - page_offset); > > + > > + if (copy_page_to_iter(pages[i], page_offset, bytes, > > + iter) != bytes) { > > + ret = -EFAULT; > > + goto out; > > + } > > + i++; > > + cur += bytes; > > + page_offset = 0; > > + } > > + ret = count; > > +out: > > + for (i = 0; i < nr_pages; i++) { > > + if (pages[i]) > > + __free_page(pages[i]); > > + } > > + kfree(pages); > > + return ret; > > +} > > + > > +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, > > + struct btrfs_ioctl_encoded_io_args *encoded) > > +{ > > + struct inode *inode = file_inode(iocb->ki_filp); > > + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > > + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; > > + ssize_t ret; > > + size_t count = iov_iter_count(iter); > > + u64 start, lockend, offset, disk_io_size; > > + struct extent_state *cached_state = NULL; > > + struct extent_map *em; > > + bool unlocked = false; > > + > > + file_accessed(iocb->ki_filp); > > + > > + inode_lock_shared(inode); > > + > > + if (iocb->ki_pos >= inode->i_size) { > > + inode_unlock_shared(inode); > > + return 0; > > Don't we need to signal beyond EOF reads somehow. As it stands returning > 0 means returning zeroed portion of btrfs_ioctl_encoded_io_args to user > space? If you do a normal read/pread beyond EOF, the syscall returns 0, indicating that there are no bytes to read at that offset. We're doing the same thing here: returning 0 means 0 compressed bytes were read, and setting btrfs_ioctl_encoded_io_args::len to 0 means 0 bytes in the file were read. > > + } > > + start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize); > > + /* > > + * We don't know how long the extent containing iocb->ki_pos is, but if > > + * it's compressed we know that it won't be longer than this. > > + */ > > + lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; > > + > > + for (;;) { > > + struct btrfs_ordered_extent *ordered; > > + > > + ret = btrfs_wait_ordered_range(inode, start, > > + lockend - start + 1); > > + if (ret) > > + goto out_unlock_inode; > > + lock_extent_bits(io_tree, start, lockend, &cached_state); > > + ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start, > > + lockend - start + 1); > > + if (!ordered) > > + break; > > + btrfs_put_ordered_extent(ordered); > > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > > + cond_resched(); > > + } > Can't you simply use btrfs_lock_and_flush_ordered_range, the major > difference is btrfs_wait_ordered_range basically instantiates any > pending delalloc, whilst btrfs_lock_and_flush_ordered_range returns with > any, already-instantiated OE run to completion and the range locked ? Josef asked this before here: https://lore.kernel.org/linux-btrfs/1286c8c7-521f-d60c-97d5-c42dc57ce6a9@toxicpanda.com/. It's not sufficient to run instantiated ordered extents. We actually need to flush pending buffered writes. > > + > > + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, > > + lockend - start + 1); > > + if (IS_ERR(em)) { > > + ret = PTR_ERR(em); > > + goto out_unlock_extent; > > + } > > + > > + if (em->block_start == EXTENT_MAP_INLINE) { > > + u64 extent_start = em->start; > > + > > + /* > > + * For inline extents we get everything we need out of the > > + * extent item. > > + */ > > + free_extent_map(em); > > + em = NULL; > > + ret = btrfs_encoded_read_inline(iocb, iter, start, lockend, > > + &cached_state, extent_start, > > + count, encoded, &unlocked); > > + goto out; > > + } > > + > > + /* > > + * We only want to return up to EOF even if the extent extends beyond > > + * that. > > + */ > > + encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) - > > + iocb->ki_pos); > > + if (em->block_start == EXTENT_MAP_HOLE || > > + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { > > + offset = EXTENT_MAP_HOLE; > > + encoded->len = encoded->unencoded_len = count = > > + min_t(u64, count, encoded->len); > > + } else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) { > > + offset = em->block_start; > > + /* > > + * Bail if the buffer isn't large enough to return the whole > > + * compressed extent. > > + */ > > + if (em->block_len > count) { > > + ret = -ENOBUFS; > > + goto out_em; > > + } > > + disk_io_size = count = em->block_len; > > + encoded->unencoded_len = em->ram_bytes; > > + encoded->unencoded_offset = iocb->ki_pos - em->orig_start; > > + ret = btrfs_encoded_io_compression_from_extent( > > + em->compress_type); > > + if (ret < 0) > > + goto out_em; > > + encoded->compression = ret; > > + } else { > > + offset = em->block_start + (start - em->start); > > + if (encoded->len > count) > > + encoded->len = count; > > + /* > > + * Don't read beyond what we locked. This also limits the page > > + * allocations that we'll do. > > + */ > > + disk_io_size = min(lockend + 1, > > + iocb->ki_pos + encoded->len) - start; > > + encoded->len = encoded->unencoded_len = count = > > + start + disk_io_size - iocb->ki_pos; > > + disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize); > > + } > > + free_extent_map(em); > > + em = NULL; > > + > > + if (offset == EXTENT_MAP_HOLE) { > > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > > + inode_unlock_shared(inode); > > + unlocked = true; > > + ret = iov_iter_zero(count, iter); > > + if (ret != count) > > + ret = -EFAULT; > > + } else { > > + ret = btrfs_encoded_read_regular(iocb, iter, start, lockend, > > + &cached_state, offset, > > + disk_io_size, count, > > + encoded->compression, > > + &unlocked); > > + } > > + > > +out: > > + if (ret >= 0) > > + iocb->ki_pos += encoded->len; > > +out_em: > > + free_extent_map(em); > > +out_unlock_extent: > > + if (!unlocked) > > + unlock_extent_cached(io_tree, start, lockend, &cached_state); > > +out_unlock_inode: > > + if (!unlocked) > > + inode_unlock_shared(inode); > > + return ret; > > +} > > + > > #ifdef CONFIG_SWAP > > /* > > * Add an entry indicating a block group or device which is pinned by a > > <snip> > > > /* Mask out flags that are inappropriate for the given type of inode. */ > > @@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat) > > return ret; > > } > > > > +static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp, > > + bool compat) > > +{ > > + struct btrfs_ioctl_encoded_io_args args; > > nit: If you make this args = {}; you guarantee it's zeroed out then you > can get rid of the ugly memset further down. Sure, I'll do that.
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 973616d80080..b68d8ea42f6e 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3219,6 +3219,10 @@ int btrfs_writepage_cow_fixup(struct page *page); void btrfs_writepage_endio_finish_ordered(struct btrfs_inode *inode, struct page *page, u64 start, u64 end, bool uptodate); +struct btrfs_ioctl_encoded_io_args; +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, + struct btrfs_ioctl_encoded_io_args *encoded); + extern const struct dentry_operations btrfs_dentry_operations; extern const struct iomap_ops btrfs_dio_iomap_ops; extern const struct iomap_dio_ops btrfs_dio_ops; diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 0b5ff14aa7fd..6d7fae859fb5 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -10496,6 +10496,495 @@ void btrfs_set_range_writeback(struct btrfs_inode *inode, u64 start, u64 end) } } +static int btrfs_encoded_io_compression_from_extent(int compress_type) +{ + switch (compress_type) { + case BTRFS_COMPRESS_NONE: + return BTRFS_ENCODED_IO_COMPRESSION_NONE; + case BTRFS_COMPRESS_ZLIB: + return BTRFS_ENCODED_IO_COMPRESSION_ZLIB; + case BTRFS_COMPRESS_LZO: + /* + * The LZO format depends on the page size. 64k is the maximum + * sectorsize (and thus page size) that we support. + */ + if (PAGE_SIZE < SZ_4K || PAGE_SIZE > SZ_64K) + return -EINVAL; + return BTRFS_ENCODED_IO_COMPRESSION_LZO_4K + (PAGE_SHIFT - 12); + case BTRFS_COMPRESS_ZSTD: + return BTRFS_ENCODED_IO_COMPRESSION_ZSTD; + default: + return -EUCLEAN; + } +} + +static ssize_t btrfs_encoded_read_inline( + struct kiocb *iocb, + struct iov_iter *iter, u64 start, + u64 lockend, + struct extent_state **cached_state, + u64 extent_start, size_t count, + struct btrfs_ioctl_encoded_io_args *encoded, + bool *unlocked) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + struct btrfs_path *path; + struct extent_buffer *leaf; + struct btrfs_file_extent_item *item; + u64 ram_bytes; + unsigned long ptr; + void *tmp; + ssize_t ret; + + path = btrfs_alloc_path(); + if (!path) { + ret = -ENOMEM; + goto out; + } + ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root, path, + btrfs_ino(BTRFS_I(inode)), extent_start, + 0); + if (ret) { + if (ret > 0) { + /* The extent item disappeared? */ + ret = -EIO; + } + goto out; + } + leaf = path->nodes[0]; + item = btrfs_item_ptr(leaf, path->slots[0], + struct btrfs_file_extent_item); + + ram_bytes = btrfs_file_extent_ram_bytes(leaf, item); + ptr = btrfs_file_extent_inline_start(item); + + encoded->len = (min_t(u64, extent_start + ram_bytes, inode->i_size) - + iocb->ki_pos); + ret = btrfs_encoded_io_compression_from_extent( + btrfs_file_extent_compression(leaf, item)); + if (ret < 0) + goto out; + encoded->compression = ret; + if (encoded->compression) { + size_t inline_size; + + inline_size = btrfs_file_extent_inline_item_len(leaf, + btrfs_item_nr(path->slots[0])); + if (inline_size > count) { + ret = -ENOBUFS; + goto out; + } + count = inline_size; + encoded->unencoded_len = ram_bytes; + encoded->unencoded_offset = iocb->ki_pos - extent_start; + } else { + encoded->len = encoded->unencoded_len = count = + min_t(u64, count, encoded->len); + ptr += iocb->ki_pos - extent_start; + } + + tmp = kmalloc(count, GFP_NOFS); + if (!tmp) { + ret = -ENOMEM; + goto out; + } + read_extent_buffer(leaf, tmp, ptr, count); + btrfs_release_path(path); + unlock_extent_cached(io_tree, start, lockend, cached_state); + inode_unlock_shared(inode); + *unlocked = true; + + ret = copy_to_iter(tmp, count, iter); + if (ret != count) + ret = -EFAULT; + kfree(tmp); +out: + btrfs_free_path(path); + return ret; +} + +struct btrfs_encoded_read_private { + struct inode *inode; + wait_queue_head_t wait; + atomic_t pending; + blk_status_t status; + bool skip_csum; +}; + +static blk_status_t submit_encoded_read_bio(struct inode *inode, + struct bio *bio, int mirror_num, + unsigned long bio_flags) +{ + struct btrfs_encoded_read_private *priv = bio->bi_private; + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + blk_status_t ret; + + if (!priv->skip_csum) { + ret = btrfs_lookup_bio_sums(inode, bio, NULL); + if (ret) + return ret; + } + + ret = btrfs_bio_wq_end_io(fs_info, bio, BTRFS_WQ_ENDIO_DATA); + if (ret) { + btrfs_io_bio_free_csum(io_bio); + return ret; + } + + atomic_inc(&priv->pending); + ret = btrfs_map_bio(fs_info, bio, mirror_num); + if (ret) { + atomic_dec(&priv->pending); + btrfs_io_bio_free_csum(io_bio); + } + return ret; +} + +static blk_status_t btrfs_encoded_read_check_bio(struct btrfs_io_bio *io_bio) +{ + const bool uptodate = io_bio->bio.bi_status == BLK_STS_OK; + struct btrfs_encoded_read_private *priv = io_bio->bio.bi_private; + struct inode *inode = priv->inode; + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + u32 sectorsize = fs_info->sectorsize; + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + u64 start = io_bio->logical; + u32 bio_offset = 0; + + if (priv->skip_csum || !uptodate) + return io_bio->bio.bi_status; + + bio_for_each_segment_all(bvec, &io_bio->bio, iter_all) { + unsigned int i, nr_sectors, pgoff; + + nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, bvec->bv_len); + pgoff = bvec->bv_offset; + for (i = 0; i < nr_sectors; i++) { + ASSERT(pgoff < PAGE_SIZE); + if (check_data_csum(inode, io_bio, bio_offset, + bvec->bv_page, pgoff, start)) + return BLK_STS_IOERR; + start += sectorsize; + bio_offset += sectorsize; + pgoff += sectorsize; + } + } + return BLK_STS_OK; +} + +static void btrfs_encoded_read_endio(struct bio *bio) +{ + struct btrfs_encoded_read_private *priv = bio->bi_private; + struct btrfs_io_bio *io_bio = btrfs_io_bio(bio); + blk_status_t status; + + status = btrfs_encoded_read_check_bio(io_bio); + if (status) { + /* + * The memory barrier implied by the atomic_dec_return() here + * pairs with the memory barrier implied by the + * atomic_dec_return() or io_wait_event() in + * btrfs_encoded_read_regular_fill_pages() to ensure that this + * write is observed before the load of status in + * btrfs_encoded_read_regular_fill_pages(). + */ + WRITE_ONCE(priv->status, status); + } + if (!atomic_dec_return(&priv->pending)) + wake_up(&priv->wait); + btrfs_io_bio_free_csum(io_bio); + bio_put(bio); +} + +static int btrfs_encoded_read_regular_fill_pages(struct inode *inode, u64 offset, + u64 disk_io_size, struct page **pages) +{ + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct btrfs_encoded_read_private priv = { + .inode = inode, + .pending = ATOMIC_INIT(1), + .skip_csum = BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM, + }; + unsigned long i = 0; + u64 cur = 0; + int ret; + + init_waitqueue_head(&priv.wait); + /* + * Submit bios for the extent, splitting due to bio or stripe limits as + * necessary. + */ + while (cur < disk_io_size) { + struct extent_map *em; + struct btrfs_io_geometry geom; + struct bio *bio = NULL; + u64 remaining; + + em = btrfs_get_chunk_map(fs_info, offset + cur, + disk_io_size - cur); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + } else { + ret = btrfs_get_io_geometry(fs_info, em, BTRFS_MAP_READ, + offset + cur, &geom); + free_extent_map(em); + } + if (ret) { + WRITE_ONCE(priv.status, errno_to_blk_status(ret)); + break; + } + remaining = min(geom.len, disk_io_size - cur); + while (bio || remaining) { + size_t bytes = min_t(u64, remaining, PAGE_SIZE); + + if (!bio) { + bio = btrfs_bio_alloc(offset + cur); + bio->bi_end_io = btrfs_encoded_read_endio; + bio->bi_private = &priv; + bio->bi_opf = REQ_OP_READ; + } + + if (!bytes || + bio_add_page(bio, pages[i], bytes, 0) < bytes) { + blk_status_t status; + + status = submit_encoded_read_bio(inode, bio, 0, + 0); + if (status) { + WRITE_ONCE(priv.status, status); + bio_put(bio); + goto out; + } + bio = NULL; + continue; + } + + i++; + cur += bytes; + remaining -= bytes; + } + } + +out: + if (atomic_dec_return(&priv.pending)) + io_wait_event(priv.wait, !atomic_read(&priv.pending)); + /* See btrfs_encoded_read_endio() for ordering. */ + return blk_status_to_errno(READ_ONCE(priv.status)); +} + +static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, + struct iov_iter *iter, + u64 start, u64 lockend, + struct extent_state **cached_state, + u64 offset, u64 disk_io_size, + size_t count, bool compressed, + bool *unlocked) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + struct page **pages; + unsigned long nr_pages, i; + u64 cur; + size_t page_offset; + ssize_t ret; + + nr_pages = DIV_ROUND_UP(disk_io_size, PAGE_SIZE); + pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); + if (!pages) + return -ENOMEM; + for (i = 0; i < nr_pages; i++) { + pages[i] = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (!pages[i]) { + ret = -ENOMEM; + goto out; + } + } + + ret = btrfs_encoded_read_regular_fill_pages(inode, offset, disk_io_size, + pages); + if (ret) + goto out; + + unlock_extent_cached(io_tree, start, lockend, cached_state); + inode_unlock_shared(inode); + *unlocked = true; + + if (compressed) { + i = 0; + page_offset = 0; + } else { + i = (iocb->ki_pos - start) >> PAGE_SHIFT; + page_offset = (iocb->ki_pos - start) & (PAGE_SIZE - 1); + } + cur = 0; + while (cur < count) { + size_t bytes = min_t(size_t, count - cur, + PAGE_SIZE - page_offset); + + if (copy_page_to_iter(pages[i], page_offset, bytes, + iter) != bytes) { + ret = -EFAULT; + goto out; + } + i++; + cur += bytes; + page_offset = 0; + } + ret = count; +out: + for (i = 0; i < nr_pages; i++) { + if (pages[i]) + __free_page(pages[i]); + } + kfree(pages); + return ret; +} + +ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, + struct btrfs_ioctl_encoded_io_args *encoded) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); + struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; + ssize_t ret; + size_t count = iov_iter_count(iter); + u64 start, lockend, offset, disk_io_size; + struct extent_state *cached_state = NULL; + struct extent_map *em; + bool unlocked = false; + + file_accessed(iocb->ki_filp); + + inode_lock_shared(inode); + + if (iocb->ki_pos >= inode->i_size) { + inode_unlock_shared(inode); + return 0; + } + start = ALIGN_DOWN(iocb->ki_pos, fs_info->sectorsize); + /* + * We don't know how long the extent containing iocb->ki_pos is, but if + * it's compressed we know that it won't be longer than this. + */ + lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; + + for (;;) { + struct btrfs_ordered_extent *ordered; + + ret = btrfs_wait_ordered_range(inode, start, + lockend - start + 1); + if (ret) + goto out_unlock_inode; + lock_extent_bits(io_tree, start, lockend, &cached_state); + ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start, + lockend - start + 1); + if (!ordered) + break; + btrfs_put_ordered_extent(ordered); + unlock_extent_cached(io_tree, start, lockend, &cached_state); + cond_resched(); + } + + em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, start, + lockend - start + 1); + if (IS_ERR(em)) { + ret = PTR_ERR(em); + goto out_unlock_extent; + } + + if (em->block_start == EXTENT_MAP_INLINE) { + u64 extent_start = em->start; + + /* + * For inline extents we get everything we need out of the + * extent item. + */ + free_extent_map(em); + em = NULL; + ret = btrfs_encoded_read_inline(iocb, iter, start, lockend, + &cached_state, extent_start, + count, encoded, &unlocked); + goto out; + } + + /* + * We only want to return up to EOF even if the extent extends beyond + * that. + */ + encoded->len = (min_t(u64, extent_map_end(em), inode->i_size) - + iocb->ki_pos); + if (em->block_start == EXTENT_MAP_HOLE || + test_bit(EXTENT_FLAG_PREALLOC, &em->flags)) { + offset = EXTENT_MAP_HOLE; + encoded->len = encoded->unencoded_len = count = + min_t(u64, count, encoded->len); + } else if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) { + offset = em->block_start; + /* + * Bail if the buffer isn't large enough to return the whole + * compressed extent. + */ + if (em->block_len > count) { + ret = -ENOBUFS; + goto out_em; + } + disk_io_size = count = em->block_len; + encoded->unencoded_len = em->ram_bytes; + encoded->unencoded_offset = iocb->ki_pos - em->orig_start; + ret = btrfs_encoded_io_compression_from_extent( + em->compress_type); + if (ret < 0) + goto out_em; + encoded->compression = ret; + } else { + offset = em->block_start + (start - em->start); + if (encoded->len > count) + encoded->len = count; + /* + * Don't read beyond what we locked. This also limits the page + * allocations that we'll do. + */ + disk_io_size = min(lockend + 1, + iocb->ki_pos + encoded->len) - start; + encoded->len = encoded->unencoded_len = count = + start + disk_io_size - iocb->ki_pos; + disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize); + } + free_extent_map(em); + em = NULL; + + if (offset == EXTENT_MAP_HOLE) { + unlock_extent_cached(io_tree, start, lockend, &cached_state); + inode_unlock_shared(inode); + unlocked = true; + ret = iov_iter_zero(count, iter); + if (ret != count) + ret = -EFAULT; + } else { + ret = btrfs_encoded_read_regular(iocb, iter, start, lockend, + &cached_state, offset, + disk_io_size, count, + encoded->compression, + &unlocked); + } + +out: + if (ret >= 0) + iocb->ki_pos += encoded->len; +out_em: + free_extent_map(em); +out_unlock_extent: + if (!unlocked) + unlock_extent_cached(io_tree, start, lockend, &cached_state); +out_unlock_inode: + if (!unlocked) + inode_unlock_shared(inode); + return ret; +} + #ifdef CONFIG_SWAP /* * Add an entry indicating a block group or device which is pinned by a diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 41524f9aeac3..7a0a9c752624 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -28,6 +28,7 @@ #include <linux/iversion.h> #include <linux/fileattr.h> #include <linux/fsverity.h> +#include <linux/sched/xacct.h> #include "ctree.h" #include "disk-io.h" #include "export.h" @@ -86,6 +87,22 @@ struct btrfs_ioctl_send_args_32 { #define BTRFS_IOC_SEND_32 _IOW(BTRFS_IOCTL_MAGIC, 38, \ struct btrfs_ioctl_send_args_32) + +struct btrfs_ioctl_encoded_io_args_32 { + compat_uptr_t iov; + compat_ulong_t iovcnt; + __s64 offset; + __u64 flags; + __u64 len; + __u64 unencoded_len; + __u64 unencoded_offset; + __u32 compression; + __u32 encryption; + __u32 reserved[8]; +}; + +#define BTRFS_IOC_ENCODED_READ_32 _IOR(BTRFS_IOCTL_MAGIC, 64, \ + struct btrfs_ioctl_encoded_io_args_32) #endif /* Mask out flags that are inappropriate for the given type of inode. */ @@ -4887,6 +4904,94 @@ static int _btrfs_ioctl_send(struct file *file, void __user *argp, bool compat) return ret; } +static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp, + bool compat) +{ + struct btrfs_ioctl_encoded_io_args args; + size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, + flags); + size_t copy_end; + struct iovec iovstack[UIO_FASTIOV]; + struct iovec *iov = iovstack; + struct iov_iter iter; + loff_t pos; + struct kiocb kiocb; + ssize_t ret; + + if (!capable(CAP_SYS_ADMIN)) { + ret = -EPERM; + goto out_acct; + } + + if (compat) { +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) + struct btrfs_ioctl_encoded_io_args_32 args32; + + copy_end = offsetofend(struct btrfs_ioctl_encoded_io_args_32, + flags); + if (copy_from_user(&args32, argp, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + args.iov = compat_ptr(args32.iov); + args.iovcnt = args32.iovcnt; + args.offset = args32.offset; + args.flags = args32.flags; +#else + return -ENOTTY; +#endif + } else { + copy_end = copy_end_kernel; + if (copy_from_user(&args, argp, copy_end)) { + ret = -EFAULT; + goto out_acct; + } + } + if (args.flags != 0) { + ret = -EINVAL; + goto out_acct; + } + memset((char *)&args + copy_end_kernel, 0, + sizeof(args) - copy_end_kernel); + + ret = import_iovec(READ, args.iov, args.iovcnt, ARRAY_SIZE(iovstack), + &iov, &iter); + if (ret < 0) + goto out_acct; + + if (iov_iter_count(&iter) == 0) { + ret = 0; + goto out_iov; + } + pos = args.offset; + ret = rw_verify_area(READ, file, &pos, args.len); + if (ret < 0) + goto out_iov; + + init_sync_kiocb(&kiocb, file); + ret = kiocb_set_rw_flags(&kiocb, 0); + if (ret) + goto out_iov; + kiocb.ki_pos = pos; + + ret = btrfs_encoded_read(&kiocb, &iter, &args); + if (ret >= 0) { + fsnotify_access(file); + if (copy_to_user(argp + copy_end, + (char *)&args + copy_end_kernel, + sizeof(args) - copy_end_kernel)) + ret = -EFAULT; + } + +out_iov: + kfree(iov); +out_acct: + if (ret > 0) + add_rchar(current, ret); + inc_syscr(current); + return ret; +} + long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -5031,6 +5136,12 @@ long btrfs_ioctl(struct file *file, unsigned int return fsverity_ioctl_enable(file, (const void __user *)argp); case FS_IOC_MEASURE_VERITY: return fsverity_ioctl_measure(file, argp); + case BTRFS_IOC_ENCODED_READ: + return btrfs_ioctl_encoded_read(file, argp, false); +#if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT) + case BTRFS_IOC_ENCODED_READ_32: + return btrfs_ioctl_encoded_read(file, argp, true); +#endif } return -ENOTTY;