From: Omar Sandoval <osandov@xxxxxx>
The implementation resembles direct I/O: we have to flush any ordered
extents, invalidate the page cache, and do the io tree/delalloc/extent
map/ordered extent dance. From there, we can reuse the compression code
with a minor modification to distinguish the write from writeback.
Now that read and write are implemented, this also sets the
FMODE_ENCODED_IO flag in btrfs_file_open().
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
fs/btrfs/compression.c | 6 +-
fs/btrfs/compression.h | 5 +-
fs/btrfs/ctree.h | 2 +
fs/btrfs/file.c | 40 +++++++--
fs/btrfs/inode.c | 197 ++++++++++++++++++++++++++++++++++++++++-
5 files changed, 237 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index b05b361e2062..6632dd8d2e4d 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -276,7 +276,8 @@ static void end_compressed_bio_write(struct bio *bio)
bio->bi_status == BLK_STS_OK);
cb->compressed_pages[0]->mapping = NULL;
- end_compressed_writeback(inode, cb);
+ if (cb->writeback)
+ end_compressed_writeback(inode, cb);
/* note, our inode could be gone now */
/*
@@ -311,7 +312,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
unsigned long compressed_len,
struct page **compressed_pages,
unsigned long nr_pages,
- unsigned int write_flags)
+ unsigned int write_flags, bool writeback)
{
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct bio *bio = NULL;
@@ -336,6 +337,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
cb->mirror_num = 0;
cb->compressed_pages = compressed_pages;
cb->compressed_len = compressed_len;
+ cb->writeback = writeback;
cb->orig_bio = NULL;
cb->nr_pages = nr_pages;
diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h
index 4cb8be9ff88b..d4176384ec15 100644
--- a/fs/btrfs/compression.h
+++ b/fs/btrfs/compression.h
@@ -47,6 +47,9 @@ struct compressed_bio {
/* the compression algorithm for this bio */
int compress_type;
+ /* Whether this is a write for writeback. */
+ bool writeback;
+
/* number of compressed pages in the array */
unsigned long nr_pages;
@@ -93,7 +96,7 @@ blk_status_t btrfs_submit_compressed_write(struct inode *inode, u64 start,
unsigned long compressed_len,
struct page **compressed_pages,
unsigned long nr_pages,
- unsigned int write_flags);
+ unsigned int write_flags, bool writeback);
blk_status_t btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
int mirror_num, unsigned long bio_flags);
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 3b2aa1c7218c..9e1719e82cc8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2907,6 +2907,8 @@ int btrfs_writepage_cow_fixup(struct page *page, u64 start, u64 end);
void btrfs_writepage_endio_finish_ordered(struct page *page, u64 start,
u64 end, int uptodate);
ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter);
+ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
+ struct encoded_iov *encoded);
extern const struct dentry_operations btrfs_dentry_operations;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 51740cee39fc..8de6ac9b4b9c 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1893,8 +1893,7 @@ static void update_time_for_write(struct inode *inode)
inode_inc_iversion(inode);
}
-static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
- struct iov_iter *from)
+static ssize_t btrfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
@@ -1904,14 +1903,22 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
u64 end_pos;
ssize_t num_written = 0;
const bool sync = iocb->ki_flags & IOCB_DSYNC;
+ struct encoded_iov encoded;
ssize_t err;
loff_t pos;
size_t count;
loff_t oldsize;
int clean_page = 0;
- if (!(iocb->ki_flags & IOCB_DIRECT) &&
- (iocb->ki_flags & IOCB_NOWAIT))
+ if (iocb->ki_flags & IOCB_ENCODED) {
+ err = import_encoded_write(iocb, &encoded, from);
+ if (err)
+ return err;
+ }
+
+ if ((iocb->ki_flags & IOCB_NOWAIT) &&
+ (!(iocb->ki_flags & IOCB_DIRECT) ||
+ (iocb->ki_flags & IOCB_ENCODED)))
return -EOPNOTSUPP;
if (!inode_trylock(inode)) {
@@ -1920,14 +1927,27 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
inode_lock(inode);
}
- err = generic_write_checks(iocb, from);
- if (err <= 0) {
+ if (iocb->ki_flags & IOCB_ENCODED) {
+ err = generic_encoded_write_checks(iocb, &encoded);
+ if (err) {
+ inode_unlock(inode);
+ return err;
+ }
+ count = encoded.len;
+ } else {
+ err = generic_write_checks(iocb, from);
+ if (err < 0) {
+ inode_unlock(inode);
+ return err;
+ }
+ count = iov_iter_count(from);
+ }
+ if (count == 0) {
inode_unlock(inode);
return err;
}
pos = iocb->ki_pos;
- count = iov_iter_count(from);
if (iocb->ki_flags & IOCB_NOWAIT) {
/*
* We will allocate space in case nodatacow is not set,
@@ -1986,7 +2006,9 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
if (sync)
atomic_inc(&BTRFS_I(inode)->sync_writers);
- if (iocb->ki_flags & IOCB_DIRECT) {
+ if (iocb->ki_flags & IOCB_ENCODED) {
+ num_written = btrfs_encoded_write(iocb, from, &encoded);
+ } else if (iocb->ki_flags & IOCB_DIRECT) {
num_written = __btrfs_direct_write(iocb, from);
} else {
num_written = btrfs_buffered_write(iocb, from);
@@ -3461,7 +3483,7 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence)
static int btrfs_file_open(struct inode *inode, struct file *filp)
{
- filp->f_mode |= FMODE_NOWAIT;
+ filp->f_mode |= FMODE_NOWAIT | FMODE_ENCODED_IO;
return generic_file_open(inode, filp);
}
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 174d0738d2c9..bcc5a2bed22b 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -865,7 +865,7 @@ static noinline void submit_compressed_extents(struct async_chunk *async_chunk)
ins.objectid,
ins.offset, async_extent->pages,
async_extent->nr_pages,
- async_chunk->write_flags)) {
+ async_chunk->write_flags, true)) {
struct page *p = async_extent->pages[0];
const u64 start = async_extent->start;
const u64 end = start + async_extent->ram_size - 1;
@@ -11055,6 +11055,201 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter)
return ret;
}
+ssize_t btrfs_encoded_write(struct kiocb *iocb, struct iov_iter *from,
+ struct encoded_iov *encoded)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+ struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
+ struct extent_changeset *data_reserved = NULL;
+ struct extent_state *cached_state = NULL;
+ int compression;
+ size_t orig_count;
+ u64 disk_num_bytes, num_bytes;
+ u64 start, end;
+ unsigned long nr_pages, i;
+ struct page **pages;
+ struct btrfs_key ins;
+ struct extent_map *em;
+ ssize_t ret;
+
+ switch (encoded->compression) {
+ case ENCODED_IOV_COMPRESSION_ZLIB:
+ compression = BTRFS_COMPRESS_ZLIB;
+ break;
+ case ENCODED_IOV_COMPRESSION_LZO:
+ compression = BTRFS_COMPRESS_LZO;
+ break;
+ case ENCODED_IOV_COMPRESSION_ZSTD:
+ compression = BTRFS_COMPRESS_ZSTD;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ disk_num_bytes = orig_count = iov_iter_count(from);
+
+ /* For now, it's too hard to support bookend extents. */
+ if (encoded->unencoded_len != encoded->len ||
+ encoded->unencoded_offset != 0)
+ return -EINVAL;
+
+ /* The extent size must be sane. */
+ if (encoded->unencoded_len > BTRFS_MAX_UNCOMPRESSED ||
+ disk_num_bytes > BTRFS_MAX_COMPRESSED || disk_num_bytes == 0)
+ return -EINVAL;
+
+ /*
+ * The compressed data on disk must be sector-aligned. For convenience,
+ * we extend it with zeroes if it isn't.
+ */
+ disk_num_bytes = ALIGN(disk_num_bytes, fs_info->sectorsize);
+
+ /*
+ * The extent in the file must also be sector-aligned. However, we allow
+ * a write which ends at or extends i_size to have an unaligned length;
+ * we round up the extent size and set i_size to the given length.
+ */
+ start = iocb->ki_pos;
+ if (!IS_ALIGNED(start, fs_info->sectorsize))
+ return -EINVAL;
+ if (start + encoded->len >= inode->i_size) {
+ num_bytes = ALIGN(encoded->len, fs_info->sectorsize);
+ } else {
+ num_bytes = encoded->len;
+ if (!IS_ALIGNED(num_bytes, fs_info->sectorsize))
+ return -EINVAL;
+ }
+
+ /*
+ * It's valid to have compressed data which is larger than or the same
+ * size as the decompressed data. However, for buffered I/O, we fall
+ * back to writing the decompressed data if compression didn't shrink
+ * it. So, for now, let's not allow creating such extents.
+ *
+ * Note that for now this also implicitly prevents writing data that
+ * would fit in an inline extent.
+ */
+ if (disk_num_bytes >= num_bytes)
+ return -EINVAL;
+
+ end = start + num_bytes - 1;
+
+ nr_pages = (disk_num_bytes + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ pages = kvcalloc(nr_pages, sizeof(struct page *), GFP_USER);
+ if (!pages)
+ return -ENOMEM;
+ for (i = 0; i < nr_pages; i++) {
+ size_t bytes = min_t(size_t, PAGE_SIZE, iov_iter_count(from));
+ char *kaddr;
+
+ pages[i] = alloc_page(GFP_HIGHUSER);
+ if (!pages[i]) {
+ ret = -ENOMEM;
+ goto out_pages;
+ }
+ kaddr = kmap(pages[i]);
+ if (copy_from_iter(kaddr, bytes, from) != bytes) {
+ kunmap(pages[i]);
+ ret = -EFAULT;
+ goto out_pages;
+ }
+ if (bytes < PAGE_SIZE)
+ memset(kaddr + bytes, 0, PAGE_SIZE - bytes);
+ kunmap(pages[i]);
+ }
+
+ for (;;) {
+ struct btrfs_ordered_extent *ordered;
+
+ ret = btrfs_wait_ordered_range(inode, start, end - start + 1);
+ if (ret)
+ goto out_pages;
+ ret = invalidate_inode_pages2_range(inode->i_mapping,
+ start >> PAGE_SHIFT,
+ end >> PAGE_SHIFT);
+ if (ret)
+ goto out_pages;
+ lock_extent_bits(io_tree, start, end, &cached_state);
+ ordered = btrfs_lookup_ordered_range(BTRFS_I(inode), start,
+ end - start + 1);
+ if (!ordered &&
+ !filemap_range_has_page(inode->i_mapping, start, end))
+ break;
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
+ unlock_extent_cached(io_tree, start, end, &cached_state);
+ cond_resched();
+ }
+
+ ret = btrfs_delalloc_reserve_space(inode, &data_reserved, start,
+ num_bytes);
+ if (ret)
+ goto out_unlock;
+
+ ret = btrfs_reserve_extent(root, num_bytes, disk_num_bytes,
+ disk_num_bytes, 0, 0, &ins, 1, 1);
+ if (ret)
+ goto out_delalloc_release;
+
+ em = create_io_em(inode, start, num_bytes, start, ins.objectid,
+ ins.offset, ins.offset, num_bytes, compression,
+ BTRFS_ORDERED_COMPRESSED);
+ if (IS_ERR(em)) {
+ ret = PTR_ERR(em);
+ goto out_free_reserve;
+ }
+ free_extent_map(em);
+
+ ret = btrfs_add_ordered_extent_compress(inode, start, ins.objectid,
+ num_bytes, ins.offset,
+ BTRFS_ORDERED_COMPRESSED,
+ compression);
+ if (ret) {
+ btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
+ goto out_free_reserve;
+ }
+ btrfs_dec_block_group_reservations(fs_info, ins.objectid);
+
+ if (start + encoded->len > inode->i_size)
+ i_size_write(inode, start + encoded->len);
+
+ unlock_extent_cached(io_tree, start, end, &cached_state);
+
+ btrfs_delalloc_release_extents(BTRFS_I(inode), num_bytes, false);
+
+ if (btrfs_submit_compressed_write(inode, start, num_bytes, ins.objectid,
+ ins.offset, pages, nr_pages, 0,
+ false)) {
+ struct page *page = pages[0];
+
+ page->mapping = inode->i_mapping;
+ btrfs_writepage_endio_finish_ordered(page, start, end, 0);
+ page->mapping = NULL;
+ ret = -EIO;
+ goto out_pages;
+ }
+ iocb->ki_pos += encoded->len;
+ return orig_count;
+
+out_free_reserve:
+ btrfs_dec_block_group_reservations(fs_info, ins.objectid);
+ btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 1);
+out_delalloc_release:
+ btrfs_delalloc_release_space(inode, data_reserved, start, num_bytes,
+ true);
+out_unlock:
+ unlock_extent_cached(io_tree, start, end, &cached_state);
+out_pages:
+ for (i = 0; i < nr_pages; i++) {
+ if (pages[i])
+ put_page(pages[i]);
+ }
+ kvfree(pages);
+ return ret;
+}
+
#ifdef CONFIG_SWAP
/*
* Add an entry indicating a block group or device which is pinned by a
--
2.23.0
