From: Omar Sandoval <osandov@xxxxxx>
send_write() currently copies from the page cache to sctx->read_buf, and
then from sctx->read_buf to sctx->send_buf. Similarly, send_hole()
zeroes sctx->read_buf and then copies from sctx->read_buf to
sctx->send_buf. However, if we write the TLV header manually, we can
copy to sctx->send_buf directly and get rid of sctx->read_buf.
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
fs/btrfs/send.c | 65 +++++++++++++++++++++++++++++--------------------
fs/btrfs/send.h | 1 -
2 files changed, 39 insertions(+), 27 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 8af5e867e4ca..e70f5ceb3261 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -122,8 +122,6 @@ struct send_ctx {
struct file_ra_state ra;
- char *read_buf;
-
/*
* We process inodes by their increasing order, so if before an
* incremental send we reverse the parent/child relationship of
@@ -4794,7 +4792,25 @@ static int process_all_new_xattrs(struct send_ctx *sctx)
return ret;
}
-static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
+static u64 max_send_read_size(struct send_ctx *sctx)
+{
+ return sctx->send_max_size - SZ_16K;
+}
+
+static int put_data_header(struct send_ctx *sctx, u32 len)
+{
+ struct btrfs_tlv_header *hdr;
+
+ if (sctx->send_max_size - sctx->send_size < sizeof(*hdr) + len)
+ return -EOVERFLOW;
+ hdr = (struct btrfs_tlv_header *)(sctx->send_buf + sctx->send_size);
+ hdr->tlv_type = cpu_to_le16(BTRFS_SEND_A_DATA);
+ hdr->tlv_len = cpu_to_le16(len);
+ sctx->send_size += sizeof(*hdr);
+ return 0;
+}
+
+static int put_file_data(struct send_ctx *sctx, u64 offset, u32 len)
{
struct btrfs_root *root = sctx->send_root;
struct btrfs_fs_info *fs_info = root->fs_info;
@@ -4804,8 +4820,11 @@ static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
pgoff_t index = offset >> PAGE_SHIFT;
pgoff_t last_index;
unsigned pg_offset = offset_in_page(offset);
- int ret = 0;
- size_t read = 0;
+ int ret;
+
+ ret = put_data_header(sctx, len);
+ if (ret)
+ return ret;
inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);
if (IS_ERR(inode))
@@ -4851,14 +4870,15 @@ static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)
}
addr = kmap(page);
- memcpy(sctx->read_buf + read, addr + pg_offset, cur_len);
+ memcpy(sctx->send_buf + sctx->send_size, addr + pg_offset,
+ cur_len);
kunmap(page);
unlock_page(page);
put_page(page);
index++;
pg_offset = 0;
len -= cur_len;
- read += cur_len;
+ sctx->send_size += cur_len;
}
iput(inode);
return ret;
@@ -4880,10 +4900,6 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);
- ret = fill_read_buf(sctx, offset, len);
- if (ret < 0)
- goto out;
-
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
goto out;
@@ -4894,7 +4910,9 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len)
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
- TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
+ ret = put_file_data(sctx, offset, len);
+ if (ret < 0)
+ goto out;
ret = send_cmd(sctx);
@@ -5013,8 +5031,8 @@ static int send_update_extent(struct send_ctx *sctx,
static int send_hole(struct send_ctx *sctx, u64 end)
{
struct fs_path *p = NULL;
+ u64 read_size = max_send_read_size(sctx);
u64 offset = sctx->cur_inode_last_extent;
- u64 len;
int ret = 0;
/*
@@ -5041,16 +5059,19 @@ static int send_hole(struct send_ctx *sctx, u64 end)
ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
if (ret < 0)
goto tlv_put_failure;
- memset(sctx->read_buf, 0, BTRFS_SEND_READ_SIZE);
while (offset < end) {
- len = min_t(u64, end - offset, BTRFS_SEND_READ_SIZE);
+ u64 len = min(end - offset, read_size);
ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);
if (ret < 0)
break;
TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
- TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);
+ ret = put_data_header(sctx, len);
+ if (ret < 0)
+ break;
+ memset(sctx->send_buf + sctx->send_size, 0, len);
+ sctx->send_size += len;
ret = send_cmd(sctx);
if (ret < 0)
break;
@@ -5066,17 +5087,16 @@ static int send_extent_data(struct send_ctx *sctx,
const u64 offset,
const u64 len)
{
+ u64 read_size = max_send_read_size(sctx);
u64 sent = 0;
if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA)
return send_update_extent(sctx, offset, len);
while (sent < len) {
- u64 size = len - sent;
+ u64 size = min(len - sent, read_size);
int ret;
- if (size > BTRFS_SEND_READ_SIZE)
- size = BTRFS_SEND_READ_SIZE;
ret = send_write(sctx, offset + sent, size);
if (ret < 0)
return ret;
@@ -7145,12 +7165,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
goto out;
}
- sctx->read_buf = kvmalloc(BTRFS_SEND_READ_SIZE, GFP_KERNEL);
- if (!sctx->read_buf) {
- ret = -ENOMEM;
- goto out;
- }
-
sctx->pending_dir_moves = RB_ROOT;
sctx->waiting_dir_moves = RB_ROOT;
sctx->orphan_dirs = RB_ROOT;
@@ -7354,7 +7368,6 @@ long btrfs_ioctl_send(struct file *mnt_file, struct btrfs_ioctl_send_args *arg)
kvfree(sctx->clone_roots);
kvfree(sctx->send_buf);
- kvfree(sctx->read_buf);
name_cache_free(sctx);
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index ead397f7034f..de91488b7cd0 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -13,7 +13,6 @@
#define BTRFS_SEND_STREAM_VERSION 1
#define BTRFS_SEND_BUF_SIZE SZ_64K
-#define BTRFS_SEND_READ_SIZE (48 * SZ_1K)
enum btrfs_tlv_type {
BTRFS_TLV_U8,
--
2.28.0
