Instead of sending a write command with a data buffer filled with 0 value bytes,
use the fallocate command, introduced in the send stream version 2, to tell the
receiver to punch a file hole using the fallocate system call.
Signed-off-by: Filipe David Borba Manana <fdman...@gmail.com>
---
V2: A v2 stream is now only produced if the send ioctl caller passes in one of
the new flags (BTRFS_SEND_FLAG_CALCULATE_DATA_SIZE |
BTRFS_SEND_FLAG_SUPPORT_FALLOCATE)
to avoid breaking old clients.
V3: Added missing path allocation, messed up rebase.
fs/btrfs/send.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++---
fs/btrfs/send.h | 4 ++++
2 files changed, 56 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index f5db492..bb9afea 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -564,6 +564,7 @@ static int tlv_put(struct send_ctx *sctx, u16 attr, const
void *data, int len)
return tlv_put(sctx, attr, &__tmp, sizeof(__tmp)); \
}
+TLV_PUT_DEFINE_INT(32)
TLV_PUT_DEFINE_INT(64)
static int tlv_put_string(struct send_ctx *sctx, u16 attr,
@@ -4483,18 +4484,59 @@ out:
return ret;
}
+static int send_fallocate(struct send_ctx *sctx, u32 flags,
+ u64 offset, u64 len)
+{
+ struct fs_path *p = NULL;
+ int ret = 0;
+
+ ASSERT(sctx->flags & BTRFS_SEND_FLAG_SUPPORT_FALLOCATE);
+
+ if (sctx->phase == SEND_PHASE_COMPUTE_DATA_SIZE) {
+ sctx->total_data_size += len;
+ return 0;
+ }
+
+ p = fs_path_alloc();
+ if (!p)
+ return -ENOMEM;
+ ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, p);
+ if (ret < 0)
+ goto out;
+
+ ret = begin_cmd(sctx, BTRFS_SEND_C_FALLOCATE);
+ if (ret < 0)
+ goto out;
+ TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);
+ TLV_PUT_U32(sctx, BTRFS_SEND_A_FALLOCATE_FLAGS, flags);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);
+ TLV_PUT_U64(sctx, BTRFS_SEND_A_SIZE, len);
+ ret = send_cmd(sctx);
+
+tlv_put_failure:
+out:
+ fs_path_free(p);
+ return ret;
+}
+
static int send_hole(struct send_ctx *sctx, u64 end)
{
struct fs_path *p = NULL;
u64 offset = sctx->cur_inode_last_extent;
- u64 len;
+ u64 len = end - offset;
int ret = 0;
if (sctx->phase == SEND_PHASE_COMPUTE_DATA_SIZE) {
- sctx->total_data_size += end - offset;
+ sctx->total_data_size += len;
return 0;
}
+ if (sctx->flags & BTRFS_SEND_FLAG_SUPPORT_FALLOCATE)
+ return send_fallocate(sctx,
+ BTRFS_SEND_PUNCH_HOLE_FALLOC_FLAGS,
+ offset,
+ len);
+
p = fs_path_alloc();
if (!p)
return -ENOMEM;
@@ -4551,7 +4593,8 @@ static int send_write_or_clone(struct send_ctx *sctx,
len = btrfs_file_extent_num_bytes(path->nodes[0], ei);
}
- if (offset + len > sctx->cur_inode_size)
+ if (offset < sctx->cur_inode_size &&
+ offset + len > sctx->cur_inode_size)
len = sctx->cur_inode_size - offset;
if (len == 0) {
ret = 0;
@@ -4568,6 +4611,12 @@ static int send_write_or_clone(struct send_ctx *sctx,
ret = send_clone(sctx, offset, len, clone_root);
} else if (sctx->flags & BTRFS_SEND_FLAG_NO_FILE_DATA) {
ret = send_update_extent(sctx, offset, len);
+ } else if (btrfs_file_extent_disk_bytenr(path->nodes[0], ei) == 0 &&
+ type != BTRFS_FILE_EXTENT_INLINE &&
+ (sctx->flags & BTRFS_SEND_FLAG_SUPPORT_FALLOCATE) &&
+ offset < sctx->cur_inode_size) {
+ ret = send_fallocate(sctx, BTRFS_SEND_PUNCH_HOLE_FALLOC_FLAGS,
+ offset, len);
} else {
while (pos < len) {
l = len - pos;
diff --git a/fs/btrfs/send.h b/fs/btrfs/send.h
index 367030d..a632c0d 100644
--- a/fs/btrfs/send.h
+++ b/fs/btrfs/send.h
@@ -141,6 +141,10 @@ enum {
#define BTRFS_SEND_A_FALLOCATE_FLAG_KEEP_SIZE (1 << 0)
#define BTRFS_SEND_A_FALLOCATE_FLAG_PUNCH_HOLE (1 << 1)
+#define BTRFS_SEND_PUNCH_HOLE_FALLOC_FLAGS \
+ (BTRFS_SEND_A_FALLOCATE_FLAG_KEEP_SIZE | \
+ BTRFS_SEND_A_FALLOCATE_FLAG_PUNCH_HOLE)
+
#ifdef __KERNEL__
long btrfs_ioctl_send(struct file *mnt_file, void __user *arg);
#endif
--
1.9.1
--
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