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. fs/btrfs/send.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++----- fs/btrfs/send.h | 4 ++++ 2 files changed, 55 insertions(+), 5 deletions(-) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index f5db492..2c6d58c 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, @@ -4483,15 +4484,16 @@ out: return ret; } -static int send_hole(struct send_ctx *sctx, u64 end) +static int send_fallocate(struct send_ctx *sctx, u32 flags, + u64 offset, u64 len) { struct fs_path *p = NULL; - u64 offset = sctx->cur_inode_last_extent; - u64 len; int ret = 0; + ASSERT(sctx->flags & BTRFS_SEND_FLAG_SUPPORT_FALLOCATE); + if (sctx->phase == SEND_PHASE_COMPUTE_DATA_SIZE) { - sctx->total_data_size += end - offset; + sctx->total_data_size += len; return 0; } @@ -4500,6 +4502,43 @@ static int send_hole(struct send_ctx *sctx, u64 end) 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 = end - offset; + int ret = 0; + + if (sctx->phase == SEND_PHASE_COMPUTE_DATA_SIZE) { + 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); + + 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) { @@ -4551,7 +4590,8 @@ 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 +4608,12 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html