[PATCH v10 07/10] btrfs-progs: receive: process fallocate commands

Omar Sandoval
2021-08-17T21:07:58Z

From: Boris Burkov <boris@bur.io>

Send stream v2 can emit fallocate commands, so receive must support them
as well. The implementation simply passes along the arguments to the
syscall. Note that mode is encoded as a u32 in send stream but fallocate
takes an int, so there is a unsigned->signed conversion there.

Signed-off-by: Boris Burkov <boris@bur.io>
---
cmds/receive-dump.c | 9 +++++++++
cmds/receive.c | 25 +++++++++++++++++++++++++
common/send-stream.c | 9 +++++++++
common/send-stream.h | 2 ++
4 files changed, 45 insertions(+)

diff --git a/cmds/receive-dump.c b/cmds/receive-dump.c
index 20ec2b70..acc0ba32 100644
--- a/cmds/receive-dump.c
+++ b/cmds/receive-dump.c
@@ -329,6 +329,14 @@ static int print_encoded_write(const char *path, const void *data, u64 offset,
unencoded_offset, compression, encryption);
}

+static int print_fallocate(const char *path, int mode, u64 offset, u64 len,
+ void *user)
+{
+ return PRINT_DUMP(user, path, "fallocate",
+ "mode=%d offset=%llu len=%llu",
+ mode, offset, len);
+}
+
struct btrfs_send_ops btrfs_print_send_ops = {
.subvol = print_subvol,
.snapshot = print_snapshot,
@@ -352,4 +360,5 @@ struct btrfs_send_ops btrfs_print_send_ops = {
.utimes = print_utimes,
.update_extent = print_update_extent,
.encoded_write = print_encoded_write,
+ .fallocate = print_fallocate,
};
diff --git a/cmds/receive.c b/cmds/receive.c
index 7506f992..dd27af95 100644
--- a/cmds/receive.c
+++ b/cmds/receive.c
@@ -1264,6 +1264,30 @@ static int process_encoded_write(const char *path, const void *data, u64 offset,
compression);
}

+static int process_fallocate(const char *path, int mode, u64 offset, u64 len,
+ void *user)
+{
+ int ret;
+ struct btrfs_receive *rctx = user;
+ char full_path[PATH_MAX];
+
+ ret = path_cat_out(full_path, rctx->full_subvol_path, path);
+ if (ret < 0) {
+ error("fallocate: path invalid: %s", path);
+ return ret;
+ }
+ ret = open_inode_for_write(rctx, full_path);
+ if (ret < 0)
+ return ret;
+ ret = fallocate(rctx->write_fd, mode, offset, len);
+ if (ret < 0) {
+ ret = -errno;
+ error("fallocate: fallocate on %s failed: %m", path);
+ return ret;
+ }
+ return 0;
+}
+
static struct btrfs_send_ops send_ops = {
.subvol = process_subvol,
.snapshot = process_snapshot,
@@ -1287,6 +1311,7 @@ static struct btrfs_send_ops send_ops = {
.utimes = process_utimes,
.update_extent = process_update_extent,
.encoded_write = process_encoded_write,
+ .fallocate = process_fallocate,
};

static int do_receive(struct btrfs_receive *rctx, const char *tomnt,
diff --git a/common/send-stream.c b/common/send-stream.c
index 044e101b..bc41396e 100644
--- a/common/send-stream.c
+++ b/common/send-stream.c
@@ -369,6 +369,7 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
u64 unencoded_offset;
int len;
int xattr_len;
+ int fallocate_mode;

ret = read_cmd(sctx);
if (ret)
@@ -514,6 +515,14 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx)
case BTRFS_SEND_C_END:
ret = 1;
break;
+ case BTRFS_SEND_C_FALLOCATE:
+ TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path);
+ TLV_GET_U32(sctx, BTRFS_SEND_A_FALLOCATE_MODE, &fallocate_mode);
+ TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset);
+ TLV_GET_U64(sctx, BTRFS_SEND_A_SIZE, &tmp);
+ ret = sctx->ops->fallocate(path, fallocate_mode, offset, tmp,
+ sctx->user);
+ break;
}

tlv_get_failed:
diff --git a/common/send-stream.h b/common/send-stream.h
index 607bc007..a58739bb 100644
--- a/common/send-stream.h
+++ b/common/send-stream.h
@@ -70,6 +70,8 @@ struct btrfs_send_ops {
u64 len, u64 unencoded_file_len, u64 unencoded_len,
u64 unencoded_offset, u32 compression,
u32 encryption, void *user);
+ int (*fallocate)(const char *path, int mode, u64 offset, u64 len,
+ void *user);
};

int btrfs_read_and_process_send_stream(int fd,
--
2.32.0