The fallocate send stream command, added in stream version 2, is used to
pre-allocate space for files and punch file holes. This change implements
the callback for that new command, using the fallocate function from the
standard C library to carry out the specified action (allocate file space
or punch a file hole).
Signed-off-by: Filipe David Borba Manana <fdman...@gmail.com>
---
V2: Use the new send ioctl flag BTRFS_SEND_FLAG_SUPPORT_FALLOCATE if the user
asks for it (-a command line option), which will make the kernel generate
a version 2 send stream, so that old clients aren't affected.
Documentation/btrfs-send.txt | 3 +++
cmds-receive.c | 38 ++++++++++++++++++++++++++++++++++++++
cmds-send.c | 12 ++++++++++--
send-stream.c | 13 +++++++++++++
send-stream.h | 2 ++
5 files changed, 66 insertions(+), 2 deletions(-)
diff --git a/Documentation/btrfs-send.txt b/Documentation/btrfs-send.txt
index 38470b0..e96be07 100644
--- a/Documentation/btrfs-send.txt
+++ b/Documentation/btrfs-send.txt
@@ -43,6 +43,9 @@ An alternative would be to use pipes.
-o::
Obtain the total data size for each subvolume or snapshot to send. This
demands additional
processing (mostly IO bound) but is useful for the receive command to report
progress.
+-a::
+Use fallocate to pre-allocate file extents and to punch file holes, instead of
writing zeroes
+to files.
EXIT STATUS
-----------
diff --git a/cmds-receive.c b/cmds-receive.c
index 19300fc..3f30066 100644
--- a/cmds-receive.c
+++ b/cmds-receive.c
@@ -41,6 +41,7 @@
#include <sys/types.h>
#include <sys/xattr.h>
#include <uuid/uuid.h>
+#include <linux/falloc.h>
#include "ctree.h"
#include "ioctl.h"
@@ -887,6 +888,42 @@ out:
return ret;
}
+static int process_fallocate(const char *path, u32 flags, u64 offset,
+ u64 len, void *user)
+{
+ struct btrfs_receive *r = user;
+ char *full_path = path_cat(r->full_subvol_path, path);
+ int mode = 0;
+ int ret;
+
+ if (flags & BTRFS_SEND_A_FALLOCATE_FLAG_KEEP_SIZE)
+ mode |= FALLOC_FL_KEEP_SIZE;
+ if (flags & BTRFS_SEND_A_FALLOCATE_FLAG_PUNCH_HOLE)
+ mode |= FALLOC_FL_PUNCH_HOLE;
+
+ if (g_verbose >= 2)
+ fprintf(stderr,
+ "fallocate %s - flags %u, offset %llu, len %llu\n",
+ path, flags, offset, len);
+
+ ret = open_inode_for_write(r, full_path);
+ if (ret < 0)
+ goto out;
+
+ ret = fallocate(r->write_fd, mode, offset, len);
+ if (ret) {
+ ret = -errno;
+ fprintf(stderr,
+ "ERROR: fallocate against %s failed. %s\n",
+ path, strerror(-ret));
+ goto out;
+ }
+ update_progress(r, len);
+
+out:
+ free(full_path);
+ return ret;
+}
static struct btrfs_send_ops send_ops = {
.subvol = process_subvol,
@@ -910,6 +947,7 @@ static struct btrfs_send_ops send_ops = {
.chown = process_chown,
.utimes = process_utimes,
.total_data_size = process_total_data_size,
+ .fallocate = process_fallocate,
};
static int do_receive(struct btrfs_receive *r, const char *tomnt, int r_fd)
diff --git a/cmds-send.c b/cmds-send.c
index 69f5ba1..2a62e68 100644
--- a/cmds-send.c
+++ b/cmds-send.c
@@ -46,6 +46,7 @@
static int g_verbose = 0;
static int g_total_data_size = 0;
+static int g_fallocate = 0;
struct btrfs_send {
int send_fd;
@@ -284,6 +285,8 @@ static int do_send(struct btrfs_send *send, u64
parent_root_id,
io_send.flags |= BTRFS_SEND_FLAG_OMIT_END_CMD;
if (g_total_data_size)
io_send.flags |= BTRFS_SEND_FLAG_CALCULATE_DATA_SIZE;
+ if (g_fallocate)
+ io_send.flags |= BTRFS_SEND_FLAG_SUPPORT_FALLOCATE;
ret = ioctl(subvol_fd, BTRFS_IOC_SEND, &io_send);
if (ret) {
ret = -errno;
@@ -427,7 +430,7 @@ int cmd_send(int argc, char **argv)
memset(&send, 0, sizeof(send));
send.dump_fd = fileno(stdout);
- while ((c = getopt(argc, argv, "veoc:f:i:p:")) != -1) {
+ while ((c = getopt(argc, argv, "veoac:f:i:p:")) != -1) {
switch (c) {
case 'v':
g_verbose++;
@@ -517,6 +520,9 @@ int cmd_send(int argc, char **argv)
case 'o':
g_total_data_size = 1;
break;
+ case 'a':
+ g_fallocate = 1;
+ break;
case '?':
default:
fprintf(stderr, "ERROR: send args invalid.\n");
@@ -679,7 +685,7 @@ out:
}
const char * const cmd_send_usage[] = {
- "btrfs send [-veo] [-p <parent>] [-c <clone-src>] [-f <outfile>]
<subvol> [<subvol>...]",
+ "btrfs send [-veoa] [-p <parent>] [-c <clone-src>] [-f <outfile>]
<subvol> [<subvol>...]",
"Send the subvolume(s) to stdout.",
"Sends the subvolume(s) specified by <subvol> to stdout.",
"By default, this will send the whole subvolume. To do an incremental",
@@ -707,5 +713,7 @@ const char * const cmd_send_usage[] = {
" snapshot to send. This demands additional processing",
" (mostly IO bound) but is useful for the receive ",
" command to report progress.",
+ "-a Use fallocate to pre-allocate file extents and to",
+ " punch file holes, instead of writing zeroes to
files.",
NULL
};
diff --git a/send-stream.c b/send-stream.c
index 474d012..f117533 100644
--- a/send-stream.c
+++ b/send-stream.c
@@ -425,6 +425,19 @@ static int read_and_process_cmd(struct btrfs_send_stream
*s)
TLV_GET_U64(s, BTRFS_SEND_A_SIZE, &tmp);
ret = s->ops->total_data_size(tmp, s->user);
break;
+ case BTRFS_SEND_C_FALLOCATE:
+ {
+ u32 flags;
+ u64 len;
+
+ TLV_GET_STRING(s, BTRFS_SEND_A_PATH, &path);
+ TLV_GET_U32(s, BTRFS_SEND_A_FALLOCATE_FLAGS, &flags);
+ TLV_GET_U64(s, BTRFS_SEND_A_FILE_OFFSET, &offset);
+ TLV_GET_U64(s, BTRFS_SEND_A_SIZE, &len);
+ ret = s->ops->fallocate(path, flags, offset, len,
+ s->user);
+ }
+ break;
case BTRFS_SEND_C_END:
ret = 1;
break;
diff --git a/send-stream.h b/send-stream.h
index 3a653a9..479e40c 100644
--- a/send-stream.h
+++ b/send-stream.h
@@ -55,6 +55,8 @@ struct btrfs_send_ops {
void *user);
int (*update_extent)(const char *path, u64 offset, u64 len, void *user);
int (*total_data_size)(u64 size, void *user);
+ int (*fallocate)(const char *path, u32 flags, u64 offset,
+ u64 len, void *user);
};
int btrfs_read_and_process_send_stream(int fd,
--
1.9.1
--
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