Hey,
this is my first patch against something related to btrfs. The attached
patch adds the subvol current-generation command to retrieve the current
generation of the given subvol. This is inteded to be used with the
subvol find-new command.
After writing this patch I noticed that Sean Reifschneider already
sugested something similar in 2010 [1]. His patch reminded me of adding
a part to the manpage.
Thanks and Greetings
fabian
--
[1] http://markmail.org/thread/iztosuxysjt4zx2b
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Content-Disposition: attachment;
filename="0001-btrfs-Add-subvol-current-generation-command.patch"
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name="0001-btrfs-Add-subvol-current-generation-command.patch";
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From d7fd192b7e013701560e9abba7a01bb7dbaade18 Mon Sep 17 00:00:00 2001
From: Fabian Deutsch <fabian.deutsch@gmx.de>
Date: Sat, 16 Jun 2012 22:50:57 +0200
Subject: [PATCH] btrfs: Add subvol current-generation command
Add a command (current-generation) to get the current generation of a subvolume.
This is useful in combination with find-new.
Signed-off-by: Fabian Deutsch <fabian.deutsch@gmx.de>
---
btrfs-list.c | 7 +++++++
cmds-subvolume.c | 43 +++++++++++++++++++++++++++++++++++++++++++
man/btrfs.8.in | 8 ++++++++
3 Dateien geändert, 58 Zeilen hinzugefügt(+)
diff --git a/btrfs-list.c b/btrfs-list.c
index 5f4a9be..ccbaf44 100644
--- a/btrfs-list.c
+++ b/btrfs-list.c
@@ -799,6 +799,13 @@ static int print_one_extent(int fd, struct
btrfs_ioctl_search_header *sh,
return 0;
}
+u64 current_generation(int fd, u64 root_id)
+{
+ u64 max_found = 0;
+ max_found = find_root_gen(fd);
+ return max_found;
+}
+
int find_updated_files(int fd, u64 root_id, u64 oldest_gen)
{
int ret;
diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 950fa8f..2a185b1 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -31,6 +31,7 @@
/* btrfs-list.c */
int list_subvols(int fd, int print_parent, int get_default);
+u64 current_generation(int fd, u64 root_id);
int find_updated_files(int fd, u64 root_id, u64 oldest_gen);
static const char * const subvolume_cmd_group_usage[] = {
@@ -512,6 +513,47 @@ static int cmd_find_new(int argc, char **argv)
return 0;
}
+
+static const char * const cmd_current_generation_usage[] = {
+ "btrfs subvolume current-generation <path>",
+ "Get the current generation of the filesystem",
+ NULL
+};
+
+static int cmd_current_generation(int argc, char **argv)
+{
+ int fd;
+ int ret;
+ char *subvol;
+ u64 current_gen;
+
+ if (check_argc_exact(argc, 2))
+ usage(cmd_current_generation_usage);
+
+ subvol = argv[1];
+
+ ret = test_issubvolume(subvol);
+ if (ret < 0) {
+ fprintf(stderr, "ERROR: error accessing ''%s''\n",
subvol);
+ return 12;
+ }
+ if (!ret) {
+ fprintf(stderr, "ERROR: ''%s'' is not a
subvolume\n", subvol);
+ return 13;
+ }
+
+ fd = open_file_or_dir(subvol);
+ if (fd < 0) {
+ fprintf(stderr, "ERROR: can''t access
''%s''\n", subvol);
+ return 12;
+ }
+ current_gen = current_generation(fd, 0);
+
+ fprintf(stdout, "%llu\n", current_gen);
+
+ return 0;
+}
+
const struct cmd_group subvolume_cmd_group = {
subvolume_cmd_group_usage, NULL, {
{ "create", cmd_subvol_create, cmd_subvol_create_usage, NULL, 0 },
@@ -523,6 +565,7 @@ const struct cmd_group subvolume_cmd_group = {
{ "set-default", cmd_subvol_set_default,
cmd_subvol_set_default_usage, NULL, 0 },
{ "find-new", cmd_find_new, cmd_find_new_usage, NULL, 0 },
+ { "current-generation", cmd_current_generation,
cmd_current_generation_usage, NULL, 0 },
{ 0, 0, 0, 0, 0 }
}
};
diff --git a/man/btrfs.8.in b/man/btrfs.8.in
index be478e0..3c71f57 100644
--- a/man/btrfs.8.in
+++ b/man/btrfs.8.in
@@ -25,6 +25,8 @@ btrfs \- control a btrfs filesystem
.PP
\fBbtrfs\fP \fBfilesystem defrag\fP\fI [options] <file>|<dir>
[<file>|<dir>...]\fP
.PP
+\fBbtrfs\fP \fBsubvolume current-generation\fP\fI <subvolume>\fP
+.PP
\fBbtrfs\fP \fBsubvolume find-new\fP\fI <subvolume> <last_gen>\fP
.PP
\fBbtrfs\fP \fBfilesystem balance\fP\fI <path> \fP
@@ -154,6 +156,12 @@ The start position and the number of bytes to deframention
can be specified by \
NOTE: defragmenting with kernels up to 2.6.37 will unlink COW-ed copies of
data, don''t
use it if you use snapshots, have de-duplicated your data or made copies with
\fBcp --reflink\fP.
+.TP
+
+\fBsubvolume current-generation\fR\fI <subvolume>\fR
+Return the current generation used in subvolume \fI<subvolume>\fR. This
number can be used with the \fBsubvolume find-new\fR command.
+.TP
+
\fBsubvolume find-new\fR\fI <subvolume> <last_gen>\fR
List the recently modified files in a subvolume, after \fI<last_gen>\fR
ID.
.TP
--
1.7.10.4
--=-1dQ+4lg2volhID9WDtmE--
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