File 2000-btrfs-full-balance-warning.diff of Package btrfsprogs
Index: btrfs-progs-v4.3/Documentation/btrfs-balance.asciidoc
===================================================================
--- btrfs-progs-v4.3.orig/Documentation/btrfs-balance.asciidoc
+++ btrfs-progs-v4.3/Documentation/btrfs-balance.asciidoc
@@ -67,6 +67,12 @@ resume interrupted balance
start the balance operation according to the specified filters, no filters
will rewrite the entire filesystem. The process runs in the foreground.
+
+NOTE: the balance command without filters will basically rewrite everything
+int the filesystem. The run time is potentially very long, depending on the
+filesystem size. To prevent starting a full balance by accident, the user is
+warned and has a few seconds to cancel the operation before it starts. The
+warning and delay can be skipped with '--full-balance' option.
++
`Options`
+
-d[<filters>]::::
Index: btrfs-progs-v4.3/cmds-balance.c
===================================================================
--- btrfs-progs-v4.3.orig/cmds-balance.c
+++ btrfs-progs-v4.3/cmds-balance.c
@@ -383,8 +383,13 @@ static int do_balance_v1(int fd)
return ret;
}
+enum {
+ BALANCE_START_FILTERS = 1 << 0,
+ BALANCE_START_NOWARN = 1 << 1
+};
+
static int do_balance(const char *path, struct btrfs_ioctl_balance_args *args,
- int nofilters)
+ unsigned flags)
{
int fd;
int ret;
@@ -395,6 +400,24 @@ static int do_balance(const char *path,
if (fd < 0)
return 1;
+ if (!(flags & BALANCE_START_FILTERS) && !(flags & BALANCE_START_NOWARN)) {
+ int delay = 10;
+
+ printf("WARNING:\n\n");
+ printf("\tFull balance without filters requested. This operation is very\n");
+ printf("\tintense and takes potentially very long. It is recommended to\n");
+ printf("\tuse the balance filters to narrow down the balanced data.\n");
+ printf("\tUse 'btrfs balance start --full-balance' option to skip this\n");
+ printf("\twarning. The operation printf will start in %d seconds.\n", delay);
+ printf("\tUse Ctrl-C to stop it.\n");
+ while (delay) {
+ sleep(1);
+ printf("%2d", delay--);
+ fflush(stdout);
+ }
+ printf("\nStarting balance without any filters.\n");
+ }
+
ret = ioctl(fd, BTRFS_IOC_BALANCE_V2, args);
e = errno;
@@ -404,7 +427,7 @@ static int do_balance(const char *path,
* old one. But, the old one doesn't know any filters, so
* don't fall back if they tried to use the fancy new things
*/
- if (e == ENOTTY && nofilters) {
+ if (e == ENOTTY && !(flags & BALANCE_START_FILTERS)) {
ret = do_balance_v1(fd);
if (ret == 0)
goto out;
@@ -444,13 +467,16 @@ static const char * const cmd_balance_st
"passed all filters in a comma-separated list of filters for a",
"particular chunk type. If filter list is not given balance all",
"chunks of that type. In case none of the -d, -m or -s options is",
- "given balance all chunks in a filesystem.",
+ "given balance all chunks in a filesystem. This is potentially",
+ "long operation and the user is warned before this start, with",
+ "a delay to stop it.",
"",
"-d[filters] act on data chunks",
"-m[filters] act on metadata chunks",
"-s[filters] act on system chunks (only under -f)",
"-v be verbose",
"-f force reducing of metadata integrity",
+ "--full-balance do not print warning and do not delay start",
NULL
};
@@ -461,19 +487,22 @@ static int cmd_balance_start(int argc, c
&args.meta, NULL };
int force = 0;
int verbose = 0;
- int nofilters = 1;
+ unsigned start_flags = 0;
int i;
memset(&args, 0, sizeof(args));
optind = 1;
while (1) {
+ enum { GETOPT_VAL_FULL_BALANCE = 256 };
static const struct option longopts[] = {
{ "data", optional_argument, NULL, 'd'},
{ "metadata", optional_argument, NULL, 'm' },
{ "system", optional_argument, NULL, 's' },
{ "force", no_argument, NULL, 'f' },
{ "verbose", no_argument, NULL, 'v' },
+ { "full-balance", no_argument, NULL,
+ GETOPT_VAL_FULL_BALANCE },
{ NULL, 0, NULL, 0 }
};
@@ -483,21 +512,21 @@ static int cmd_balance_start(int argc, c
switch (opt) {
case 'd':
- nofilters = 0;
+ start_flags |= BALANCE_START_FILTERS;
args.flags |= BTRFS_BALANCE_DATA;
if (parse_filters(optarg, &args.data))
return 1;
break;
case 's':
- nofilters = 0;
+ start_flags |= BALANCE_START_FILTERS;
args.flags |= BTRFS_BALANCE_SYSTEM;
if (parse_filters(optarg, &args.sys))
return 1;
break;
case 'm':
- nofilters = 0;
+ start_flags |= BALANCE_START_FILTERS;
args.flags |= BTRFS_BALANCE_METADATA;
if (parse_filters(optarg, &args.meta))
@@ -509,6 +538,9 @@ static int cmd_balance_start(int argc, c
case 'v':
verbose = 1;
break;
+ case GETOPT_VAL_FULL_BALANCE:
+ start_flags |= BALANCE_START_NOWARN;
+ break;
default:
usage(cmd_balance_start_usage);
}
@@ -534,7 +566,7 @@ static int cmd_balance_start(int argc, c
sizeof(struct btrfs_balance_args));
}
- if (nofilters) {
+ if (!(start_flags & BALANCE_START_FILTERS)) {
/* relocate everything - no filters */
args.flags |= BTRFS_BALANCE_TYPE_MASK;
}
@@ -564,7 +596,7 @@ static int cmd_balance_start(int argc, c
if (verbose)
dump_ioctl_balance_args(&args);
- return do_balance(argv[optind], &args, nofilters);
+ return do_balance(argv[optind], &args, start_flags);
}
static const char * const cmd_balance_pause_usage[] = {
@@ -798,6 +830,16 @@ static int cmd_balance_status(int argc,
return 1;
}
+static int cmd_balance_full(int argc, char **argv)
+{
+ struct btrfs_ioctl_balance_args args;
+
+ memset(&args, 0, sizeof(args));
+ args.flags |= BTRFS_BALANCE_TYPE_MASK;
+
+ return do_balance(argv[1], &args, BALANCE_START_NOWARN);
+}
+
static const char balance_cmd_group_info[] =
"balance data accross devices, or change block groups using filters";
@@ -808,20 +850,21 @@ const struct cmd_group balance_cmd_group
{ "cancel", cmd_balance_cancel, cmd_balance_cancel_usage, NULL, 0 },
{ "resume", cmd_balance_resume, cmd_balance_resume_usage, NULL, 0 },
{ "status", cmd_balance_status, cmd_balance_status_usage, NULL, 0 },
+ { "--full-balance", cmd_balance_full, NULL, NULL, 1 },
NULL_CMD_STRUCT
}
};
int cmd_balance(int argc, char **argv)
{
- if (argc == 2) {
+ if (argc == 2 && strcmp("start", argv[1]) != 0) {
/* old 'btrfs filesystem balance <path>' syntax */
struct btrfs_ioctl_balance_args args;
memset(&args, 0, sizeof(args));
args.flags |= BTRFS_BALANCE_TYPE_MASK;
- return do_balance(argv[1], &args, 1);
+ return do_balance(argv[1], &args, 0);
}
return handle_command_group(&balance_cmd_group, argc, argv);
