@@ -197,8 +197,11 @@ resize [options] [<devid>:][+/-]<size>[kKmMgGtTpPeE]|[<devid>:]max <path>
as expected and does not resize the image. This would resize the underlying
filesystem instead.
- The *devid* can be found in the output of **btrfs filesystem show** and
- defaults to 1 if not specified.
+ The *devid* can be found in the output of **btrfs filesystem show**.
+
+ If the filesystem contains only one device, it can be
+ resized without specifying a specific device.
+
The *size* parameter specifies the new size of the filesystem.
If the prefix *+* or *-* is present the size is increased or decreased
by the quantity *size*.
@@ -208,7 +211,7 @@ resize [options] [<devid>:][+/-]<size>[kKmMgGtTpPeE]|[<devid>:]max <path>
KiB, MiB, GiB, TiB, PiB, or EiB, respectively (case does not matter).
If *max* is passed, the filesystem will occupy all available space on the
- device respecting *devid* (remember, devid 1 by default).
+ device respecting *devid*.
The resize command does not manipulate the size of underlying
partition. If you wish to enlarge/reduce a filesystem, you must make sure you
@@ -413,14 +416,19 @@ even if run repeatedly.
**$ btrfs filesystem resize -1G /path**
+Let's assume that filesystem contains only one device.
+Shrink size of the filesystem's single-device by 1GiB.
+
+
**$ btrfs filesystem resize 1:-1G /path**
-Shrink size of the filesystem's device id 1 by 1GiB. The first syntax expects a
-device with id 1 to exist, otherwise fails. The second is equivalent and more
-explicit. For a single-device filesystem it's typically not necessary to
-specify the devid though.
+Shrink size of the filesystem's device id 1 by 1GiB. This command expects a
+device with id 1 to exist, otherwise fails.
**$ btrfs filesystem resize max /path**
+Let's assume that filesystem contains only one device and the filesystem
+does not occupy the whole block device,By simply using *max* as size we
+will achieve that.
**$ btrfs filesystem resize 1:max /path**
@@ -1078,6 +1078,7 @@ static DEFINE_SIMPLE_COMMAND(filesystem_defrag, "defragment");
static const char * const cmd_filesystem_resize_usage[] = {
"btrfs filesystem resize [options] [devid:][+/-]<newsize>[kKmMgGtTpPeE]|[devid:]max <path>",
"Resize a filesystem",
+ "If the filesystem contains only one device, devid can be ignored.",
"If 'max' is passed, the filesystem will occupy all available space",
"on the device 'devid'.",
"[kK] means KiB, which denotes 1KiB = 1024B, 1MiB = 1024KiB, etc.",
@@ -1087,7 +1088,8 @@ static const char * const cmd_filesystem_resize_usage[] = {
NULL
};
-static int check_resize_args(const char *amount, const char *path) {
+static int check_resize_args(char * const amount, const char *path)
+{
struct btrfs_ioctl_fs_info_args fi_args;
struct btrfs_ioctl_dev_info_args *di_args = NULL;
int ret, i, dev_idx = -1;
@@ -1112,11 +1114,14 @@ static int check_resize_args(const char *amount, const char *path) {
}
ret = snprintf(amount_dup, BTRFS_VOL_NAME_MAX, "%s", amount);
+check:
if (strlen(amount) != ret) {
error("newsize argument is too long");
ret = 1;
goto out;
}
+ if (strcmp(amount, amount_dup) != 0)
+ strcpy(amount, amount_dup);
sizestr = amount_dup;
devstr = strchr(sizestr, ':');
@@ -1133,6 +1138,17 @@ static int check_resize_args(const char *amount, const char *path) {
ret = 1;
goto out;
}
+ } else if (fi_args.num_devices != 1) {
+ error("The file system has multiple devices, please specify devid exactly.");
+ error("To view detailed device information, use the subcommand filesystem show.");
+ ret = 1;
+ goto out;
+ } else {
+ memset(amount_dup, 0, BTRFS_VOL_NAME_MAX);
+ ret = snprintf(amount_dup, BTRFS_VOL_NAME_MAX, "%llu:", di_args[0].devid);
+ ret = snprintf(amount_dup + strlen(amount_dup),
+ BTRFS_VOL_NAME_MAX - strlen(amount_dup), "%s", amount);
+ goto check;
}
dev_idx = -1;
@@ -1200,10 +1216,11 @@ static int check_resize_args(const char *amount, const char *path) {
di_args[dev_idx].path,
pretty_size_mode(di_args[dev_idx].total_bytes, UNITS_DEFAULT),
res_str);
+ ret = 0;
out:
free(di_args);
- return 0;
+ return ret;
}
static int cmd_filesystem_resize(const struct cmd_struct *cmd,
@@ -1213,9 +1230,10 @@ static int cmd_filesystem_resize(const struct cmd_struct *cmd,
int fd, res, len, e;
char *amount, *path;
DIR *dirstream = NULL;
- int ret;
+ int ret = 0;
bool enqueue = false;
bool cancel = false;
+ char amountbuf[BTRFS_VOL_NAME_MAX];
/*
* Simplified option parser, accept only long options, the resize value
@@ -1277,6 +1295,11 @@ static int cmd_filesystem_resize(const struct cmd_struct *cmd,
}
}
+ memset(amountbuf, 0, BTRFS_VOL_NAME_MAX);
+ amount = amountbuf;
+
+ strncpy(amount, argv[optind], BTRFS_VOL_NAME_MAX);
+
ret = check_resize_args(amount, path);
if (ret != 0) {
close_file_or_dir(fd, dirstream);
[BUG] 1. If there is no devid=1, when the user uses the btrfs file system tool, the following error will be reported, $ sudo btrfs filesystem show /mnt/1 Label: none uuid: 64dc0f68-9afa-4465-9ea1-2bbebfdb6cec Total devices 2 FS bytes used 704.00KiB devid 2 size 15.00GiB used 1.16GiB path /dev/loop2 devid 3 size 15.00GiB used 1.16GiB path /dev/loop3 $ sudo btrfs filesystem resize -1G /mnt/1 ERROR: cannot find devid: 1 ERROR: unable to resize '/mnt/1': No such device 2. Function check_resize_args, if get_fs_info is successful, check_resize_args always returns 0, Even if the parameter passed to kernel space is longer than the size allowed to be passed to kernel space (BTRFS_VOL_NAME_MAX). [CAUSE] 1. If the user does not specify the devid id explicitly, btrfs will use the default devid 1, so it will report an error when dev 1 is missing. 2. The last line of the function check_resize_args is return 0. [FIX] 1. If the file system contains multiple devices, output an error message to the user. If the filesystem has only one device, resize should automatically add the unique devid. 2. The function check_resize_args should not return 0 on the last line, it should return ret representing the return value. 3. Update the "btrfs-filesystem" man page [RESULT] $ sudo btrfs filesystem resize --help usage: btrfs filesystem resize [options] [devid:][+/-]<newsize>[kKmMgGtTpPeE]|[devid:]max <path> Resize a filesystem If the filesystem contains only one device, devid can be ignored. If 'max' is passed, the filesystem will occupy all available space on the device 'devid'. [kK] means KiB, which denotes 1KiB = 1024B, 1MiB = 1024KiB, etc. --enqueue wait if there's another exclusive operation running, otherwise continue $ sudo btrfs filesystem show /mnt/1/ Label: none uuid: 2025e6ae-0b6d-40b4-8685-3e7e9fc9b2c2 Total devices 2 FS bytes used 144.00KiB devid 2 size 15.00GiB used 1.16GiB path /dev/loop2 devid 3 size 15.00GiB used 1.16GiB path /dev/loop3 $ sudo btrfs filesystem resize -1G /mnt/1 ERROR: The file system has multiple devices, please specify devid exactly. ERROR: To view detailed device information, use the subcommand filesystem show. $ sudo btrfs device delete 2 /mnt/1/ $ sudo btrfs filesystem show /mnt/1/ Label: none uuid: 2025e6ae-0b6d-40b4-8685-3e7e9fc9b2c2 Total devices 1 FS bytes used 144.00KiB devid 3 size 15.00GiB used 1.28GiB path /dev/loop3 $ sudo btrfs filesystem resize -1G /mnt/1 Resize device id 3 (/dev/loop3) from 15.00GiB to 14.00GiB $ sudo btrfs filesystem show /mnt/1/ Label: none uuid: cc6e1beb-255b-431f-baf5-02e8056fd0b6 Total devices 1 FS bytes used 144.00KiB devid 3 size 14.00GiB used 1.28GiB path /dev/loop3 Signed-off-by: Li Zhang <zhanglikernel@gmail.com> --- Issue: 470 V1: * Automatically add devid if device is not specific V2: * resize fails if filesystem has multiple devices V3: * Fix incorrect behavior of function check_resize_args * Updated resize help information V4: * Update man pages V5: * Use safe strcpy function * Reduced error messages when resizing filesystems containing multiple devices * Use stack variable buffer Documentation/btrfs-filesystem.rst | 22 +++++++++++++++------- cmds/filesystem.c | 29 ++++++++++++++++++++++++++--- 2 files changed, 41 insertions(+), 10 deletions(-)