On 10/23/2017 12:45 PM, Misono, Tomohiro wrote:
Currently "fi usage" (and "dev usage") cannot run for the filesystem using seed device. This is because FS_INFO ioctl returns the number of devices excluding seeds, but load_device_info() tries to access valid device from devid 0 to max_id, and results in accessing seeds too (thus causing mismatching of number of devices).
A long time back I tried to fix this by fixing the FS_INFO num_devs itself, but the concern was backward compatibility of the ioctl. However there is no such a concern here. I am ok with this approach.
Since only the size of non-seed devices is matter, fix this by just skipping seed device by checking device's fsid and comparing it to the fsid obtained by FS_INFO ioctl. Signed-off-by: Tomohiro Misono <misono.tomoh...@jp.fujitsu.com>
Reviewed-by: Anand Jain <anand.j...@oracle.com> Thanks, Anand
--- cmds-fi-usage.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/cmds-fi-usage.c b/cmds-fi-usage.c index a72fb4e..50c7e51 100644 --- a/cmds-fi-usage.c +++ b/cmds-fi-usage.c @@ -545,6 +545,7 @@ static int load_device_info(int fd, struct device_info **device_info_ptr, struct btrfs_ioctl_fs_info_args fi_args; struct btrfs_ioctl_dev_info_args dev_info; struct device_info *info; + __u8 fsid[BTRFS_UUID_SIZE];*device_info_count = 0;*device_info_ptr = NULL; @@ -568,6 +569,7 @@ static int load_device_info(int fd, struct device_info **device_info_ptr, if (ndevs >= fi_args.num_devices) { error("unexpected number of devices: %d >= %llu", ndevs, (unsigned long long)fi_args.num_devices); + error("if seed device is used, try run as root."); goto out; } memset(&dev_info, 0, sizeof(dev_info)); @@ -580,6 +582,19 @@ static int load_device_info(int fd, struct device_info **device_info_ptr, goto out; }+ /*+ * Skip seed device by cheking device's fsid (require root). + * Ignore EACCES since if seed is not used this function works + * correctly without root privilege. + */ + ret = dev_to_fsid((const char *)dev_info.path, fsid); + if (ret != -EACCES) { + if (ret) + goto out; + if (memcmp(fi_args.fsid, fsid, BTRFS_FSID_SIZE) != 0) + continue; + } + info[ndevs].devid = dev_info.devid; if (!dev_info.path[0]) { strcpy(info[ndevs].path, "missing");
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