Hi Chris,
please consider this patch for 3.5-rc before it goes final. Thanks.
From: David Sterba <dste...@suse.cz>
Commit c11d2c236cc260b36 (Btrfs: add ioctl to get and reset the device
stats) introduced two ioctls doing almost the same thing distinguished
by just the ioctl number which encodes "do reset after read". I have
suggested
http://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg16604.html
to implement it via the ioctl args. This hasn't happen, and I think we
should use a more clean way to pass flags and should not waste ioctl
numbers.
CC: Stefan Behrens <sbehr...@giantdisaster.de>
Signed-off-by: David Sterba <dste...@suse.cz>
---
fs/btrfs/ioctl.c | 16 ++++++++--------
fs/btrfs/ioctl.h | 6 ++++--
fs/btrfs/volumes.c | 5 ++---
fs/btrfs/volumes.h | 3 +--
4 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 0e92e57..670c5d2 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -3063,19 +3063,21 @@ static long btrfs_ioctl_scrub_progress(struct
btrfs_root *root,
}
static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
- void __user *arg, int reset_after_read)
+ void __user *arg)
{
struct btrfs_ioctl_get_dev_stats *sa;
int ret;
- if (reset_after_read && !capable(CAP_SYS_ADMIN))
- return -EPERM;
-
sa = memdup_user(arg, sizeof(*sa));
if (IS_ERR(sa))
return PTR_ERR(sa);
- ret = btrfs_get_dev_stats(root, sa, reset_after_read);
+ if ((sa->flags & BTRFS_DEV_STATS_RESET) && !capable(CAP_SYS_ADMIN)) {
+ kfree(sa);
+ return -EPERM;
+ }
+
+ ret = btrfs_get_dev_stats(root, sa);
if (copy_to_user(arg, sa, sizeof(*sa)))
ret = -EFAULT;
@@ -3473,9 +3475,7 @@ long btrfs_ioctl(struct file *file, unsigned int
case BTRFS_IOC_BALANCE_PROGRESS:
return btrfs_ioctl_balance_progress(root, argp);
case BTRFS_IOC_GET_DEV_STATS:
- return btrfs_ioctl_get_dev_stats(root, argp, 0);
- case BTRFS_IOC_GET_AND_RESET_DEV_STATS:
- return btrfs_ioctl_get_dev_stats(root, argp, 1);
+ return btrfs_ioctl_get_dev_stats(root, argp);
}
return -ENOTTY;
diff --git a/fs/btrfs/ioctl.h b/fs/btrfs/ioctl.h
index 497c530..c4089c5 100644
--- a/fs/btrfs/ioctl.h
+++ b/fs/btrfs/ioctl.h
@@ -285,9 +285,13 @@ enum btrfs_dev_stat_values {
BTRFS_DEV_STAT_VALUES_MAX
};
+/* Reset statistics after reading; needs SYS_ADMIN capability */
+#define BTRFS_DEV_STATS_RESET (1ULL << 0)
+
struct btrfs_ioctl_get_dev_stats {
__u64 devid; /* in */
__u64 nr_items; /* in/out */
+ __u64 flags; /* in/out */
/* out values: */
__u64 values[BTRFS_DEV_STAT_VALUES_MAX];
@@ -361,7 +365,5 @@ struct btrfs_ioctl_get_dev_stats {
struct btrfs_ioctl_ino_path_args)
#define BTRFS_IOC_GET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 52, \
struct btrfs_ioctl_get_dev_stats)
-#define BTRFS_IOC_GET_AND_RESET_DEV_STATS _IOWR(BTRFS_IOCTL_MAGIC, 53, \
- struct btrfs_ioctl_get_dev_stats)
#endif
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index 8a3d259..661e6ca 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -4871,8 +4871,7 @@ static void btrfs_dev_stat_print_on_load(struct
btrfs_device *dev)
}
int btrfs_get_dev_stats(struct btrfs_root *root,
- struct btrfs_ioctl_get_dev_stats *stats,
- int reset_after_read)
+ struct btrfs_ioctl_get_dev_stats *stats)
{
struct btrfs_device *dev;
struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
@@ -4890,7 +4889,7 @@ int btrfs_get_dev_stats(struct btrfs_root *root,
printk(KERN_WARNING
"btrfs: get dev_stats failed, not yet valid\n");
return -ENODEV;
- } else if (reset_after_read) {
+ } else if (stats->flags & BTRFS_DEV_STATS_RESET) {
for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
if (stats->nr_items > i)
stats->values[i] =
diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 74366f2..e673589 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -292,8 +292,7 @@ struct btrfs_device *btrfs_find_device_for_logical(struct
btrfs_root *root,
void btrfs_dev_stat_print_on_error(struct btrfs_device *device);
void btrfs_dev_stat_inc_and_print(struct btrfs_device *dev, int index);
int btrfs_get_dev_stats(struct btrfs_root *root,
- struct btrfs_ioctl_get_dev_stats *stats,
- int reset_after_read);
+ struct btrfs_ioctl_get_dev_stats *stats);
int btrfs_init_dev_stats(struct btrfs_fs_info *fs_info);
int btrfs_run_dev_stats(struct btrfs_trans_handle *trans,
struct btrfs_fs_info *fs_info);
