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Btrfs: add ioctl to get and reset the device stats 

An ioctl interface is added to get the device statistic counters.
A second ioctl is added to atomically get and reset these counters.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
This commit is contained in:
Stefan Behrens 2012-05-25 16:06:09 +02:00 committed by Josef Bacik
parent 442a4f6308
commit c11d2c236c
4 changed files with 77 additions and 0 deletions
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26
fs/btrfs/ioctl.c
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@ -3046,6 +3046,28 @@ static long btrfs_ioctl_scrub_progress(struct btrfs_root *root,
return ret;
}
static long btrfs_ioctl_get_dev_stats(struct btrfs_root *root,
void __user *arg, int reset_after_read)
{
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 (copy_to_user(arg, sa, sizeof(*sa)))
ret = -EFAULT;
kfree(sa);
return ret;
}
static long btrfs_ioctl_ino_to_path(struct btrfs_root *root, void __user *arg)
{
int ret = 0;
@ -3434,6 +3456,10 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_balance_ctl(root, arg);
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 -ENOTTY;

14
fs/btrfs/ioctl.h
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@ -285,6 +285,16 @@ enum btrfs_dev_stat_values {
BTRFS_DEV_STAT_VALUES_MAX
};
struct btrfs_ioctl_get_dev_stats {
__u64 devid; /* in */
__u64 nr_items; /* in/out */
/* out values: */
__u64 values[BTRFS_DEV_STAT_VALUES_MAX];
__u64 unused[128 - 2 - BTRFS_DEV_STAT_VALUES_MAX]; /* pad to 1k */
};
#define BTRFS_IOC_SNAP_CREATE _IOW(BTRFS_IOCTL_MAGIC, 1, \
struct btrfs_ioctl_vol_args)
#define BTRFS_IOC_DEFRAG _IOW(BTRFS_IOCTL_MAGIC, 2, \
@ -349,5 +359,9 @@ enum btrfs_dev_stat_values {
struct btrfs_ioctl_ino_path_args)
#define BTRFS_IOC_LOGICAL_INO _IOWR(BTRFS_IOCTL_MAGIC, 36, \
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

34
fs/btrfs/volumes.c
View File

@ -4673,3 +4673,37 @@ void btrfs_dev_stat_print_on_error(struct btrfs_device *dev)
btrfs_dev_stat_read(dev,
BTRFS_DEV_STAT_GENERATION_ERRS));
}
int btrfs_get_dev_stats(struct btrfs_root *root,
struct btrfs_ioctl_get_dev_stats *stats,
int reset_after_read)
{
struct btrfs_device *dev;
struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
int i;
mutex_lock(&fs_devices->device_list_mutex);
dev = btrfs_find_device(root, stats->devid, NULL, NULL);
mutex_unlock(&fs_devices->device_list_mutex);
if (!dev) {
printk(KERN_WARNING
"btrfs: get dev_stats failed, device not found\n");
return -ENODEV;
} else if (reset_after_read) {
for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++) {
if (stats->nr_items > i)
stats->values[i] =
btrfs_dev_stat_read_and_reset(dev, i);
else
btrfs_dev_stat_reset(dev, i);
}
} else {
for (i = 0; i < BTRFS_DEV_STAT_VALUES_MAX; i++)
if (stats->nr_items > i)
stats->values[i] = btrfs_dev_stat_read(dev, i);
}
if (stats->nr_items > BTRFS_DEV_STAT_VALUES_MAX)
stats->nr_items = BTRFS_DEV_STAT_VALUES_MAX;
return 0;
}

3
fs/btrfs/volumes.h
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@ -290,6 +290,9 @@ struct btrfs_device *btrfs_find_device_for_logical(struct btrfs_root *root,
u64 logical, int mirror_num);
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);
static inline void btrfs_dev_stat_inc(struct btrfs_device *dev,
int index)