[RFC v1 10/11] vfs: add 3 new ioctl interfaces

zwu.kernel
2012-09-17T07:20:01Z

FS_IOC_GET_HEAT_INFO: return a struct containing the various
metrics collected in btrfs_freq_data structs, and also return a
calculated data temperature based on those metrics. Optionally, retrieve
the temperature from the hot data hash list instead of recalculating it.

FS_IOC_GET_HEAT_OPTS: return an integer representing the current
state of hot data tracking and migration:

0 = do nothing
1 = track frequency of access

FS_IOC_SET_HEAT_OPTS: change the state of hot data tracking and
migration, as described above.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
fs/compat_ioctl.c | 8 +++
fs/ioctl.c | 132 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/fs.h | 11 ++++
include/linux/hot_track.h | 12 ++++
4 files changed, 163 insertions(+), 0 deletions(-)

diff --git a/fs/compat_ioctl.c b/fs/compat_ioctl.c
index debdfe0..a88c7de 100644
--- a/fs/compat_ioctl.c
+++ b/fs/compat_ioctl.c
@@ -1390,6 +1390,11 @@ COMPATIBLE_IOCTL(TIOCSTART)
COMPATIBLE_IOCTL(TIOCSTOP)
#endif

+/*Hot data tracking*/
+COMPATIBLE_IOCTL(FS_IOC_GET_HEAT_INFO)
+COMPATIBLE_IOCTL(FS_IOC_SET_HEAT_OPTS)
+COMPATIBLE_IOCTL(FS_IOC_GET_HEAT_OPTS)
+
/* fat 'r' ioctls. These are handled by fat with ->compat_ioctl,
but we don't want warnings on other file systems. So declare
them as compatible here. */
@@ -1572,6 +1577,9 @@ asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
case FIBMAP:
case FIGETBSZ:
case FIONREAD:
+ case FS_IOC_GET_HEAT_INFO:
+ case FS_IOC_SET_HEAT_OPTS:
+ case FS_IOC_GET_HEAT_OPTS:
if (S_ISREG(filp->f_path.dentry->d_inode->i_mode))
break;
/*FALL THROUGH*/
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 29167be..9242969 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -18,6 +18,9 @@

#include <asm/ioctls.h>

+#include "hot_hash.h"
+#include "hot_rb.h"
+
/* So that the fiemap access checks can't overflow on 32 bit machines. */
#define FIEMAP_MAX_EXTENTS (UINT_MAX / sizeof(struct fiemap_extent))

@@ -537,6 +540,126 @@ static int ioctl_fsthaw(struct file *filp)
}

/*
+ * Retrieve information about access frequency for the given file. Return it in
+ * a userspace-friendly struct for btrfsctl (or another tool) to parse.
+ *
+ * The temperature that is returned can be "live" -- that is, recalculated when
+ * the ioctl is called -- or it can be returned from the hashtable, reflecting
+ * the (possibly old) value that the system will use when considering files
+ * for migration. This behavior is determined by heat_info->live.
+ */
+static int ioctl_heat_info(struct file *file, void __user *argp)
+{
+ struct inode *mnt_inode = file->f_path.dentry->d_inode;
+ struct inode *file_inode;
+ struct file *file_filp;
+ struct hot_info *root = &(mnt_inode->i_sb->s_hotinfo);
+ struct heat_info *heat_info;
+ struct hot_inode_tree *hitree;
+ struct hot_inode_item *he;
+ int ret;
+
+ heat_info = kmalloc(sizeof(struct heat_info),
+ GFP_KERNEL | GFP_NOFS);
+
+ if (copy_from_user((void *) heat_info,
+ argp,
+ sizeof(struct heat_info)) != 0) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ file_filp = filp_open(heat_info->filename, O_RDONLY, 0);
+ file_inode = file_filp->f_dentry->d_inode;
+ filp_close(file_filp, NULL);
+
+ hitree = &root->hot_inode_tree;
+ read_lock(&hitree->lock);
+ he = hot_rb_lookup_hot_inode_item(hitree, file_inode->i_ino);
+ read_unlock(&hitree->lock);
+ if (!he) {
+ /* we don't have any info on this file yet */
+ ret = -ENODATA;
+ goto err;
+ }
+
+ spin_lock(&he->lock);
+ heat_info->avg_delta_reads =
+ (__u64) he->hot_freq_data.avg_delta_reads;
+ heat_info->avg_delta_writes =
+ (__u64) he->hot_freq_data.avg_delta_writes;
+ heat_info->last_read_time =
+ (__u64) timespec_to_ns(&he->hot_freq_data.last_read_time);
+ heat_info->last_write_time =
+ (__u64) timespec_to_ns(&he->hot_freq_data.last_write_time);
+ heat_info->num_reads =
+ (__u32) he->hot_freq_data.nr_reads;
+ heat_info->num_writes =
+ (__u32) he->hot_freq_data.nr_writes;
+
+ if (heat_info->live > 0) {
+ /* got a request for live temperature,
+ * call hot_hash_calc_temperature to recalculate
+ */
+ heat_info->temperature =
+ hot_hash_calc_temperature(&he->hot_freq_data);
+ } else {
+ /* not live temperature, get it from the hashlist */
+ read_lock(&he->heat_node->hlist->rwlock);
+ heat_info->temperature = he->heat_node->hlist->temperature;
+ read_unlock(&he->heat_node->hlist->rwlock);
+ }
+ spin_unlock(&he->lock);
+
+ hot_rb_free_hot_inode_item(he);
+
+ if (copy_to_user(argp, (void *) heat_info,
+ sizeof(struct heat_info))) {
+ ret = -EFAULT;
+ goto err;
+ }
+
+ kfree(heat_info);
+ return 0;
+
+err:
+ kfree(heat_info);
+ return ret;
+}
+
+static int ioctl_heat_opts(struct file *file, void __user *argp, int set)
+{
+ struct inode *inode = file->f_path.dentry->d_inode;
+ int arg, ret = 0;
+
+ if (!set) {
+ arg = TRACK_THIS_INODE(inode) ? 1 : 0;
+
+ if (copy_to_user(argp, (void *) &arg, sizeof(int)) != 0)
+ ret = -EFAULT;
+ } else {
+ if (copy_from_user((void *) &arg, argp, sizeof(int)) != 0) {
+ ret = -EFAULT;
+ } else {
+ switch (arg) {
+ case 0: /* track nothing */
+ /* set S_NOHOTDATATRACK */
+ inode->i_flags |= S_NOHOTDATATRACK;
+ break;
+ case 1: /* do tracking */
+ /* clear S_NOHOTDATATRACK */
+ inode->i_flags &= ~S_NOHOTDATATRACK;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+ }
+ }
+
+ return ret;
+}
+
+/*
* When you add any new common ioctls to the switches above and below
* please update compat_sys_ioctl() too.
*
@@ -591,6 +714,15 @@ int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
case FIGETBSZ:
return put_user(inode->i_sb->s_blocksize, argp);

+ case FS_IOC_GET_HEAT_INFO:
+ return ioctl_heat_info(filp, argp);
+
+ case FS_IOC_SET_HEAT_OPTS:
+ return ioctl_heat_opts(filp, argp, 1);
+
+ case FS_IOC_GET_HEAT_OPTS:
+ return ioctl_heat_opts(filp, argp, 0);
+
default:
if (S_ISREG(inode->i_mode))
error = file_ioctl(filp, cmd, arg);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6229895..99698f1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -256,6 +256,7 @@ struct inodes_stat_t {
#define S_IMA 1024 /* Inode has an associated IMA struct */
#define S_AUTOMOUNT 2048 /* Automount/referral quasi-directory */
#define S_NOSEC 4096 /* no suid or xattr security attributes */
+#define S_NOHOTDATATRACK (1 << 13) /* hot data tracking */

/*
* Note that nosuid etc flags are inode-specific: setting some file-system
@@ -354,6 +355,16 @@ struct inodes_stat_t {
#define FS_IOC32_SETVERSION _IOW('v', 2, int)

/*
+ * Hot data tracking ioctls:
+ *
+ * HOT_INFO - retrieve info on frequency of access
+ */
+#define FS_IOC_GET_HEAT_INFO _IOR('f', 17, \
+ struct heat_info)
+#define FS_IOC_SET_HEAT_OPTS _IOW('f', 18, int)
+#define FS_IOC_GET_HEAT_OPTS _IOR('f', 19, int)
+
+/*
* Inode flags (FS_IOC_GETFLAGS / FS_IOC_SETFLAGS)
*/
#define FS_SECRM_FL 0x00000001 /* Secure deletion */
diff --git a/include/linux/hot_track.h b/include/linux/hot_track.h
index 0f4c3b3..206dc31 100644
--- a/include/linux/hot_track.h
+++ b/include/linux/hot_track.h
@@ -68,6 +68,18 @@ struct hot_freq_data {
u32 last_temperature;
};

+struct heat_info {
+ __u64 avg_delta_reads;
+ __u64 avg_delta_writes;
+ __u64 last_read_time;
+ __u64 last_write_time;
+ __u32 num_reads;
+ __u32 num_writes;
+ __u32 temperature;
+ __u8 live;
+ char filename[PATH_MAX];
+};
+
/* Hash list heads for hot hash table */
struct hot_hash_head {
struct hlist_head hashhead;
--
1.7.6.5