This ioctl gets the information of all inode PAs in the target inode.
The interface of this ioctl is like FS_IOC_FIEMAP. If we call this ioctl, we
get the array of struct ext4_prealloc_info that stores the information of inode
PA.
INTERFACE
-----------
#define EXT4_IOC_GET_PA _IOWR('f', 17, struct ext4_prealloc_list)
struct ext4_prealloc_list {
__u32 pl_count; /* size of pl_space array (in) */
__u32 pl_mapped; /* number of PAs that were mapped (out) */
__u32 pl_entries; /* number of PAs the inode has (out) */
struct ext4_prealloc_info pl_space[0]; /* array of mapped PAs (out) */
};
pl_count specifies the number of elements in the pl_space[] array that can be
used to return inode PAs. If pl_count is zero, no inode PAs will be returned.
Moreover, if pl_count is set the value that is better than the number of
elements in the pl_space array, this ioctl returns EFAULT.
pl_mapped shows the number of getting inode PAs, and pl_entries shows the
number of inode PAs in the target inode. You can confirm that we could get all
inode PAs in the target inode by comparison with pl_mapped and pl_entries.
Signed-off-by: Kazuya Mio <k-mio@xxxxxxxxxxxxx>
Signed-off-by: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
---
fs/ext4/ext4.h | 11 +++++++++++
fs/ext4/ioctl.c | 32 ++++++++++++++++++++++++++++++++
fs/ext4/mballoc.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index b6be407..4b03362 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -141,6 +141,14 @@ struct ext4_prealloc_info {
__u16 pi_flags; /* flags for the inode PA setting ioctl (in) */
};
+/* inode PA list */
+struct ext4_prealloc_list {
+ __u32 pl_count; /* size of pl_space array (in) */
+ __u32 pl_mapped; /* number of PAs that were mapped (out) */
+ __u32 pl_entries; /* number of PAs the inode has (out) */
+ struct ext4_prealloc_info pl_space[0]; /* array of mapped PAs (out) */
+};
+
/*
* For delayed allocation tracking
*/
@@ -414,6 +422,7 @@ struct ext4_new_group_data {
#define EXT4_IOC_ALLOC_DA_BLKS _IO('f', 12)
#define EXT4_IOC_MOVE_EXT _IOWR('f', 15, struct move_extent)
#define EXT4_IOC_CONTROL_PA _IOWR('f', 16, struct ext4_prealloc_info)
+#define EXT4_IOC_GET_PA _IOWR('f', 17, struct ext4_prealloc_list)
/*
* ioctl commands in 32 bit emulation
@@ -1461,6 +1470,8 @@ extern void ext4_mb_put_buddy_cache_lock(struct super_block *,
ext4_group_t, int);
extern int ext4_mb_control_pa(struct inode *inode,
struct ext4_prealloc_info *pi);
+extern int ext4_mb_get_pa(struct inode *inode, struct ext4_prealloc_list *pl,
+ struct ext4_prealloc_info *dest);
/* inode.c */
struct buffer_head *ext4_getblk(handle_t *, struct inode *,
ext4_lblk_t, int, int *);
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index ed68a83..81e2016 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -424,6 +424,37 @@ mext_out:
return err;
}
+ case EXT4_IOC_GET_PA:
+ {
+ struct ext4_prealloc_list pl;
+ struct ext4_prealloc_info *dest;
+ int err;
+
+ if (!S_ISREG(inode->i_mode))
+ return -EINVAL;
+ if (!(filp->f_mode & FMODE_READ))
+ return -EBADF;
+
+ if (copy_from_user(&pl,
+ (struct ext4_prealloc_list __user *)arg, sizeof(pl)))
+ return -EFAULT;
+
+ dest = (struct ext4_prealloc_info *)(arg + sizeof(pl));
+ if (!access_ok(VERIFY_WRITE,
+ (struct ext4_prealloc_info __force __user *)dest,
+ pl.pl_count * sizeof(struct ext4_prealloc_info)))
+ return -EFAULT;
+
+ err = ext4_mb_get_pa(inode, &pl, dest);
+
+ if (err)
+ return err;
+
+ if (copy_to_user((struct ext4_prealloc_list __user *)arg,
+ &pl, sizeof(pl)))
+ return -EFAULT;
+ return err;
+ }
default:
return -ENOTTY;
@@ -473,6 +504,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_MOVE_EXT:
break;
case EXT4_IOC_CONTROL_PA:
+ case EXT4_IOC_GET_PA:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 317a98a..af8b15b 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5041,3 +5041,47 @@ out:
return err1;
}
+/**
+ * ext4_mb_get_pa - Pass inode PA information to user space
+ *
+ * @inode: target inode
+ * @pl: information of the inode PA list (in/out)
+ * @dest: user space address where PAs' information is written to
+ *
+ * Return 0 if success or error code on failure.
+ */
+int ext4_mb_get_pa(struct inode *inode, struct ext4_prealloc_list *pl,
+ struct ext4_prealloc_info *dest)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct ext4_prealloc_space *pa;
+ struct ext4_prealloc_info pi;
+
+ pl->pl_entries = 0;
+ pl->pl_mapped = 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
+ pl->pl_entries++;
+ if (pl->pl_mapped < pl->pl_count) {
+ memset(&pi, 0, sizeof(pi));
+ pi.pi_pstart = pa->pa_pstart;
+ pi.pi_lstart = pa->pa_lstart;
+ pi.pi_len = pa->pa_len;
+ pi.pi_free = pa->pa_free;
+
+ rcu_read_unlock();
+ if (copy_to_user(
+ (struct ext4_prealloc_info __force __user *)dest,
+ &pi, sizeof(pi))) {
+ return -EFAULT;
+ }
+ dest++;
+ pl->pl_mapped++;
+ rcu_read_lock();
+ }
+ }
+ rcu_read_unlock();
+
+ return 0;
+}
--
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