ext4: online defrag -- Add the EXT4_IOC_SUPER_INFO ioctl
From: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
EXT4_IOC_SUPER_INFO gets super block information on disk.
Super block information is necessary for relevant (-r) and force (-f) defrag.
Non-root user can't get this information by opening the block device directly,
so implement this ioctl newly.
Signed-off-by: Akira Fujita <a-fujita@xxxxxxxxxxxxx>
Signed-off-by: Takashi Sato <t-sato@xxxxxxxxxxxxx>
--- fs/ext4/ext4.h | 1 +
fs/ext4/ioctl.c | 10 ++++++++++
2 files changed, 11 insertions(+), 0 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index ccea421..94c4186 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -303,6 +303,7 @@ struct ext4_new_group_data {
#define EXT4_IOC_MIGRATE _IO('f', 9)
/* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
#define EXT4_IOC_DEFRAG _IOW('f', 15, struct ext4_ext_defrag_data)
+#define EXT4_IOC_SUPER_INFO _IOR('f', 16, struct ext4_super_block)
/*
* ioctl commands in 32 bit emulation
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index d5e1fe7..f8ce89b 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -246,6 +246,16 @@ setversion_out:
return err;
}
+ case EXT4_IOC_SUPER_INFO: {
+ struct ext4_super_block es;
+
+ if (copy_to_user((struct ext4_super_block __user *)arg,
+ EXT4_SB(inode->i_sb)->s_es, sizeof(es)))
+ return -EFAULT;
+ else
+ return 0;
+ }
+
case EXT4_IOC_GROUP_ADD: {
struct ext4_new_group_data input;
struct super_block *sb = inode->i_sb;
--
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