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Message-Id: <20240815074408.5550-4-konishi.ryusuke@gmail.com>
Date: Thu, 15 Aug 2024 16:44:07 +0900
From: Ryusuke Konishi <konishi.ryusuke@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-nilfs@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] nilfs2: add support for FS_IOC_GETFSLABEL
Implement support for FS_IOC_GETFSLABEL ioctl to read filesystem
label.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@...il.com>
---
fs/nilfs2/ioctl.c | 27 +++++++++++++++++++++++++++
fs/nilfs2/nilfs.h | 12 ++++++++++++
2 files changed, 39 insertions(+)
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 8be471ce4f19..b5c6a50d6d5d 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -17,6 +17,7 @@
#include <linux/mount.h> /* mnt_want_write_file(), mnt_drop_write_file() */
#include <linux/buffer_head.h>
#include <linux/fileattr.h>
+#include <linux/string.h>
#include "nilfs.h"
#include "segment.h"
#include "bmap.h"
@@ -1266,6 +1267,29 @@ static int nilfs_ioctl_set_suinfo(struct inode *inode, struct file *filp,
return ret;
}
+/**
+ * nilfs_ioctl_get_fslabel - get the volume name of the file system
+ * @sb: super block instance
+ * @argp: pointer to userspace memory where the volume name should be stored
+ *
+ * Return: 0 on success, %-EFAULT if copying to userspace memory fails.
+ */
+static int nilfs_ioctl_get_fslabel(struct super_block *sb, void __user *argp)
+{
+ struct the_nilfs *nilfs = sb->s_fs_info;
+ char label[NILFS_MAX_VOLUME_NAME + 1];
+
+ BUILD_BUG_ON(NILFS_MAX_VOLUME_NAME >= FSLABEL_MAX);
+
+ down_read(&nilfs->ns_sem);
+ memtostr_pad(label, nilfs->ns_sbp[0]->s_volume_name);
+ up_read(&nilfs->ns_sem);
+
+ if (copy_to_user(argp, label, sizeof(label)))
+ return -EFAULT;
+ return 0;
+}
+
long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -1308,6 +1332,8 @@ long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return nilfs_ioctl_set_alloc_range(inode, argp);
case FITRIM:
return nilfs_ioctl_trim_fs(inode, argp);
+ case FS_IOC_GETFSLABEL:
+ return nilfs_ioctl_get_fslabel(inode->i_sb, argp);
default:
return -ENOTTY;
}
@@ -1334,6 +1360,7 @@ long nilfs_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
case NILFS_IOCTL_RESIZE:
case NILFS_IOCTL_SET_ALLOC_RANGE:
case FITRIM:
+ case FS_IOC_GETFSLABEL:
break;
default:
return -ENOIOCTLCMD;
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index 4017f7856440..3097490b6621 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -103,6 +103,18 @@ enum {
NILFS_SB_COMMIT_ALL /* Commit both super blocks */
};
+/**
+ * define NILFS_MAX_VOLUME_NAME - maximum number of characters (bytes) in a
+ * file system volume name
+ *
+ * Defined by the size of the volume name field in the on-disk superblocks.
+ * This volume name does not include the terminating NULL byte if the string
+ * length matches the field size, so use (NILFS_MAX_VOLUME_NAME + 1) for the
+ * size of the buffer that requires a NULL byte termination.
+ */
+#define NILFS_MAX_VOLUME_NAME \
+ sizeof_field(struct nilfs_super_block, s_volume_name)
+
/*
* Macros to check inode numbers
*/
--
2.34.1
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