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nilfs2: use mnt_want_write in ioctls where write access is needed 

A few nilfs2 ioctls need to ask for and then later release write
access to the mount in order to avoid potential write to read-only
mounts.

This adds the missing mnt_want_write and mnt_drop_write in
nilfs_ioctl_change_cpmode, nilfs_ioctl_delete_checkpoint, and
nilfs_ioctl_clean_segments.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi 2010-01-26 13:59:40 +09:00
parent e902ec9906
commit 7512487e6d
1 changed files with 44 additions and 18 deletions
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62
fs/nilfs2/ioctl.c
View File

@ -26,6 +26,7 @@
#include <linux/capability.h> /* capable() */
#include <linux/uaccess.h> /* copy_from_user(), copy_to_user() */
#include <linux/vmalloc.h>
#include <linux/mount.h> /* mnt_want_write(), mnt_drop_write() */
#include <linux/nilfs2_fs.h>
#include "nilfs.h"
#include "segment.h"
@ -107,20 +108,28 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
ret = mnt_want_write(filp->f_path.mnt);
if (ret)
return ret;
ret = -EFAULT;
if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
return -EFAULT;
goto out;
mutex_lock(&nilfs->ns_mount_mutex);
nilfs_transaction_begin(inode->i_sb, &ti, 0);
ret = nilfs_cpfile_change_cpmode(
cpfile, cpmode.cm_cno, cpmode.cm_mode);
if (unlikely(ret < 0)) {
if (unlikely(ret < 0))
nilfs_transaction_abort(inode->i_sb);
mutex_unlock(&nilfs->ns_mount_mutex);
return ret;
}
nilfs_transaction_commit(inode->i_sb); /* never fails */
else
nilfs_transaction_commit(inode->i_sb); /* never fails */
mutex_unlock(&nilfs->ns_mount_mutex);
out:
mnt_drop_write(filp->f_path.mnt);
return ret;
}
@ -135,16 +144,23 @@ nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
ret = mnt_want_write(filp->f_path.mnt);
if (ret)
return ret;
ret = -EFAULT;
if (copy_from_user(&cno, argp, sizeof(cno)))
return -EFAULT;
goto out;
nilfs_transaction_begin(inode->i_sb, &ti, 0);
ret = nilfs_cpfile_delete_checkpoint(cpfile, cno);
if (unlikely(ret < 0)) {
if (unlikely(ret < 0))
nilfs_transaction_abort(inode->i_sb);
return ret;
}
nilfs_transaction_commit(inode->i_sb); /* never fails */
else
nilfs_transaction_commit(inode->i_sb); /* never fails */
out:
mnt_drop_write(filp->f_path.mnt);
return ret;
}
@ -496,12 +512,19 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (copy_from_user(argv, argp, sizeof(argv)))
return -EFAULT;
ret = mnt_want_write(filp->f_path.mnt);
if (ret)
return ret;
ret = -EFAULT;
if (copy_from_user(argv, argp, sizeof(argv)))
goto out;
ret = -EINVAL;
nsegs = argv[4].v_nmembs;
if (argv[4].v_size != argsz[4])
return -EINVAL;
goto out;
/*
* argv[4] points to segment numbers this ioctl cleans. We
* use kmalloc() for its buffer because memory used for the
@ -509,9 +532,10 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
*/
kbufs[4] = memdup_user((void __user *)(unsigned long)argv[4].v_base,
nsegs * sizeof(__u64));
if (IS_ERR(kbufs[4]))
return PTR_ERR(kbufs[4]);
if (IS_ERR(kbufs[4])) {
ret = PTR_ERR(kbufs[4]);
goto out;
}
nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
for (n = 0; n < 4; n++) {
@ -563,10 +587,12 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
nilfs_remove_all_gcinode(nilfs);
clear_nilfs_gc_running(nilfs);
out_free:
out_free:
while (--n >= 0)
vfree(kbufs[n]);
kfree(kbufs[4]);
out:
mnt_drop_write(filp->f_path.mnt);
return ret;
}