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Commit e7848683 authored by Jan Kara's avatar Jan Kara Committed by Al Viro
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btrfs: Push mnt_want_write() outside of i_mutex 



When mnt_want_write() starts to handle freezing it will get a full lock
semantics requiring proper lock ordering. So push mnt_want_write() call
consistently outside of i_mutex.

CC: Chris Mason <chris.mason@oracle.com>
CC: linux-btrfs@vger.kernel.org
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e24f17da

fs/btrfs/ioctl.c

+11 −12
Original line number Original line Diff line number Diff line
@@ -193,6 +193,10 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) 
	if (!inode_owner_or_capable(inode))

	if (!inode_owner_or_capable(inode))

		return -EACCES;

		return -EACCES;





	ret = mnt_want_write_file(file);

	if (ret)

		return ret;



	mutex_lock(&inode->i_mutex);

	mutex_lock(&inode->i_mutex);





	ip_oldflags = ip->flags;

	ip_oldflags = ip->flags;
@@ -207,10 +211,6 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) 
		}

		}

	}

	}





	ret = mnt_want_write_file(file);

	if (ret)

		goto out_unlock;



	if (flags & FS_SYNC_FL)

	if (flags & FS_SYNC_FL)

		ip->flags |= BTRFS_INODE_SYNC;

		ip->flags |= BTRFS_INODE_SYNC;

	else

	else
@@ -273,9 +273,9 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg) 
		inode->i_flags = i_oldflags;

		inode->i_flags = i_oldflags;

	}

	}





	mnt_drop_write_file(file);

 out_unlock:

 out_unlock:

	mutex_unlock(&inode->i_mutex);

	mutex_unlock(&inode->i_mutex);

	mnt_drop_write_file(file);

	return ret;

	return ret;

}

}
@@ -641,6 +641,10 @@ static noinline int btrfs_mksubvol(struct path *parent, 
	struct dentry *dentry;

	struct dentry *dentry;

	int error;

	int error;





	error = mnt_want_write(parent->mnt);

	if (error)

		return error;



	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);

	mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);





	dentry = lookup_one_len(name, parent->dentry, namelen);

	dentry = lookup_one_len(name, parent->dentry, namelen);
@@ -652,13 +656,9 @@ static noinline int btrfs_mksubvol(struct path *parent, 
	if (dentry->d_inode)

	if (dentry->d_inode)

		goto out_dput;

		goto out_dput;





	error = mnt_want_write(parent->mnt);

	if (error)

		goto out_dput;



	error = btrfs_may_create(dir, dentry);

	error = btrfs_may_create(dir, dentry);

	if (error)

	if (error)

		goto out_drop_write;

		goto out_dput;





	down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);

	down_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);
@@ -676,12 +676,11 @@ static noinline int btrfs_mksubvol(struct path *parent, 
		fsnotify_mkdir(dir, dentry);

		fsnotify_mkdir(dir, dentry);

out_up_read:

out_up_read:

	up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);

	up_read(&BTRFS_I(dir)->root->fs_info->subvol_sem);

out_drop_write:

	mnt_drop_write(parent->mnt);

out_dput:

out_dput:

	dput(dentry);

	dput(dentry);

out_unlock:

out_unlock:

	mutex_unlock(&dir->i_mutex);

	mutex_unlock(&dir->i_mutex);

	mnt_drop_write(parent->mnt);

	return error;

	return error;

}

}