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Commit ac046f1d authored by Peng Tao's avatar Peng Tao Committed by Theodore Ts'o
Browse files

ext4: fix null handler of ioctls in no journal mode 



The EXT4_IOC_GROUP_ADD and EXT4_IOC_GROUP_EXTEND ioctls should not
flush the journal in no_journal mode.  Otherwise, running resize2fs on
a mounted no_journal partition triggers the following error messages:

BUG: unable to handle kernel NULL pointer dereference at 00000014
IP: [<c039d282>] _spin_lock+0x8/0x19
*pde = 00000000 
Oops: 0002 [#1] SMP

Signed-off-by: default avatarPeng Tao <bergwolf@gmail.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent e6b5d301

fs/ext4/ioctl.c

+12 −8
Original line number Original line Diff line number Diff line
@@ -192,7 +192,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
	case EXT4_IOC_GROUP_EXTEND: {

	case EXT4_IOC_GROUP_EXTEND: {

		ext4_fsblk_t n_blocks_count;

		ext4_fsblk_t n_blocks_count;

		struct super_block *sb = inode->i_sb;

		struct super_block *sb = inode->i_sb;

		int err, err2;

		int err, err2=0;





		if (!capable(CAP_SYS_RESOURCE))

		if (!capable(CAP_SYS_RESOURCE))

			return -EPERM;

			return -EPERM;
@@ -205,9 +205,11 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			return err;

			return err;





		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);

		err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count);

		if (EXT4_SB(sb)->s_journal) {

			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);

			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);

			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);

			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);

			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);

			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);

		}

		if (err == 0)

		if (err == 0)

			err = err2;

			err = err2;

		mnt_drop_write(filp->f_path.mnt);

		mnt_drop_write(filp->f_path.mnt);
@@ -252,7 +254,7 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
	case EXT4_IOC_GROUP_ADD: {

	case EXT4_IOC_GROUP_ADD: {

		struct ext4_new_group_data input;

		struct ext4_new_group_data input;

		struct super_block *sb = inode->i_sb;

		struct super_block *sb = inode->i_sb;

		int err, err2;

		int err, err2=0;





		if (!capable(CAP_SYS_RESOURCE))

		if (!capable(CAP_SYS_RESOURCE))

			return -EPERM;

			return -EPERM;
@@ -266,9 +268,11 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) 
			return err;

			return err;





		err = ext4_group_add(sb, &input);

		err = ext4_group_add(sb, &input);

		if (EXT4_SB(sb)->s_journal) {

			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);

			jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal);

			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);

			err2 = jbd2_journal_flush(EXT4_SB(sb)->s_journal);

			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);

			jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);

		}

		if (err == 0)

		if (err == 0)

			err = err2;

			err = err2;

		mnt_drop_write(filp->f_path.mnt);

		mnt_drop_write(filp->f_path.mnt);