On Thu, Feb 02, 2017 at 05:59:24PM -0500, Theodore Ts'o wrote:
> This ioctl is modeled after the xfs's XFS_IOC_GOINGDOWN ioctl. (In
> fact, it uses the same code points.)
>
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
> ---
> fs/ext4/ext4.h | 10 ++++++++++
> fs/ext4/ioctl.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> fs/ext4/super.c | 2 +-
> 3 files changed, 53 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 94064b7ce16c..eae92f1a52e1 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -679,6 +679,16 @@ struct fsxattr {
> #define EXT4_IOC_FSGETXATTR FS_IOC_FSGETXATTR
> #define EXT4_IOC_FSSETXATTR FS_IOC_FSSETXATTR
>
> +#define EXT4_IOC_GOiNGDOWN _IOR ('X', 125, __u32)
Lowercase 'i'?
ISTR Dave asking if we could rename it IOC_SHUTDOWN way back when f2fs
was trying to implement it.
> +
> +/*
> + * Flags for going down operation
> + */
> +#define EXT4_GOING_FLAGS_DEFAULT 0x0 /* going down */
> +#define EXT4_GOING_FLAGS_LOGFLUSH 0x1 /* flush log but not data */
> +#define EXT4_GOING_FLAGS_NOLOGFLUSH 0x2 /* don't flush log nor data */
> +
> +
> #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
> /*
> * ioctl commands in 32 bit emulation
> diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
> index d534399cf607..6d5443cf4a47 100644
> --- a/fs/ext4/ioctl.c
> +++ b/fs/ext4/ioctl.c
> @@ -442,6 +442,45 @@ static inline unsigned long ext4_xflags_to_iflags(__u32 xflags)
> return iflags;
> }
>
> +int ext4_goingdown(struct super_block *sb, unsigned long arg)
> +{
> + struct ext4_sb_info *sbi = EXT4_SB(sb);
> + __u32 flags;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + if (get_user(flags, (__u32 __user *)arg))
> + return -EFAULT;
> +
> + if (flags > EXT4_GOING_FLAGS_NOLOGFLUSH)
> + return -EINVAL;
> +
> + if (ext4_forced_shutdown(sbi))
> + return 0;
> +
> + switch (flags) {
> + case EXT4_GOING_FLAGS_DEFAULT:
> + freeze_bdev(sb->s_bdev);
> + set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
> + thaw_bdev(sb->s_bdev, sb);
> + break;
> + case EXT4_GOING_FLAGS_LOGFLUSH:
> + if (sbi->s_journal && !is_journal_aborted(sbi->s_journal))
> + (void) ext4_force_commit(sb);
> + /* fall through */
> + case EXT4_GOING_FLAGS_NOLOGFLUSH:
> + if (sbi->s_journal && !is_journal_aborted(sbi->s_journal))
> + (void) jbd2_journal_destroy(sbi->s_journal);
> + sbi->s_journal = NULL;
> + set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
> + break;
> + default:
> + return -EINVAL;
> + }
> + return 0;
/me wonders if mount -o errors=shutdown follows from this? :)
(Something a little less drastic than errors=panic that stops everything
in its tracks.)
--D
> +}
> +
> long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct inode *inode = file_inode(filp);
> @@ -893,6 +932,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>
> return 0;
> }
> + case EXT4_IOC_GOiNGDOWN:
> + return ext4_goingdown(sb, arg);
> default:
> return -ENOTTY;
> }
> @@ -959,6 +1000,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> case EXT4_IOC_SET_ENCRYPTION_POLICY:
> case EXT4_IOC_GET_ENCRYPTION_PWSALT:
> case EXT4_IOC_GET_ENCRYPTION_POLICY:
> + case EXT4_IOC_GOiNGDOWN:
> break;
> default:
> return -ENOIOCTLCMD;
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 829e4a7b59e4..8db181c4dad6 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -4797,7 +4797,7 @@ static int ext4_freeze(struct super_block *sb)
> */
> static int ext4_unfreeze(struct super_block *sb)
> {
> - if (sb->s_flags & MS_RDONLY)
> + if ((sb->s_flags & MS_RDONLY) || ext4_forced_shutdown(EXT4_SB(sb)))
> return 0;
>
> if (EXT4_SB(sb)->s_journal) {
> --
> 2.11.0.rc0.7.gbe5a750
>
