add-shutdown-ioctl

   1 ext4: add EXT4_IOC_GOINGDOWN ioctl
   2
   3 This ioctl is modeled after the xfs's XFS_IOC_GOINGDOWN ioctl.  (In
   4 fact, it uses the same code points.)
   5
   6 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   7 ---
   8  fs/ext4/ext4.h  | 10 ++++++++++
   9  fs/ext4/ioctl.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
  10  fs/ext4/super.c |  2 +-
  11  3 files changed, 61 insertions(+), 1 deletion(-)
  12
  13 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
  14 index 35d93ab7f3fb..55b7a77a0444 100644
  15 --- a/fs/ext4/ext4.h
  16 +++ b/fs/ext4/ext4.h
  17 @@ -679,6 +679,16 @@ struct fsxattr {
  18  #define EXT4_IOC_FSGETXATTR            FS_IOC_FSGETXATTR
  19  #define EXT4_IOC_FSSETXATTR            FS_IOC_FSSETXATTR
  20
  21 +#define EXT4_IOC_GOINGDOWN _IOR ('X', 125, __u32)
  22 +
  23 +/*
  24 + * Flags for going down operation
  25 + */
  26 +#define EXT4_GOING_FLAGS_DEFAULT               0x0     /* going down */
  27 +#define EXT4_GOING_FLAGS_LOGFLUSH              0x1     /* flush log but not data */
  28 +#define EXT4_GOING_FLAGS_NOLOGFLUSH            0x2     /* don't flush log nor data */
  29 +
  30 +
  31  #if defined(__KERNEL__) && defined(CONFIG_COMPAT)
  32  /*
  33   * ioctl commands in 32 bit emulation
  34 diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
  35 index d534399cf607..b383ebf4020c 100644
  36 --- a/fs/ext4/ioctl.c
  37 +++ b/fs/ext4/ioctl.c
  38 @@ -16,6 +16,7 @@
  39  #include <linux/quotaops.h>
  40  #include <linux/uuid.h>
  41  #include <linux/uaccess.h>
  42 +#include <linux/delay.h>
  43  #include "ext4_jbd2.h"
  44  #include "ext4.h"
  45
  46 @@ -442,6 +443,52 @@ static inline unsigned long ext4_xflags_to_iflags(__u32 xflags)
  47         return iflags;
  48  }
  49
  50 +int ext4_goingdown(struct super_block *sb, unsigned long arg)
  51 +{
  52 +       struct ext4_sb_info *sbi = EXT4_SB(sb);
  53 +       __u32 flags;
  54 +
  55 +       if (!capable(CAP_SYS_ADMIN))
  56 +               return -EPERM;
  57 +
  58 +       if (get_user(flags, (__u32 __user *)arg))
  59 +               return -EFAULT;
  60 +
  61 +       if (flags > EXT4_GOING_FLAGS_NOLOGFLUSH)
  62 +               return -EINVAL;
  63 +
  64 +       if (ext4_forced_shutdown(sbi))
  65 +               return 0;
  66 +
  67 +       ext4_msg(sb, KERN_ALERT, "shut down requested (%d)", flags);
  68 +
  69 +       switch (flags) {
  70 +       case EXT4_GOING_FLAGS_DEFAULT:
  71 +               freeze_bdev(sb->s_bdev);
  72 +               set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
  73 +               thaw_bdev(sb->s_bdev, sb);
  74 +               break;
  75 +       case EXT4_GOING_FLAGS_LOGFLUSH:
  76 +               set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
  77 +               if (sbi->s_journal && !is_journal_aborted(sbi->s_journal)) {
  78 +                       (void) ext4_force_commit(sb);
  79 +                       jbd2_journal_abort(sbi->s_journal, 0);
  80 +               }
  81 +               break;
  82 +       case EXT4_GOING_FLAGS_NOLOGFLUSH:
  83 +               set_bit(EXT4_FLAGS_SHUTDOWN, &sbi->s_ext4_flags);
  84 +               if (sbi->s_journal && !is_journal_aborted(sbi->s_journal)) {
  85 +                       msleep(100);
  86 +                       jbd2_journal_abort(sbi->s_journal, 0);
  87 +               }
  88 +               break;
  89 +       default:
  90 +               return -EINVAL;
  91 +       }
  92 +       clear_opt(sb, DISCARD);
  93 +       return 0;
  94 +}
  95 +
  96  long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
  97  {
  98         struct inode *inode = file_inode(filp);
  99 @@ -893,6 +940,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 100
 101                 return 0;
 102         }
 103 +       case EXT4_IOC_GOINGDOWN:
 104 +               return ext4_goingdown(sb, arg);
 105         default:
 106                 return -ENOTTY;
 107         }
 108 @@ -959,6 +1008,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 109         case EXT4_IOC_SET_ENCRYPTION_POLICY:
 110         case EXT4_IOC_GET_ENCRYPTION_PWSALT:
 111         case EXT4_IOC_GET_ENCRYPTION_POLICY:
 112 +       case EXT4_IOC_GOINGDOWN:
 113                 break;
 114         default:
 115                 return -ENOIOCTLCMD;
 116 diff --git a/fs/ext4/super.c b/fs/ext4/super.c
 117 index 91d6a6199fe0..f9a2252610a8 100644
 118 --- a/fs/ext4/super.c
 119 +++ b/fs/ext4/super.c
 120 @@ -4817,7 +4817,7 @@ static int ext4_freeze(struct super_block *sb)
 121   */
 122  static int ext4_unfreeze(struct super_block *sb)
 123  {
 124 -       if (sb->s_flags & MS_RDONLY)
 125 +       if ((sb->s_flags & MS_RDONLY) || ext4_forced_shutdown(EXT4_SB(sb)))
 126                 return 0;
 127
 128         if (EXT4_SB(sb)->s_journal) {