The FIISFROZEN ioctl can be use by HA and monitoring software to check
the freeze state of the filesystem sitting on top of a block device.
This will not work for filesystems that can handle multiple devices,
i.e. btrfs.
Signed-off-by: Fernando Luis Vazquez Cao <fernando@xxxxxxxxxxxxx>
---
diff -urNp linux-3.0-rc7-orig/block/compat_ioctl.c linux-3.0-rc7/block/compat_ioctl.c
--- linux-3.0-rc7-orig/block/compat_ioctl.c 2011-05-19 13:06:34.000000000 +0900
+++ linux-3.0-rc7/block/compat_ioctl.c 2011-07-20 15:20:31.439999983 +0900
@@ -757,6 +757,13 @@ long compat_blkdev_ioctl(struct file *fi
case BLKTRACETEARDOWN: /* compatible */
ret = blk_trace_ioctl(bdev, cmd, compat_ptr(arg));
return ret;
+ case BLKISFROZEN:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ ret = isfrozen_bdev(bdev);
+ if (ret >= 0)
+ return compat_put_int(arg, ret);
+ return ret;
default:
if (disk->fops->compat_ioctl)
ret = disk->fops->compat_ioctl(bdev, mode, cmd, arg);
diff -urNp linux-3.0-rc7-orig/block/ioctl.c linux-3.0-rc7/block/ioctl.c
--- linux-3.0-rc7-orig/block/ioctl.c 2011-05-19 13:06:34.000000000 +0900
+++ linux-3.0-rc7/block/ioctl.c 2011-07-20 15:20:22.140020393 +0900
@@ -322,6 +322,13 @@ int blkdev_ioctl(struct block_device *bd
case BLKTRACETEARDOWN:
ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
break;
+ case BLKISFROZEN:
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ ret = isfrozen_bdev(bdev);
+ if (ret >= 0)
+ return put_int(arg, ret);
+ return ret;
default:
ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
}
diff -urNp linux-3.0-rc7-orig/fs/block_dev.c linux-3.0-rc7/fs/block_dev.c
--- linux-3.0-rc7-orig/fs/block_dev.c 2011-07-12 09:55:49.656000005 +0900
+++ linux-3.0-rc7/fs/block_dev.c 2011-07-21 09:40:36.900005798 +0900
@@ -310,6 +310,25 @@ out:
}
EXPORT_SYMBOL(thaw_bdev);
+int isfrozen_bdev(struct block_device *bdev)
+{
+ int ret;
+ struct super_block *sb;
+
+ mutex_lock(&bdev->bd_fsfreeze_mutex);
+
+ ret = -EINVAL;
+ sb = get_active_super(bdev);
+ if (!sb)
+ goto out;
+ ret = isfrozen_super(sb);
+ deactivate_super(sb);
+out:
+ mutex_unlock(&bdev->bd_fsfreeze_mutex);
+
+ return ret;
+}
+
static int blkdev_writepage(struct page *page, struct writeback_control *wbc)
{
return block_write_full_page(page, blkdev_get_block, wbc);
diff -urNp linux-3.0-rc7-orig/include/linux/fs.h linux-3.0-rc7/include/linux/fs.h
--- linux-3.0-rc7-orig/include/linux/fs.h 2011-07-12 09:55:51.192000002 +0900
+++ linux-3.0-rc7/include/linux/fs.h 2011-07-20 12:27:59.443932676 +0900
@@ -317,6 +317,7 @@ struct inodes_stat_t {
#define BLKPBSZGET _IO(0x12,123)
#define BLKDISCARDZEROES _IO(0x12,124)
#define BLKSECDISCARD _IO(0x12,125)
+#define BLKISFROZEN _IOR(0x12,126, int) /* get file system freeze state */
#define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
#define FIBMAP _IO(0x00,1) /* bmap access */
@@ -2036,6 +2039,7 @@ extern int sync_blockdev(struct block_de
extern struct super_block *freeze_bdev(struct block_device *);
extern void emergency_thaw_all(void);
extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);
+extern int isfrozen_bdev(struct block_device *bdev);
extern int fsync_bdev(struct block_device *);
#else
static inline void bd_forget(struct inode *inode) {}
@@ -2051,6 +2055,11 @@ static inline int thaw_bdev(struct block
{
return 0;
}
+
+static int isfrozen_bdev(struct block_device *bdev)
+{
+ return 0;
+}
#endif
extern int sync_filesystem(struct super_block *);
extern const struct file_operations def_blk_fops;
--
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