From 6e5b93ee55d401f1619092fb675b57c28c9ed7ec Mon Sep 17 00:00:00 2001 From: Mike Lockwood Date: Mon, 8 Jul 2013 16:00:46 -0700 Subject: fatfs: add FAT_IOCTL_GET_VOLUME_ID This patch, originally from Android kernel, adds vfat ioctl command FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID using following code: ioctl(fd, FAT_IOCTL_GET_VOLUME_ID, &volume_ID) This patch is a modified version of the patch by Mike Lockwood, with changes from Dmitry Pervushin, who noticed the original patch makes some volume IDs abiguous with error returns: for example, if volume id is 0xFFFFFDAD, that matches -ENOIOCTLCMD, we get "FFFFFFFF" from the user space. So add a parameter to ioctl to get the correct volume ID. Android uses vfat volume ID to identify different sd card, when a new sd card is inserted to device, android can scan the media on it and pop up new contents. Signed-off-by: Bintian Wang Cc: dmitry pervushin Cc: Mike Lockwood Cc: Colin Cross Acked-by: OGAWA Hirofumi Cc: John Stultz Cc: Sean McNeil Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/fat/file.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'fs/fat/file.c') diff --git a/fs/fat/file.c b/fs/fat/file.c index b0b632e50ddb..9b104f543056 100644 --- a/fs/fat/file.c +++ b/fs/fat/file.c @@ -114,6 +114,12 @@ out: return err; } +static int fat_ioctl_get_volume_id(struct inode *inode, u32 __user *user_attr) +{ + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + return put_user(sbi->vol_id, user_attr); +} + long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); @@ -124,6 +130,8 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) return fat_ioctl_get_attributes(inode, user_attr); case FAT_IOCTL_SET_ATTRIBUTES: return fat_ioctl_set_attributes(filp, user_attr); + case FAT_IOCTL_GET_VOLUME_ID: + return fat_ioctl_get_volume_id(inode, user_attr); default: return -ENOTTY; /* Inappropriate ioctl for device */ } -- cgit v1.2.3