Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752194Ab3GACmh (ORCPT ); Sun, 30 Jun 2013 22:42:37 -0400 Received: from mail-pd0-f178.google.com ([209.85.192.178]:50230 "EHLO mail-pd0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845Ab3GACmf (ORCPT ); Sun, 30 Jun 2013 22:42:35 -0400 From: bintian.wang@linaro.org To: linux-kernel@vger.kernel.org Cc: Mike Lockwood , dmitry pervushin , Colin Cross , Android Kernel Team , OGAWA Hirofumi , Andrew Morton , John Stultz , Bintian Wang Subject: [PATCH RFC] Add FAT_IOCTL_GET_VOLUME_ID Date: Mon, 1 Jul 2013 10:39:58 +0800 Message-Id: <1372646398-4204-1-git-send-email-bintian.wang@linaro.org> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6046 Lines: 170 From: Mike Lockwood This patch, originally from Android kernel, adds vfat directory ioctl command FAT_IOCTL_GET_VOLUME_ID, with this command we can get the vfat volume ID using following code: ioctl(dirfd(dir), 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. Cc: dmitry pervushin Cc: Mike Lockwood Cc: Colin Cross Cc: Android Kernel Team Cc: OGAWA Hirofumi Cc: Andrew Morton Cc: John Stultz Signed-off-by: Bintian Wang --- fs/fat/dir.c | 14 ++++++++++++++ fs/fat/fat.h | 1 + fs/fat/inode.c | 9 +++++++++ include/uapi/linux/msdos_fs.h | 13 +++++++++++++ 4 files changed, 37 insertions(+) diff --git a/fs/fat/dir.c b/fs/fat/dir.c index 7a6f02c..4c59108 100644 --- a/fs/fat/dir.c +++ b/fs/fat/dir.c @@ -776,12 +776,19 @@ static int fat_ioctl_readdir(struct inode *inode, struct file *filp, return ret; } +static unsigned int fat_ioctl_volume_id(struct inode *inode) +{ + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + return sbi->vol_id; +} + static long fat_dir_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = file_inode(filp); struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg; int short_only, both; + unsigned int id; switch (cmd) { case VFAT_IOCTL_READDIR_SHORT: @@ -792,6 +799,9 @@ static long fat_dir_ioctl(struct file *filp, unsigned int cmd, short_only = 0; both = 1; break; + case FAT_IOCTL_GET_VOLUME_ID: + id = fat_ioctl_volume_id(inode); + return copy_to_user((unsigned int *)arg, &id, sizeof(id)); default: return fat_generic_ioctl(filp, cmd, arg); } @@ -822,6 +832,7 @@ static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd, struct inode *inode = file_inode(filp); struct compat_dirent __user *d1 = compat_ptr(arg); int short_only, both; + unsigned int id; switch (cmd) { case VFAT_IOCTL_READDIR_SHORT32: @@ -832,6 +843,9 @@ static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd, short_only = 0; both = 1; break; + case FAT_IOCTL_GET_VOLUME_ID: + id = fat_ioctl_volume_id(inode); + return copy_to_user((unsigned int *)arg, &id, sizeof(id)); default: return fat_generic_ioctl(filp, cmd, (unsigned long)arg); } diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 21664fc..4241e6f 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -86,6 +86,7 @@ struct msdos_sb_info { const void *dir_ops; /* Opaque; default directory operations */ int dir_per_block; /* dir entries per block */ int dir_per_block_bits; /* log2(dir_per_block) */ + unsigned int vol_id; /*volume ID*/ int fatent_shift; struct fatent_operations *fatent_ops; diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 5d4513c..a14dd4c 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -1252,6 +1252,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, struct inode *fsinfo_inode = NULL; struct buffer_head *bh; struct fat_boot_sector *b; + struct fat_boot_bsx *bsx; struct msdos_sb_info *sbi; u16 logical_sector_size; u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors; @@ -1398,6 +1399,8 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, goto out_fail; } + bsx = (struct fat_boot_bsx *)(bh->b_data + FAT32_BSX_OFFSET); + fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data; if (!IS_FSINFO(fsinfo)) { fat_msg(sb, KERN_WARNING, "Invalid FSINFO signature: " @@ -1413,8 +1416,14 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat, } brelse(fsinfo_bh); + } else { + bsx = (struct fat_boot_bsx *)(bh->b_data + FAT16_BSX_OFFSET); } + /* interpret volume ID as a little endian 32 bit integer */ + sbi->vol_id = (((u32)bsx->vol_id[0]) | ((u32)bsx->vol_id[1] << 8) | + ((u32)bsx->vol_id[2] << 16) | ((u32)bsx->vol_id[3] << 24)); + sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry); sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1; diff --git a/include/uapi/linux/msdos_fs.h b/include/uapi/linux/msdos_fs.h index f055e58..be142ee 100644 --- a/include/uapi/linux/msdos_fs.h +++ b/include/uapi/linux/msdos_fs.h @@ -104,6 +104,8 @@ struct __fat_dirent { /* has used 0x72 ('r') in collision, so skip a few */ #define FAT_IOCTL_GET_ATTRIBUTES _IOR('r', 0x10, __u32) #define FAT_IOCTL_SET_ATTRIBUTES _IOW('r', 0x11, __u32) +/*Android kernel has used 0x12, so we use 0x13*/ +#define FAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x13, __u32) struct fat_boot_sector { __u8 ignored[3]; /* Boot strap short or near jump */ @@ -161,6 +163,17 @@ struct fat_boot_fsinfo { __le32 reserved2[4]; }; +struct fat_boot_bsx { + __u8 drive; /* drive number */ + __u8 reserved1; + __u8 signature; /* extended boot signature */ + __u8 vol_id[4]; /* volume ID */ + __u8 vol_label[11]; /* volume label */ + __u8 type[8]; /* file system type */ +}; +#define FAT16_BSX_OFFSET 36 /* offset of fat_boot_bsx in FAT12 and FAT16 */ +#define FAT32_BSX_OFFSET 64 /* offset of fat_boot_bsx in FAT32 */ + struct msdos_dir_entry { __u8 name[MSDOS_NAME];/* name and extension */ __u8 attr; /* attribute bits */ -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/