Add support for writing to the volume label of a FAT filesystem via the
FS_IOC_SETFSLABEL ioctl.
Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>
---
fs/fat/dir.c | 51 +++++++++++++++++++++++++++++++++++
fs/fat/fat.h | 6 +++++
fs/fat/file.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
fs/fat/inode.c | 15 +++++++++++
fs/fat/namei_msdos.c | 4 +--
5 files changed, 137 insertions(+), 2 deletions(-)
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 07d95f1442c8..1b11713309ae 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -1425,3 +1425,54 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
return err;
}
EXPORT_SYMBOL_GPL(fat_add_entries);
+
+static int fat_create_volume_label_dentry(struct super_block *sb, char *vol_label)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct inode *root_inode = sb->s_root->d_inode;
+ struct msdos_dir_entry de;
+ struct fat_slot_info sinfo;
+ struct timespec64 ts = current_time(root_inode);
+ __le16 date, time;
+ u8 time_cs;
+
+ memcpy(de.name, vol_label, MSDOS_NAME);
+ de.attr = ATTR_VOLUME;
+ de.starthi = de.start = de.size = de.lcase = 0;
+
+ fat_time_unix2fat(sbi, &ts, &time, &date, &time_cs);
+ de.time = time;
+ de.date = date;
+ if (sbi->options.isvfat) {
+ de.cdate = de.adate = date;
+ de.ctime = time;
+ de.ctime_cs = time_cs;
+ } else
+ de.cdate = de.adate = de.ctime = de.ctime_cs = 0;
+
+ return fat_add_entries(root_inode, &de, 1, &sinfo);
+}
+
+int fat_rename_volume_label_dentry(struct super_block *sb, char *vol_label)
+{
+ struct inode *root_inode = sb->s_root->d_inode;
+ struct buffer_head *bh = NULL;
+ struct msdos_dir_entry *de;
+ loff_t cpos = 0;
+ int err = 0;
+
+ while (1) {
+ if (fat_get_entry(root_inode, &cpos, &bh, &de) == -1)
+ return fat_create_volume_label_dentry(sb, vol_label);
+
+ if (de->attr == ATTR_VOLUME) {
+ memcpy(de->name, vol_label, MSDOS_NAME);
+ mark_buffer_dirty_inode(bh, root_inode);
+ if (IS_DIRSYNC(root_inode))
+ err = sync_dirty_buffer(bh);
+ brelse(bh);
+ return err;
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(fat_rename_volume_label_dentry);
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 4350c00dba34..3b75223fbe76 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -341,6 +341,8 @@ extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
struct fat_slot_info *sinfo);
extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
+extern int fat_rename_volume_label_dentry(struct super_block *sb,
+ char *vol_label);
/* fat/fatent.c */
struct fat_entry {
@@ -480,6 +482,10 @@ extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
int fat_cache_init(void);
void fat_cache_destroy(void);
+/* fat/namei/msdos.c */
+int msdos_format_name(const unsigned char *name, int len,
+ unsigned char *res, struct fat_mount_options *opts);
+
/* fat/nfs.c */
extern const struct export_operations fat_export_ops;
extern const struct export_operations fat_export_ops_nostale;
diff --git a/fs/fat/file.c b/fs/fat/file.c
index 029b1750d1ec..5d445c2d8657 100644
--- a/fs/fat/file.c
+++ b/fs/fat/file.c
@@ -167,6 +167,67 @@ static int fat_ioctl_get_volume_label(struct super_block *sb, char __user *arg)
return 0;
}
+static int fat_convert_volume_label_str(struct msdos_sb_info *sbi, char *in,
+ char *out)
+{
+ int ret, in_len = max(strnlen(in, FSLABEL_MAX), 11);
+ char *needle;
+
+ /*
+ * '.' is not included in any bad_chars list in this driver,
+ * but it is specifically not allowed for volume labels
+ */
+ for (needle = in; needle - in < in_len; needle++)
+ if (*needle == '.')
+ return -EINVAL;
+
+ ret = msdos_format_name(in, in_len, out, &sbi->options);
+ if (ret)
+ return ret;
+
+ /*
+ * msdos_format_name assumes we're translating an 8.3 name, but
+ * we can handle 11 chars
+ */
+ if (in_len > 8)
+ ret = msdos_format_name(in + 8, in_len - 8, out + 8,
+ &sbi->options);
+ return ret;
+}
+
+static int fat_ioctl_set_volume_label(struct super_block *sb, char __user *arg)
+{
+ struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct inode *root_inode = sb->s_root->d_inode;
+ char from_user[FSLABEL_MAX];
+ char new_vol_label[MSDOS_NAME];
+ int ret;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (sb_rdonly(sb))
+ return -EROFS;
+
+ if (copy_from_user(from_user, arg, FSLABEL_MAX))
+ return -EFAULT;
+
+ ret = fat_convert_volume_label_str(sbi, from_user, new_vol_label);
+ if (ret)
+ return ret;
+
+ inode_lock(root_inode);
+ ret = fat_rename_volume_label_dentry(sb, new_vol_label);
+ inode_unlock(root_inode);
+ if (ret)
+ return ret;
+
+ mutex_lock(&sbi->s_lock);
+ memcpy(sbi->vol_label, new_vol_label, MSDOS_NAME);
+ mutex_unlock(&sbi->s_lock);
+ return 0;
+}
+
long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@@ -181,6 +242,8 @@ long fat_generic_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
return fat_ioctl_get_volume_id(inode, user_attr);
case FS_IOC_GETFSLABEL:
return fat_ioctl_get_volume_label(inode->i_sb, (char __user *) arg);
+ case FS_IOC_SETFSLABEL:
+ return fat_ioctl_set_volume_label(inode->i_sb, (char __user *) arg);
case FITRIM:
return fat_ioctl_fitrim(inode, arg);
default:
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 6f9a8cc1ad2a..a7528937383b 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -736,6 +736,21 @@ static void delayed_free(struct rcu_head *p)
static void fat_put_super(struct super_block *sb)
{
struct msdos_sb_info *sbi = MSDOS_SB(sb);
+ struct buffer_head *bh = NULL;
+ struct fat_boot_sector *bs;
+
+ bh = sb_bread(sb, 0);
+ if (bh == NULL)
+ fat_msg(sb, KERN_ERR, "unable to read boot sector");
+ else if (!sb_rdonly(sb)) {
+ bs = (struct fat_boot_sector *)bh->b_data;
+ if (is_fat32(sbi))
+ memcpy(bs->fat32.vol_label, sbi->vol_label, MSDOS_NAME);
+ else
+ memcpy(bs->fat16.vol_label, sbi->vol_label, MSDOS_NAME);
+ mark_buffer_dirty(bh);
+ }
+ brelse(bh);
fat_set_state(sb, 0, 0);
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
index ba0152ed0810..92b5d387f88e 100644
--- a/fs/fat/namei_msdos.c
+++ b/fs/fat/namei_msdos.c
@@ -16,8 +16,8 @@ static unsigned char bad_chars[] = "*?<>|\"";
static unsigned char bad_if_strict[] = "+=,; ";
/***** Formats an MS-DOS file name. Rejects invalid names. */
-static int msdos_format_name(const unsigned char *name, int len,
- unsigned char *res, struct fat_mount_options *opts)
+int msdos_format_name(const unsigned char *name, int len, unsigned char *res,
+ struct fat_mount_options *opts)
/*
* name is the proposed name, len is its length, res is
* the resulting name, opts->name_check is either (r)elaxed,
--
2.43.0Hi Ethan, kernel test robot noticed the following build errors: [auto build test ERROR on 9f2693489ef8558240d9e80bfad103650daed0af] url: https://github.com/intel-lab-lkp/linux/commits/Ethan-Ferguson/fat-Add-FS_IOC_GETFSLABEL-ioctl/20260218-071019 base: 9f2693489ef8558240d9e80bfad103650daed0af patch link: https://lore.kernel.org/r/20260217230628.719475-3-ethan.ferguson%40zetier.com patch subject: [PATCH v2 2/2] fat: Add FS_IOC_SETFSLABEL ioctl config: arm-vexpress_defconfig (https://download.01.org/0day-ci/archive/20260218/202602181429.zMfoW0eg-lkp@intel.com/config) compiler: arm-linux-gnueabi-gcc (GCC) 15.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260218/202602181429.zMfoW0eg-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202602181429.zMfoW0eg-lkp@intel.com/ All errors (new ones prefixed by >>): arm-linux-gnueabi-ld: fs/fat/file.o: in function `fat_convert_volume_label_str': fs/fat/file.c:184:(.text+0x14c): undefined reference to `msdos_format_name' >> arm-linux-gnueabi-ld: fs/fat/file.c:193:(.text+0x168): undefined reference to `msdos_format_name' -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Hi Ethan, kernel test robot noticed the following build errors: [auto build test ERROR on 9f2693489ef8558240d9e80bfad103650daed0af] url: https://github.com/intel-lab-lkp/linux/commits/Ethan-Ferguson/fat-Add-FS_IOC_GETFSLABEL-ioctl/20260218-071019 base: 9f2693489ef8558240d9e80bfad103650daed0af patch link: https://lore.kernel.org/r/20260217230628.719475-3-ethan.ferguson%40zetier.com patch subject: [PATCH v2 2/2] fat: Add FS_IOC_SETFSLABEL ioctl config: i386-randconfig-014-20260218 (https://download.01.org/0day-ci/archive/20260218/202602181513.zGRm1yrD-lkp@intel.com/config) compiler: gcc-14 (Debian 14.2.0-19) 14.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260218/202602181513.zGRm1yrD-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202602181513.zGRm1yrD-lkp@intel.com/ All errors (new ones prefixed by >>): ld: fs/fat/file.o: in function `fat_convert_volume_label_str': fs/fat/file.c:184:(.text+0x108): undefined reference to `msdos_format_name' >> ld: fs/fat/file.c:193:(.text+0x12a): undefined reference to `msdos_format_name' -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Ethan Ferguson <ethan.ferguson@zetier.com> writes:
> Add support for writing to the volume label of a FAT filesystem via the
> FS_IOC_SETFSLABEL ioctl.
>
> Signed-off-by: Ethan Ferguson <ethan.ferguson@zetier.com>
> ---
> fs/fat/dir.c | 51 +++++++++++++++++++++++++++++++++++
> fs/fat/fat.h | 6 +++++
> fs/fat/file.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
> fs/fat/inode.c | 15 +++++++++++
> fs/fat/namei_msdos.c | 4 +--
> 5 files changed, 137 insertions(+), 2 deletions(-)
>
> diff --git a/fs/fat/dir.c b/fs/fat/dir.c
> index 07d95f1442c8..1b11713309ae 100644
> --- a/fs/fat/dir.c
> +++ b/fs/fat/dir.c
> @@ -1425,3 +1425,54 @@ int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
> return err;
> }
> EXPORT_SYMBOL_GPL(fat_add_entries);
> +
> +static int fat_create_volume_label_dentry(struct super_block *sb, char *vol_label)
> +{
> + struct msdos_sb_info *sbi = MSDOS_SB(sb);
> + struct inode *root_inode = sb->s_root->d_inode;
> + struct msdos_dir_entry de;
> + struct fat_slot_info sinfo;
> + struct timespec64 ts = current_time(root_inode);
> + __le16 date, time;
> + u8 time_cs;
> +
> + memcpy(de.name, vol_label, MSDOS_NAME);
> + de.attr = ATTR_VOLUME;
> + de.starthi = de.start = de.size = de.lcase = 0;
> +
> + fat_time_unix2fat(sbi, &ts, &time, &date, &time_cs);
> + de.time = time;
> + de.date = date;
> + if (sbi->options.isvfat) {
> + de.cdate = de.adate = date;
> + de.ctime = time;
> + de.ctime_cs = time_cs;
> + } else
> + de.cdate = de.adate = de.ctime = de.ctime_cs = 0;
> +
> + return fat_add_entries(root_inode, &de, 1, &sinfo);
> +}
> +
> +int fat_rename_volume_label_dentry(struct super_block *sb, char *vol_label)
> +{
> + struct inode *root_inode = sb->s_root->d_inode;
> + struct buffer_head *bh = NULL;
> + struct msdos_dir_entry *de;
> + loff_t cpos = 0;
> + int err = 0;
> +
> + while (1) {
> + if (fat_get_entry(root_inode, &cpos, &bh, &de) == -1)
> + return fat_create_volume_label_dentry(sb, vol_label);
> +
> + if (de->attr == ATTR_VOLUME) {
> + memcpy(de->name, vol_label, MSDOS_NAME);
> + mark_buffer_dirty_inode(bh, root_inode);
> + if (IS_DIRSYNC(root_inode))
> + err = sync_dirty_buffer(bh);
> + brelse(bh);
> + return err;
> + }
> + }
I didn't check how to know the label though, the label is only if
ATTR_VOLUME? IOW, any other attributes are disallowed?
What if label is marked as deleted?
I'm not sure though, no need to update timestamps? (need to investigate
spec or windows behavior)
> +static int fat_convert_volume_label_str(struct msdos_sb_info *sbi, char *in,
> + char *out)
> +{
> + int ret, in_len = max(strnlen(in, FSLABEL_MAX), 11);
> + char *needle;
Silently truncate is the common way for this ioctl?
> + /*
> + * '.' is not included in any bad_chars list in this driver,
> + * but it is specifically not allowed for volume labels
> + */
> + for (needle = in; needle - in < in_len; needle++)
> + if (*needle == '.')
> + return -EINVAL;
memchr() or such?
> + ret = msdos_format_name(in, in_len, out, &sbi->options);
> + if (ret)
> + return ret;
> + /*
> + * msdos_format_name assumes we're translating an 8.3 name, but
> + * we can handle 11 chars
> + */
> + if (in_len > 8)
> + ret = msdos_format_name(in + 8, in_len - 8, out + 8,
> + &sbi->options);
> + return ret;
fat module should not import msdos module.
> +static int fat_ioctl_set_volume_label(struct super_block *sb, char __user *arg)
> +{
> + struct msdos_sb_info *sbi = MSDOS_SB(sb);
> + struct inode *root_inode = sb->s_root->d_inode;
> + char from_user[FSLABEL_MAX];
> + char new_vol_label[MSDOS_NAME];
> + int ret;
> +
> + if (!capable(CAP_SYS_ADMIN))
> + return -EPERM;
> +
> + if (sb_rdonly(sb))
> + return -EROFS;
> +
> + if (copy_from_user(from_user, arg, FSLABEL_MAX))
> + return -EFAULT;
> +
> + ret = fat_convert_volume_label_str(sbi, from_user, new_vol_label);
> + if (ret)
> + return ret;
> +
> + inode_lock(root_inode);
> + ret = fat_rename_volume_label_dentry(sb, new_vol_label);
> + inode_unlock(root_inode);
> + if (ret)
> + return ret;
This rename will have to take same or similar locks with rename(2)?
> diff --git a/fs/fat/inode.c b/fs/fat/inode.c
> index 6f9a8cc1ad2a..a7528937383b 100644
> --- a/fs/fat/inode.c
> +++ b/fs/fat/inode.c
> @@ -736,6 +736,21 @@ static void delayed_free(struct rcu_head *p)
> static void fat_put_super(struct super_block *sb)
> {
> struct msdos_sb_info *sbi = MSDOS_SB(sb);
> + struct buffer_head *bh = NULL;
> + struct fat_boot_sector *bs;
> +
> + bh = sb_bread(sb, 0);
> + if (bh == NULL)
> + fat_msg(sb, KERN_ERR, "unable to read boot sector");
> + else if (!sb_rdonly(sb)) {
> + bs = (struct fat_boot_sector *)bh->b_data;
> + if (is_fat32(sbi))
> + memcpy(bs->fat32.vol_label, sbi->vol_label, MSDOS_NAME);
> + else
> + memcpy(bs->fat16.vol_label, sbi->vol_label, MSDOS_NAME);
> + mark_buffer_dirty(bh);
> + }
> + brelse(bh);
Why this unconditionally update the vol_label at unmount?
Thanks.
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Hi Ethan, kernel test robot noticed the following build errors: [auto build test ERROR on 9f2693489ef8558240d9e80bfad103650daed0af] url: https://github.com/intel-lab-lkp/linux/commits/Ethan-Ferguson/fat-Add-FS_IOC_GETFSLABEL-ioctl/20260218-071019 base: 9f2693489ef8558240d9e80bfad103650daed0af patch link: https://lore.kernel.org/r/20260217230628.719475-3-ethan.ferguson%40zetier.com patch subject: [PATCH v2 2/2] fat: Add FS_IOC_SETFSLABEL ioctl config: x86_64-rhel-9.4-ltp (https://download.01.org/0day-ci/archive/20260218/202602181149.k8dhUKY6-lkp@intel.com/config) compiler: gcc-14 (Debian 14.2.0-19) 14.2.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260218/202602181149.k8dhUKY6-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <lkp@intel.com> | Closes: https://lore.kernel.org/oe-kbuild-all/202602181149.k8dhUKY6-lkp@intel.com/ All errors (new ones prefixed by >>, old ones prefixed by <<): >> ERROR: modpost: "msdos_format_name" [fs/fat/fat.ko] undefined! -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
Hi Ethan,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 9f2693489ef8558240d9e80bfad103650daed0af]
url: https://github.com/intel-lab-lkp/linux/commits/Ethan-Ferguson/fat-Add-FS_IOC_GETFSLABEL-ioctl/20260218-071019
base: 9f2693489ef8558240d9e80bfad103650daed0af
patch link: https://lore.kernel.org/r/20260217230628.719475-3-ethan.ferguson%40zetier.com
patch subject: [PATCH v2 2/2] fat: Add FS_IOC_SETFSLABEL ioctl
config: hexagon-randconfig-r121-20260218 (https://download.01.org/0day-ci/archive/20260219/202602190010.tPRKu8kq-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project e86750b29fa0ff207cd43213d66dabe565417638)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260219/202602190010.tPRKu8kq-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202602190010.tPRKu8kq-lkp@intel.com/
sparse warnings: (new ones prefixed by >>)
>> fs/fat/dir.c:1439:41: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __le32 [addressable] [assigned] [usertype] size @@ got unsigned char [addressable] [assigned] [usertype] lcase @@
fs/fat/dir.c:1439:41: sparse: expected restricted __le32 [addressable] [assigned] [usertype] size
fs/fat/dir.c:1439:41: sparse: got unsigned char [addressable] [assigned] [usertype] lcase
>> fs/fat/dir.c:1449:48: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __le16 [addressable] [assigned] [usertype] ctime @@ got unsigned char [addressable] [assigned] [usertype] ctime_cs @@
fs/fat/dir.c:1449:48: sparse: expected restricted __le16 [addressable] [assigned] [usertype] ctime
fs/fat/dir.c:1449:48: sparse: got unsigned char [addressable] [assigned] [usertype] ctime_cs
vim +1439 fs/fat/dir.c
1426
1427 static int fat_create_volume_label_dentry(struct super_block *sb, char *vol_label)
1428 {
1429 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1430 struct inode *root_inode = sb->s_root->d_inode;
1431 struct msdos_dir_entry de;
1432 struct fat_slot_info sinfo;
1433 struct timespec64 ts = current_time(root_inode);
1434 __le16 date, time;
1435 u8 time_cs;
1436
1437 memcpy(de.name, vol_label, MSDOS_NAME);
1438 de.attr = ATTR_VOLUME;
> 1439 de.starthi = de.start = de.size = de.lcase = 0;
1440
1441 fat_time_unix2fat(sbi, &ts, &time, &date, &time_cs);
1442 de.time = time;
1443 de.date = date;
1444 if (sbi->options.isvfat) {
1445 de.cdate = de.adate = date;
1446 de.ctime = time;
1447 de.ctime_cs = time_cs;
1448 } else
> 1449 de.cdate = de.adate = de.ctime = de.ctime_cs = 0;
1450
1451 return fat_add_entries(root_inode, &de, 1, &sinfo);
1452 }
1453
--
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