diff --git a/fs/namespace.c b/fs/namespace.c index dbd89fffd919..d32b5afa99dc 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -5012,6 +5012,32 @@ static void statmount_fs_subtype(struct kstatmount *s, struct seq_file *seq) seq_puts(seq, sb->s_subtype); } +static int statmount_sb_source(struct kstatmount *s, struct seq_file *seq) +{ + struct super_block *sb = s->mnt->mnt_sb; + struct mount *r = real_mount(s->mnt); + + if (sb->s_op->show_devname) { + size_t start = seq->count; + int ret; + + ret = sb->s_op->show_devname(seq, s->mnt->mnt_root); + if (ret) + return ret; + + if (unlikely(seq_has_overflowed(seq))) + return -EAGAIN; + + /* Unescape the result */ + seq->buf[seq->count] = '\0'; + seq->count = start; + seq_commit(seq, string_unescape_inplace(seq->buf + start, UNESCAPE_OCTAL)); + } else if (r->mnt_devname) { + seq_puts(seq, r->mnt_devname); + } + return 0; +} + static void statmount_mnt_ns_id(struct kstatmount *s, struct mnt_namespace *ns) { s->sm.mask |= STATMOUNT_MNT_NS_ID; @@ -5075,6 +5101,10 @@ static int statmount_string(struct kstatmount *s, u64 flag) sm->fs_subtype = start; statmount_fs_subtype(s, seq); break; + case STATMOUNT_SB_SOURCE: + sm->sb_source = start; + ret = statmount_sb_source(s, seq); + break; default: WARN_ON_ONCE(true); return -EINVAL; @@ -5223,6 +5253,9 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id, if (!err && s->mask & STATMOUNT_FS_SUBTYPE) err = statmount_string(s, STATMOUNT_FS_SUBTYPE); + if (!err && s->mask & STATMOUNT_SB_SOURCE) + err = statmount_string(s, STATMOUNT_SB_SOURCE); + if (!err && s->mask & STATMOUNT_MNT_NS_ID) statmount_mnt_ns_id(s, ns); @@ -5244,7 +5277,8 @@ static inline bool retry_statmount(const long ret, size_t *seq_size) } #define STATMOUNT_STRING_REQ (STATMOUNT_MNT_ROOT | STATMOUNT_MNT_POINT | \ - STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE) + STATMOUNT_FS_TYPE | STATMOUNT_MNT_OPTS | \ + STATMOUNT_FS_SUBTYPE | STATMOUNT_SB_SOURCE) static int prepare_kstatmount(struct kstatmount *ks, struct mnt_id_req *kreq, struct statmount __user *buf, size_t bufsize, diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h index 2e939dddf9cb..2b49e9131d77 100644 --- a/include/uapi/linux/mount.h +++ b/include/uapi/linux/mount.h @@ -174,7 +174,7 @@ struct statmount { __u32 mnt_point; /* [str] Mountpoint relative to current root */ __u64 mnt_ns_id; /* ID of the mount namespace */ __u32 fs_subtype; /* [str] Subtype of fs_type (if any) */ - __u32 __spare1[1]; + __u32 sb_source; /* [str] Source string of the mount */ __u64 __spare2[48]; char str[]; /* Variable size part containing strings */ }; @@ -210,6 +210,7 @@ struct mnt_id_req { #define STATMOUNT_MNT_NS_ID 0x00000040U /* Want/got mnt_ns_id */ #define STATMOUNT_MNT_OPTS 0x00000080U /* Want/got mnt_opts */ #define STATMOUNT_FS_SUBTYPE 0x00000100U /* Want/got fs_subtype */ +#define STATMOUNT_SB_SOURCE 0x00000200U /* Want/got sb_source */ /* * Special @mnt_id values that can be passed to listmount