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| author | Jeff Layton <jlayton@kernel.org> | 2024-11-11 10:09:56 -0500 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-11-12 14:37:12 +0100 |
| commit | ed9d95f691c29748f21bc019de9566b698fdfab7 (patch) | |
| tree | 5b2e64ff56e7ac75f0c4e938918f8d0d3ea2a2e1 /fs | |
| parent | 75ead69a717332efa70303fba85e1876793c74a9 (diff) | |
| download | lwn-ed9d95f691c29748f21bc019de9566b698fdfab7.tar.gz lwn-ed9d95f691c29748f21bc019de9566b698fdfab7.zip | |
fs: add the ability for statmount() to report the fs_subtype
/proc/self/mountinfo prints out the sb->s_subtype after the type. This
is particularly useful for disambiguating FUSE mounts (at least when the
userland driver bothers to set it). Add STATMOUNT_FS_SUBTYPE and claim
one of the __spare2 fields to point to the offset into the str[] array.
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ian Kent <raven@themaw.net>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20241111-statmount-v4-2-2eaf35d07a80@kernel.org
Acked-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/namespace.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index 23187a414754..dbd89fffd919 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -5004,6 +5004,14 @@ static int statmount_fs_type(struct kstatmount *s, struct seq_file *seq) return 0; } +static void statmount_fs_subtype(struct kstatmount *s, struct seq_file *seq) +{ + struct super_block *sb = s->mnt->mnt_sb; + + if (sb->s_subtype) + seq_puts(seq, sb->s_subtype); +} + static void statmount_mnt_ns_id(struct kstatmount *s, struct mnt_namespace *ns) { s->sm.mask |= STATMOUNT_MNT_NS_ID; @@ -5040,7 +5048,7 @@ static int statmount_mnt_opts(struct kstatmount *s, struct seq_file *seq) static int statmount_string(struct kstatmount *s, u64 flag) { - int ret; + int ret = 0; size_t kbufsize; struct seq_file *seq = &s->seq; struct statmount *sm = &s->sm; @@ -5063,6 +5071,10 @@ static int statmount_string(struct kstatmount *s, u64 flag) sm->mnt_opts = start; ret = statmount_mnt_opts(s, seq); break; + case STATMOUNT_FS_SUBTYPE: + sm->fs_subtype = start; + statmount_fs_subtype(s, seq); + break; default: WARN_ON_ONCE(true); return -EINVAL; @@ -5208,6 +5220,9 @@ static int do_statmount(struct kstatmount *s, u64 mnt_id, u64 mnt_ns_id, if (!err && s->mask & STATMOUNT_MNT_OPTS) err = statmount_string(s, STATMOUNT_MNT_OPTS); + if (!err && s->mask & STATMOUNT_FS_SUBTYPE) + err = statmount_string(s, STATMOUNT_FS_SUBTYPE); + if (!err && s->mask & STATMOUNT_MNT_NS_ID) statmount_mnt_ns_id(s, ns); @@ -5229,7 +5244,7 @@ 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_TYPE | STATMOUNT_MNT_OPTS | STATMOUNT_FS_SUBTYPE) static int prepare_kstatmount(struct kstatmount *ks, struct mnt_id_req *kreq, struct statmount __user *buf, size_t bufsize, |