vfs: Add file timestamp range support

Add fields to the superblock to track the min and max
timestamps supported by filesystems.

Initially, when a superblock is allocated, initialize
it to the max and min values the fields can hold.
Individual filesystems override these to match their
actual limits.

Pseudo filesystems are assumed to always support the
min and max allowable values for the fields.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Jeff Layton <jlayton@kernel.org>

diff --git a/fs/super.c b/fs/super.c
index 5960578..3e232e8 100644 (file)
--- a/fs/super.c
+++ b/fs/super.c
@@ -257,6 +257,8 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags,
        s->s_maxbytes = MAX_NON_LFS;
        s->s_op = &default_op;
        s->s_time_gran = 1000000000;
+       s->s_time_min = TIME64_MIN;
+       s->s_time_max = TIME64_MAX;
        s->cleancache_poolid = CLEANCACHE_NO_POOL;
 
        s->s_shrink.seeks = DEFAULT_SEEKS;

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 997a530..4b34985 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1448,6 +1448,9 @@ struct super_block {
 
        /* Granularity of c/m/atime in ns (cannot be worse than a second) */
        u32                     s_time_gran;
+       /* Time limits for c/m/atime in seconds */
+       time64_t                   s_time_min;
+       time64_t                   s_time_max;
 #ifdef CONFIG_FSNOTIFY
        __u32                   s_fsnotify_mask;
        struct fsnotify_mark_connector __rcu    *s_fsnotify_marks;

diff --git a/include/linux/time64.h b/include/linux/time64.h
index a620ee6..1912548 100644 (file)
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -30,6 +30,8 @@ struct itimerspec64 {
 
 /* Located here for timespec[64]_valid_strict */
 #define TIME64_MAX                     ((s64)~((u64)1 << 63))
+#define TIME64_MIN                     (-TIME64_MAX - 1)
+
 #define KTIME_MAX                      ((s64)~((u64)1 << 63))
 #define KTIME_SEC_MAX                  (KTIME_MAX / NSEC_PER_SEC)