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 5960578a40760a26bc0ecd88e28177ce748f4380..3e232e8c51b926e90d1a764f093f5e0ac0da3c82 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 997a530ff4e9d038d1e705c582833f8f6817a436..4b349851b00c2796d309415ed11a10a2df585799 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 a620ee610b9f3e07ae76fc4e8d28563258f5c0df..19125489ae948b3ee5efc929561118db867d85fc 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)