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 <[email protected]> Acked-by: Jeff Layton <[email protected]>
jbrandeb · Aug 30, 2019 · 188d20b · 188d20b
1 parent a55aa89
commit 188d20b
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diff --git 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
@@ -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
@@ -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)