From 188d20bcd1ebd8277d9b8a79525bd66b66d40a2a Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Sun, 21 Jan 2018 18:04:23 -0800 Subject: 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 Acked-by: Jeff Layton --- include/linux/fs.h | 3 +++ include/linux/time64.h | 2 ++ 2 files changed, 5 insertions(+) (limited to 'include') diff --git a/include/linux/fs.h b/include/linux/fs.h index 997a530ff4e9..4b349851b00c 100644 --- 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 a620ee610b9f..19125489ae94 100644 --- 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) -- cgit v1.2.3 From 50e17c000c467fbc927fc001df99beb4027a5323 Mon Sep 17 00:00:00 2001 From: Deepa Dinamani Date: Sun, 21 Jan 2018 18:04:25 -0800 Subject: vfs: Add timestamp_truncate() api timespec_trunc() function is used to truncate a filesystem timestamp to the right granularity. But, the function does not clamp tv_sec part of the timestamps according to the filesystem timestamp limits. The replacement api: timestamp_truncate() also alters the signature of the function to accommodate filesystem timestamp clamping according to flesystem limits. Note that the tv_nsec part is set to 0 if tv_sec is not within the range supported for the filesystem. Signed-off-by: Deepa Dinamani Acked-by: Jeff Layton --- fs/inode.c | 33 ++++++++++++++++++++++++++++++++- include/linux/fs.h | 2 ++ 2 files changed, 34 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/fs/inode.c b/fs/inode.c index 0f1e3b563c47..64bf28cf05cd 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -2166,6 +2166,37 @@ struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran) } EXPORT_SYMBOL(timespec64_trunc); +/** + * timestamp_truncate - Truncate timespec to a granularity + * @t: Timespec + * @inode: inode being updated + * + * Truncate a timespec to the granularity supported by the fs + * containing the inode. Always rounds down. gran must + * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns). + */ +struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + unsigned int gran = sb->s_time_gran; + + t.tv_sec = clamp(t.tv_sec, sb->s_time_min, sb->s_time_max); + if (unlikely(t.tv_sec == sb->s_time_max || t.tv_sec == sb->s_time_min)) + t.tv_nsec = 0; + + /* Avoid division in the common cases 1 ns and 1 s. */ + if (gran == 1) + ; /* nothing */ + else if (gran == NSEC_PER_SEC) + t.tv_nsec = 0; + else if (gran > 1 && gran < NSEC_PER_SEC) + t.tv_nsec -= t.tv_nsec % gran; + else + WARN(1, "invalid file time granularity: %u", gran); + return t; +} +EXPORT_SYMBOL(timestamp_truncate); + /** * current_time - Return FS time * @inode: inode. @@ -2187,7 +2218,7 @@ struct timespec64 current_time(struct inode *inode) return now; } - return timespec64_trunc(now, inode->i_sb->s_time_gran); + return timestamp_truncate(now, inode); } EXPORT_SYMBOL(current_time); diff --git a/include/linux/fs.h b/include/linux/fs.h index 4b349851b00c..7e6be3bf0ce0 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -726,6 +726,8 @@ struct inode { void *i_private; /* fs or device private pointer */ } __randomize_layout; +struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode); + static inline unsigned int i_blocksize(const struct inode *node) { return (1 << node->i_blkbits); -- cgit v1.2.3