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authorDeepa Dinamani <deepa.kernel@gmail.com>2018-01-21 18:04:25 -0800
committerDeepa Dinamani <deepa.kernel@gmail.com>2019-08-30 07:27:17 -0700
commit50e17c000c467fbc927fc001df99beb4027a5323 (patch)
treefd820b8e8992477f3fa474f152358ed8c09247fd
parent188d20bcd1ebd8277d9b8a79525bd66b66d40a2a (diff)
downloadlinux-50e17c000c467fbc927fc001df99beb4027a5323.tar.bz2
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 <deepa.kernel@gmail.com> Acked-by: Jeff Layton <jlayton@kernel.org>
-rw-r--r--fs/inode.c33
-rw-r--r--include/linux/fs.h2
2 files changed, 34 insertions, 1 deletions
diff --git a/fs/inode.c b/fs/inode.c
index 0f1e3b563c47..64bf28cf05cd 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2167,6 +2167,37 @@ 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);