Guarantee that the on-disk timestamps will be no more than 24 hours
stale.
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
fs/fs-writeback.c | 1 +
fs/inode.c | 20 ++++++++++++++++++++
include/linux/fs.h | 1 +
3 files changed, 22 insertions(+)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 518f3bb..15dec84 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1147,6 +1147,7 @@ void __mark_inode_dirty(struct inode *inode, int flags)
if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) {
trace_writeback_dirty_inode_start(inode, flags);
+ inode->i_ts_dirty_day = 0;
if (sb->s_op->dirty_inode)
sb->s_op->dirty_inode(inode, flags);
diff --git a/fs/inode.c b/fs/inode.c
index 1ec0629..84a5a3d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1507,6 +1507,9 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
*/
static int update_time(struct inode *inode, struct timespec *time, int flags)
{
+ struct timespec uptime;
+ unsigned short days_since_boot;
+
if (inode->i_op->update_time)
return inode->i_op->update_time(inode, time, flags);
@@ -1524,6 +1527,22 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
!(inode->i_state & I_DIRTY_WB)) {
if (inode->i_state & I_DIRTY_TIME)
return 0;
+ get_monotonic_boottime(&uptime);
+ days_since_boot = div_u64(uptime.tv_sec, 86400);
+ /*
+ * If i_ts_dirty_day is zero, then either we have not
+ * deferred timestamp updates, or the system has been
+ * up for less than a day (so days_since_boot is
+ * zero), so we can defer timestamp updates in that
+ * case. If a day or more has passed, then
+ * i_ts_dirty_day will be different from
+ * days_since_boot, and then we should update the
+ * on-disk inode and then we can clear i_ts_dirty_day.
+ */
+ if (inode->i_ts_dirty_day &&
+ (inode->i_ts_dirty_day != days_since_boot))
+ goto force_dirty;
+
spin_lock(&inode->i_lock);
if (inode->i_state & I_DIRTY_WB) {
spin_unlock(&inode->i_lock);
@@ -1534,6 +1553,7 @@ static int update_time(struct inode *inode, struct timespec *time, int flags)
return 0;
}
inode->i_state |= I_DIRTY_TIME;
+ inode->i_ts_dirty_day = days_since_boot;
spin_unlock(&inode->i_lock);
inode_requeue_dirtytime(inode);
return 0;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7932482..2b86b5d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -575,6 +575,7 @@ struct inode {
struct timespec i_ctime;
spinlock_t i_lock; /* i_blocks, i_bytes, maybe i_size */
unsigned short i_bytes;
+ unsigned short i_ts_dirty_day;
unsigned int i_blkbits;
blkcnt_t i_blocks;
--
2.1.0
--
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