Guarantee that the on-disk timestamps will be no more than 24 hours
stale.
Signed-off-by: Theodore Ts'o <ty...@mit.edu>
---
fs/fs-writeback.c | 1 +
fs/inode.c | 28 +++++++++++++++++++++++-----
include/linux/fs.h | 1 +
3 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index ce7de22..eb04277 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1141,6 +1141,7 @@ 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 2093a84..34a443f 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1511,6 +1511,8 @@ 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 daycode;
int ret;
if (inode->i_op->update_time) {
@@ -1525,17 +1527,33 @@ static int update_time(struct inode *inode, struct
timespec *time, int flags)
if (flags & S_CTIME)
inode->i_ctime = *time;
if (flags & S_MTIME)
- inode->i_mtime = *time;
+ inode->i_mtime = *time;
}
+ /*
+ * 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 defer timestamp
+ * updates in that case and set the I_DIRTY_TIME flag. 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_sb->s_flags & MS_LAZYTIME) &&
!(flags & S_VERSION)) {
if (inode->i_state & I_DIRTY_TIME)
return 0;
- spin_lock(&inode->i_lock);
- inode->i_state |= I_DIRTY_TIME;
- spin_unlock(&inode->i_lock);
- return 0;
+ get_monotonic_boottime(&uptime);
+ daycode = div_u64(uptime.tv_sec, (HZ * 86400));
+ if (!inode->i_ts_dirty_day ||
+ inode->i_ts_dirty_day == daycode) {
+ spin_lock(&inode->i_lock);
+ inode->i_state |= I_DIRTY_TIME;
+ spin_unlock(&inode->i_lock);
+ inode->i_ts_dirty_day = daycode;
+ return 0;
+ }
}
+ inode->i_ts_dirty_day = 0;
if (inode->i_op->write_time)
return inode->i_op->write_time(inode);
mark_inode_dirty_sync(inode);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 489b2f2..e3574cd 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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