Commit 11ff6f05 authored by Matthew Garrett's avatar Matthew Garrett Committed by Linus Torvalds

Allow relatime to update atime once a day

Allow atime to be updated once per day even with relatime. This lets
utilities like tmpreaper (which delete files based on last access time)
continue working, making relatime a plausible default for distributions.
Signed-off-by: default avatarMatthew Garrett <mjg@redhat.com>
Reviewed-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Acked-by: default avatarValerie Aurora Henson <vaurora@redhat.com>
Acked-by: default avatarAlan Cox <alan@redhat.com>
Acked-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8e0ee43b
......@@ -1290,6 +1290,40 @@ sector_t bmap(struct inode * inode, sector_t block)
}
EXPORT_SYMBOL(bmap);
/*
* With relative atime, only update atime if the previous atime is
* earlier than either the ctime or mtime or if at least a day has
* passed since the last atime update.
*/
static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
struct timespec now)
{
if (!(mnt->mnt_flags & MNT_RELATIME))
return 1;
/*
* Is mtime younger than atime? If yes, update atime:
*/
if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
return 1;
/*
* Is ctime younger than atime? If yes, update atime:
*/
if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
return 1;
/*
* Is the previous atime value older than a day? If yes,
* update atime:
*/
if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
return 1;
/*
* Good, we can skip the atime update:
*/
return 0;
}
/**
* touch_atime - update the access time
* @mnt: mount the inode is accessed on
......@@ -1317,17 +1351,12 @@ void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
goto out;
if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
goto out;
if (mnt->mnt_flags & MNT_RELATIME) {
/*
* With relative atime, only update atime if the previous
* atime is earlier than either the ctime or mtime.
*/
if (timespec_compare(&inode->i_mtime, &inode->i_atime) < 0 &&
timespec_compare(&inode->i_ctime, &inode->i_atime) < 0)
goto out;
}
now = current_fs_time(inode->i_sb);
if (!relatime_need_update(mnt, inode, now))
goto out;
if (timespec_equal(&inode->i_atime, &now))
goto out;
......
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