Ocfs2 devel - Mar 2011 - [PATCH 0/2] support strictatime in ocfs2

Hi, all,

As strictatime was introduced into vfs, we must support it in ocfs2.
This two patches (one for kernel, one for tools) adding support to it 
and update the relative document in ocfs2.
Vfs set RELATIME by default at the beginning, so we need STRICTATIME to 
clear that flag, otherwise we can not always update atime.
With strictatime, the the minimum update interval is specified by 
atime_quantum,  and these two options need work together.

thanks,
tiger

Strictatime was introduced into vfs, so this patch adding support
to it in ocfs2. Now we have three types behavior about update atime,
noatime, relatime and strictatime. With strictatime, the minimum
update interval is specified by atime_quantum, which defaults to 60 secs.

Signed-off-by: Tiger Yang <tiger.yang at oracle.com>
---
 mount.ocfs2/mount.ocfs2.8.in  |   11 ++++++-----
 mount.ocfs2/mount_constants.h |    3 +++
 mount.ocfs2/opts.c            |    2 +-
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/mount.ocfs2/mount.ocfs2.8.in b/mount.ocfs2/mount.ocfs2.8.in
index b367bf1..3bd1d09 100644
--- a/mount.ocfs2/mount.ocfs2.8.in
+++ b/mount.ocfs2/mount.ocfs2.8.in
@@ -20,17 +20,18 @@ specify this mount option to delay the system from mounting
the volume until
 after the network has been enabled.
 
 .TP
-\fBatime\_quantum=nrsec\fR
-The file system will not update atime unless this number of seconds has passed
-since the last update. Set to zero to always update atime. It defaults to 60
secs.
+\fBnoatime\fR
+The file system will not update access time.
 
 .TP
 \fBrelatime\fR
 The file system only update atime if the previous atime is older than mtime or
ctime.
 
 .TP
-\fBnoatime\fR
-The file system will not update access time.
+\fBstrictatime,atime\_quantum=nrsec\fR
+The file system will always perform atime updates, but the minimum update
+interval is specified by atime_quantum. Atime_quantum defaults to 60 secs,
+set it to zero to always update atime. These two options need work together.
 
 .TP
 \fBacl / noacl\fR
diff --git a/mount.ocfs2/mount_constants.h b/mount.ocfs2/mount_constants.h
index ed475db..feffe8f 100644
--- a/mount.ocfs2/mount_constants.h
+++ b/mount.ocfs2/mount_constants.h
@@ -60,6 +60,9 @@ if we have a stack or plain mount - mount atop of it, forming
a stack. */
 #ifndef MS_RELATIME
 #define MS_RELATIME	(1<<21)	/* Update atime relative to mtime/ctime. */
 #endif
+#ifndef MS_STRICTATIME
+#define MS_STRICTATIME	(1<<24)	/* Strict atime semantics */
+#endif
 /*
  * Magic mount flag number. Had to be or-ed to the flag values.
  */
diff --git a/mount.ocfs2/opts.c b/mount.ocfs2/opts.c
index 5ecd36b..96037da 100644
--- a/mount.ocfs2/opts.c
+++ b/mount.ocfs2/opts.c
@@ -78,12 +78,12 @@ static const struct opt_map opt_map[] = {
   { "mand",	0, 0, MS_MANDLOCK },	/* Allow mandatory locks on this FS
*/
   { "nomand",	0, 1, MS_MANDLOCK },	/* Forbid mandatory locks on this
FS */
   { "loop",	1, 0, MS_LOOP	},	/* use a loop device */
-  { "atime",	0, 1, MS_NOATIME },	/* Update access time */
   { "noatime",	0, 0, MS_NOATIME },	/* Do not update access time */
   { "relatime",	0, 0, MS_RELATIME },	/* only update atime if previous
*/
 					/* atime is older than mtime/ctime */
   { "diratime",	0, 1, MS_NODIRATIME },	/* Update dir access times */
   { "nodiratime", 0, 0, MS_NODIRATIME },/* Do not update dir access
times */
+  { "strictatime", 0, 0, MS_STRICTATIME },/* Strict atime semantics
*/
   { "kudzu",	0, 0, MS_COMMENT },	/* Silently remove this option
(backwards compat use only) */
   { "managed",	0, 0, MS_COMMENT },	/* Silently remove this option */
   { NULL,	0, 0, 0	}
-- 
1.7.2.1

As ocfs2 supports relatime and strictatime, we need update the
relative document. Atime_quantum need work with strictatime, so only
show it in procfs when mount with strictatime.

Signed-off-by: Tiger Yang <tiger.yang at oracle.com>
---
 Documentation/filesystems/ocfs2.txt |    8 +++++++-
 fs/ocfs2/super.c                    |    2 +-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/Documentation/filesystems/ocfs2.txt
b/Documentation/filesystems/ocfs2.txt
index 5393e66..a149606 100644
--- a/Documentation/filesystems/ocfs2.txt
+++ b/Documentation/filesystems/ocfs2.txt
@@ -46,9 +46,15 @@ errors=panic		Panic and halt the machine if an error occurs.
 intr		(*)	Allow signals to interrupt cluster operations.
 nointr			Do not allow signals to interrupt cluster
 			operations.
+noatime			Do not update access time.
+relatime(*)		Update atime if the previous atime is older than
+			mtime or ctime
+strictatime		Always update atime, but the minimum update interval
+			is specified by atime_quantum.
 atime_quantum=60(*)	OCFS2 will not update atime unless this number
 			of seconds has passed since the last update.
-			Set to zero to always update atime.
+			Set to zero to always update atime. This option need
+			work with strictatime.
 data=ordered	(*)	All data are forced directly out to the main file
 			system prior to its metadata being committed to the
 			journal.
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 38f986d..f5463a6 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -1564,7 +1564,7 @@ static int ocfs2_show_options(struct seq_file *s, struct
vfsmount *mnt)
 	if (osb->preferred_slot != OCFS2_INVALID_SLOT)
 		seq_printf(s, ",preferred_slot=%d", osb->preferred_slot);
 
-	if (osb->s_atime_quantum != OCFS2_DEFAULT_ATIME_QUANTUM)
+	if (!(mnt->mnt_flags & MNT_NOATIME) && !(mnt->mnt_flags
& MNT_RELATIME))
 		seq_printf(s, ",atime_quantum=%u", osb->s_atime_quantum);
 
 	if (osb->osb_commit_interval)
-- 
1.7.2.1