Currently touch_atime and file_update_time directly update a/c/mtime
in the inode and just mark the inode dirty afterwards. This is pretty
bad for some more complex filesystems that have various different types
of dirtying an inode and/or need to store the data in another place
for example for a buffer to be logged.
This patch changes touch_atime and file_update_time to not update the
inode directly but rather call through ->setattr into the filessystem.
There is a new ATTR_UPDTIMES flag for these two calls so filesystems
know it's just a timestampts update. This allows some optimizations
and also allow to kill the IS_NOCMTIME we curretly have for networked
filesystem by letting them simpliy ignore these kind of updates.
There is also a new ATTR_VERSION flag sent from file_update_time
that tells the filesystem to update i_version because this update
has the same issues as the timestamp updates.
The optimiztion to avoid redundant timestamp updates in touch_atime and
file_update_time is moved into ->setattr and made conditional on
the ATTR_UPDTIMES flag.
Also in this patch are the changes to XFS that clean up all the mess
that was caused by the previous behaviour.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Index: linux-2.6/fs/attr.c
===================================================================
--- linux-2.6.orig/fs/attr.c 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/fs/attr.c 2008-05-20 20:48:14.000000000 +0200
@@ -68,6 +68,26 @@ int inode_setattr(struct inode * inode,
unsigned int ia_valid = attr->ia_valid;
int sync_it = 0;
+ /*
+ * Optimize away timestamp updates that happen as side-effect
+ * of data I/O if the new timestamp equals to the one saved
+ * in the inode.
+ *
+ * This optimization is not safe for networked filesystems
+ * that update their timestamps on the server and might not
+ * have the right cached values in the the client inode. But
+ * those network filesystems also turn off client-side timestamp
+ * updates completely, so we don't care about them here.
+ */
+ if (ia_valid & ATTR_UPDTIMES) {
+ if (timespec_equal(&inode->i_atime, &attr->ia_atime))
+ ia_valid &= ~ATTR_ATIME;
+ if (timespec_equal(&inode->i_ctime, &attr->ia_ctime))
+ ia_valid &= ~ATTR_CTIME;
+ if (timespec_equal(&inode->i_mtime, &attr->ia_mtime))
+ ia_valid &= ~ATTR_MTIME;
+ }
+
if (ia_valid & ATTR_SIZE &&
attr->ia_size != i_size_read(inode)) {
int error = vmtruncate(inode, attr->ia_size);
@@ -107,6 +127,10 @@ int inode_setattr(struct inode * inode,
inode->i_mode = mode;
sync_it = 1;
}
+ if (ia_valid & ATTR_VERSION) {
+ inode_inc_iversion(inode);
+ sync_it = 1;
+ }
if (sync_it)
mark_inode_dirty(inode);
Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/fs/inode.c 2008-05-20 20:44:38.000000000 +0200
@@ -1190,7 +1190,7 @@ EXPORT_SYMBOL(bmap);
void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
{
struct inode *inode = dentry->d_inode;
- struct timespec now;
+ struct iattr attr;
if (mnt_want_write(mnt))
return;
@@ -1215,12 +1215,8 @@ void touch_atime(struct vfsmount *mnt, s
goto out;
}
- now = current_fs_time(inode->i_sb);
- if (timespec_equal(&inode->i_atime, &now))
- goto out;
-
- inode->i_atime = now;
- mark_inode_dirty_sync(inode);
+ attr.ia_valid = ATTR_ATIME|ATTR_UPDTIMES;
+ notify_change(dentry, &attr);
out:
mnt_drop_write(mnt);
}
@@ -1241,8 +1237,7 @@ EXPORT_SYMBOL(touch_atime);
void file_update_time(struct file *file)
{
struct inode *inode = file->f_path.dentry->d_inode;
- struct timespec now;
- int sync_it = 0;
+ struct iattr attr;
int err;
if (IS_NOCMTIME(inode))
@@ -1252,27 +1247,13 @@ void file_update_time(struct file *file)
if (err)
return;
- now = current_fs_time(inode->i_sb);
- if (!timespec_equal(&inode->i_mtime, &now)) {
- inode->i_mtime = now;
- sync_it = 1;
- }
-
- if (!timespec_equal(&inode->i_ctime, &now)) {
- inode->i_ctime = now;
- sync_it = 1;
- }
-
- if (IS_I_VERSION(inode)) {
- inode_inc_iversion(inode);
- sync_it = 1;
- }
+ attr.ia_valid = ATTR_MTIME|ATTR_CTIME|ATTR_UPDTIMES;
+ if (IS_I_VERSION(inode))
+ attr.ia_valid |= ATTR_VERSION;
+ notify_change(file->f_path.dentry, &attr);
- if (sync_it)
- mark_inode_dirty_sync(inode);
mnt_drop_write(file->f_path.mnt);
}
-
EXPORT_SYMBOL(file_update_time);
int inode_needs_sync(struct inode *inode)
Index: linux-2.6/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_iops.c 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/linux-2.6/xfs_iops.c 2008-05-20 20:56:42.000000000
+0200
@@ -55,22 +55,6 @@
#include <linux/falloc.h>
/*
- * Bring the atime in the XFS inode uptodate.
- * Used before logging the inode to disk or when the Linux inode goes away.
- */
-void
-xfs_synchronize_atime(
- xfs_inode_t *ip)
-{
- struct inode *inode = ip->i_vnode;
-
- if (inode) {
- ip->i_d.di_atime.t_sec = (__int32_t)inode->i_atime.tv_sec;
- ip->i_d.di_atime.t_nsec = (__int32_t)inode->i_atime.tv_nsec;
- }
-}
-
-/*
* If the linux inode exists, mark it dirty.
* Used when commiting a dirty inode into a transaction so that
* the inode will get written back by the linux code
@@ -136,34 +120,43 @@ xfs_ichgtime(
mark_inode_dirty_sync(inode);
}
-/*
- * Variant on the above which avoids querying the system clock
- * in situations where we know the Linux inode timestamps have
- * just been updated (and so we can update our inode cheaply).
- */
-void
-xfs_ichgtime_fast(
- xfs_inode_t *ip,
- struct inode *inode,
- int flags)
+STATIC int
+xfs_update_timestamps(
+ struct inode *inode,
+ struct iattr *attr)
{
- timespec_t *tvp;
+ struct xfs_inode *ip = XFS_I(inode);
+ unsigned int ia_valid = attr->ia_valid;
+ int sync_it = 0;
- /*
- * Atime updates for read() & friends are handled lazily now, and
- * explicit updates must go through xfs_ichgtime()
- */
- ASSERT((flags & XFS_ICHGTIME_ACC) == 0);
+ ASSERT(!(ia_valid & ~(ATTR_ATIME|ATTR_CTIME|ATTR_MTIME|ATTR_UPDTIMES)));
+ ASSERT(!IS_RDONLY(inode));
- if (flags & XFS_ICHGTIME_MOD) {
- tvp = &inode->i_mtime;
- ip->i_d.di_mtime.t_sec = (__int32_t)tvp->tv_sec;
- ip->i_d.di_mtime.t_nsec = (__int32_t)tvp->tv_nsec;
- }
- if (flags & XFS_ICHGTIME_CHG) {
- tvp = &inode->i_ctime;
- ip->i_d.di_ctime.t_sec = (__int32_t)tvp->tv_sec;
- ip->i_d.di_ctime.t_nsec = (__int32_t)tvp->tv_nsec;
+ if ((ia_valid & ATTR_ATIME) &&
+ !timespec_equal(&inode->i_atime, &attr->ia_atime)) {
+ inode->i_atime = attr->ia_atime;
+ ip->i_d.di_atime.t_sec = attr->ia_atime.tv_sec;
+ ip->i_d.di_atime.t_nsec = attr->ia_atime.tv_nsec;
+ /*
+ * The atime is updated lazily, so we don't mark
+ * the inode dirty here.
+ */
+ }
+
+ if ((ia_valid & ATTR_MTIME) &&
+ !timespec_equal(&inode->i_mtime, &attr->ia_mtime)) {
+ inode->i_mtime = attr->ia_mtime;
+ ip->i_d.di_mtime.t_sec = attr->ia_mtime.tv_sec;
+ ip->i_d.di_mtime.t_nsec = attr->ia_mtime.tv_nsec;
+ sync_it = 1;
+ }
+
+ if ((ia_valid & ATTR_CTIME) &&
+ !timespec_equal(&inode->i_ctime, &attr->ia_ctime)) {
+ inode->i_ctime = attr->ia_ctime;
+ ip->i_d.di_ctime.t_sec = attr->ia_ctime.tv_sec;
+ ip->i_d.di_ctime.t_nsec = attr->ia_ctime.tv_nsec;
+ sync_it = 1;
}
/*
@@ -175,12 +168,14 @@ xfs_ichgtime_fast(
* ensure that the compiler does not reorder the update
* of i_update_core above the timestamp updates above.
*/
- SYNCHRONIZE();
- ip->i_update_core = 1;
- if (!(inode->i_state & I_NEW))
+ if (sync_it) {
+ SYNCHRONIZE();
+ ip->i_update_core = 1;
mark_inode_dirty_sync(inode);
-}
+ }
+ return 0;
+}
/*
* Pull the link count and size up from the xfs inode to the linux inode
@@ -668,6 +663,13 @@ xfs_vn_setattr(
int flags = 0;
int error;
+ /*
+ * Timestamps do not need to be logged and hence do not
+ * need to be done within a transaction.
+ */
+ if (ia_valid & ATTR_UPDTIMES)
+ return xfs_update_timestamps(inode, attr);
+
if (ia_valid & ATTR_UID) {
vattr.va_mask |= XFS_AT_UID;
vattr.va_uid = attr->ia_uid;
Index: linux-2.6/fs/xfs/linux-2.6/xfs_vnode.h
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_vnode.h 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/linux-2.6/xfs_vnode.h 2008-05-20 20:44:38.000000000
+0200
@@ -111,9 +111,6 @@ typedef struct bhv_vattr {
#define XFS_AT_NBLOCKS 0x00002000
#define XFS_AT_VCODE 0x00004000
#define XFS_AT_MAC 0x00008000
-#define XFS_AT_UPDATIME 0x00010000
-#define XFS_AT_UPDMTIME 0x00020000
-#define XFS_AT_UPDCTIME 0x00040000
#define XFS_AT_ACL 0x00080000
#define XFS_AT_CAP 0x00100000
#define XFS_AT_INF 0x00200000
@@ -139,8 +136,6 @@ typedef struct bhv_vattr {
#define XFS_AT_TIMES (XFS_AT_ATIME|XFS_AT_MTIME|XFS_AT_CTIME)
-#define XFS_AT_UPDTIMES
(XFS_AT_UPDATIME|XFS_AT_UPDMTIME|XFS_AT_UPDCTIME)
-
#define XFS_AT_NOSET (XFS_AT_NLINK|XFS_AT_RDEV|XFS_AT_FSID|XFS_AT_NODEID|\
XFS_AT_TYPE|XFS_AT_BLKSIZE|XFS_AT_NBLOCKS|XFS_AT_VCODE|\
XFS_AT_NEXTENTS|XFS_AT_ANEXTENTS|XFS_AT_GENCOUNT)
@@ -193,25 +188,6 @@ static inline int VN_BAD(bhv_vnode_t *vp
}
/*
- * Extracting atime values in various formats
- */
-static inline void vn_atime_to_bstime(bhv_vnode_t *vp, xfs_bstime_t *bs_atime)
-{
- bs_atime->tv_sec = vp->i_atime.tv_sec;
- bs_atime->tv_nsec = vp->i_atime.tv_nsec;
-}
-
-static inline void vn_atime_to_timespec(bhv_vnode_t *vp, struct timespec *ts)
-{
- *ts = vp->i_atime;
-}
-
-static inline void vn_atime_to_time_t(bhv_vnode_t *vp, time_t *tt)
-{
- *tt = vp->i_atime.tv_sec;
-}
-
-/*
* Some useful predicates.
*/
#define VN_MAPPED(vp) mapping_mapped(vn_to_inode(vp)->i_mapping)
Index: linux-2.6/fs/xfs/xfs_inode.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_inode.c 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/fs/xfs/xfs_inode.c 2008-05-20 20:44:38.000000000 +0200
@@ -3330,11 +3330,6 @@ xfs_iflush_int(
ip->i_update_core = 0;
SYNCHRONIZE();
- /*
- * Make sure to get the latest atime from the Linux inode.
- */
- xfs_synchronize_atime(ip);
-
if (XFS_TEST_ERROR(be16_to_cpu(dip->di_core.di_magic) !=
XFS_DINODE_MAGIC,
mp, XFS_ERRTAG_IFLUSH_1, XFS_RANDOM_IFLUSH_1)) {
xfs_cmn_err(XFS_PTAG_IFLUSH, CE_ALERT, mp,
Index: linux-2.6/fs/xfs/xfs_inode.h
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_inode.h 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/fs/xfs/xfs_inode.h 2008-05-20 20:44:38.000000000 +0200
@@ -526,7 +526,6 @@ void xfs_ichgtime(xfs_inode_t *, int);
xfs_fsize_t xfs_file_last_byte(xfs_inode_t *);
void xfs_lock_inodes(xfs_inode_t **, int, uint);
-void xfs_synchronize_atime(xfs_inode_t *);
void xfs_mark_inode_dirty_sync(xfs_inode_t *);
xfs_bmbt_rec_host_t *xfs_iext_get_ext(xfs_ifork_t *, xfs_extnum_t);
Index: linux-2.6/fs/xfs/xfs_inode_item.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_inode_item.c 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/xfs_inode_item.c 2008-05-20 20:44:38.000000000 +0200
@@ -271,11 +271,6 @@ xfs_inode_item_format(
ip->i_update_size = 0;
/*
- * Make sure to get the latest atime from the Linux inode.
- */
- xfs_synchronize_atime(ip);
-
- /*
* make sure the linux inode is dirty
*/
xfs_mark_inode_dirty_sync(ip);
Index: linux-2.6/fs/xfs/xfs_itable.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_itable.c 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/fs/xfs/xfs_itable.c 2008-05-20 20:44:38.000000000 +0200
@@ -85,7 +85,8 @@ xfs_bulkstat_one_iget(
buf->bs_uid = dic->di_uid;
buf->bs_gid = dic->di_gid;
buf->bs_size = dic->di_size;
- vn_atime_to_bstime(vp, &buf->bs_atime);
+ buf->bs_atime.tv_sec = dic->di_atime.t_sec;
+ buf->bs_atime.tv_nsec = dic->di_atime.t_nsec;
buf->bs_mtime.tv_sec = dic->di_mtime.t_sec;
buf->bs_mtime.tv_nsec = dic->di_mtime.t_nsec;
buf->bs_ctime.tv_sec = dic->di_ctime.t_sec;
Index: linux-2.6/fs/xfs/xfs_vnodeops.c
===================================================================
--- linux-2.6.orig/fs/xfs/xfs_vnodeops.c 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/xfs_vnodeops.c 2008-05-20 20:44:38.000000000 +0200
@@ -115,19 +115,6 @@ xfs_setattr(
if (XFS_FORCED_SHUTDOWN(mp))
return XFS_ERROR(EIO);
- /*
- * Timestamps do not need to be logged and hence do not
- * need to be done within a transaction.
- */
- if (mask & XFS_AT_UPDTIMES) {
- ASSERT((mask & ~XFS_AT_UPDTIMES) == 0);
- timeflags = ((mask & XFS_AT_UPDATIME) ? XFS_ICHGTIME_ACC : 0) |
- ((mask & XFS_AT_UPDCTIME) ? XFS_ICHGTIME_CHG : 0) |
- ((mask & XFS_AT_UPDMTIME) ? XFS_ICHGTIME_MOD : 0);
- xfs_ichgtime(ip, timeflags);
- return 0;
- }
-
olddquot1 = olddquot2 = NULL;
udqp = gdqp = NULL;
@@ -3226,12 +3213,6 @@ xfs_reclaim(
ASSERT(XFS_FORCED_SHUTDOWN(ip->i_mount) || ip->i_delayed_blks == 0);
/*
- * Make sure the atime in the XFS inode is correct before freeing the
- * Linux inode.
- */
- xfs_synchronize_atime(ip);
-
- /*
* If we have nothing to flush with this inode then complete the
* teardown now, otherwise break the link between the xfs inode and the
* linux inode and clean up the xfs inode later. This avoids flushing
Index: linux-2.6/fs/xfs/linux-2.6/xfs_iops.h
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_iops.h 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/linux-2.6/xfs_iops.h 2008-05-20 20:44:38.000000000
+0200
@@ -29,7 +29,6 @@ extern const struct file_operations xfs_
struct xfs_inode;
extern void xfs_ichgtime(struct xfs_inode *, int);
-extern void xfs_ichgtime_fast(struct xfs_inode *, struct inode *, int);
#define xfs_vtoi(vp) \
((struct xfs_inode *)vn_to_inode(vp)->i_private)
Index: linux-2.6/fs/xfs/linux-2.6/xfs_lrw.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_lrw.c 2008-05-20 20:44:12.000000000
+0200
+++ linux-2.6/fs/xfs/linux-2.6/xfs_lrw.c 2008-05-20 20:44:38.000000000
+0200
@@ -668,17 +668,8 @@ start:
if (new_size > xip->i_size)
xip->i_new_size = new_size;
- /*
- * We're not supposed to change timestamps in readonly-mounted
- * filesystems. Throw it away if anyone asks us.
- */
- if (likely(!(ioflags & IO_INVIS) &&
- !mnt_want_write(file->f_path.mnt))) {
+ if (likely(!(ioflags & IO_INVIS)))
file_update_time(file);
- xfs_ichgtime_fast(xip, inode,
- XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
- mnt_drop_write(file->f_path.mnt);
- }
/*
* If the offset is beyond the size of the file, we have a couple
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h 2008-05-20 20:44:12.000000000 +0200
+++ linux-2.6/include/linux/fs.h 2008-05-20 20:44:38.000000000 +0200
@@ -333,6 +333,9 @@ typedef void (dio_iodone_t)(struct kiocb
#define ATTR_FILE 8192
#define ATTR_KILL_PRIV 16384
#define ATTR_OPEN 32768 /* Truncating from open(O_TRUNC) */
+#define ATTR_VERSION 65536 /* increment i_version */
+#define ATTR_UPDTIMES 131072 /* timestamp updates are side-effect of
+ read/write operations */
/*
* This is the Inode Attributes structure, used for notify_change(). It
|