A few weeks ago, during one of the discussions around i_version, Dave
Chinner wrote this:
"You've missed the part where I suggested lifting the "nfsd sampled
i_version" state into an inode state flag rather than hiding it in
the i_version field. At that point, we could optimise away the
secondary ctime updates just like you are proposing we do with the
i_version updates. Further, we could also use that state it to
decide whether we need to use high resolution timestamps when
recording ctime updates - if the nfsd has not sampled the
ctime/i_version, we don't need high res timestamps to be recorded
for ctime...."
While I don't think we can practically optimize away ctime updates
like we do with i_version, I do like the idea of using this scheme to
indicate when we need to use a high-res timestamp.
This patchset is a first stab at a scheme to do this. It declares a new
i_state flag for this purpose and adds two new vfs-layer functions to
implement conditional high-res timestamp fetching. It then converts both
tmpfs and xfs to use it.
This seems to behave fine under xfstests, but I haven't yet done
any performance testing with it. I wouldn't expect it to create huge
regressions though since we're only grabbing high res timestamps after
each query.
I like this scheme because we can potentially convert any filesystem to
use it. No special storage requirements like with i_version field. I
think it'd potentially improve NFS cache coherency with a whole swath of
exportable filesystems, and helps out NFSv3 too.
This is really just a proof-of-concept. There are a number of things we
could change:
1/ We could use the top bit in the tv_sec field as the flag. That'd give
us different flags for ctime and mtime. We also wouldn't need to use
a spinlock.
2/ We could probably optimize away the high-res timestamp fetch in more
cases. Basically, always do a coarse-grained ts fetch and only fetch
the high-res ts when the QUERIED flag is set and the existing time
hasn't changed.
If this approach looks reasonable, I'll plan to start working on
converting more filesystems.
One thing I'm not clear on is how widely available high res timestamps
are. Is this something we need to gate on particular CONFIG_* options?
Thoughts?
Jeff Layton (3):
fs: add infrastructure for opportunistic high-res ctime/mtime updates
shmem: mark for high-res timestamps on next update after getattr
xfs: mark the inode for high-res timestamp update in getattr
fs/inode.c | 40 +++++++++++++++++++++++++++++++--
fs/stat.c | 10 +++++++++
fs/xfs/libxfs/xfs_trans_inode.c | 2 +-
fs/xfs/xfs_acl.c | 2 +-
fs/xfs/xfs_inode.c | 2 +-
fs/xfs/xfs_iops.c | 15 ++++++++++---
include/linux/fs.h | 5 ++++-
mm/shmem.c | 23 ++++++++++---------
8 files changed, 80 insertions(+), 19 deletions(-)
--
2.39.2
When the mtime or ctime is being queried via getattr, ensure that we
mark the inode for a high-res timestamp update on the next pass. Also,
switch to current_cmtime for other c/mtime updates.
With this change, we're better off having the NFS server just ignore
the i_version field and have it use the ctime instead, so clear the
STATX_CHANGE_COOKIE flag in the result mask in ->getattr.
Signed-off-by: Jeff Layton <[email protected]>
---
fs/xfs/libxfs/xfs_trans_inode.c | 2 +-
fs/xfs/xfs_acl.c | 2 +-
fs/xfs/xfs_inode.c | 2 +-
fs/xfs/xfs_iops.c | 15 ++++++++++++---
4 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
index 8b5547073379..9ad7c229c617 100644
--- a/fs/xfs/libxfs/xfs_trans_inode.c
+++ b/fs/xfs/libxfs/xfs_trans_inode.c
@@ -63,7 +63,7 @@ xfs_trans_ichgtime(
ASSERT(tp);
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
- tv = current_time(inode);
+ tv = current_cmtime(inode);
if (flags & XFS_ICHGTIME_MOD)
inode->i_mtime = tv;
diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
index 791db7d9c849..461adc58cf8c 100644
--- a/fs/xfs/xfs_acl.c
+++ b/fs/xfs/xfs_acl.c
@@ -233,7 +233,7 @@ xfs_acl_set_mode(
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
inode->i_mode = mode;
- inode->i_ctime = current_time(inode);
+ inode->i_ctime = current_cmtime(inode);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
if (xfs_has_wsync(mp))
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 5808abab786c..80f9d731e261 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -843,7 +843,7 @@ xfs_init_new_inode(
ip->i_df.if_nextents = 0;
ASSERT(ip->i_nblocks == 0);
- tv = current_time(inode);
+ tv = current_cmtime(inode);
inode->i_mtime = tv;
inode->i_atime = tv;
inode->i_ctime = tv;
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index 24718adb3c16..a0b07f90e16c 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -565,6 +565,15 @@ xfs_vn_getattr(
if (xfs_is_shutdown(mp))
return -EIO;
+ /*
+ * XFS uses the i_version infrastructure to track any change to
+ * the inode, including atime updates. This means that the i_version
+ * returned by getattr doesn't conform to what the callers expect.
+ * Clear it here so that nfsd will fake up a change cookie from the
+ * ctime instead.
+ */
+ stat->result_mask &= ~STATX_CHANGE_COOKIE;
+
stat->size = XFS_ISIZE(ip);
stat->dev = inode->i_sb->s_dev;
stat->mode = inode->i_mode;
@@ -573,8 +582,8 @@ xfs_vn_getattr(
stat->gid = vfsgid_into_kgid(vfsgid);
stat->ino = ip->i_ino;
stat->atime = inode->i_atime;
- stat->mtime = inode->i_mtime;
- stat->ctime = inode->i_ctime;
+ if (request_mask & (STATX_CTIME|STATX_MTIME))
+ fill_cmtime_and_mark(inode, stat);
stat->blocks = XFS_FSB_TO_BB(mp, ip->i_nblocks + ip->i_delayed_blks);
if (xfs_has_v3inodes(mp)) {
@@ -917,7 +926,7 @@ xfs_setattr_size(
if (newsize != oldsize &&
!(iattr->ia_valid & (ATTR_CTIME | ATTR_MTIME))) {
iattr->ia_ctime = iattr->ia_mtime =
- current_time(inode);
+ current_cmtime(inode);
iattr->ia_valid |= ATTR_CTIME | ATTR_MTIME;
}
--
2.39.2
The VFS always uses coarse-grained timestamp updates for filling out the
ctime and mtime after a change. This has the benefit of allowing
filesystems to optimize away metadata updates.
Unfortunately, this has always been an issue when we're exporting via
NFSv3, which relies on timestamps to validate caches. Even with NFSv4, a
lot of exported filesystems don't properly support a change attribute
and are subject to the same problem of timestamp granularity. Other
applications have similar issues (e.g backup applications).
Switching to always using high resolution timestamps would improve the
situation for NFS, but that becomes rather expensive, as we'd have to
log a lot more metadata updates.
This patch grabs a new i_state bit to use as a flag that filesystems can
set in their getattr routine to indicate that the mtime or ctime was
queried since it was last updated.
It then adds a new current_cmtime function that acts like the
current_time helper, but will conditionally grab high-res timestamps
when the i_state flag is set in the inode.
This allows NFS and other applications to reap the benefits of high-res
ctime and mtime timestamps, but at a substantially lower cost than
fetching them every time.
Cc: Dave Chinner <[email protected]>
Signed-off-by: Jeff Layton <[email protected]>
---
fs/inode.c | 40 ++++++++++++++++++++++++++++++++++++++--
fs/stat.c | 10 ++++++++++
include/linux/fs.h | 5 ++++-
3 files changed, 52 insertions(+), 3 deletions(-)
diff --git a/fs/inode.c b/fs/inode.c
index 4558dc2f1355..3630f67fd042 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2062,6 +2062,42 @@ static int __file_update_time(struct file *file, struct timespec64 *now,
return ret;
}
+/**
+ * current_cmtime - Return FS time (possibly high-res)
+ * @inode: inode.
+ *
+ * Return the current time truncated to the time granularity supported by
+ * the fs, as suitable for a ctime or mtime change. If something recently
+ * fetched the ctime or mtime out of the inode via getattr, then get a
+ * high-resolution timestamp.
+ *
+ * Note that inode and inode->sb cannot be NULL.
+ * Otherwise, the function warns and returns coarse time without truncation.
+ */
+struct timespec64 current_cmtime(struct inode *inode)
+{
+ struct timespec64 now;
+
+ if (unlikely(!inode->i_sb)) {
+ WARN(1, "%s() called with uninitialized super_block in the inode", __func__);
+ ktime_get_coarse_real_ts64(&now);
+ return now;
+ }
+
+ /* Do a lockless check for the flag before taking the spinlock */
+ if (READ_ONCE(inode->i_state) & I_CMTIME_QUERIED) {
+ ktime_get_real_ts64(&now);
+ spin_lock(&inode->i_lock);
+ inode->i_state &= ~I_CMTIME_QUERIED;
+ spin_unlock(&inode->i_lock);
+ } else {
+ ktime_get_coarse_real_ts64(&now);
+ }
+
+ return timestamp_truncate(now, inode);
+}
+EXPORT_SYMBOL(current_cmtime);
+
/**
* file_update_time - update mtime and ctime time
* @file: file accessed
@@ -2080,7 +2116,7 @@ int file_update_time(struct file *file)
{
int ret;
struct inode *inode = file_inode(file);
- struct timespec64 now = current_time(inode);
+ struct timespec64 now = current_cmtime(inode);
ret = inode_needs_update_time(inode, &now);
if (ret <= 0)
@@ -2109,7 +2145,7 @@ static int file_modified_flags(struct file *file, int flags)
{
int ret;
struct inode *inode = file_inode(file);
- struct timespec64 now = current_time(inode);
+ struct timespec64 now = current_cmtime(inode);
/*
* Clear the security bits if the process is not being run by root.
diff --git a/fs/stat.c b/fs/stat.c
index 7c238da22ef0..d8b80a2e36b7 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -64,6 +64,16 @@ void generic_fillattr(struct mnt_idmap *idmap, struct inode *inode,
}
EXPORT_SYMBOL(generic_fillattr);
+void fill_cmtime_and_mark(struct inode *inode, struct kstat *stat)
+{
+ spin_lock(&inode->i_lock);
+ inode->i_state |= I_CMTIME_QUERIED;
+ stat->ctime = inode->i_ctime;
+ stat->mtime = inode->i_mtime;
+ spin_unlock(&inode->i_lock);
+}
+EXPORT_SYMBOL(fill_cmtime_and_mark);
+
/**
* generic_fill_statx_attr - Fill in the statx attributes from the inode flags
* @inode: Inode to use as the source
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c85916e9f7db..7dece4390979 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1457,7 +1457,8 @@ static inline bool fsuidgid_has_mapping(struct super_block *sb,
kgid_has_mapping(fs_userns, kgid);
}
-extern struct timespec64 current_time(struct inode *inode);
+struct timespec64 current_time(struct inode *inode);
+struct timespec64 current_cmtime(struct inode *inode);
/*
* Snapshotting support.
@@ -2116,6 +2117,7 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
#define I_DONTCACHE (1 << 16)
#define I_SYNC_QUEUED (1 << 17)
#define I_PINNING_FSCACHE_WB (1 << 18)
+#define I_CMTIME_QUERIED (1 << 19)
#define I_DIRTY_INODE (I_DIRTY_SYNC | I_DIRTY_DATASYNC)
#define I_DIRTY (I_DIRTY_INODE | I_DIRTY_PAGES)
@@ -2839,6 +2841,7 @@ extern int page_symlink(struct inode *inode, const char *symname, int len);
extern const struct inode_operations page_symlink_inode_operations;
extern void kfree_link(void *);
void generic_fillattr(struct mnt_idmap *, struct inode *, struct kstat *);
+void fill_cmtime_and_mark(struct inode *inode, struct kstat *stat);
void generic_fill_statx_attr(struct inode *inode, struct kstat *stat);
extern int vfs_getattr_nosec(const struct path *, struct kstat *, u32, unsigned int);
extern int vfs_getattr(const struct path *, struct kstat *, u32, unsigned int);
--
2.39.2
On Tue 11-04-23 10:27:06, Jeff Layton wrote:
> The VFS always uses coarse-grained timestamp updates for filling out the
> ctime and mtime after a change. This has the benefit of allowing
> filesystems to optimize away metadata updates.
>
> Unfortunately, this has always been an issue when we're exporting via
> NFSv3, which relies on timestamps to validate caches. Even with NFSv4, a
> lot of exported filesystems don't properly support a change attribute
> and are subject to the same problem of timestamp granularity. Other
> applications have similar issues (e.g backup applications).
>
> Switching to always using high resolution timestamps would improve the
> situation for NFS, but that becomes rather expensive, as we'd have to
> log a lot more metadata updates.
>
> This patch grabs a new i_state bit to use as a flag that filesystems can
> set in their getattr routine to indicate that the mtime or ctime was
> queried since it was last updated.
>
> It then adds a new current_cmtime function that acts like the
> current_time helper, but will conditionally grab high-res timestamps
> when the i_state flag is set in the inode.
>
> This allows NFS and other applications to reap the benefits of high-res
> ctime and mtime timestamps, but at a substantially lower cost than
> fetching them every time.
>
> Cc: Dave Chinner <[email protected]>
> Signed-off-by: Jeff Layton <[email protected]>
> ---
> fs/inode.c | 40 ++++++++++++++++++++++++++++++++++++++--
> fs/stat.c | 10 ++++++++++
> include/linux/fs.h | 5 ++++-
> 3 files changed, 52 insertions(+), 3 deletions(-)
>
> diff --git a/fs/inode.c b/fs/inode.c
> index 4558dc2f1355..3630f67fd042 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2062,6 +2062,42 @@ static int __file_update_time(struct file *file, struct timespec64 *now,
> return ret;
> }
>
> +/**
> + * current_cmtime - Return FS time (possibly high-res)
> + * @inode: inode.
> + *
> + * Return the current time truncated to the time granularity supported by
> + * the fs, as suitable for a ctime or mtime change. If something recently
> + * fetched the ctime or mtime out of the inode via getattr, then get a
> + * high-resolution timestamp.
> + *
> + * Note that inode and inode->sb cannot be NULL.
> + * Otherwise, the function warns and returns coarse time without truncation.
> + */
> +struct timespec64 current_cmtime(struct inode *inode)
> +{
> + struct timespec64 now;
> +
> + if (unlikely(!inode->i_sb)) {
I don't think we can have inodes without a superblock. Did you ever hit
this?
> + WARN(1, "%s() called with uninitialized super_block in the inode", __func__);
> + ktime_get_coarse_real_ts64(&now);
> + return now;
> + }
> +
> + /* Do a lockless check for the flag before taking the spinlock */
> + if (READ_ONCE(inode->i_state) & I_CMTIME_QUERIED) {
> + ktime_get_real_ts64(&now);
> + spin_lock(&inode->i_lock);
> + inode->i_state &= ~I_CMTIME_QUERIED;
Isn't this a bit fragile? If someone does:
inode->i_mtime = current_cmtime(inode);
inode->i_ctime = current_cmtime(inode);
the ctime update will be coarse although it should be fine-grained.
> + spin_unlock(&inode->i_lock);
> + } else {
> + ktime_get_coarse_real_ts64(&now);
> + }
> +
> + return timestamp_truncate(now, inode);
I'm a bit confused here. Isn't the point of this series also to give NFS
finer grained granularity time stamps than what the filesystem is possibly
able to store on disk?
Hmm, checking XFS it sets 1 ns granularity (as well as tmpfs) so for these
using the coarser timers indeed gives a performance benefit. And probably
you've decided not implement the "better NFS support with coarse grained
timestamps" yet.
> +}
> +EXPORT_SYMBOL(current_cmtime);
> +
> /**
> * file_update_time - update mtime and ctime time
> * @file: file accessed
> @@ -2080,7 +2116,7 @@ int file_update_time(struct file *file)
> {
> int ret;
> struct inode *inode = file_inode(file);
> - struct timespec64 now = current_time(inode);
> + struct timespec64 now = current_cmtime(inode);
>
> ret = inode_needs_update_time(inode, &now);
> if (ret <= 0)
> @@ -2109,7 +2145,7 @@ static int file_modified_flags(struct file *file, int flags)
> {
> int ret;
> struct inode *inode = file_inode(file);
> - struct timespec64 now = current_time(inode);
> + struct timespec64 now = current_cmtime(inode);
>
> /*
> * Clear the security bits if the process is not being run by root.
> diff --git a/fs/stat.c b/fs/stat.c
> index 7c238da22ef0..d8b80a2e36b7 100644
> --- a/fs/stat.c
> +++ b/fs/stat.c
> @@ -64,6 +64,16 @@ void generic_fillattr(struct mnt_idmap *idmap, struct inode *inode,
> }
> EXPORT_SYMBOL(generic_fillattr);
>
> +void fill_cmtime_and_mark(struct inode *inode, struct kstat *stat)
> +{
> + spin_lock(&inode->i_lock);
> + inode->i_state |= I_CMTIME_QUERIED;
> + stat->ctime = inode->i_ctime;
> + stat->mtime = inode->i_mtime;
> + spin_unlock(&inode->i_lock);
> +}
> +EXPORT_SYMBOL(fill_cmtime_and_mark);
The name could be better here :). Maybe stat_fill_cmtime_and_mark()?
Honza
--
Jan Kara <[email protected]>
SUSE Labs, CR
On Fri, 2023-04-21 at 12:13 +0200, Jan Kara wrote:
> On Tue 11-04-23 10:27:06, Jeff Layton wrote:
> > The VFS always uses coarse-grained timestamp updates for filling out the
> > ctime and mtime after a change. This has the benefit of allowing
> > filesystems to optimize away metadata updates.
> >
> > Unfortunately, this has always been an issue when we're exporting via
> > NFSv3, which relies on timestamps to validate caches. Even with NFSv4, a
> > lot of exported filesystems don't properly support a change attribute
> > and are subject to the same problem of timestamp granularity. Other
> > applications have similar issues (e.g backup applications).
> >
> > Switching to always using high resolution timestamps would improve the
> > situation for NFS, but that becomes rather expensive, as we'd have to
> > log a lot more metadata updates.
> >
> > This patch grabs a new i_state bit to use as a flag that filesystems can
> > set in their getattr routine to indicate that the mtime or ctime was
> > queried since it was last updated.
> >
> > It then adds a new current_cmtime function that acts like the
> > current_time helper, but will conditionally grab high-res timestamps
> > when the i_state flag is set in the inode.
> >
> > This allows NFS and other applications to reap the benefits of high-res
> > ctime and mtime timestamps, but at a substantially lower cost than
> > fetching them every time.
> >
> > Cc: Dave Chinner <[email protected]>
> > Signed-off-by: Jeff Layton <[email protected]>
> > ---
> > fs/inode.c | 40 ++++++++++++++++++++++++++++++++++++++--
> > fs/stat.c | 10 ++++++++++
> > include/linux/fs.h | 5 ++++-
> > 3 files changed, 52 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/inode.c b/fs/inode.c
> > index 4558dc2f1355..3630f67fd042 100644
> > --- a/fs/inode.c
> > +++ b/fs/inode.c
> > @@ -2062,6 +2062,42 @@ static int __file_update_time(struct file *file, struct timespec64 *now,
> > return ret;
> > }
> >
> > +/**
> > + * current_cmtime - Return FS time (possibly high-res)
> > + * @inode: inode.
> > + *
> > + * Return the current time truncated to the time granularity supported by
> > + * the fs, as suitable for a ctime or mtime change. If something recently
> > + * fetched the ctime or mtime out of the inode via getattr, then get a
> > + * high-resolution timestamp.
> > + *
> > + * Note that inode and inode->sb cannot be NULL.
> > + * Otherwise, the function warns and returns coarse time without truncation.
> > + */
> > +struct timespec64 current_cmtime(struct inode *inode)
> > +{
> > + struct timespec64 now;
> > +
> > + if (unlikely(!inode->i_sb)) {
>
> I don't think we can have inodes without a superblock. Did you ever hit
> this?
>
No, I copied this from current_time. I've already removed this in my
working branch. We can probably remove it from current_time too.
> > + WARN(1, "%s() called with uninitialized super_block in the inode", __func__);
> > + ktime_get_coarse_real_ts64(&now);
> > + return now;
> > + }
> > +
> > + /* Do a lockless check for the flag before taking the spinlock */
> > + if (READ_ONCE(inode->i_state) & I_CMTIME_QUERIED) {
> > + ktime_get_real_ts64(&now);
> > + spin_lock(&inode->i_lock);
> > + inode->i_state &= ~I_CMTIME_QUERIED;
>
> Isn't this a bit fragile? If someone does:
>
> inode->i_mtime = current_cmtime(inode);
> inode->i_ctime = current_cmtime(inode);
>
> the ctime update will be coarse although it should be fine-grained.
>
It is a bit. We'll need for users to do something like:
inode->i_mtime = inode->i_ctime = current_ctime(inode);
Fortunately, most do this already.
> > + spin_unlock(&inode->i_lock);
> > + } else {
> > + ktime_get_coarse_real_ts64(&now);
> > + }
> > +
> > + return timestamp_truncate(now, inode);
>
> I'm a bit confused here. Isn't the point of this series also to give NFS
> finer grained granularity time stamps than what the filesystem is possibly
> able to store on disk?
>
No. We actually don't want to hand out timestamps more granular than the
underlying filesystem can support, as we'd end up having to invalidate
caches for all of those inodes once the server rebooted and the
unrecordable bits get zeroed out.
The main idea here is to just ensure that we use fine-grained timestamps
when someone has queried the mtime or ctime since the last time it was
updated.
> Hmm, checking XFS it sets 1 ns granularity (as well as tmpfs) so for these
> using the coarser timers indeed gives a performance benefit. And probably
> you've decided not implement the "better NFS support with coarse grained
> timestamps" yet.
>
Yep. The coarse grained timestamps are a _good_ thing for most
filesystems as they allow you to skip a lot of metadata updates. My hope
is that this will end up being like the i_version changes such that the
extra fine-grained updates should be relatively rare and should
(hopefully!) not cause noticeable performance blips. We'll see!
> > +}
> > +EXPORT_SYMBOL(current_cmtime);
> > +
> > /**
> > * file_update_time - update mtime and ctime time
> > * @file: file accessed
> > @@ -2080,7 +2116,7 @@ int file_update_time(struct file *file)
> > {
> > int ret;
> > struct inode *inode = file_inode(file);
> > - struct timespec64 now = current_time(inode);
> > + struct timespec64 now = current_cmtime(inode);
> >
> > ret = inode_needs_update_time(inode, &now);
> > if (ret <= 0)
> > @@ -2109,7 +2145,7 @@ static int file_modified_flags(struct file *file, int flags)
> > {
> > int ret;
> > struct inode *inode = file_inode(file);
> > - struct timespec64 now = current_time(inode);
> > + struct timespec64 now = current_cmtime(inode);
> >
> > /*
> > * Clear the security bits if the process is not being run by root.
> > diff --git a/fs/stat.c b/fs/stat.c
> > index 7c238da22ef0..d8b80a2e36b7 100644
> > --- a/fs/stat.c
> > +++ b/fs/stat.c
> > @@ -64,6 +64,16 @@ void generic_fillattr(struct mnt_idmap *idmap, struct inode *inode,
> > }
> > EXPORT_SYMBOL(generic_fillattr);
> >
> > +void fill_cmtime_and_mark(struct inode *inode, struct kstat *stat)
> > +{
> > + spin_lock(&inode->i_lock);
> > + inode->i_state |= I_CMTIME_QUERIED;
> > + stat->ctime = inode->i_ctime;
> > + stat->mtime = inode->i_mtime;
> > + spin_unlock(&inode->i_lock);
> > +}
> > +EXPORT_SYMBOL(fill_cmtime_and_mark);
>
> The name could be better here :). Maybe stat_fill_cmtime_and_mark()?
>
>
I have a quite different set that I've been working on that I'll
(hopefully!) post soon. That one uses the least significant bit of the
tv_nsec field as the QUERIED flag instead of the spinlock.
Still cleaning up the set and need to test it some more though, so it's
not quite ready to post. Stay tuned!
Thanks for the review!
--
Jeff Layton <[email protected]>