[PATCH 0/7] Delete timespec64_trunc()

[PATCH 0/7] Delete timespec64_trunc()

[Deepa Dinamani]

This series aims at deleting timespec64_trunc().
There is a new api: timestamp_truncate() that is the
replacement api. The api additionally does a limits
check on the filesystem timestamps.

The suggestion to open code some of the truncate logic
came from Al Viro. And, this does make the code in some
filesystems easy to follow.

The series also does some update_time() cleanup as
suggested by Al Viro.

Deepa Dinamani (7):
  fs: fat: Eliminate timespec64_trunc() usage
  fs: cifs: Fix atime update check vs mtime
  fs: cifs: Delete usage of timespec64_trunc
  fs: ceph: Delete timespec64_trunc() usage
  fs: ubifs: Eliminate timespec64_trunc() usage
  fs: Delete timespec64_trunc()
  fs: Do not overload update_time

 fs/ceph/mds_client.c |  3 +--
 fs/cifs/inode.c      | 15 ++++++++-------
 fs/fat/misc.c        | 10 +++++++++-
 fs/inode.c           | 30 +++---------------------------
 fs/ubifs/sb.c        | 11 ++++-------
 include/linux/fs.h   |  1 -
 6 files changed, 25 insertions(+), 45 deletions(-)

-- 
2.17.1

Cc: hirofumi@mail.parknet.co.jp
Cc: jlayton@kernel.org
Cc: richard@nod.at
Cc: stfrench@microsoft.com
Cc: ceph-devel@vger.kernel.org
Cc: linux-cifs@vger.kernel.org
Cc: linux-mtd@lists.infradead.org

[PATCH 1/7] fs: fat: Eliminate timespec64_trunc() usage

[Deepa Dinamani]

timespec64_trunc() is being deleted.

timestamp_truncate() is the replacement api for
timespec64_trunc. timestamp_truncate() additionally clamps
timestamps to make sure the timestamps lie within the
permitted range for the filesystem.

But, fat always truncates the times locally after it obtains
the timestamps from current_time().
Implement a local version here along the lines of existing
truncate functions.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: hirofumi@mail.parknet.co.jp
---
 fs/fat/misc.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 1e08bd54c5fb..f1b2a1fc2a6a 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -271,6 +271,14 @@ static inline struct timespec64 fat_timespec64_trunc_2secs(struct timespec64 ts)
 {
 	return (struct timespec64){ ts.tv_sec & ~1ULL, 0 };
 }
+
+static inline struct timespec64 fat_timespec64_trunc_10ms(struct timespec64 ts)
+{
+	if (ts.tv_nsec)
+		ts.tv_nsec -= ts.tv_nsec % 10000000UL;
+	return ts;
+}
+
 /*
  * truncate the various times with appropriate granularity:
  *   root inode:
@@ -308,7 +316,7 @@ int fat_truncate_time(struct inode *inode, struct timespec64 *now, int flags)
 	}
 	if (flags & S_CTIME) {
 		if (sbi->options.isvfat)
-			inode->i_ctime = timespec64_trunc(*now, 10000000);
+			inode->i_ctime = fat_timespec64_trunc_10ms(*now);
 		else
 			inode->i_ctime = fat_timespec64_trunc_2secs(*now);
 	}
-- 
2.17.1

[PATCH 2/7] fs: cifs: Fix atime update check vs mtime

[Deepa Dinamani]

According to the comment in the code and commit log, some apps
expect atime >= mtime; but the introduced code results in
atime==mtime.  Fix the comparison to guard against atime<mtime.

Fixes: 9b9c5bea0b96 ("cifs: do not return atime less than mtime")
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: stfrench@microsoft.com
Cc: linux-cifs@vger.kernel.org
---
 fs/cifs/inode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 8a76195e8a69..ca76a9287456 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -163,7 +163,7 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
 
 	spin_lock(&inode->i_lock);
 	/* we do not want atime to be less than mtime, it broke some apps */
-	if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime))
+	if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime) < 0)
 		inode->i_atime = fattr->cf_mtime;
 	else
 		inode->i_atime = fattr->cf_atime;
-- 
2.17.1

Re: [PATCH 2/7] fs: cifs: Fix atime update check vs mtime

[Steve French]

merged into cifs-2.6.git for-next

On Fri, Nov 29, 2019 at 11:34 PM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
>
> According to the comment in the code and commit log, some apps
> expect atime >= mtime; but the introduced code results in
> atime==mtime.  Fix the comparison to guard against atime<mtime.
>
> Fixes: 9b9c5bea0b96 ("cifs: do not return atime less than mtime")
> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> Cc: stfrench@microsoft.com
> Cc: linux-cifs@vger.kernel.org
> ---
>  fs/cifs/inode.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index 8a76195e8a69..ca76a9287456 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -163,7 +163,7 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
>
>         spin_lock(&inode->i_lock);
>         /* we do not want atime to be less than mtime, it broke some apps */
> -       if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime))
> +       if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime) < 0)
>                 inode->i_atime = fattr->cf_mtime;
>         else
>                 inode->i_atime = fattr->cf_atime;
> --
> 2.17.1
>


-- 
Thanks,

Steve

[PATCH 3/7] fs: cifs: Delete usage of timespec64_trunc

[Deepa Dinamani]

timestamp_truncate() is the replacement api for
timespec64_trunc. timestamp_truncate() additionally clamps
timestamps to make sure the timestamps lie within the
permitted range for the filesystem.

Truncate the timestamps in the struct cifs_attr at the
site of assignment to inode times. This
helps us use the right fs api timestamp_trucate() to
perform the truncation.

Also update the ktime_get_* api to match the one used in
current_time(). This allows for timestamps to be updated
the same way always.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: stfrench@microsoft.com
Cc: linux-cifs@vger.kernel.org
---
 fs/cifs/inode.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index ca76a9287456..026ed49e8aa4 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -113,6 +113,7 @@ cifs_revalidate_cache(struct inode *inode, struct cifs_fattr *fattr)
 	}
 
 	 /* revalidate if mtime or size have changed */
+	fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
 	if (timespec64_equal(&inode->i_mtime, &fattr->cf_mtime) &&
 	    cifs_i->server_eof == fattr->cf_eof) {
 		cifs_dbg(FYI, "%s: inode %llu is unchanged\n",
@@ -162,6 +163,9 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
 	cifs_revalidate_cache(inode, fattr);
 
 	spin_lock(&inode->i_lock);
+	fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
+	fattr->cf_atime = timestamp_truncate(fattr->cf_atime, inode);
+	fattr->cf_ctime = timestamp_truncate(fattr->cf_ctime, inode);
 	/* we do not want atime to be less than mtime, it broke some apps */
 	if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime) < 0)
 		inode->i_atime = fattr->cf_mtime;
@@ -329,8 +333,7 @@ cifs_create_dfs_fattr(struct cifs_fattr *fattr, struct super_block *sb)
 	fattr->cf_mode = S_IFDIR | S_IXUGO | S_IRWXU;
 	fattr->cf_uid = cifs_sb->mnt_uid;
 	fattr->cf_gid = cifs_sb->mnt_gid;
-	ktime_get_real_ts64(&fattr->cf_mtime);
-	fattr->cf_mtime = timespec64_trunc(fattr->cf_mtime, sb->s_time_gran);
+	ktime_get_coarse_real_ts64(&fattr->cf_mtime);
 	fattr->cf_atime = fattr->cf_ctime = fattr->cf_mtime;
 	fattr->cf_nlink = 2;
 	fattr->cf_flags = CIFS_FATTR_DFS_REFERRAL;
@@ -609,10 +612,8 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
 
 	if (info->LastAccessTime)
 		fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
-	else {
-		ktime_get_real_ts64(&fattr->cf_atime);
-		fattr->cf_atime = timespec64_trunc(fattr->cf_atime, sb->s_time_gran);
-	}
+	else
+		ktime_get_coarse_real_ts64(&fattr->cf_atime);
 
 	fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
 	fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
-- 
2.17.1

Re: [PATCH 3/7] fs: cifs: Delete usage of timespec64_trunc

[Steve French]

Is this intended to merge separately or do you want it merged through
the cifs git tree?

On Fri, Nov 29, 2019 at 11:33 PM Deepa Dinamani <deepa.kernel@gmail.com> wrote:
>
> timestamp_truncate() is the replacement api for
> timespec64_trunc. timestamp_truncate() additionally clamps
> timestamps to make sure the timestamps lie within the
> permitted range for the filesystem.
>
> Truncate the timestamps in the struct cifs_attr at the
> site of assignment to inode times. This
> helps us use the right fs api timestamp_trucate() to
> perform the truncation.
>
> Also update the ktime_get_* api to match the one used in
> current_time(). This allows for timestamps to be updated
> the same way always.
>
> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> Cc: stfrench@microsoft.com
> Cc: linux-cifs@vger.kernel.org
> ---
>  fs/cifs/inode.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
> index ca76a9287456..026ed49e8aa4 100644
> --- a/fs/cifs/inode.c
> +++ b/fs/cifs/inode.c
> @@ -113,6 +113,7 @@ cifs_revalidate_cache(struct inode *inode, struct cifs_fattr *fattr)
>         }
>
>          /* revalidate if mtime or size have changed */
> +       fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
>         if (timespec64_equal(&inode->i_mtime, &fattr->cf_mtime) &&
>             cifs_i->server_eof == fattr->cf_eof) {
>                 cifs_dbg(FYI, "%s: inode %llu is unchanged\n",
> @@ -162,6 +163,9 @@ cifs_fattr_to_inode(struct inode *inode, struct cifs_fattr *fattr)
>         cifs_revalidate_cache(inode, fattr);
>
>         spin_lock(&inode->i_lock);
> +       fattr->cf_mtime = timestamp_truncate(fattr->cf_mtime, inode);
> +       fattr->cf_atime = timestamp_truncate(fattr->cf_atime, inode);
> +       fattr->cf_ctime = timestamp_truncate(fattr->cf_ctime, inode);
>         /* we do not want atime to be less than mtime, it broke some apps */
>         if (timespec64_compare(&fattr->cf_atime, &fattr->cf_mtime) < 0)
>                 inode->i_atime = fattr->cf_mtime;
> @@ -329,8 +333,7 @@ cifs_create_dfs_fattr(struct cifs_fattr *fattr, struct super_block *sb)
>         fattr->cf_mode = S_IFDIR | S_IXUGO | S_IRWXU;
>         fattr->cf_uid = cifs_sb->mnt_uid;
>         fattr->cf_gid = cifs_sb->mnt_gid;
> -       ktime_get_real_ts64(&fattr->cf_mtime);
> -       fattr->cf_mtime = timespec64_trunc(fattr->cf_mtime, sb->s_time_gran);
> +       ktime_get_coarse_real_ts64(&fattr->cf_mtime);
>         fattr->cf_atime = fattr->cf_ctime = fattr->cf_mtime;
>         fattr->cf_nlink = 2;
>         fattr->cf_flags = CIFS_FATTR_DFS_REFERRAL;
> @@ -609,10 +612,8 @@ cifs_all_info_to_fattr(struct cifs_fattr *fattr, FILE_ALL_INFO *info,
>
>         if (info->LastAccessTime)
>                 fattr->cf_atime = cifs_NTtimeToUnix(info->LastAccessTime);
> -       else {
> -               ktime_get_real_ts64(&fattr->cf_atime);
> -               fattr->cf_atime = timespec64_trunc(fattr->cf_atime, sb->s_time_gran);
> -       }
> +       else
> +               ktime_get_coarse_real_ts64(&fattr->cf_atime);
>
>         fattr->cf_ctime = cifs_NTtimeToUnix(info->ChangeTime);
>         fattr->cf_mtime = cifs_NTtimeToUnix(info->LastWriteTime);
> --
> 2.17.1
>


-- 
Thanks,

Steve

Re: [PATCH 3/7] fs: cifs: Delete usage of timespec64_trunc

[Deepa Dinamani]

On Sat, Nov 30, 2019 at 1:25 PM Steve French <smfrench@gmail.com> wrote:
>
> Is this intended to merge separately or do you want it merged through
> the cifs git tree?

It would be simplest for all uses of timespec64_trunc to be removed
through the same tree. Otherwise, whoever takes the [PATCH 6/7] ("fs:
Delete timespec64_trunc()") would have to depend on your tree.

Thanks,
-Deepa

[PATCH 4/7] fs: ceph: Delete timespec64_trunc() usage

[Deepa Dinamani]

Since ceph always uses ns granularity, skip the
truncation which is a no-op.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: jlayton@kernel.org
Cc: ceph-devel@vger.kernel.org
---
 fs/ceph/mds_client.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 068b029cf073..c2aa290f6c3e 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -2088,8 +2088,7 @@ ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
 	init_completion(&req->r_safe_completion);
 	INIT_LIST_HEAD(&req->r_unsafe_item);
 
-	ktime_get_coarse_real_ts64(&ts);
-	req->r_stamp = timespec64_trunc(ts, mdsc->fsc->sb->s_time_gran);
+	ktime_get_coarse_real_ts64(&req->r_stamp);
 
 	req->r_op = op;
 	req->r_direct_mode = mode;
-- 
2.17.1

[PATCH 5/7] fs: ubifs: Eliminate timespec64_trunc() usage

[Deepa Dinamani]

DEFAULT_TIME_GRAN is seconds granularity. We can
just drop the nsec while creating the default root node.
Delete the unneeded call to timespec64_trunc().

Also update the ktime_get_* api to match the one used in
current_time(). This allows for the timestamps to be updated
by using the same ktime_get_* api always.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: richard@nod.at
Cc: linux-mtd@lists.infradead.org
---
 fs/ubifs/sb.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index 2b7c04bf8983..93d550be4c11 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -84,7 +84,6 @@ static int create_default_filesystem(struct ubifs_info *c)
 	int idx_node_size;
 	long long tmp64, main_bytes;
 	__le64 tmp_le64;
-	__le32 tmp_le32;
 	struct timespec64 ts;
 	u8 hash[UBIFS_HASH_ARR_SZ];
 	u8 hash_lpt[UBIFS_HASH_ARR_SZ];
@@ -291,16 +290,14 @@ static int create_default_filesystem(struct ubifs_info *c)
 	ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
 	ino->nlink = cpu_to_le32(2);
 
-	ktime_get_real_ts64(&ts);
-	ts = timespec64_trunc(ts, DEFAULT_TIME_GRAN);
+	ktime_get_coarse_real_ts64(&ts);
 	tmp_le64 = cpu_to_le64(ts.tv_sec);
 	ino->atime_sec   = tmp_le64;
 	ino->ctime_sec   = tmp_le64;
 	ino->mtime_sec   = tmp_le64;
-	tmp_le32 = cpu_to_le32(ts.tv_nsec);
-	ino->atime_nsec  = tmp_le32;
-	ino->ctime_nsec  = tmp_le32;
-	ino->mtime_nsec  = tmp_le32;
+	ino->atime_nsec  = 0;
+	ino->ctime_nsec  = 0;
+	ino->mtime_nsec  = 0;
 	ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
 	ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
 
-- 
2.17.1

[PATCH 6/7] fs: Delete timespec64_trunc()

[Deepa Dinamani]

There are no more callers to the function remaining.

Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
 fs/inode.c         | 24 ------------------------
 include/linux/fs.h |  1 -
 2 files changed, 25 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index fef457a42882..12c9e38529c9 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2145,30 +2145,6 @@ void inode_nohighmem(struct inode *inode)
 }
 EXPORT_SYMBOL(inode_nohighmem);
 
-/**
- * timespec64_trunc - Truncate timespec64 to a granularity
- * @t: Timespec64
- * @gran: Granularity in ns.
- *
- * Truncate a timespec64 to a granularity. Always rounds down. gran must
- * not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
- */
-struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran)
-{
-	/* Avoid division in the common cases 1 ns and 1 s. */
-	if (gran == 1) {
-		/* nothing */
-	} else if (gran == NSEC_PER_SEC) {
-		t.tv_nsec = 0;
-	} else if (gran > 1 && gran < NSEC_PER_SEC) {
-		t.tv_nsec -= t.tv_nsec % gran;
-	} else {
-		WARN(1, "illegal file time granularity: %u", gran);
-	}
-	return t;
-}
-EXPORT_SYMBOL(timespec64_trunc);
-
 /**
  * timestamp_truncate - Truncate timespec to a granularity
  * @t: Timespec
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 98e0349adb52..46dd7e6f6d73 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1575,7 +1575,6 @@ static inline void i_gid_write(struct inode *inode, gid_t gid)
 	inode->i_gid = make_kgid(inode->i_sb->s_user_ns, gid);
 }
 
-extern struct timespec64 timespec64_trunc(struct timespec64 t, unsigned gran);
 extern struct timespec64 current_time(struct inode *inode);
 
 /*
-- 
2.17.1

[PATCH 7/7] fs: Do not overload update_time

[Deepa Dinamani]

update_time() also has an internal function pointer
update_time. Even though this works correctly, it is
confusing to the readers.

Use a different name for the local variable.

Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
 fs/inode.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/inode.c b/fs/inode.c
index 12c9e38529c9..0be58a680457 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1675,12 +1675,12 @@ EXPORT_SYMBOL(generic_update_time);
  */
 static int update_time(struct inode *inode, struct timespec64 *time, int flags)
 {
-	int (*update_time)(struct inode *, struct timespec64 *, int);
+	int (*cb)(struct inode *, struct timespec64 *, int);
 
-	update_time = inode->i_op->update_time ? inode->i_op->update_time :
+	cb = inode->i_op->update_time ? inode->i_op->update_time :
 		generic_update_time;
 
-	return update_time(inode, time, flags);
+	return cb(inode, time, flags);
 }
 
 /**
-- 
2.17.1

Re: [PATCH 7/7] fs: Do not overload update_time

[Dave Chinner]

On Fri, Nov 29, 2019 at 09:30:30PM -0800, Deepa Dinamani wrote:
> update_time() also has an internal function pointer
> update_time. Even though this works correctly, it is
> confusing to the readers.
> 
> Use a different name for the local variable.
> 
> Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
> Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
> ---
>  fs/inode.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/inode.c b/fs/inode.c
> index 12c9e38529c9..0be58a680457 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -1675,12 +1675,12 @@ EXPORT_SYMBOL(generic_update_time);
>   */
>  static int update_time(struct inode *inode, struct timespec64 *time, int flags)
>  {
> -	int (*update_time)(struct inode *, struct timespec64 *, int);
> +	int (*cb)(struct inode *, struct timespec64 *, int);
>  
> -	update_time = inode->i_op->update_time ? inode->i_op->update_time :
> +	cb = inode->i_op->update_time ? inode->i_op->update_time :
>  		generic_update_time;
>  
> -	return update_time(inode, time, flags);
> +	return cb(inode, time, flags);

What's wrong with a simple if() like we use everywhere else for this
sort of thing?

	if (inode->i_op->update_time)
		return inode->i_op->update_time(inode, time, flags);
	return generic_update_time(inode, time, flags);

-Dave.
-- 
Dave Chinner
david@fromorbit.com

Re: [PATCH 7/7] fs: Do not overload update_time

[Christoph Hellwig]

On Fri, Nov 29, 2019 at 09:30:30PM -0800, Deepa Dinamani wrote:
> -	int (*update_time)(struct inode *, struct timespec64 *, int);
> +	int (*cb)(struct inode *, struct timespec64 *, int);
>  
> -	update_time = inode->i_op->update_time ? inode->i_op->update_time :
> +	cb = inode->i_op->update_time ? inode->i_op->update_time :
>  		generic_update_time;
>  
> -	return update_time(inode, time, flags);
> +	return cb(inode, time, flags);

Just killing the pointless local variable cleans the function op, and
also avoids the expensive indirect call for the common case:

	if (inode->i_op->update_time)
		return inode->i_op->update_time(inode, time, flags);
	return generic_update_time(inode, time, flags);

Re: [PATCH 7/7] fs: Do not overload update_time

[Deepa Dinamani]

On Mon, Dec 2, 2019 at 9:48 AM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Fri, Nov 29, 2019 at 09:30:30PM -0800, Deepa Dinamani wrote:
> > -     int (*update_time)(struct inode *, struct timespec64 *, int);
> > +     int (*cb)(struct inode *, struct timespec64 *, int);
> >
> > -     update_time = inode->i_op->update_time ? inode->i_op->update_time :
> > +     cb = inode->i_op->update_time ? inode->i_op->update_time :
> >               generic_update_time;
> >
> > -     return update_time(inode, time, flags);
> > +     return cb(inode, time, flags);
>
> Just killing the pointless local variable cleans the function op, and
> also avoids the expensive indirect call for the common case:

Will update this in v2. Thanks.

-Deepa