xfs: fix timestamp handling in xfs_setattr

We currently have some rather odd code in xfs_setattr for
updating the a/c/mtime timestamps:

 - first we do a non-transaction update if all three are updated
   together
 - second we implicitly update the ctime for various changes
   instead of relying on the ATTR_CTIME flag
 - third we set the timestamps to the current time instead of the
   arguments in the iattr structure in many cases.

This patch makes sure we update it in a consistent way:

 - always transactional
 - ctime is only updated if ATTR_CTIME is set or we do a size
   update, which is a special case
 - always to the times passed in from the caller instead of the
   current time

The only non-size caller of xfs_setattr that doesn't come from
the VFS is updated to set ATTR_CTIME and pass in a valid ctime
value.

Reported-by: Eric Blake <ebb9@byu.net>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>

2 files changed, 41 insertions, 55 deletions

diff --git a/fs/xfs/linux-2.6/xfs_acl.c b/fs/xfs/linux-2.6/xfs_acl.c
index 2512125dfa7c..883ca5ab8af5 100644
--- a/fs/xfs/linux-2.6/xfs_acl.c
+++ b/fs/xfs/linux-2.6/xfs_acl.c
@@ -251,8 +251,9 @@ xfs_set_mode(struct inode *inode, mode_t mode)
         if (mode != inode->i_mode) {
                 struct iattr iattr;
 
-                iattr.ia_valid = ATTR_MODE;
+                iattr.ia_valid = ATTR_MODE | ATTR_CTIME;
                 iattr.ia_mode = mode;
+                iattr.ia_ctime = current_fs_time(inode->i_sb);
 
                 error = -xfs_setattr(XFS_I(inode), &iattr, XFS_ATTR_NOACL);
         }
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 6558ffd8d140..6f268756bf36 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -70,7 +70,6 @@ xfs_setattr(
         uint                    commit_flags=0;
         uid_t                   uid=0, iuid=0;
         gid_t                   gid=0, igid=0;
-        int                     timeflags = 0;
         struct xfs_dquot        *udqp, *gdqp, *olddquot1, *olddquot2;
         int                     need_iolock = 1;
 
@@ -135,16 +134,13 @@ xfs_setattr(
         if (flags & XFS_ATTR_NOLOCK)
                 need_iolock = 0;
         if (!(mask & ATTR_SIZE)) {
-                if ((mask != (ATTR_CTIME|ATTR_ATIME|ATTR_MTIME)) ||
-                    (mp->m_flags & XFS_MOUNT_WSYNC)) {
-                        tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
-                        commit_flags = 0;
-                        if ((code = xfs_trans_reserve(tp, 0,
-                                                     XFS_ICHANGE_LOG_RES(mp), 0,
-                                                     0, 0))) {
-                                lock_flags = 0;
-                                goto error_return;
-                        }
+                tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_NOT_SIZE);
+                commit_flags = 0;
+                code = xfs_trans_reserve(tp, 0, XFS_ICHANGE_LOG_RES(mp),
+                                         0, 0, 0);
+                if (code) {
+                        lock_flags = 0;
+                        goto error_return;
                 }
         } else {
                 if (DM_EVENT_ENABLED(ip, DM_EVENT_TRUNCATE) &&
@@ -295,15 +291,23 @@ xfs_setattr(
                  * or we are explicitly asked to change it. This handles
                  * the semantic difference between truncate() and ftruncate()
                  * as implemented in the VFS.
+                 *
+                 * The regular truncate() case without ATTR_CTIME and ATTR_MTIME
+                 * is a special case where we need to update the times despite
+                 * not having these flags set.  For all other operations the
+                 * VFS set these flags explicitly if it wants a timestamp
+                 * update.
                  */
-                if (iattr->ia_size != ip->i_size || (mask & ATTR_CTIME))
-                        timeflags |= XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG;
+                if (iattr->ia_size != ip->i_size &&
+                    (!(mask & (ATTR_CTIME | ATTR_MTIME)))) {
+                        iattr->ia_ctime = iattr->ia_mtime =
+                                current_fs_time(inode->i_sb);
+                        mask |= ATTR_CTIME | ATTR_MTIME;
+                }
 
                 if (iattr->ia_size > ip->i_size) {
                         ip->i_d.di_size = iattr->ia_size;
                         ip->i_size = iattr->ia_size;
-                        if (!(flags & XFS_ATTR_DMI))
-                                xfs_ichgtime(ip, XFS_ICHGTIME_CHG);
                         xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
                 } else if (iattr->ia_size <= ip->i_size ||
                            (iattr->ia_size == 0 && ip->i_d.di_nextents)) {
@@ -374,9 +378,6 @@ xfs_setattr(
                         ip->i_d.di_gid = gid;
                         inode->i_gid = gid;
                 }
-
-                xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
-                timeflags |= XFS_ICHGTIME_CHG;
         }
 
         /*
@@ -393,51 +394,37 @@ xfs_setattr(
 
                 inode->i_mode &= S_IFMT;
                 inode->i_mode |= mode & ~S_IFMT;
-
-                xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
-                timeflags |= XFS_ICHGTIME_CHG;
         }
 
         /*
          * Change file access or modified times.
          */
-        if (mask & (ATTR_ATIME|ATTR_MTIME)) {
-                if (mask & ATTR_ATIME) {
-                        inode->i_atime = iattr->ia_atime;
-                        ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
-                        ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
-                        ip->i_update_core = 1;
-                }
-                if (mask & ATTR_MTIME) {
-                        inode->i_mtime = iattr->ia_mtime;
-                        ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
-                        ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
-                        timeflags &= ~XFS_ICHGTIME_MOD;
-                        timeflags |= XFS_ICHGTIME_CHG;
-                }
-                if (tp && (mask & (ATTR_MTIME_SET|ATTR_ATIME_SET)))
-                        xfs_trans_log_inode (tp, ip, XFS_ILOG_CORE);
+        if (mask & ATTR_ATIME) {
+                inode->i_atime = iattr->ia_atime;
+                ip->i_d.di_atime.t_sec = iattr->ia_atime.tv_sec;
+                ip->i_d.di_atime.t_nsec = iattr->ia_atime.tv_nsec;
+                ip->i_update_core = 1;
         }
-
-        /*
-         * Change file inode change time only if ATTR_CTIME set
-         * AND we have been called by a DMI function.
-         */
-
-        if ((flags & XFS_ATTR_DMI) && (mask & ATTR_CTIME)) {
+        if (mask & ATTR_CTIME) {
                 inode->i_ctime = iattr->ia_ctime;
                 ip->i_d.di_ctime.t_sec = iattr->ia_ctime.tv_sec;
                 ip->i_d.di_ctime.t_nsec = iattr->ia_ctime.tv_nsec;
                 ip->i_update_core = 1;
-                timeflags &= ~XFS_ICHGTIME_CHG;
+        }
+        if (mask & ATTR_MTIME) {
+                inode->i_mtime = iattr->ia_mtime;
+                ip->i_d.di_mtime.t_sec = iattr->ia_mtime.tv_sec;
+                ip->i_d.di_mtime.t_nsec = iattr->ia_mtime.tv_nsec;
+                ip->i_update_core = 1;
         }
 
         /*
-         * Send out timestamp changes that need to be set to the
-         * current time.  Not done when called by a DMI function.
+         * And finally, log the inode core if any attribute in it
+         * has been changed.
          */
-        if (timeflags && !(flags & XFS_ATTR_DMI))
-                xfs_ichgtime(ip, timeflags);
+        if (mask & (ATTR_UID|ATTR_GID|ATTR_MODE|
+                    ATTR_ATIME|ATTR_CTIME|ATTR_MTIME))
+                xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
 
         XFS_STATS_INC(xs_ig_attrchg);
 
@@ -452,12 +439,10 @@ xfs_setattr(
          * mix so this probably isn't worth the trouble to optimize.
          */
         code = 0;
-        if (tp) {
-                if (mp->m_flags & XFS_MOUNT_WSYNC)
-                        xfs_trans_set_sync(tp);
+        if (mp->m_flags & XFS_MOUNT_WSYNC)
+                xfs_trans_set_sync(tp);
 
-                code = xfs_trans_commit(tp, commit_flags);
-        }
+        code = xfs_trans_commit(tp, commit_flags);
 
         xfs_iunlock(ip, lock_flags);