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[PATCH 2/5] xfs: always take the iolock around xfs_setattr_size

To: xfs@xxxxxxxxxxx
Subject: [PATCH 2/5] xfs: always take the iolock around xfs_setattr_size
From: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Date: Sat, 08 Dec 2012 07:08:14 -0500
References: <20121208120812.755863148@xxxxxxxxxxxxxxxxxxxxxx>
User-agent: quilt/0.48-1
There is no reason to conditionally take the iolock inside xfs_setattr_size
when we can let the caller handle it unconditionally, which just incrases
the lock hold time for the case where it was previously taken internally
by a few instructions.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>

---
 fs/xfs/xfs_file.c     |    2 +-
 fs/xfs/xfs_iops.c     |   28 +++++++++++++++-------------
 fs/xfs/xfs_vnodeops.c |    3 +--
 fs/xfs/xfs_vnodeops.h |    2 +-
 4 files changed, 18 insertions(+), 17 deletions(-)

Index: xfs/fs/xfs/xfs_file.c
===================================================================
--- xfs.orig/fs/xfs/xfs_file.c  2012-11-30 18:39:45.396020469 -0800
+++ xfs/fs/xfs/xfs_file.c       2012-11-30 18:39:56.240020746 -0800
@@ -853,7 +853,7 @@ xfs_file_fallocate(
 
                iattr.ia_valid = ATTR_SIZE;
                iattr.ia_size = new_size;
-               error = -xfs_setattr_size(ip, &iattr, XFS_ATTR_NOLOCK);
+               error = -xfs_setattr_size(ip, &iattr);
        }
 
 out_unlock:
Index: xfs/fs/xfs/xfs_iops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_iops.c  2012-11-30 18:39:45.396020469 -0800
+++ xfs/fs/xfs/xfs_iops.c       2012-11-30 18:39:56.240020746 -0800
@@ -689,8 +689,7 @@ out_dqrele:
 int
 xfs_setattr_size(
        struct xfs_inode        *ip,
-       struct iattr            *iattr,
-       int                     flags)
+       struct iattr            *iattr)
 {
        struct xfs_mount        *mp = ip->i_mount;
        struct inode            *inode = VFS_I(ip);
@@ -718,11 +717,6 @@ xfs_setattr_size(
                        ATTR_MTIME_SET|ATTR_KILL_SUID|ATTR_KILL_SGID|
                        ATTR_KILL_PRIV|ATTR_TIMES_SET)) == 0);
 
-       if (!(flags & XFS_ATTR_NOLOCK)) {
-               lock_flags |= XFS_IOLOCK_EXCL;
-               xfs_ilock(ip, lock_flags);
-       }
-
        oldsize = inode->i_size;
        newsize = iattr->ia_size;
 
@@ -736,7 +730,6 @@ xfs_setattr_size(
                /*
                 * Use the regular setattr path to update the timestamps.
                 */
-               xfs_iunlock(ip, lock_flags);
                iattr->ia_valid &= ~ATTR_SIZE;
                return xfs_setattr_nonsize(ip, iattr, 0);
        }
@@ -893,12 +886,21 @@ out_trans_cancel:
 
 STATIC int
 xfs_vn_setattr(
-       struct dentry   *dentry,
-       struct iattr    *iattr)
+       struct dentry           *dentry,
+       struct iattr            *iattr)
 {
-       if (iattr->ia_valid & ATTR_SIZE)
-               return -xfs_setattr_size(XFS_I(dentry->d_inode), iattr, 0);
-       return -xfs_setattr_nonsize(XFS_I(dentry->d_inode), iattr, 0);
+       struct xfs_inode        *ip = XFS_I(dentry->d_inode);
+       int                     error;
+
+       if (iattr->ia_valid & ATTR_SIZE) {
+               xfs_ilock(ip, XFS_IOLOCK_EXCL);
+               error = xfs_setattr_size(ip, iattr);
+               xfs_iunlock(ip, XFS_IOLOCK_EXCL);
+       } else {
+               error = xfs_setattr_nonsize(ip, iattr, 0);
+       }
+
+       return -error;
 }
 
 STATIC int
Index: xfs/fs/xfs/xfs_vnodeops.c
===================================================================
--- xfs.orig/fs/xfs/xfs_vnodeops.c      2012-11-30 18:39:45.396020469 -0800
+++ xfs/fs/xfs/xfs_vnodeops.c   2012-11-30 18:39:56.244020743 -0800
@@ -2291,8 +2291,7 @@ xfs_change_file_space(
                iattr.ia_valid = ATTR_SIZE;
                iattr.ia_size = startoffset;
 
-               error = xfs_setattr_size(ip, &iattr,
-                                        attr_flags | XFS_ATTR_NOLOCK);
+               error = xfs_setattr_size(ip, &iattr);
                xfs_iunlock(ip, XFS_IOLOCK_EXCL);
 
                if (error)
Index: xfs/fs/xfs/xfs_vnodeops.h
===================================================================
--- xfs.orig/fs/xfs/xfs_vnodeops.h      2012-11-30 18:39:53.784020685 -0800
+++ xfs/fs/xfs/xfs_vnodeops.h   2012-11-30 18:39:56.244020743 -0800
@@ -13,7 +13,7 @@ struct xfs_inode;
 
 
 int xfs_setattr_nonsize(struct xfs_inode *ip, struct iattr *vap, int flags);
-int xfs_setattr_size(struct xfs_inode *ip, struct iattr *vap, int flags);
+int xfs_setattr_size(struct xfs_inode *ip, struct iattr *iattr);
 #define        XFS_ATTR_DMI            0x01    /* invocation from a DMI 
function */
 #define XFS_ATTR_NOLOCK                0x04    /* Don't grab any conflicting 
locks */
 #define XFS_ATTR_NOACL         0x08    /* Don't call xfs_acl_chmod */

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