[PATCH 1/5 v3] xfs: always take the iolock around xfs_setattr_size

Christoph Hellwig
2013-10-14T14:09:41Z

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@lst.de>

---
fs/xfs/xfs_bmap_util.c | 3 +--
fs/xfs/xfs_file.c | 2 +-
fs/xfs/xfs_iops.c | 39 +++++++++++++++++++++------------------
fs/xfs/xfs_iops.h | 2 +-
4 files changed, 24 insertions(+), 22 deletions(-)

Index: xfs/fs/xfs/xfs_file.c
===================================================================
--- xfs.orig/fs/xfs/xfs_file.c 2013-10-11 20:05:38.272512388 +0200
+++ xfs/fs/xfs/xfs_file.c 2013-10-14 16:07:38.316153285 +0200
@@ -852,7 +852,7 @@ 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 2013-10-11 20:05:38.272512388 +0200
+++ xfs/fs/xfs/xfs_iops.c 2013-10-14 15:28:38.900097685 +0200
@@ -709,8 +709,7 @@ 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);
@@ -733,15 +732,11 @@ xfs_setattr_size(
if (error)
return XFS_ERROR(error);

+ ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
ASSERT(S_ISREG(ip->i_d.di_mode));
ASSERT((mask & (ATTR_UID|ATTR_GID|ATTR_ATIME|ATTR_ATIME_SET|
ATTR_MTIME_SET|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;

@@ -750,12 +745,11 @@ xfs_setattr_size(
*/
if (newsize == 0 && oldsize == 0 && ip->i_d.di_nextents == 0) {
if (!(mask & (ATTR_CTIME|ATTR_MTIME)))
- goto out_unlock;
+ return 0;

/*
* 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);
}
@@ -765,7 +759,7 @@ xfs_setattr_size(
*/
error = xfs_qm_dqattach(ip, 0);
if (error)
- goto out_unlock;
+ return error;

/*
* Now we can make the changes. Before we join the inode to the
@@ -783,7 +777,7 @@ xfs_setattr_size(
*/
error = xfs_zero_eof(ip, newsize, oldsize);
if (error)
- goto out_unlock;
+ return error;
}

/*
@@ -802,7 +796,7 @@ xfs_setattr_size(
error = -filemap_write_and_wait_range(VFS_I(ip)->i_mapping,
ip->i_d.di_size, newsize);
if (error)
- goto out_unlock;
+ return error;
}

/*
@@ -812,7 +806,7 @@ xfs_setattr_size(

error = -block_truncate_page(inode->i_mapping, newsize, xfs_get_blocks);
if (error)
- goto out_unlock;
+ return error;

tp = xfs_trans_alloc(mp, XFS_TRANS_SETATTR_SIZE);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_itruncate, 0, 0);
@@ -916,12 +910,21 @@ 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_bmap_util.c
===================================================================
--- xfs.orig/fs/xfs/xfs_bmap_util.c 2013-10-11 20:05:38.272512388 +0200
+++ xfs/fs/xfs/xfs_bmap_util.c 2013-10-14 16:07:38.316153285 +0200
@@ -1622,8 +1622,7 @@ 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_iops.h
===================================================================
--- xfs.orig/fs/xfs/xfs_iops.h 2013-10-11 20:05:38.272512388 +0200
+++ xfs/fs/xfs/xfs_iops.h 2013-10-14 16:07:38.440153288 +0200
@@ -38,6 +38,6 @@ extern void xfs_setup_inode(struct xfs_i

extern int xfs_setattr_nonsize(struct xfs_inode *ip, struct iattr *vap,
int flags);
-extern int xfs_setattr_size(struct xfs_inode *ip, struct iattr *vap, int flags);
+extern int xfs_setattr_size(struct xfs_inode *ip, struct iattr *vap);

#endif /* __XFS_IOPS_H__ */