From 536e43d12b9517bbbf6114cd1a12be27857a4d7a Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Tue, 17 Jan 2012 22:04:26 -0500 Subject: NFS: Optimise away unnecessary setattrs for open(O_TRUNC); Currently, we will correctly optimise away a truncate that doesn't change the file size. However, in the case of open(O_TRUNC), we also want to optimise away the time changes. Signed-off-by: Trond Myklebust --- fs/nfs/dir.c | 25 +++++++++++++++++++------ 1 file changed, 19 insertions(+), 6 deletions(-) (limited to 'fs/nfs/dir.c') diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index fd9a872fada0..bb132a88f4e8 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -1429,6 +1429,7 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry } open_flags = nd->intent.open.flags; + attr.ia_valid = 0; ctx = create_nfs_open_context(dentry, open_flags); res = ERR_CAST(ctx); @@ -1437,11 +1438,14 @@ static struct dentry *nfs_atomic_lookup(struct inode *dir, struct dentry *dentry if (nd->flags & LOOKUP_CREATE) { attr.ia_mode = nd->intent.open.create_mode; - attr.ia_valid = ATTR_MODE; + attr.ia_valid |= ATTR_MODE; attr.ia_mode &= ~current_umask(); - } else { + } else open_flags &= ~(O_EXCL | O_CREAT); - attr.ia_valid = 0; + + if (open_flags & O_TRUNC) { + attr.ia_valid |= ATTR_SIZE; + attr.ia_size = 0; } /* Open the file on the server */ @@ -1495,6 +1499,7 @@ static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) struct inode *inode; struct inode *dir; struct nfs_open_context *ctx; + struct iattr attr; int openflags, ret = 0; if (nd->flags & LOOKUP_RCU) @@ -1523,19 +1528,27 @@ static int nfs_open_revalidate(struct dentry *dentry, struct nameidata *nd) /* We cannot do exclusive creation on a positive dentry */ if ((openflags & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL)) goto no_open_dput; - /* We can't create new files, or truncate existing ones here */ - openflags &= ~(O_CREAT|O_EXCL|O_TRUNC); + /* We can't create new files here */ + openflags &= ~(O_CREAT|O_EXCL); ctx = create_nfs_open_context(dentry, openflags); ret = PTR_ERR(ctx); if (IS_ERR(ctx)) goto out; + + attr.ia_valid = 0; + if (openflags & O_TRUNC) { + attr.ia_valid |= ATTR_SIZE; + attr.ia_size = 0; + nfs_wb_all(inode); + } + /* * Note: we're not holding inode->i_mutex and so may be racing with * operations that change the directory. We therefore save the * change attribute *before* we do the RPC call. */ - inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, NULL); + inode = NFS_PROTO(dir)->open_context(dir, ctx, openflags, &attr); if (IS_ERR(inode)) { ret = PTR_ERR(inode); switch (ret) { -- cgit v1.2.3