On 02/11/2010 02:09 PM, Chuck Lever wrote:
Close-to-open isn't needed for O_DIRECT files, since their data is
never cached. So if their attribute cache hasn't expired, skip the
GETATTR.
Note that fattr->time_start is required to be set correctly by the NFS
direct I/O paths in order for this patch to work properly.
Signed-off-by: Chuck Lever<chuck.lever@xxxxxxxxxx>
---
fs/nfs/dir.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 3c7f03b..367302b 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -709,6 +709,12 @@ static int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
return nd&& nfs_lookup_check_intent(nd, LOOKUP_EXCL);
}
+static bool nfs_open_odirect(struct nameidata *nd)
+{
+ struct file *filp = nd->intent.open.file;
+ return filp&& (filp->f_flags& O_DIRECT);
+}
+
/*
* Inode and filehandle revalidation for lookups.
*
@@ -716,6 +722,9 @@ static int nfs_is_exclusive_create(struct inode *dir, struct nameidata *nd)
* or if the intent information indicates that we're about to open this
* particular file and the "nocto" mount flag is not set.
*
+ * O_DIRECT files have no locally cached data, so close-to-open checking
+ * isn't necessary. However, their attributes must be revalidated if the
+ * cache has expired, mainly to catch the case where actimeo is zero.
Missing word...
+ * attribute cache has expired,
*/
static inline
int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
@@ -730,12 +739,15 @@ int nfs_lookup_verify_inode(struct inode *inode, struct nameidata *nd)
goto out_force;
/* This is an open(2) */
if (nfs_lookup_check_intent(nd, LOOKUP_OPEN) != 0&&
- !(server->flags& NFS_MOUNT_NOCTO)&&
- (S_ISREG(inode->i_mode) ||
- S_ISDIR(inode->i_mode)))
- goto out_force;
+ (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))) {
+ if (nfs_open_odirect(nd))
+ goto out_conditional;
+ if (!(server->flags& NFS_MOUNT_NOCTO))
+ goto out_force;
+ }
return 0;
}
+out_conditional:
return nfs_revalidate_inode(server, inode);
out_force:
return __nfs_revalidate_inode(server, inode);
--
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--
chuck[dot]lever[at]oracle[dot]com
--
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