From: Sage Weil <sage@newdream.net>
Date: Fri, 9 Jan 2009 00:45:53 +0000 (-0800)
Subject: kclient: only update xattr blob when defined and newer (caps|reply)
X-Git-Tag: v0.6~1^2~121
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=c7fa14dc61f0c8e8d250b06da8c08fa257e5f006;p=ceph.git

kclient: only update xattr blob when defined and newer (caps|reply)
---

diff --git a/src/kernel/caps.c b/src/kernel/caps.c
index 3b2d0142191a..82a530920b07 100644
--- a/src/kernel/caps.c
+++ b/src/kernel/caps.c
@@ -1095,7 +1095,8 @@ void ceph_put_wrbuffer_cap_refs(struct ceph_inode_info *ci, int nr,
  */
 static int handle_cap_grant(struct inode *inode, struct ceph_mds_caps *grant,
 			    struct ceph_mds_session *session,
-			    struct ceph_cap *cap)
+			    struct ceph_cap *cap,
+			    void **xattr_data)
 	__releases(inode->i_lock)
 
 {
@@ -1188,7 +1189,19 @@ start:
 	}
 
 	if ((issued & CEPH_CAP_XATTR_EXCL) == 0 && grant->xattr_len) {
-#warning fix xattr cap update
+		int len = le32_to_cpu(grant->xattr_len);
+		u64 version = le64_to_cpu(grant->xattr_version);
+
+		if (!(len > 4 && *xattr_data == 0) &&  /* ENOMEM in caller */
+		    version > ci->i_xattr_version) {
+			dout(20, " got new xattrs v%llu on %p len %d\n",
+			     version, inode, len);
+			kfree(ci->i_xattr_data);
+			ci->i_xattr_len = len;
+			ci->i_xattr_version = version;
+			ci->i_xattr_data = *xattr_data;
+			*xattr_data = 0;
+		}
 	}
 
 	/* size/ctime/mtime/atime? */
@@ -1540,6 +1553,7 @@ void ceph_handle_caps(struct ceph_mds_client *mdsc,
 	struct ceph_vino vino;
 	u64 size, max_size;
 	int check_caps = 0;
+	void *xattr_data = 0;
 
 	dout(10, "handle_caps from mds%d\n", mds);
 
@@ -1602,6 +1616,10 @@ void ceph_handle_caps(struct ceph_mds_client *mdsc,
 
 	}
 
+	/* preallocate space for xattrs? */
+	if (le32_to_cpu(h->xattr_len) > 4)
+		xattr_data = kmalloc(le32_to_cpu(h->xattr_len), GFP_NOFS);
+
 	/* the rest require a cap */
 	spin_lock(&inode->i_lock);
 	cap = __get_cap_for_mds(inode, mds);
@@ -1616,7 +1634,7 @@ void ceph_handle_caps(struct ceph_mds_client *mdsc,
 	switch (op) {
 	case CEPH_CAP_OP_GRANT:
 		up_write(&mdsc->snap_rwsem);
-		if (handle_cap_grant(inode, h, session, cap) == 1) {
+		if (handle_cap_grant(inode, h, session, cap,&xattr_data) == 1) {
 			dout(10, " sending reply back to mds%d\n", mds);
 			ceph_msg_get(msg);
 			ceph_send_msg_mds(mdsc, msg, mds);
@@ -1645,6 +1663,7 @@ done:
 	mutex_unlock(&session->s_mutex);
 	ceph_put_mds_session(session);
 
+	kfree(xattr_data);
 	if (check_caps)
 		ceph_check_caps(ceph_inode(inode), 1, 0);
 	if (inode)
diff --git a/src/kernel/inode.c b/src/kernel/inode.c
index 5d6c8345370a..55b6c692d2da 100644
--- a/src/kernel/inode.c
+++ b/src/kernel/inode.c
@@ -405,8 +405,12 @@ static int fill_inode(struct inode *inode,
 	     inode, ceph_vinop(inode), le64_to_cpu(info->version),
 	     ci->i_version);
 
-	/* prealloc xattr data, if it looks like we'll need it */
-	if (iinfo->xattr_len && iinfo->xattr_len != ci->i_xattr_len) {
+	/*
+	 * prealloc xattr data, if it looks like we'll need it.  only
+	 * if len > 4 (meaning there are actually xattrs; the first 4
+	 * bytes are the xattr count).
+	 */
+	if (iinfo->xattr_len > 4 && iinfo->xattr_len != ci->i_xattr_len) {
 		xattr_data = kmalloc(iinfo->xattr_len, GFP_NOFS);
 		if (!xattr_data)
 			derr(10, "ENOMEM on xattr blob %d bytes\n",
@@ -451,14 +455,17 @@ static int fill_inode(struct inode *inode,
 	inode->i_blkbits = fls(le32_to_cpu(info->layout.fl_stripe_unit)) - 1;
 
 	/* xattrs */
-	if (iinfo->xattr_len && (issued & CEPH_CAP_XATTR_EXCL) == 0) {
+	/* note that if i_xattr_len <= 4, i_xattr_data will still be NULL. */
+	if (iinfo->xattr_len && (issued & CEPH_CAP_XATTR_EXCL) == 0 &&
+	    le64_to_cpu(info->xattr_version) > ci->i_xattr_version) {
 		if (ci->i_xattr_len != iinfo->xattr_len) {
 			kfree(ci->i_xattr_data);
 			ci->i_xattr_len = iinfo->xattr_len;
+			ci->i_xattr_version = le64_to_cpu(info->xattr_version);
 			ci->i_xattr_data = xattr_data;
 			xattr_data = NULL;
 		}
-		if (ci->i_xattr_len)
+		if (ci->i_xattr_len > 4)
 			memcpy(ci->i_xattr_data, iinfo->xattr_data,
 			       ci->i_xattr_len);
 	}
@@ -1802,7 +1809,7 @@ ssize_t ceph_getxattr(struct dentry *dentry, const char *name, void *value,
 	spin_lock(&inode->i_lock);
 
 	err = -ENODATA;  /* == ENOATTR */
-	if (!ci->i_xattr_len)
+	if (ci->i_xattr_len <= 4)
 		goto out;
 
 	/* find attr name */
@@ -1858,7 +1865,7 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
 	spin_lock(&inode->i_lock);
 
 	/* measure len of names */
-	if (ci->i_xattr_len) {
+	if (ci->i_xattr_len > 4) {
 		p = ci->i_xattr_data;
 		end = p + ci->i_xattr_len;
 		ceph_decode_32_safe(&p, end, numattr, bad);
@@ -1886,7 +1893,7 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
 		goto out;
 
 	/* copy names */
-	if (ci->i_xattr_len) {
+	if (ci->i_xattr_len> 4) {
 		p = ci->i_xattr_data;
 		ceph_decode_32(&p, numattr);
 		while (numattr--) {
diff --git a/src/kernel/super.h b/src/kernel/super.h
index 0c75cc793a51..b4a8ca505d06 100644
--- a/src/kernel/super.h
+++ b/src/kernel/super.h
@@ -160,7 +160,8 @@ struct ceph_cap_snap {
 	gid_t gid;
 
 	void *xattr_blob;
-	int xattr_len;	
+	int xattr_len;
+	u64 xattr_version;
 
 	u64 size;
 	struct timespec mtime, atime, ctime;
@@ -220,10 +221,17 @@ struct ceph_inode_info {
 	struct rb_root i_fragtree;
 	struct mutex i_fragtree_mutex;
 
-	/* (still encoded) xattr blob. we avoid the overhead of parsing
-	 * this until someone actually called getxattr, etc. */
+	/*
+	 * (still encoded) xattr blob. we avoid the overhead of parsing
+	 * this until someone actually calls getxattr, etc.
+	 *
+	 * if i_xattr_len == 0 or 4, i_xattr_data == NULL.
+	 * i_xattr_len == 4 implies there are no xattrs; 0 means we
+	 * don't know.
+	 */
 	int i_xattr_len;
 	char *i_xattr_data;
+	u64 i_xattr_version;
 
 	/* capabilities.  protected _both_ by i_lock and cap->session's
 	 * s_mutex. */