Three important fixes tagged for stable (an indefinite hang, a crash on

an assert and a NULL pointer dereference) plus a small series from Luis
 fixing instances of vfree() under spinlock.
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Merge tag 'ceph-for-5.3-rc6' of git://github.com/ceph/ceph-client

Pull ceph fixes from Ilya Dryomov:
 "Three important fixes tagged for stable (an indefinite hang, a crash
  on an assert and a NULL pointer dereference) plus a small series from
  Luis fixing instances of vfree() under spinlock"

* tag 'ceph-for-5.3-rc6' of git://github.com/ceph/ceph-client:
  libceph: fix PG split vs OSD (re)connect race
  ceph: don't try fill file_lock on unsuccessful GETFILELOCK reply
  ceph: clear page dirty before invalidate page
  ceph: fix buffer free while holding i_ceph_lock in fill_inode()
  ceph: fix buffer free while holding i_ceph_lock in __ceph_build_xattrs_blob()
  ceph: fix buffer free while holding i_ceph_lock in __ceph_setxattr()
  libceph: allow ceph_buffer_put() to receive a NULL ceph_buffer

fs/ceph/addr.c

@@ -913,8 +913,9 @@ get_more_pages:
 			if (page_offset(page) >= ceph_wbc.i_size) {
 				dout("%p page eof %llu\n",
 				     page, ceph_wbc.i_size);
-				if (ceph_wbc.size_stable ||
-				    page_offset(page) >= i_size_read(inode))
+				if ((ceph_wbc.size_stable ||
+				    page_offset(page) >= i_size_read(inode)) &&
+				    clear_page_dirty_for_io(page))
 					mapping->a_ops->invalidatepage(page,
 								0, PAGE_SIZE);
 				unlock_page(page);

fs/ceph/caps.c

@@ -1301,6 +1301,7 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
 {
 	struct ceph_inode_info *ci = cap->ci;
 	struct inode *inode = &ci->vfs_inode;
+	struct ceph_buffer *old_blob = NULL;
 	struct cap_msg_args arg;
 	int held, revoking;
 	int wake = 0;
@@ -1365,7 +1366,7 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
 	ci->i_requested_max_size = arg.max_size;
 
 	if (flushing & CEPH_CAP_XATTR_EXCL) {
-		__ceph_build_xattrs_blob(ci);
+		old_blob = __ceph_build_xattrs_blob(ci);
 		arg.xattr_version = ci->i_xattrs.version;
 		arg.xattr_buf = ci->i_xattrs.blob;
 	} else {
@@ -1409,6 +1410,8 @@ static int __send_cap(struct ceph_mds_client *mdsc, struct ceph_cap *cap,
 
 	spin_unlock(&ci->i_ceph_lock);
 
+	ceph_buffer_put(old_blob);
+
 	ret = send_cap_msg(&arg);
 	if (ret < 0) {
 		dout("error sending cap msg, must requeue %p\n", inode);

fs/ceph/inode.c

@@ -736,6 +736,7 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
 	int issued, new_issued, info_caps;
 	struct timespec64 mtime, atime, ctime;
 	struct ceph_buffer *xattr_blob = NULL;
+	struct ceph_buffer *old_blob = NULL;
 	struct ceph_string *pool_ns = NULL;
 	struct ceph_cap *new_cap = NULL;
 	int err = 0;
@@ -881,7 +882,7 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
 	if ((ci->i_xattrs.version == 0 || !(issued & CEPH_CAP_XATTR_EXCL))  &&
 	    le64_to_cpu(info->xattr_version) > ci->i_xattrs.version) {
 		if (ci->i_xattrs.blob)
-			ceph_buffer_put(ci->i_xattrs.blob);
+			old_blob = ci->i_xattrs.blob;
 		ci->i_xattrs.blob = xattr_blob;
 		if (xattr_blob)
 			memcpy(ci->i_xattrs.blob->vec.iov_base,
@@ -1022,8 +1023,8 @@ static int fill_inode(struct inode *inode, struct page *locked_page,
 out:
 	if (new_cap)
 		ceph_put_cap(mdsc, new_cap);
-	if (xattr_blob)
-		ceph_buffer_put(xattr_blob);
+	ceph_buffer_put(old_blob);
+	ceph_buffer_put(xattr_blob);
 	ceph_put_string(pool_ns);
 	return err;
 }

fs/ceph/locks.c

@@ -111,8 +111,7 @@ static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
 		req->r_wait_for_completion = ceph_lock_wait_for_completion;
 
 	err = ceph_mdsc_do_request(mdsc, inode, req);
-
-	if (operation == CEPH_MDS_OP_GETFILELOCK) {
+	if (!err && operation == CEPH_MDS_OP_GETFILELOCK) {
 		fl->fl_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid);
 		if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
 			fl->fl_type = F_RDLCK;

fs/ceph/snap.c

@@ -465,6 +465,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 	struct inode *inode = &ci->vfs_inode;
 	struct ceph_cap_snap *capsnap;
 	struct ceph_snap_context *old_snapc, *new_snapc;
+	struct ceph_buffer *old_blob = NULL;
 	int used, dirty;
 
 	capsnap = kzalloc(sizeof(*capsnap), GFP_NOFS);
@@ -541,7 +542,7 @@ void ceph_queue_cap_snap(struct ceph_inode_info *ci)
 	capsnap->gid = inode->i_gid;
 
 	if (dirty & CEPH_CAP_XATTR_EXCL) {
-		__ceph_build_xattrs_blob(ci);
+		old_blob = __ceph_build_xattrs_blob(ci);
 		capsnap->xattr_blob =
 			ceph_buffer_get(ci->i_xattrs.blob);
 		capsnap->xattr_version = ci->i_xattrs.version;
@@ -584,6 +585,7 @@ update_snapc:
 	}
 	spin_unlock(&ci->i_ceph_lock);
 
+	ceph_buffer_put(old_blob);
 	kfree(capsnap);
 	ceph_put_snap_context(old_snapc);
 }

fs/ceph/super.h

@@ -926,7 +926,7 @@ extern int ceph_getattr(const struct path *path, struct kstat *stat,
 int __ceph_setxattr(struct inode *, const char *, const void *, size_t, int);
 ssize_t __ceph_getxattr(struct inode *, const char *, void *, size_t);
 extern ssize_t ceph_listxattr(struct dentry *, char *, size_t);
-extern void __ceph_build_xattrs_blob(struct ceph_inode_info *ci);
+extern struct ceph_buffer *__ceph_build_xattrs_blob(struct ceph_inode_info *ci);
 extern void __ceph_destroy_xattrs(struct ceph_inode_info *ci);
 extern const struct xattr_handler *ceph_xattr_handlers[];
 

fs/ceph/xattr.c

@@ -754,12 +754,15 @@ static int __get_required_blob_size(struct ceph_inode_info *ci, int name_size,
 
 /*
  * If there are dirty xattrs, reencode xattrs into the prealloc_blob
- * and swap into place.
+ * and swap into place.  It returns the old i_xattrs.blob (or NULL) so
+ * that it can be freed by the caller as the i_ceph_lock is likely to be
+ * held.
  */
-void __ceph_build_xattrs_blob(struct ceph_inode_info *ci)
+struct ceph_buffer *__ceph_build_xattrs_blob(struct ceph_inode_info *ci)
 {
 	struct rb_node *p;
 	struct ceph_inode_xattr *xattr = NULL;
+	struct ceph_buffer *old_blob = NULL;
 	void *dest;
 
 	dout("__build_xattrs_blob %p\n", &ci->vfs_inode);
@@ -790,12 +793,14 @@ void __ceph_build_xattrs_blob(struct ceph_inode_info *ci)
 			dest - ci->i_xattrs.prealloc_blob->vec.iov_base;
 
 		if (ci->i_xattrs.blob)
-			ceph_buffer_put(ci->i_xattrs.blob);
+			old_blob = ci->i_xattrs.blob;
 		ci->i_xattrs.blob = ci->i_xattrs.prealloc_blob;
 		ci->i_xattrs.prealloc_blob = NULL;
 		ci->i_xattrs.dirty = false;
 		ci->i_xattrs.version++;
 	}
+
+	return old_blob;
 }
 
 static inline int __get_request_mask(struct inode *in) {
@@ -1036,6 +1041,7 @@ int __ceph_setxattr(struct inode *inode, const char *name,
 	struct ceph_inode_info *ci = ceph_inode(inode);
 	struct ceph_mds_client *mdsc = ceph_sb_to_client(inode->i_sb)->mdsc;
 	struct ceph_cap_flush *prealloc_cf = NULL;
+	struct ceph_buffer *old_blob = NULL;
 	int issued;
 	int err;
 	int dirty = 0;
@@ -1109,13 +1115,15 @@ retry:
 		struct ceph_buffer *blob;
 
 		spin_unlock(&ci->i_ceph_lock);
-		dout(" preaallocating new blob size=%d\n", required_blob_size);
+		ceph_buffer_put(old_blob); /* Shouldn't be required */
+		dout(" pre-allocating new blob size=%d\n", required_blob_size);
 		blob = ceph_buffer_new(required_blob_size, GFP_NOFS);
 		if (!blob)
 			goto do_sync_unlocked;
 		spin_lock(&ci->i_ceph_lock);
+		/* prealloc_blob can't be released while holding i_ceph_lock */
 		if (ci->i_xattrs.prealloc_blob)
-			ceph_buffer_put(ci->i_xattrs.prealloc_blob);
+			old_blob = ci->i_xattrs.prealloc_blob;
 		ci->i_xattrs.prealloc_blob = blob;
 		goto retry;
 	}
@@ -1131,6 +1139,7 @@ retry:
 	}
 
 	spin_unlock(&ci->i_ceph_lock);
+	ceph_buffer_put(old_blob);
 	if (lock_snap_rwsem)
 		up_read(&mdsc->snap_rwsem);
 	if (dirty)

include/linux/ceph/buffer.h

@@ -30,7 +30,8 @@ static inline struct ceph_buffer *ceph_buffer_get(struct ceph_buffer *b)
 
 static inline void ceph_buffer_put(struct ceph_buffer *b)
 {
-	kref_put(&b->kref, ceph_buffer_release);
+	if (b)
+		kref_put(&b->kref, ceph_buffer_release);
 }
 
 extern int ceph_decode_buffer(struct ceph_buffer **b, void **p, void *end);

net/ceph/osd_client.c

@@ -1496,7 +1496,7 @@ static enum calc_target_result calc_target(struct ceph_osd_client *osdc,
 	struct ceph_osds up, acting;
 	bool force_resend = false;
 	bool unpaused = false;
-	bool legacy_change;
+	bool legacy_change = false;
 	bool split = false;
 	bool sort_bitwise = ceph_osdmap_flag(osdc, CEPH_OSDMAP_SORTBITWISE);
 	bool recovery_deletes = ceph_osdmap_flag(osdc,
@@ -1584,15 +1584,14 @@ static enum calc_target_result calc_target(struct ceph_osd_client *osdc,
 		t->osd = acting.primary;
 	}
 
-	if (unpaused || legacy_change || force_resend ||
-	    (split && con && CEPH_HAVE_FEATURE(con->peer_features,
-					       RESEND_ON_SPLIT)))
+	if (unpaused || legacy_change || force_resend || split)
 		ct_res = CALC_TARGET_NEED_RESEND;
 	else
 		ct_res = CALC_TARGET_NO_ACTION;
 
 out:
-	dout("%s t %p -> ct_res %d osd %d\n", __func__, t, ct_res, t->osd);
+	dout("%s t %p -> %d%d%d%d ct_res %d osd%d\n", __func__, t, unpaused,
+	     legacy_change, force_resend, split, ct_res, t->osd);
 	return ct_res;
 }