4 files changed, 66 insertions, 15 deletions
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 5b400730c21..4ee522b3f66 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -86,7 +86,31 @@ static struct {
 #endif /* CONFIG_CIFS_WEAK_PW_HASH */
 #endif /* CIFS_POSIX */
 
-/* Forward declarations */
+#ifdef CONFIG_HIGHMEM
+/*
+ * On arches that have high memory, kmap address space is limited. By
+ * serializing the kmap operations on those arches, we ensure that we don't
+ * end up with a bunch of threads in writeback with partially mapped page
+ * arrays, stuck waiting for kmap to come back. That situation prevents
+ * progress and can deadlock.
+ */
+static DEFINE_MUTEX(cifs_kmap_mutex);
+
+static inline void
+cifs_kmap_lock(void)
+{
+	mutex_lock(&cifs_kmap_mutex);
+}
+
+static inline void
+cifs_kmap_unlock(void)
+{
+	mutex_unlock(&cifs_kmap_mutex);
+}
+#else /* !CONFIG_HIGHMEM */
+#define cifs_kmap_lock() do { ; } while(0)
+#define cifs_kmap_unlock() do { ; } while(0)
+#endif /* CONFIG_HIGHMEM */
 
 /* Mark as invalid, all open files on tree connections since they
    were closed when session to server was lost */
@@ -1503,7 +1527,9 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	}
 
 	/* marshal up the page array */
+	cifs_kmap_lock();
 	len = rdata->marshal_iov(rdata, data_len);
+	cifs_kmap_unlock();
 	data_len -= len;
 
 	/* issue the read if we have any iovecs left to fill */
@@ -2069,7 +2095,9 @@ cifs_async_writev(struct cifs_writedata *wdata)
 	 * and set the iov_len properly for each one. It may also set
 	 * wdata->bytes too.
 	 */
+	cifs_kmap_lock();
 	wdata->marshal_iov(iov, wdata);
+	cifs_kmap_unlock();
 
 	cFYI(1, "async write at %llu %u bytes", wdata->offset, wdata->bytes);
 
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0ae86ddf221..94b7788c318 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3445,6 +3445,18 @@ void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
 #define CIFS_DEFAULT_NON_POSIX_RSIZE (60 * 1024)
 #define CIFS_DEFAULT_NON_POSIX_WSIZE (65536)
 
+/*
+ * On hosts with high memory, we can't currently support wsize/rsize that are
+ * larger than we can kmap at once. Cap the rsize/wsize at
+ * LAST_PKMAP * PAGE_SIZE. We'll never be able to fill a read or write request
+ * larger than that anyway.
+ */
+#ifdef CONFIG_HIGHMEM
+#define CIFS_KMAP_SIZE_LIMIT	(LAST_PKMAP * PAGE_CACHE_SIZE)
+#else /* CONFIG_HIGHMEM */
+#define CIFS_KMAP_SIZE_LIMIT	(1<<24)
+#endif /* CONFIG_HIGHMEM */
+
 static unsigned int
 cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 {
@@ -3475,6 +3487,9 @@ cifs_negotiate_wsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 		wsize = min_t(unsigned int, wsize,
 				server->maxBuf - sizeof(WRITE_REQ) + 4);
 
+	/* limit to the amount that we can kmap at once */
+	wsize = min_t(unsigned int, wsize, CIFS_KMAP_SIZE_LIMIT);
+
 	/* hard limit of CIFS_MAX_WSIZE */
 	wsize = min_t(unsigned int, wsize, CIFS_MAX_WSIZE);
 
@@ -3516,6 +3531,9 @@ cifs_negotiate_rsize(struct cifs_tcon *tcon, struct smb_vol *pvolume_info)
 	if (!(server->capabilities & CAP_LARGE_READ_X))
 		rsize = min_t(unsigned int, CIFSMaxBufSize, rsize);
 
+	/* limit to the amount that we can kmap at once */
+	rsize = min_t(unsigned int, rsize, CIFS_KMAP_SIZE_LIMIT);
+
 	/* hard limit of CIFS_MAX_RSIZE */
 	rsize = min_t(unsigned int, rsize, CIFS_MAX_RSIZE);
 
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 0a8224d1c4c..a4217f02fab 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -86,9 +86,12 @@ cifs_readdir_lookup(struct dentry *parent, struct qstr *name,
 
 	dentry = d_lookup(parent, name);
 	if (dentry) {
-		/* FIXME: check for inode number changes? */
-		if (dentry->d_inode != NULL)
+		inode = dentry->d_inode;
+		/* update inode in place if i_ino didn't change */
+		if (inode && CIFS_I(inode)->uniqueid == fattr->cf_uniqueid) {
+			cifs_fattr_to_inode(inode, fattr);
 			return dentry;
+		}
 		d_drop(dentry);
 		dput(dentry);
 	}
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 3097ee58fd7..f25d4ea14be 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -365,16 +365,14 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov,
 	if (mid == NULL)
 		return -ENOMEM;
 
-	/* put it on the pending_mid_q */
-	spin_lock(&GlobalMid_Lock);
-	list_add_tail(&mid->qhead, &server->pending_mid_q);
-	spin_unlock(&GlobalMid_Lock);
-
 	rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number);
-	if (rc)
-		delete_mid(mid);
+	if (rc) {
+		DeleteMidQEntry(mid);
+		return rc;
+	}
+
 	*ret_mid = mid;
-	return rc;
+	return 0;
 }
 
 /*
@@ -407,17 +405,21 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov,
 	mid->callback_data = cbdata;
 	mid->mid_state = MID_REQUEST_SUBMITTED;
 
+	/* put it on the pending_mid_q */
+	spin_lock(&GlobalMid_Lock);
+	list_add_tail(&mid->qhead, &server->pending_mid_q);
+	spin_unlock(&GlobalMid_Lock);
+
+
 	cifs_in_send_inc(server);
 	rc = smb_sendv(server, iov, nvec);
 	cifs_in_send_dec(server);
 	cifs_save_when_sent(mid);
 	mutex_unlock(&server->srv_mutex);
 
-	if (rc)
-		goto out_err;
+	if (rc == 0)
+		return 0;
 
-	return rc;
-out_err:
 	delete_mid(mid);
 	add_credits(server, 1);
 	wake_up(&server->request_q);