4 files changed, 66 insertions, 15 deletions

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 5b400730c213..4ee522b3f66f 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 0ae86ddf2213..94b7788c3189 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 0a8224d1c4c5..a4217f02fab2 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 3097ee58fd7d..f25d4ea14be4 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);