1 files changed, 32 insertions, 33 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 4ad5cc4e63e8..8fda38d23e38 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5181,32 +5181,6 @@ static int restart_array(struct mddev *mddev)
         return 0;
 }
 
-/* similar to deny_write_access, but accounts for our holding a reference
- * to the file ourselves */
-static int deny_bitmap_write_access(struct file * file)
-{
-        struct inode *inode = file->f_mapping->host;
-
-        spin_lock(&inode->i_lock);
-        if (atomic_read(&inode->i_writecount) > 1) {
-                spin_unlock(&inode->i_lock);
-                return -ETXTBSY;
-        }
-        atomic_set(&inode->i_writecount, -1);
-        spin_unlock(&inode->i_lock);
-
-        return 0;
-}
-
-void restore_bitmap_write_access(struct file *file)
-{
-        struct inode *inode = file->f_mapping->host;
-
-        spin_lock(&inode->i_lock);
-        atomic_set(&inode->i_writecount, 1);
-        spin_unlock(&inode->i_lock);
-}
-
 static void md_clean(struct mddev *mddev)
 {
         mddev->array_sectors = 0;
@@ -5427,7 +5401,6 @@ static int do_md_stop(struct mddev * mddev, int mode,
 
                 bitmap_destroy(mddev);
                 if (mddev->bitmap_info.file) {
-                        restore_bitmap_write_access(mddev->bitmap_info.file);
                         fput(mddev->bitmap_info.file);
                         mddev->bitmap_info.file = NULL;
                 }
@@ -5979,7 +5952,7 @@ abort_export:
 
 static int set_bitmap_file(struct mddev *mddev, int fd)
 {
-        int err;
+        int err = 0;
 
         if (mddev->pers) {
                 if (!mddev->pers->quiesce)
@@ -5991,6 +5964,7 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
 
 
         if (fd >= 0) {
+                struct inode *inode;
                 if (mddev->bitmap)
                         return -EEXIST; /* cannot add when bitmap is present */
                 mddev->bitmap_info.file = fget(fd);
@@ -6001,10 +5975,21 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
                         return -EBADF;
                 }
 
-                err = deny_bitmap_write_access(mddev->bitmap_info.file);
-                if (err) {
+                inode = mddev->bitmap_info.file->f_mapping->host;
+                if (!S_ISREG(inode->i_mode)) {
+                        printk(KERN_ERR "%s: error: bitmap file must be a regular file\n",
+                               mdname(mddev));
+                        err = -EBADF;
+                } else if (!(mddev->bitmap_info.file->f_mode & FMODE_WRITE)) {
+                        printk(KERN_ERR "%s: error: bitmap file must open for write\n",
+                               mdname(mddev));
+                        err = -EBADF;
+                } else if (atomic_read(&inode->i_writecount) != 1) {
                         printk(KERN_ERR "%s: error: bitmap file is already in use\n",
                                mdname(mddev));
+                        err = -EBUSY;
+                }
+                if (err) {
                         fput(mddev->bitmap_info.file);
                         mddev->bitmap_info.file = NULL;
                         return err;
@@ -6027,10 +6012,8 @@ static int set_bitmap_file(struct mddev *mddev, int fd)
                 mddev->pers->quiesce(mddev, 0);
         }
         if (fd < 0) {
-                if (mddev->bitmap_info.file) {
-                        restore_bitmap_write_access(mddev->bitmap_info.file);
+                if (mddev->bitmap_info.file)
                         fput(mddev->bitmap_info.file);
-                }
                 mddev->bitmap_info.file = NULL;
         }
 
@@ -7182,11 +7165,14 @@ static int md_seq_open(struct inode *inode, struct file *file)
         return error;
 }
 
+static int md_unloading;
 static unsigned int mdstat_poll(struct file *filp, poll_table *wait)
 {
         struct seq_file *seq = filp->private_data;
         int mask;
 
+        if (md_unloading)
+                return POLLIN|POLLRDNORM|POLLERR|POLLPRI;;
         poll_wait(filp, &md_event_waiters, wait);
 
         /* always allow read */
@@ -8672,6 +8658,7 @@ static __exit void md_exit(void)
 {
         struct mddev *mddev;
         struct list_head *tmp;
+        int delay = 1;
 
         blk_unregister_region(MKDEV(MD_MAJOR,0), 1U << MINORBITS);
         blk_unregister_region(MKDEV(mdp_major,0), 1U << MINORBITS);
@@ -8680,7 +8667,19 @@ static __exit void md_exit(void)
         unregister_blkdev(mdp_major, "mdp");
         unregister_reboot_notifier(&md_notifier);
         unregister_sysctl_table(raid_table_header);
+
+        /* We cannot unload the modules while some process is
+         * waiting for us in select() or poll() - wake them up
+         */
+        md_unloading = 1;
+        while (waitqueue_active(&md_event_waiters)) {
+                /* not safe to leave yet */
+                wake_up(&md_event_waiters);
+                msleep(delay);
+                delay += delay;
+        }
         remove_proc_entry("mdstat", NULL);
+
         for_each_mddev(mddev, tmp) {
                 export_array(mddev);
                 mddev->hold_active = 0;