md: change bitmap_unplug and others to void functions

bitmap_unplug only ever returns 0, so it may as well be void.  Two callers try
to print a message if it returns non-zero, but that message is already printed
by bitmap_file_kick.

write_page returns an error which is not consistently checked.  It always
causes BITMAP_WRITE_ERROR to be set on an error, and that can more
conveniently be checked.

When the return of write_page is checked, an error causes bitmap_file_kick to
be called - so move that call into write_page - and protect against recursive
calls into bitmap_file_kick.

bitmap_update_sb returns an error that is never checked.

So make these 'void' and be consistent about checking the bit.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 75 insertions, 74 deletions

diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index ae94f3beb5fc..927cb34c4805 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -305,10 +305,11 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
         return 0;
 }
 
+static void bitmap_file_kick(struct bitmap *bitmap);
 /*
  * write out a page to a file
  */
-static int write_page(struct bitmap *bitmap, struct page *page, int wait)
+static void write_page(struct bitmap *bitmap, struct page *page, int wait)
 {
         struct buffer_head *bh;
 
@@ -316,27 +317,26 @@ static int write_page(struct bitmap *bitmap, struct page *page, int wait)
                 switch (write_sb_page(bitmap, page, wait)) {
                 case -EINVAL:
                         bitmap->flags |= BITMAP_WRITE_ERROR;
-                        return -EIO;
                 }
-                return 0;
-        }
+        } else {
 
-        bh = page_buffers(page);
+                bh = page_buffers(page);
 
-        while (bh && bh->b_blocknr) {
-                atomic_inc(&bitmap->pending_writes);
-                set_buffer_locked(bh);
-                set_buffer_mapped(bh);
-                submit_bh(WRITE, bh);
-                bh = bh->b_this_page;
-        }
+                while (bh && bh->b_blocknr) {
+                        atomic_inc(&bitmap->pending_writes);
+                        set_buffer_locked(bh);
+                        set_buffer_mapped(bh);
+                        submit_bh(WRITE, bh);
+                        bh = bh->b_this_page;
+                }
 
-        if (wait) {
-                wait_event(bitmap->write_wait,
-                           atomic_read(&bitmap->pending_writes)==0);
-                return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
+                if (wait) {
+                        wait_event(bitmap->write_wait,
+                                   atomic_read(&bitmap->pending_writes)==0);
+                }
         }
-        return 0;
+        if (bitmap->flags & BITMAP_WRITE_ERROR)
+                bitmap_file_kick(bitmap);
 }
 
 static void end_bitmap_write(struct buffer_head *bh, int uptodate)
@@ -456,17 +456,17 @@ out:
  */
 
 /* update the event counter and sync the superblock to disk */
-int bitmap_update_sb(struct bitmap *bitmap)
+void bitmap_update_sb(struct bitmap *bitmap)
 {
         bitmap_super_t *sb;
         unsigned long flags;
 
         if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
-                return 0;
+                return;
         spin_lock_irqsave(&bitmap->lock, flags);
         if (!bitmap->sb_page) { /* no superblock */
                 spin_unlock_irqrestore(&bitmap->lock, flags);
-                return 0;
+                return;
         }
         spin_unlock_irqrestore(&bitmap->lock, flags);
         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
@@ -474,7 +474,7 @@ int bitmap_update_sb(struct bitmap *bitmap)
         if (!bitmap->mddev->degraded)
                 sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
         kunmap_atomic(sb, KM_USER0);
-        return write_page(bitmap, bitmap->sb_page, 1);
+        write_page(bitmap, bitmap->sb_page, 1);
 }
 
 /* print out the bitmap file superblock */
@@ -603,20 +603,22 @@ enum bitmap_mask_op {
         MASK_UNSET
 };
 
-/* record the state of the bitmap in the superblock */
-static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
-                                enum bitmap_mask_op op)
+/* record the state of the bitmap in the superblock.  Return the old value */
+static int bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
+                             enum bitmap_mask_op op)
 {
         bitmap_super_t *sb;
         unsigned long flags;
+        int old;
 
         spin_lock_irqsave(&bitmap->lock, flags);
         if (!bitmap->sb_page) { /* can't set the state */
                 spin_unlock_irqrestore(&bitmap->lock, flags);
-                return;
+                return 0;
         }
         spin_unlock_irqrestore(&bitmap->lock, flags);
         sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
+        old = le32_to_cpu(sb->state) & bits;
         switch (op) {
                 case MASK_SET: sb->state |= cpu_to_le32(bits);
                                 break;
@@ -625,6 +627,7 @@ static void bitmap_mask_state(struct bitmap *bitmap, enum bitmap_state bits,
                 default: BUG();
         }
         kunmap_atomic(sb, KM_USER0);
+        return old;
 }
 
 /*
@@ -718,18 +721,23 @@ static void bitmap_file_kick(struct bitmap *bitmap)
 {
         char *path, *ptr = NULL;
 
-        bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
-        bitmap_update_sb(bitmap);
+        if (bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET) == 0) {
+                bitmap_update_sb(bitmap);
 
-        if (bitmap->file) {
-                path = kmalloc(PAGE_SIZE, GFP_KERNEL);
-                if (path)
-                        ptr = file_path(bitmap->file, path, PAGE_SIZE);
+                if (bitmap->file) {
+                        path = kmalloc(PAGE_SIZE, GFP_KERNEL);
+                        if (path)
+                                ptr = file_path(bitmap->file, path, PAGE_SIZE);
 
-                printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
-                       bmname(bitmap), ptr ? ptr : "");
+                        printk(KERN_ALERT
+                              "%s: kicking failed bitmap file %s from array!\n",
+                              bmname(bitmap), ptr ? ptr : "");
 
-                kfree(path);
+                        kfree(path);
+                } else
+                        printk(KERN_ALERT
+                               "%s: disabling internal bitmap due to errors\n",
+                               bmname(bitmap));
         }
 
         bitmap_file_put(bitmap);
@@ -800,16 +808,15 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
 /* this gets called when the md device is ready to unplug its underlying
  * (slave) device queues -- before we let any writes go down, we need to
  * sync the dirty pages of the bitmap file to disk */
-int bitmap_unplug(struct bitmap *bitmap)
+void bitmap_unplug(struct bitmap *bitmap)
 {
         unsigned long i, flags;
         int dirty, need_write;
         struct page *page;
         int wait = 0;
-        int err;
 
         if (!bitmap)
-                return 0;
+                return;
 
         /* look at each page to see if there are any set bits that need to be
          * flushed out to disk */
@@ -817,7 +824,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                 spin_lock_irqsave(&bitmap->lock, flags);
                 if (!bitmap->filemap) {
                         spin_unlock_irqrestore(&bitmap->lock, flags);
-                        return 0;
+                        return;
                 }
                 page = bitmap->filemap[i];
                 dirty = test_page_attr(bitmap, page, BITMAP_PAGE_DIRTY);
@@ -829,7 +836,7 @@ int bitmap_unplug(struct bitmap *bitmap)
                 spin_unlock_irqrestore(&bitmap->lock, flags);
 
                 if (dirty | need_write)
-                        err = write_page(bitmap, page, 0);
+                        write_page(bitmap, page, 0);
         }
         if (wait) { /* if any writes were performed, we need to wait on them */
                 if (bitmap->file)
@@ -840,7 +847,6 @@ int bitmap_unplug(struct bitmap *bitmap)
         }
         if (bitmap->flags & BITMAP_WRITE_ERROR)
                 bitmap_file_kick(bitmap);
-        return 0;
 }
 
 static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
@@ -889,21 +895,21 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                         bmname(bitmap),
                         (unsigned long) i_size_read(file->f_mapping->host),
                         bytes + sizeof(bitmap_super_t));
-                goto out;
+                goto err;
         }
 
         ret = -ENOMEM;
 
         bitmap->filemap = kmalloc(sizeof(struct page *) * num_pages, GFP_KERNEL);
         if (!bitmap->filemap)
-                goto out;
+                goto err;
 
         /* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
         bitmap->filemap_attr = kzalloc(
                 roundup( DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
                 GFP_KERNEL);
         if (!bitmap->filemap_attr)
-                goto out;
+                goto err;
 
         oldindex = ~0L;
 
@@ -936,7 +942,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                         }
                         if (IS_ERR(page)) { /* read error */
                                 ret = PTR_ERR(page);
-                                goto out;
+                                goto err;
                         }
 
                         oldindex = index;
@@ -951,11 +957,13 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                                 memset(paddr + offset, 0xff,
                                        PAGE_SIZE - offset);
                                 kunmap_atomic(paddr, KM_USER0);
-                                ret = write_page(bitmap, page, 1);
-                                if (ret) {
+                                write_page(bitmap, page, 1);
+
+                                ret = -EIO;
+                                if (bitmap->flags & BITMAP_WRITE_ERROR) {
                                         /* release, page not in filemap yet */
                                         put_page(page);
-                                        goto out;
+                                        goto err;
                                 }
                         }
 
@@ -987,11 +995,15 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
                 md_wakeup_thread(bitmap->mddev->thread);
         }
 
-out:
         printk(KERN_INFO "%s: bitmap initialized from disk: "
-                "read %lu/%lu pages, set %lu bits, status: %d\n",
-                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt, ret);
+                "read %lu/%lu pages, set %lu bits\n",
+                bmname(bitmap), bitmap->file_pages, num_pages, bit_cnt);
+
+        return 0;
 
+ err:
+        printk(KERN_INFO "%s: bitmap initialisation failed: %d\n",
+               bmname(bitmap), ret);
         return ret;
 }
 
@@ -1028,19 +1040,18 @@ static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
  *                      out to disk
  */
 
-int bitmap_daemon_work(struct bitmap *bitmap)
+void bitmap_daemon_work(struct bitmap *bitmap)
 {
         unsigned long j;
         unsigned long flags;
         struct page *page = NULL, *lastpage = NULL;
-        int err = 0;
         int blocks;
         void *paddr;
 
         if (bitmap == NULL)
-                return 0;
+                return;
         if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
-                return 0;
+                return;
         bitmap->daemon_lastrun = jiffies;
 
         for (j = 0; j < bitmap->chunks; j++) {
@@ -1063,14 +1074,8 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                         clear_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
 
                                 spin_unlock_irqrestore(&bitmap->lock, flags);
-                                if (need_write) {
-                                        switch (write_page(bitmap, page, 0)) {
-                                        case 0:
-                                                break;
-                                        default:
-                                                bitmap_file_kick(bitmap);
-                                        }
-                                }
+                                if (need_write)
+                                        write_page(bitmap, page, 0);
                                 continue;
                         }
 
@@ -1079,13 +1084,11 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                         spin_unlock_irqrestore(&bitmap->lock, flags);
-                                        err = write_page(bitmap, lastpage, 0);
+                                        write_page(bitmap, lastpage, 0);
                                 } else {
                                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                                         spin_unlock_irqrestore(&bitmap->lock, flags);
                                 }
-                                if (err)
-                                        bitmap_file_kick(bitmap);
                         } else
                                 spin_unlock_irqrestore(&bitmap->lock, flags);
                         lastpage = page;
@@ -1128,14 +1131,13 @@ int bitmap_daemon_work(struct bitmap *bitmap)
                 if (test_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE)) {
                         clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                         spin_unlock_irqrestore(&bitmap->lock, flags);
-                        err = write_page(bitmap, lastpage, 0);
+                        write_page(bitmap, lastpage, 0);
                 } else {
                         set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
                         spin_unlock_irqrestore(&bitmap->lock, flags);
                 }
         }
 
-        return err;
 }
 
 static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
@@ -1548,7 +1550,9 @@ int bitmap_create(mddev_t *mddev)
 
         mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 
-        return bitmap_update_sb(bitmap);
+        bitmap_update_sb(bitmap);
+
+        return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
 
  error:
         bitmap_free(bitmap);
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 36c05ba7855a..65ddc887dfd7 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -1640,7 +1640,6 @@ static void sync_sbs(mddev_t * mddev, int nospares)
 
 static void md_update_sb(mddev_t * mddev, int force_change)
 {
-        int err;
         struct list_head *tmp;
         mdk_rdev_t *rdev;
         int sync_req;
@@ -1727,7 +1726,7 @@ repeat:
                 "md: updating %s RAID superblock on device (in sync %d)\n",
                 mdname(mddev),mddev->in_sync);
 
-        err = bitmap_update_sb(mddev->bitmap);
+        bitmap_update_sb(mddev->bitmap);
         ITERATE_RDEV(mddev,rdev,tmp) {
                 char b[BDEVNAME_SIZE];
                 dprintk(KERN_INFO "md: ");
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index 46677d7d9980..00c78b77b13d 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -1526,8 +1526,7 @@ static void raid1d(mddev_t *mddev)
                         blk_remove_plug(mddev->queue);
                         spin_unlock_irqrestore(&conf->device_lock, flags);
                         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
-                        if (bitmap_unplug(mddev->bitmap) != 0)
-                                printk("%s: bitmap file write failed!\n", mdname(mddev));
+                        bitmap_unplug(mddev->bitmap);
 
                         while (bio) { /* submit pending writes */
                                 struct bio *next = bio->bi_next;
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 9eb66c1b523b..a95ada1cfac4 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -1510,8 +1510,7 @@ static void raid10d(mddev_t *mddev)
                         blk_remove_plug(mddev->queue);
                         spin_unlock_irqrestore(&conf->device_lock, flags);
                         /* flush any pending bitmap writes to disk before proceeding w/ I/O */
-                        if (bitmap_unplug(mddev->bitmap) != 0)
-                                printk("%s: bitmap file write failed!\n", mdname(mddev));
+                        bitmap_unplug(mddev->bitmap);
 
                         while (bio) { /* submit pending writes */
                                 struct bio *next = bio->bi_next;