1 files changed, 49 insertions, 48 deletions

diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 46a7d6a9d976..7f5451cd1d38 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -32,8 +32,14 @@
 
 static struct kmem_cache *io_page_cachep, *io_end_cachep;
 
+#define WQ_HASH_SZ              37
+#define to_ioend_wq(v)  (&ioend_wq[((unsigned long)v) % WQ_HASH_SZ])
+static wait_queue_head_t ioend_wq[WQ_HASH_SZ];
+
 int __init ext4_init_pageio(void)
 {
+        int i;
+
         io_page_cachep = KMEM_CACHE(ext4_io_page, SLAB_RECLAIM_ACCOUNT);
         if (io_page_cachep == NULL)
                 return -ENOMEM;
@@ -42,6 +48,8 @@ int __init ext4_init_pageio(void)
                 kmem_cache_destroy(io_page_cachep);
                 return -ENOMEM;
         }
+        for (i = 0; i < WQ_HASH_SZ; i++)
+                init_waitqueue_head(&ioend_wq[i]);
 
         return 0;
 }
@@ -52,24 +60,37 @@ void ext4_exit_pageio(void)
         kmem_cache_destroy(io_page_cachep);
 }
 
+void ext4_ioend_wait(struct inode *inode)
+{
+        wait_queue_head_t *wq = to_ioend_wq(inode);
+
+        wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_ioend_count) == 0));
+}
+
+static void put_io_page(struct ext4_io_page *io_page)
+{
+        if (atomic_dec_and_test(&io_page->p_count)) {
+                end_page_writeback(io_page->p_page);
+                put_page(io_page->p_page);
+                kmem_cache_free(io_page_cachep, io_page);
+        }
+}
+
 void ext4_free_io_end(ext4_io_end_t *io)
 {
         int i;
+        wait_queue_head_t *wq;
 
         BUG_ON(!io);
         if (io->page)
                 put_page(io->page);
-        for (i = 0; i < io->num_io_pages; i++) {
-                if (--io->pages[i]->p_count == 0) {
-                        struct page *page = io->pages[i]->p_page;
-
-                        end_page_writeback(page);
-                        put_page(page);
-                        kmem_cache_free(io_page_cachep, io->pages[i]);
-                }
-        }
+        for (i = 0; i < io->num_io_pages; i++)
+                put_io_page(io->pages[i]);
         io->num_io_pages = 0;
-        iput(io->inode);
+        wq = to_ioend_wq(io->inode);
+        if (atomic_dec_and_test(&EXT4_I(io->inode)->i_ioend_count) &&
+            waitqueue_active(wq))
+                wake_up_all(wq);
         kmem_cache_free(io_end_cachep, io);
 }
 
@@ -142,8 +163,8 @@ ext4_io_end_t *ext4_init_io_end(struct inode *inode, gfp_t flags)
         io = kmem_cache_alloc(io_end_cachep, flags);
         if (io) {
                 memset(io, 0, sizeof(*io));
-                io->inode = igrab(inode);
-                BUG_ON(!io->inode);
+                atomic_inc(&EXT4_I(inode)->i_ioend_count);
+                io->inode = inode;
                 INIT_WORK(&io->work, ext4_end_io_work);
                 INIT_LIST_HEAD(&io->list);
         }
@@ -171,35 +192,15 @@ static void ext4_end_bio(struct bio *bio, int error)
         struct workqueue_struct *wq;
         struct inode *inode;
         unsigned long flags;
-        ext4_fsblk_t err_block;
         int i;
 
         BUG_ON(!io_end);
-        inode = io_end->inode;
         bio->bi_private = NULL;
         bio->bi_end_io = NULL;
         if (test_bit(BIO_UPTODATE, &bio->bi_flags))
                 error = 0;
-        err_block = bio->bi_sector >> (inode->i_blkbits - 9);
         bio_put(bio);
 
-        if (!(inode->i_sb->s_flags & MS_ACTIVE)) {
-                pr_err("sb umounted, discard end_io request for inode %lu\n",
-                        io_end->inode->i_ino);
-                ext4_free_io_end(io_end);
-                return;
-        }
-
-        if (error) {
-                io_end->flag |= EXT4_IO_END_ERROR;
-                ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
-                             "(offset %llu size %ld starting block %llu)",
-                             inode->i_ino,
-                             (unsigned long long) io_end->offset,
-                             (long) io_end->size,
-                             (unsigned long long) err_block);
-        }
-
         for (i = 0; i < io_end->num_io_pages; i++) {
                 struct page *page = io_end->pages[i]->p_page;
                 struct buffer_head *bh, *head;
@@ -236,13 +237,7 @@ static void ext4_end_bio(struct bio *bio, int error)
                         } while (bh != head);
                 }
 
-                if (--io_end->pages[i]->p_count == 0) {
-                        struct page *page = io_end->pages[i]->p_page;
-
-                        end_page_writeback(page);
-                        put_page(page);
-                        kmem_cache_free(io_page_cachep, io_end->pages[i]);
-                }
+                put_io_page(io_end->pages[i]);
 
                 /*
                  * If this is a partial write which happened to make
@@ -254,8 +249,19 @@ static void ext4_end_bio(struct bio *bio, int error)
                 if (!partial_write)
                         SetPageUptodate(page);
         }
-
         io_end->num_io_pages = 0;
+        inode = io_end->inode;
+
+        if (error) {
+                io_end->flag |= EXT4_IO_END_ERROR;
+                ext4_warning(inode->i_sb, "I/O error writing to inode %lu "
+                             "(offset %llu size %ld starting block %llu)",
+                             inode->i_ino,
+                             (unsigned long long) io_end->offset,
+                             (long) io_end->size,
+                             (unsigned long long)
+                             bio->bi_sector >> (inode->i_blkbits - 9));
+        }
 
         /* Add the io_end to per-inode completed io list*/
         spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
@@ -305,7 +311,6 @@ static int io_submit_init(struct ext4_io_submit *io,
         bio->bi_private = io->io_end = io_end;
         bio->bi_end_io = ext4_end_bio;
 
-        io_end->inode = inode;
         io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
 
         io->io_bio = bio;
@@ -360,7 +365,7 @@ submit_and_retry:
         if ((io_end->num_io_pages == 0) ||
             (io_end->pages[io_end->num_io_pages-1] != io_page)) {
                 io_end->pages[io_end->num_io_pages++] = io_page;
-                io_page->p_count++;
+                atomic_inc(&io_page->p_count);
         }
         return 0;
 }
@@ -389,7 +394,7 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
                 return -ENOMEM;
         }
         io_page->p_page = page;
-        io_page->p_count = 0;
+        atomic_set(&io_page->p_count, 1);
         get_page(page);
 
         for (bh = head = page_buffers(page), block_start = 0;
@@ -421,10 +426,6 @@ int ext4_bio_write_page(struct ext4_io_submit *io,
          * PageWriteback bit from the page to prevent the system from
          * wedging later on.
          */
-        if (io_page->p_count == 0) {
-                put_page(page);
-                end_page_writeback(page);
-                kmem_cache_free(io_page_cachep, io_page);
-        }
+        put_io_page(io_page);
         return ret;
 }