iomap: fix sub-page uptodate handling

commit 1cea335d1db1ce6ab71b3d2f94a807112b738a0f upstream.

bio completions can race when a page spans more than one file system
block.  Add a spinlock to synchronize marking the page uptodate.

Fixes: 9dc55f1389f9 ("iomap: add support for sub-pagesize buffered I/O without buffer heads")
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 80867a1a94f268e19d419b2ab0274aa92c7bb947..5c73751adb2d36b73e79bbda8907a8173c73a0fd 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -30,6 +30,7 @@ iomap_page_create(struct inode *inode, struct page *page)
        iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
        atomic_set(&iop->read_count, 0);
        atomic_set(&iop->write_count, 0);
+       spin_lock_init(&iop->uptodate_lock);
        bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
 
        /*
@@ -118,25 +119,38 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
 }
 
 static void
-iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
+iomap_iop_set_range_uptodate(struct page *page, unsigned off, unsigned len)
 {
        struct iomap_page *iop = to_iomap_page(page);
        struct inode *inode = page->mapping->host;
        unsigned first = off >> inode->i_blkbits;
        unsigned last = (off + len - 1) >> inode->i_blkbits;
-       unsigned int i;
        bool uptodate = true;
+       unsigned long flags;
+       unsigned int i;
 
-       if (iop) {
-               for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
-                       if (i >= first && i <= last)
-                               set_bit(i, iop->uptodate);
-                       else if (!test_bit(i, iop->uptodate))
-                               uptodate = false;
-               }
+       spin_lock_irqsave(&iop->uptodate_lock, flags);
+       for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
+               if (i >= first && i <= last)
+                       set_bit(i, iop->uptodate);
+               else if (!test_bit(i, iop->uptodate))
+                       uptodate = false;
        }
 
-       if (uptodate && !PageError(page))
+       if (uptodate)
+               SetPageUptodate(page);
+       spin_unlock_irqrestore(&iop->uptodate_lock, flags);
+}
+
+static void
+iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
+{
+       if (PageError(page))
+               return;
+
+       if (page_has_private(page))
+               iomap_iop_set_range_uptodate(page, off, len);
+       else
                SetPageUptodate(page);
 }
 

diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 7aa5d61179361d3bbdd3e949645568160d25ae15..53b16f104081bf9d06cc5a8d693f1eeec3597b02 100644 (file)
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -139,6 +139,7 @@ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length,
 struct iomap_page {
        atomic_t                read_count;
        atomic_t                write_count;
+       spinlock_t              uptodate_lock;
        DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
 };