1 files changed, 76 insertions, 12 deletions

diff --git a/fs/logfs/dev_bdev.c b/fs/logfs/dev_bdev.c
index 58a057b6e1af..9718c22f186d 100644
--- a/fs/logfs/dev_bdev.c
+++ b/fs/logfs/dev_bdev.c
@@ -167,27 +167,91 @@ static void bdev_writeseg(struct super_block *sb, u64 ofs, size_t len)
         generic_unplug_device(bdev_get_queue(logfs_super(sb)->s_bdev));
 }
 
-static int bdev_erase(struct super_block *sb, loff_t to, size_t len)
+
+static void erase_end_io(struct bio *bio, int err) 
+{ 
+        const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); 
+        struct super_block *sb = bio->bi_private; 
+        struct logfs_super *super = logfs_super(sb); 
+
+        BUG_ON(!uptodate); /* FIXME: Retry io or write elsewhere */ 
+        BUG_ON(err); 
+        BUG_ON(bio->bi_vcnt == 0); 
+        bio_put(bio); 
+        if (atomic_dec_and_test(&super->s_pending_writes))
+                wake_up(&wq); 
+} 
+
+static int do_erase(struct super_block *sb, u64 ofs, pgoff_t index,
+                size_t nr_pages)
+{
+        struct logfs_super *super = logfs_super(sb);
+        struct bio *bio;
+        struct request_queue *q = bdev_get_queue(sb->s_bdev);
+        unsigned int max_pages = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
+        int i;
+
+        bio = bio_alloc(GFP_NOFS, max_pages);
+        BUG_ON(!bio); /* FIXME: handle this */
+
+        for (i = 0; i < nr_pages; i++) {
+                if (i >= max_pages) {
+                        /* Block layer cannot split bios :( */
+                        bio->bi_vcnt = i;
+                        bio->bi_idx = 0;
+                        bio->bi_size = i * PAGE_SIZE;
+                        bio->bi_bdev = super->s_bdev;
+                        bio->bi_sector = ofs >> 9;
+                        bio->bi_private = sb;
+                        bio->bi_end_io = erase_end_io;
+                        atomic_inc(&super->s_pending_writes);
+                        submit_bio(WRITE, bio);
+
+                        ofs += i * PAGE_SIZE;
+                        index += i;
+                        nr_pages -= i;
+                        i = 0;
+
+                        bio = bio_alloc(GFP_NOFS, max_pages);
+                        BUG_ON(!bio);
+                }
+                bio->bi_io_vec[i].bv_page = super->s_erase_page;
+                bio->bi_io_vec[i].bv_len = PAGE_SIZE;
+                bio->bi_io_vec[i].bv_offset = 0;
+        }
+        bio->bi_vcnt = nr_pages;
+        bio->bi_idx = 0;
+        bio->bi_size = nr_pages * PAGE_SIZE;
+        bio->bi_bdev = super->s_bdev;
+        bio->bi_sector = ofs >> 9;
+        bio->bi_private = sb;
+        bio->bi_end_io = erase_end_io;
+        atomic_inc(&super->s_pending_writes);
+        submit_bio(WRITE, bio);
+        return 0;
+}
+
+static int bdev_erase(struct super_block *sb, loff_t to, size_t len,
+                int ensure_write)
 {
         struct logfs_super *super = logfs_super(sb);
-        struct address_space *mapping = super->s_mapping_inode->i_mapping;
-        struct page *page;
-        pgoff_t index = to >> PAGE_SHIFT;
-        int i, nr_pages = len >> PAGE_SHIFT;
 
         BUG_ON(to & (PAGE_SIZE - 1));
         BUG_ON(len & (PAGE_SIZE - 1));
 
-        if (logfs_super(sb)->s_flags & LOGFS_SB_FLAG_RO)
+        if (super->s_flags & LOGFS_SB_FLAG_RO)
                 return -EROFS;
 
-        for (i = 0; i < nr_pages; i++) {
-                page = find_get_page(mapping, index + i);
-                if (page) {
-                        memset(page_address(page), 0xFF, PAGE_SIZE);
-                        page_cache_release(page);
-                }
+        if (ensure_write) {
+                /*
+                 * Object store doesn't care whether erases happen or not.
+                 * But for the journal they are required.  Otherwise a scan
+                 * can find an old commit entry and assume it is the current
+                 * one, travelling back in time.
+                 */
+                do_erase(sb, to, to >> PAGE_SHIFT, len >> PAGE_SHIFT);
         }
+
         return 0;
 }