ocfs2: Read support for inline data

This hooks up ocfs2_readpage() to populate a page with data from an inode
block. Direct IO reads from inline data are modified to fall back to
buffered I/O. Appropriate checks are also placed in the extent map code to
avoid reading an extent list when inline data might be stored.

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Reviewed-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 76 insertions, 4 deletions

diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
index 8416e383197c..fef0186a91cd 100644
--- a/fs/ocfs2/aops.c
+++ b/fs/ocfs2/aops.c
@@ -206,9 +206,70 @@ bail:
         return err;
 }
 
+static int ocfs2_read_inline_data(struct inode *inode, struct page *page,
+                                  struct buffer_head *di_bh)
+{
+        void *kaddr;
+        unsigned int size;
+        struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
+
+        if (!(le16_to_cpu(di->i_dyn_features) & OCFS2_INLINE_DATA_FL)) {
+                ocfs2_error(inode->i_sb, "Inode %llu lost inline data flag",
+                            (unsigned long long)OCFS2_I(inode)->ip_blkno);
+                return -EROFS;
+        }
+
+        size = i_size_read(inode);
+
+        if (size > PAGE_CACHE_SIZE ||
+            size > ocfs2_max_inline_data(inode->i_sb)) {
+                ocfs2_error(inode->i_sb,
+                            "Inode %llu has with inline data has bad size: %u",
+                            (unsigned long long)OCFS2_I(inode)->ip_blkno, size);
+                return -EROFS;
+        }
+
+        kaddr = kmap_atomic(page, KM_USER0);
+        if (size)
+                memcpy(kaddr, di->id2.i_data.id_data, size);
+        /* Clear the remaining part of the page */
+        memset(kaddr + size, 0, PAGE_CACHE_SIZE - size);
+        flush_dcache_page(page);
+        kunmap_atomic(kaddr, KM_USER0);
+
+        SetPageUptodate(page);
+
+        return 0;
+}
+
+static int ocfs2_readpage_inline(struct inode *inode, struct page *page)
+{
+        int ret;
+        struct buffer_head *di_bh = NULL;
+        struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
+
+        BUG_ON(!PageLocked(page));
+        BUG_ON(!OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL);
+
+        ret = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &di_bh,
+                               OCFS2_BH_CACHED, inode);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        ret = ocfs2_read_inline_data(inode, page, di_bh);
+out:
+        unlock_page(page);
+
+        brelse(di_bh);
+        return ret;
+}
+
 static int ocfs2_readpage(struct file *file, struct page *page)
 {
         struct inode *inode = page->mapping->host;
+        struct ocfs2_inode_info *oi = OCFS2_I(inode);
         loff_t start = (loff_t)page->index << PAGE_CACHE_SHIFT;
         int ret, unlock = 1;
 
@@ -222,7 +283,7 @@ static int ocfs2_readpage(struct file *file, struct page *page)
                 goto out;
         }
 
-        if (down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem) == 0) {
+        if (down_read_trylock(&oi->ip_alloc_sem) == 0) {
                 ret = AOP_TRUNCATED_PAGE;
                 goto out_meta_unlock;
         }
@@ -252,7 +313,10 @@ static int ocfs2_readpage(struct file *file, struct page *page)
                 goto out_alloc;
         }
 
-        ret = block_read_full_page(page, ocfs2_get_block);
+        if (oi->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+                ret = ocfs2_readpage_inline(inode, page);
+        else
+                ret = block_read_full_page(page, ocfs2_get_block);
         unlock = 0;
 
         ocfs2_data_unlock(inode, 0);
@@ -397,7 +461,9 @@ static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
                 down_read(&OCFS2_I(inode)->ip_alloc_sem);
         }
 
-        err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL, NULL);
+        if (!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL))
+                err = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
+                                                  NULL);
 
         if (!INODE_JOURNAL(inode)) {
                 up_read(&OCFS2_I(inode)->ip_alloc_sem);
@@ -411,7 +477,6 @@ static sector_t ocfs2_bmap(struct address_space *mapping, sector_t block)
                 goto bail;
         }
 
-
 bail:
         status = err ? 0 : p_blkno;
 
@@ -566,6 +631,13 @@ static ssize_t ocfs2_direct_IO(int rw,
 
         mlog_entry_void();
 
+        /*
+         * Fallback to buffered I/O if we see an inode without
+         * extents.
+         */
+        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+                return 0;
+
         if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
                 /*
                  * We get PR data locks even for O_DIRECT.  This