1 files changed, 159 insertions, 0 deletions

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 4c1399cc03f3..b4ca5911caaf 100644
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -2185,3 +2185,162 @@ out:
 
         return ret;
 }
+
+/*
+ * Read the inode specified by blkno to get suballoc_slot and
+ * suballoc_bit.
+ */
+static int ocfs2_get_suballoc_slot_bit(struct ocfs2_super *osb, u64 blkno,
+                                       u16 *suballoc_slot, u16 *suballoc_bit)
+{
+        int status;
+        struct buffer_head *inode_bh = NULL;
+        struct ocfs2_dinode *inode_fe;
+
+        mlog_entry("blkno: %llu\n", blkno);
+
+        /* dirty read disk */
+        status = ocfs2_read_blocks_sync(osb, blkno, 1, &inode_bh);
+        if (status < 0) {
+                mlog(ML_ERROR, "read block %llu failed %d\n", blkno, status);
+                goto bail;
+        }
+
+        inode_fe = (struct ocfs2_dinode *) inode_bh->b_data;
+        if (!OCFS2_IS_VALID_DINODE(inode_fe)) {
+                mlog(ML_ERROR, "invalid inode %llu requested\n", blkno);
+                status = -EINVAL;
+                goto bail;
+        }
+
+        if (le16_to_cpu(inode_fe->i_suballoc_slot) != OCFS2_INVALID_SLOT &&
+            (u32)le16_to_cpu(inode_fe->i_suballoc_slot) > osb->max_slots - 1) {
+                mlog(ML_ERROR, "inode %llu has invalid suballoc slot %u\n",
+                     blkno, (u32)le16_to_cpu(inode_fe->i_suballoc_slot));
+                status = -EINVAL;
+                goto bail;
+        }
+
+        if (suballoc_slot)
+                *suballoc_slot = le16_to_cpu(inode_fe->i_suballoc_slot);
+        if (suballoc_bit)
+                *suballoc_bit = le16_to_cpu(inode_fe->i_suballoc_bit);
+
+bail:
+        brelse(inode_bh);
+
+        mlog_exit(status);
+        return status;
+}
+
+/*
+ * test whether bit is SET in allocator bitmap or not.  on success, 0
+ * is returned and *res is 1 for SET; 0 otherwise.  when fails, errno
+ * is returned and *res is meaningless.  Call this after you have
+ * cluster locked against suballoc, or you may get a result based on
+ * non-up2date contents
+ */
+static int ocfs2_test_suballoc_bit(struct ocfs2_super *osb,
+                                   struct inode *suballoc,
+                                   struct buffer_head *alloc_bh, u64 blkno,
+                                   u16 bit, int *res)
+{
+        struct ocfs2_dinode *alloc_fe;
+        struct ocfs2_group_desc *group;
+        struct buffer_head *group_bh = NULL;
+        u64 bg_blkno;
+        int status;
+
+        mlog_entry("blkno: %llu bit: %u\n", blkno, (unsigned int)bit);
+
+        alloc_fe = (struct ocfs2_dinode *)alloc_bh->b_data;
+        if ((bit + 1) > ocfs2_bits_per_group(&alloc_fe->id2.i_chain)) {
+                mlog(ML_ERROR, "suballoc bit %u out of range of %u\n",
+                     (unsigned int)bit,
+                     ocfs2_bits_per_group(&alloc_fe->id2.i_chain));
+                status = -EINVAL;
+                goto bail;
+        }
+
+        bg_blkno = ocfs2_which_suballoc_group(blkno, bit);
+        status = ocfs2_read_group_descriptor(suballoc, alloc_fe, bg_blkno,
+                                             &group_bh);
+        if (status < 0) {
+                mlog(ML_ERROR, "read group %llu failed %d\n", bg_blkno, status);
+                goto bail;
+        }
+
+        group = (struct ocfs2_group_desc *) group_bh->b_data;
+        *res = ocfs2_test_bit(bit, (unsigned long *)group->bg_bitmap);
+
+bail:
+        brelse(group_bh);
+
+        mlog_exit(status);
+        return status;
+}
+
+/*
+ * Test if the bit representing this inode (blkno) is set in the
+ * suballocator.
+ *
+ * On success, 0 is returned and *res is 1 for SET; 0 otherwise.
+ *
+ * In the event of failure, a negative value is returned and *res is
+ * meaningless.
+ *
+ * Callers must make sure to hold nfs_sync_lock to prevent
+ * ocfs2_delete_inode() on another node from accessing the same
+ * suballocator concurrently.
+ */
+int ocfs2_test_inode_bit(struct ocfs2_super *osb, u64 blkno, int *res)
+{
+        int status;
+        u16 suballoc_bit = 0, suballoc_slot = 0;
+        struct inode *inode_alloc_inode;
+        struct buffer_head *alloc_bh = NULL;
+
+        mlog_entry("blkno: %llu", blkno);
+
+        status = ocfs2_get_suballoc_slot_bit(osb, blkno, &suballoc_slot,
+                                             &suballoc_bit);
+        if (status < 0) {
+                mlog(ML_ERROR, "get alloc slot and bit failed %d\n", status);
+                goto bail;
+        }
+
+        inode_alloc_inode =
+                ocfs2_get_system_file_inode(osb, INODE_ALLOC_SYSTEM_INODE,
+                                            suballoc_slot);
+        if (!inode_alloc_inode) {
+                /* the error code could be inaccurate, but we are not able to
+                 * get the correct one. */
+                status = -EINVAL;
+                mlog(ML_ERROR, "unable to get alloc inode in slot %u\n",
+                     (u32)suballoc_slot);
+                goto bail;
+        }
+
+        mutex_lock(&inode_alloc_inode->i_mutex);
+        status = ocfs2_inode_lock(inode_alloc_inode, &alloc_bh, 0);
+        if (status < 0) {
+                mutex_unlock(&inode_alloc_inode->i_mutex);
+                mlog(ML_ERROR, "lock on alloc inode on slot %u failed %d\n",
+                     (u32)suballoc_slot, status);
+                goto bail;
+        }
+
+        status = ocfs2_test_suballoc_bit(osb, inode_alloc_inode, alloc_bh,
+                                         blkno, suballoc_bit, res);
+        if (status < 0)
+                mlog(ML_ERROR, "test suballoc bit failed %d\n", status);
+
+        ocfs2_inode_unlock(inode_alloc_inode, 0);
+        mutex_unlock(&inode_alloc_inode->i_mutex);
+
+        iput(inode_alloc_inode);
+        brelse(alloc_bh);
+bail:
+        mlog_exit(status);
+        return status;
+}