1 files changed, 108 insertions, 20 deletions

diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index 762360d95e93..5bddee110091 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -44,7 +44,8 @@
 
 struct ocfs2_slot_info {
         struct inode *si_inode;
-        struct buffer_head *si_bh;
+        unsigned int si_blocks;
+        struct buffer_head **si_bh;
         unsigned int si_num_slots;
         unsigned int si_size;
         s16 si_global_node_nums[OCFS2_MAX_SLOTS];
@@ -68,7 +69,7 @@ static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
 
         /* we don't read the slot block here as ocfs2_super_lock
          * should've made sure we have the most recent copy. */
-        disk_info = (__le16 *) si->si_bh->b_data;
+        disk_info = (__le16 *) si->si_bh[0]->b_data;
 
         for (i = 0; i < si->si_size; i++)
                 si->si_global_node_nums[i] = le16_to_cpu(disk_info[i]);
@@ -78,13 +79,23 @@ int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
 {
         int ret;
         struct ocfs2_slot_info *si = osb->slot_info;
-        struct buffer_head *bh;
 
         if (si == NULL)
                 return 0;
 
-        bh = si->si_bh;
-        ret = ocfs2_read_block(osb, bh->b_blocknr, &bh, 0, si->si_inode);
+        BUG_ON(si->si_blocks == 0);
+        BUG_ON(si->si_bh == NULL);
+
+        mlog(0, "Refreshing slot map, reading %u block(s)\n",
+             si->si_blocks);
+
+        /*
+         * We pass -1 as blocknr because we expect all of si->si_bh to
+         * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
+         * this is not true, the read of -1 (UINT64_MAX) will fail.
+         */
+        ret = ocfs2_read_blocks(osb, -1, si->si_blocks, si->si_bh, 0,
+                                si->si_inode);
         if (ret == 0) {
                 spin_lock(&osb->osb_lock);
                 ocfs2_update_slot_info(si);
@@ -100,20 +111,42 @@ static int ocfs2_update_disk_slots(struct ocfs2_super *osb,
                                    struct ocfs2_slot_info *si)
 {
         int status, i;
-        __le16 *disk_info = (__le16 *) si->si_bh->b_data;
+        __le16 *disk_info = (__le16 *) si->si_bh[0]->b_data;
 
         spin_lock(&osb->osb_lock);
         for (i = 0; i < si->si_size; i++)
                 disk_info[i] = cpu_to_le16(si->si_global_node_nums[i]);
         spin_unlock(&osb->osb_lock);
 
-        status = ocfs2_write_block(osb, si->si_bh, si->si_inode);
+        status = ocfs2_write_block(osb, si->si_bh[0], si->si_inode);
         if (status < 0)
                 mlog_errno(status);
 
         return status;
 }
 
+/*
+ * Calculate how many bytes are needed by the slot map.  Returns
+ * an error if the slot map file is too small.
+ */
+static int ocfs2_slot_map_physical_size(struct ocfs2_super *osb,
+                                        struct inode *inode,
+                                        unsigned long long *bytes)
+{
+        unsigned long long bytes_needed;
+
+        bytes_needed = osb->max_slots * sizeof(__le16);
+        if (bytes_needed > i_size_read(inode)) {
+                mlog(ML_ERROR,
+                     "Slot map file is too small!  (size %llu, needed %llu)\n",
+                     i_size_read(inode), bytes_needed);
+                return -ENOSPC;
+        }
+
+        *bytes = bytes_needed;
+        return 0;
+}
+
 /* try to find global node in the slot info. Returns
  * OCFS2_INVALID_SLOT if nothing is found. */
 static s16 __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
@@ -188,13 +221,22 @@ int ocfs2_slot_to_node_num_locked(struct ocfs2_super *osb, int slot_num,
 
 static void __ocfs2_free_slot_info(struct ocfs2_slot_info *si)
 {
+        unsigned int i;
+
         if (si == NULL)
                 return;
 
         if (si->si_inode)
                 iput(si->si_inode);
-        if (si->si_bh)
-                brelse(si->si_bh);
+        if (si->si_bh) {
+                for (i = 0; i < si->si_blocks; i++) {
+                        if (si->si_bh[i]) {
+                                brelse(si->si_bh[i]);
+                                si->si_bh[i] = NULL;
+                        }
+                }
+                kfree(si->si_bh);
+        }
 
         kfree(si);
 }
@@ -225,12 +267,65 @@ int ocfs2_clear_slot(struct ocfs2_super *osb, s16 slot_num)
         return ocfs2_update_disk_slots(osb, osb->slot_info);
 }
 
+static int ocfs2_map_slot_buffers(struct ocfs2_super *osb,
+                                  struct ocfs2_slot_info *si)
+{
+        int status = 0;
+        u64 blkno;
+        unsigned long long blocks, bytes;
+        unsigned int i;
+        struct buffer_head *bh;
+
+        status = ocfs2_slot_map_physical_size(osb, si->si_inode, &bytes);
+        if (status)
+                goto bail;
+
+        blocks = ocfs2_blocks_for_bytes(si->si_inode->i_sb, bytes);
+        BUG_ON(blocks > UINT_MAX);
+        si->si_blocks = blocks;
+        if (!si->si_blocks)
+                goto bail;
+
+        mlog(0, "Slot map needs %u buffers for %llu bytes\n",
+             si->si_blocks, bytes);
+
+        si->si_bh = kzalloc(sizeof(struct buffer_head *) * si->si_blocks,
+                            GFP_KERNEL);
+        if (!si->si_bh) {
+                status = -ENOMEM;
+                mlog_errno(status);
+                goto bail;
+        }
+
+        for (i = 0; i < si->si_blocks; i++) {
+                status = ocfs2_extent_map_get_blocks(si->si_inode, i,
+                                                     &blkno, NULL, NULL);
+                if (status < 0) {
+                        mlog_errno(status);
+                        goto bail;
+                }
+
+                mlog(0, "Reading slot map block %u at %llu\n", i,
+                     (unsigned long long)blkno);
+
+                bh = NULL;  /* Acquire a fresh bh */
+                status = ocfs2_read_block(osb, blkno, &bh, 0, si->si_inode);
+                if (status < 0) {
+                        mlog_errno(status);
+                        goto bail;
+                }
+
+                si->si_bh[i] = bh;
+        }
+
+bail:
+        return status;
+}
+
 int ocfs2_init_slot_info(struct ocfs2_super *osb)
 {
         int status, i;
-        u64 blkno;
         struct inode *inode = NULL;
-        struct buffer_head *bh = NULL;
         struct ocfs2_slot_info *si;
 
         si = kzalloc(sizeof(struct ocfs2_slot_info), GFP_KERNEL);
@@ -254,20 +349,13 @@ int ocfs2_init_slot_info(struct ocfs2_super *osb)
                 goto bail;
         }
 
-        status = ocfs2_extent_map_get_blocks(inode, 0ULL, &blkno, NULL, NULL);
-        if (status < 0) {
-                mlog_errno(status);
-                goto bail;
-        }
-
-        status = ocfs2_read_block(osb, blkno, &bh, 0, inode);
+        si->si_inode = inode;
+        status = ocfs2_map_slot_buffers(osb, si);
         if (status < 0) {
                 mlog_errno(status);
                 goto bail;
         }
 
-        si->si_inode = inode;
-        si->si_bh = bh;
         osb->slot_info = (struct ocfs2_slot_info *)si;
 bail:
         if (status < 0 && si)