1 files changed, 56 insertions, 24 deletions

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index dd0fcfcb35ce..ef97f19c2f9d 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -627,21 +627,19 @@ static ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
         return block;
 }
 
+static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
+{
 #if BITS_PER_LONG == 64
-#define mb_correct_addr_and_bit(bit, addr)              \
-{                                                       \
-        bit += ((unsigned long) addr & 7UL) << 3;       \
-        addr = (void *) ((unsigned long) addr & ~7UL);  \
-}
+        *bit += ((unsigned long) addr & 7UL) << 3;
+        addr = (void *) ((unsigned long) addr & ~7UL);
 #elif BITS_PER_LONG == 32
-#define mb_correct_addr_and_bit(bit, addr)              \
-{                                                       \
-        bit += ((unsigned long) addr & 3UL) << 3;       \
-        addr = (void *) ((unsigned long) addr & ~3UL);  \
-}
+        *bit += ((unsigned long) addr & 3UL) << 3;
+        addr = (void *) ((unsigned long) addr & ~3UL);
 #else
 #error "how many bits you are?!"
 #endif
+        return addr;
+}
 
 static inline int mb_test_bit(int bit, void *addr)
 {
@@ -649,34 +647,54 @@ static inline int mb_test_bit(int bit, void *addr)
          * ext4_test_bit on architecture like powerpc
          * needs unsigned long aligned address
          */
-        mb_correct_addr_and_bit(bit, addr);
+        addr = mb_correct_addr_and_bit(&bit, addr);
         return ext4_test_bit(bit, addr);
 }
 
 static inline void mb_set_bit(int bit, void *addr)
 {
-        mb_correct_addr_and_bit(bit, addr);
+        addr = mb_correct_addr_and_bit(&bit, addr);
         ext4_set_bit(bit, addr);
 }
 
 static inline void mb_set_bit_atomic(spinlock_t *lock, int bit, void *addr)
 {
-        mb_correct_addr_and_bit(bit, addr);
+        addr = mb_correct_addr_and_bit(&bit, addr);
         ext4_set_bit_atomic(lock, bit, addr);
 }
 
 static inline void mb_clear_bit(int bit, void *addr)
 {
-        mb_correct_addr_and_bit(bit, addr);
+        addr = mb_correct_addr_and_bit(&bit, addr);
         ext4_clear_bit(bit, addr);
 }
 
 static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr)
 {
-        mb_correct_addr_and_bit(bit, addr);
+        addr = mb_correct_addr_and_bit(&bit, addr);
         ext4_clear_bit_atomic(lock, bit, addr);
 }
 
+static inline int mb_find_next_zero_bit(void *addr, int max, int start)
+{
+        int fix = 0;
+        addr = mb_correct_addr_and_bit(&fix, addr);
+        max += fix;
+        start += fix;
+
+        return ext4_find_next_zero_bit(addr, max, start) - fix;
+}
+
+static inline int mb_find_next_bit(void *addr, int max, int start)
+{
+        int fix = 0;
+        addr = mb_correct_addr_and_bit(&fix, addr);
+        max += fix;
+        start += fix;
+
+        return ext4_find_next_bit(addr, max, start) - fix;
+}
+
 static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
 {
         char *bb;
@@ -906,7 +924,7 @@ static void ext4_mb_mark_free_simple(struct super_block *sb,
         unsigned short chunk;
         unsigned short border;
 
-        BUG_ON(len >= EXT4_BLOCKS_PER_GROUP(sb));
+        BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
 
         border = 2 << sb->s_blocksize_bits;
 
@@ -946,12 +964,12 @@ static void ext4_mb_generate_buddy(struct super_block *sb,
 
         /* initialize buddy from bitmap which is aggregation
          * of on-disk bitmap and preallocations */
-        i = ext4_find_next_zero_bit(bitmap, max, 0);
+        i = mb_find_next_zero_bit(bitmap, max, 0);
         grp->bb_first_free = i;
         while (i < max) {
                 fragments++;
                 first = i;
-                i = ext4_find_next_bit(bitmap, max, i);
+                i = mb_find_next_bit(bitmap, max, i);
                 len = i - first;
                 free += len;
                 if (len > 1)
@@ -959,7 +977,7 @@ static void ext4_mb_generate_buddy(struct super_block *sb,
                 else
                         grp->bb_counters[0]++;
                 if (i < max)
-                        i = ext4_find_next_zero_bit(bitmap, max, i);
+                        i = mb_find_next_zero_bit(bitmap, max, i);
         }
         grp->bb_fragments = fragments;
 
@@ -967,6 +985,10 @@ static void ext4_mb_generate_buddy(struct super_block *sb,
                 ext4_error(sb, __FUNCTION__,
                         "EXT4-fs: group %lu: %u blocks in bitmap, %u in gd\n",
                         group, free, grp->bb_free);
+                /*
+                 * If we intent to continue, we consider group descritor
+                 * corrupt and update bb_free using bitmap value
+                 */
                 grp->bb_free = free;
         }
 
@@ -1778,7 +1800,7 @@ static void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
                 buddy = mb_find_buddy(e4b, i, &max);
                 BUG_ON(buddy == NULL);
 
-                k = ext4_find_next_zero_bit(buddy, max, 0);
+                k = mb_find_next_zero_bit(buddy, max, 0);
                 BUG_ON(k >= max);
 
                 ac->ac_found++;
@@ -1818,11 +1840,11 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
         i = e4b->bd_info->bb_first_free;
 
         while (free && ac->ac_status == AC_STATUS_CONTINUE) {
-                i = ext4_find_next_zero_bit(bitmap,
+                i = mb_find_next_zero_bit(bitmap,
                                                 EXT4_BLOCKS_PER_GROUP(sb), i);
                 if (i >= EXT4_BLOCKS_PER_GROUP(sb)) {
                         /*
-                         * IF we corrupt the bitmap  we won't find any
+                         * IF we have corrupt bitmap, we won't find any
                          * free blocks even though group info says we
                          * we have free blocks
                          */
@@ -1838,6 +1860,12 @@ static void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
                         ext4_error(sb, __FUNCTION__, "%d free blocks as per "
                                         "group info. But got %d blocks\n",
                                         free, ex.fe_len);
+                        /*
+                         * The number of free blocks differs. This mostly
+                         * indicate that the bitmap is corrupt. So exit
+                         * without claiming the space.
+                         */
+                        break;
                 }
 
                 ext4_mb_measure_extent(ac, &ex, e4b);
@@ -3740,10 +3768,10 @@ static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b,
         }
 
         while (bit < end) {
-                bit = ext4_find_next_zero_bit(bitmap_bh->b_data, end, bit);
+                bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
                 if (bit >= end)
                         break;
-                next = ext4_find_next_bit(bitmap_bh->b_data, end, bit);
+                next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
                 if (next > end)
                         next = end;
                 start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
@@ -3771,6 +3799,10 @@ static int ext4_mb_release_inode_pa(struct ext4_buddy *e4b,
                         (unsigned long) pa->pa_len);
                 ext4_error(sb, __FUNCTION__, "free %u, pa_free %u\n",
                                                 free, pa->pa_free);
+                /*
+                 * pa is already deleted so we use the value obtained
+                 * from the bitmap and continue.
+                 */
         }
         atomic_add(free, &sbi->s_mb_discarded);
         if (ac)