ocfs2: properly set and use inode group alloc hint

We were setting ac->ac_last_group in ocfs2_claim_suballoc_bits from
res->sr_bg_blkno.  Unfortunately, res->sr_bg_blkno is going to be zero under
normal (non-fragmented) circumstances. The discontig block group patches
effectively turned off that feature. Fix this by correctly calculating what
the next group hint should be.

Acked-by: Tao Ma <tao.ma@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.de>
Signed-off-by: Tao Ma <tao.ma@oracle.com>

diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
index 8a009ee1f7fd74f39d912887216e9440ac68b856..b93d7e72175a563fe781baa7c024ef54f1d82b28 100644 (file)
--- a/fs/ocfs2/suballoc.c
+++ b/fs/ocfs2/suballoc.c
@@ -62,6 +62,17 @@ struct ocfs2_suballoc_result {
        unsigned int    sr_bits;        /* How many bits we claimed */
 };
 
+static u64 ocfs2_group_from_res(struct ocfs2_suballoc_result *res)
+{
+       if (res->sr_blkno == 0)
+               return 0;
+
+       if (res->sr_bg_blkno)
+               return res->sr_bg_blkno;
+
+       return ocfs2_which_suballoc_group(res->sr_blkno, res->sr_bit_offset);
+}
+
 static inline void ocfs2_debug_bg(struct ocfs2_group_desc *bg);
 static inline void ocfs2_debug_suballoc_inode(struct ocfs2_dinode *fe);
 static inline u16 ocfs2_find_victim_chain(struct ocfs2_chain_list *cl);
@@ -1845,6 +1856,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
        int status;
        u16 victim, i;
        u16 bits_left = 0;
+       u64 hint = ac->ac_last_group;
        struct ocfs2_chain_list *cl;
        struct ocfs2_dinode *fe;
 
@@ -1872,7 +1884,7 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
                goto bail;
        }
 
-       res->sr_bg_blkno = ac->ac_last_group;
+       res->sr_bg_blkno = hint;
        if (res->sr_bg_blkno) {
                /* Attempt to short-circuit the usual search mechanism
                 * by jumping straight to the most recently used
@@ -1896,8 +1908,10 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
 
        status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits,
                                    res, &bits_left);
-       if (!status)
+       if (!status) {
+               hint = ocfs2_group_from_res(res);
                goto set_hint;
+       }
        if (status < 0 && status != -ENOSPC) {
                mlog_errno(status);
                goto bail;
@@ -1920,8 +1934,10 @@ static int ocfs2_claim_suballoc_bits(struct ocfs2_alloc_context *ac,
                ac->ac_chain = i;
                status = ocfs2_search_chain(ac, handle, bits_wanted, min_bits,
                                            res, &bits_left);
-               if (!status)
+               if (!status) {
+                       hint = ocfs2_group_from_res(res);
                        break;
+               }
                if (status < 0 && status != -ENOSPC) {
                        mlog_errno(status);
                        goto bail;
@@ -1936,7 +1952,7 @@ set_hint:
                if (bits_left < min_bits)
                        ac->ac_last_group = 0;
                else
-                       ac->ac_last_group = res->sr_bg_blkno;
+                       ac->ac_last_group = hint;
        }
 
 bail: