1 files changed, 122 insertions, 4 deletions

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index 9cbd11a3f804..9a55f53be5ff 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -1,5 +1,6 @@
 /*
  *   Copyright (C) International Business Machines Corp., 2000-2004
+ *   Portions Copyright (C) Tino Reichardt, 2012
  *
  *   This program is free software;  you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -25,6 +26,7 @@
 #include "jfs_lock.h"
 #include "jfs_metapage.h"
 #include "jfs_debug.h"
+#include "jfs_discard.h"
 
 /*
  *      SERIALIZATION of the Block Allocation Map.
@@ -104,7 +106,6 @@ static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
 static int dbFreeDmap(struct bmap * bmp, struct dmap * dp, s64 blkno,
                       int nblocks);
 static int dbMaxBud(u8 * cp);
-s64 dbMapFileSizeToMapSize(struct inode *ipbmap);
 static int blkstol2(s64 nb);
 
 static int cntlz(u32 value);
@@ -145,7 +146,6 @@ static const s8 budtab[256] = {
         2, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1
 };
 
-
 /*
  * NAME:        dbMount()
  *
@@ -310,7 +310,6 @@ int dbSync(struct inode *ipbmap)
         return (0);
 }
 
-
 /*
  * NAME:        dbFree()
  *
@@ -337,6 +336,7 @@ int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
         s64 lblkno, rem;
         struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
         struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+        struct super_block *sb = ipbmap->i_sb;
 
         IREAD_LOCK(ipbmap, RDWRLOCK_DMAP);
 
@@ -351,6 +351,13 @@ int dbFree(struct inode *ip, s64 blkno, s64 nblocks)
                 return -EIO;
         }
 
+        /**
+         * TRIM the blocks, when mounted with discard option
+         */
+        if (JFS_SBI(sb)->flag & JFS_DISCARD)
+                if (JFS_SBI(sb)->minblks_trim <= nblocks)
+                        jfs_issue_discard(ipbmap, blkno, nblocks);
+
         /*
          * free the blocks a dmap at a time.
          */
@@ -1095,7 +1102,6 @@ static int dbExtend(struct inode *ip, s64 blkno, s64 nblocks, s64 addnblocks)
                 /* we were not successful */
                 release_metapage(mp);
 
-
         return (rc);
 }
 
@@ -1590,6 +1596,118 @@ static int dbAllocAny(struct bmap * bmp, s64 nblocks, int l2nb, s64 * results)
 
 
 /*
+ * NAME:        dbDiscardAG()
+ *
+ * FUNCTION:    attempt to discard (TRIM) all free blocks of specific AG
+ *
+ *              algorithm:
+ *              1) allocate blocks, as large as possible and save them
+ *                 while holding IWRITE_LOCK on ipbmap
+ *              2) trim all these saved block/length values
+ *              3) mark the blocks free again
+ *
+ *              benefit:
+ *              - we work only on one ag at some time, minimizing how long we
+ *                need to lock ipbmap
+ *              - reading / writing the fs is possible most time, even on
+ *                trimming
+ *
+ *              downside:
+ *              - we write two times to the dmapctl and dmap pages
+ *              - but for me, this seems the best way, better ideas?
+ *              /TR 2012
+ *
+ * PARAMETERS:
+ *      ip      - pointer to in-core inode
+ *      agno    - ag to trim
+ *      minlen  - minimum value of contiguous blocks
+ *
+ * RETURN VALUES:
+ *      s64     - actual number of blocks trimmed
+ */
+s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen)
+{
+        struct inode *ipbmap = JFS_SBI(ip->i_sb)->ipbmap;
+        struct bmap *bmp = JFS_SBI(ip->i_sb)->bmap;
+        s64 nblocks, blkno;
+        u64 trimmed = 0;
+        int rc, l2nb;
+        struct super_block *sb = ipbmap->i_sb;
+
+        struct range2trim {
+                u64 blkno;
+                u64 nblocks;
+        } *totrim, *tt;
+
+        /* max blkno / nblocks pairs to trim */
+        int count = 0, range_cnt;
+        u64 max_ranges;
+
+        /* prevent others from writing new stuff here, while trimming */
+        IWRITE_LOCK(ipbmap, RDWRLOCK_DMAP);
+
+        nblocks = bmp->db_agfree[agno];
+        max_ranges = nblocks;
+        do_div(max_ranges, minlen);
+        range_cnt = min_t(u64, max_ranges + 1, 32 * 1024);
+        totrim = kmalloc(sizeof(struct range2trim) * range_cnt, GFP_NOFS);
+        if (totrim == NULL) {
+                jfs_error(bmp->db_ipbmap->i_sb,
+                          "dbDiscardAG: no memory for trim array");
+                IWRITE_UNLOCK(ipbmap);
+                return 0;
+        }
+
+        tt = totrim;
+        while (nblocks >= minlen) {
+                l2nb = BLKSTOL2(nblocks);
+
+                /* 0 = okay, -EIO = fatal, -ENOSPC -> try smaller block */
+                rc = dbAllocAG(bmp, agno, nblocks, l2nb, &blkno);
+                if (rc == 0) {
+                        tt->blkno = blkno;
+                        tt->nblocks = nblocks;
+                        tt++; count++;
+
+                        /* the whole ag is free, trim now */
+                        if (bmp->db_agfree[agno] == 0)
+                                break;
+
+                        /* give a hint for the next while */
+                        nblocks = bmp->db_agfree[agno];
+                        continue;
+                } else if (rc == -ENOSPC) {
+                        /* search for next smaller log2 block */
+                        l2nb = BLKSTOL2(nblocks) - 1;
+                        nblocks = 1 << l2nb;
+                } else {
+                        /* Trim any already allocated blocks */
+                        jfs_error(bmp->db_ipbmap->i_sb,
+                                "dbDiscardAG: -EIO");
+                        break;
+                }
+
+                /* check, if our trim array is full */
+                if (unlikely(count >= range_cnt - 1))
+                        break;
+        }
+        IWRITE_UNLOCK(ipbmap);
+
+        tt->nblocks = 0; /* mark the current end */
+        for (tt = totrim; tt->nblocks != 0; tt++) {
+                /* when mounted with online discard, dbFree() will
+                 * call jfs_issue_discard() itself */
+                if (!(JFS_SBI(sb)->flag & JFS_DISCARD))
+                        jfs_issue_discard(ip, tt->blkno, tt->nblocks);
+                dbFree(ip, tt->blkno, tt->nblocks);
+                trimmed += tt->nblocks;
+        }
+        kfree(totrim);
+
+        return trimmed;
+}
+
+/*
  * NAME:        dbFindCtl()
  *
  * FUNCTION:    starting at a specified dmap control page level and block