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authorDavid Woodhouse <David.Woodhouse@intel.com>2008-08-05 21:08:56 +0400
committerJens Axboe <jens.axboe@oracle.com>2008-10-09 10:56:01 +0400
commitfdc53971bce56d299cb5f1f06ecbff30b34cbaf2 (patch)
tree96ffa11fb549ef059e167c3fc0afaabe48204763
parenteae9acd13a8d14b50c00a961fa959606f34bbd92 (diff)
downloadlinux-fdc53971bce56d299cb5f1f06ecbff30b34cbaf2.tar.xz
Support 'discard sectors' operation.
We can benefit from knowing that the file system no longer cares about the contents of certain sectors, by throwing them away immediately and then never having to garbage collect them, and using the extra free space to make our operations more efficient. Do so. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--drivers/mtd/ftl.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/drivers/mtd/ftl.c b/drivers/mtd/ftl.c
index f34f20c78911..9bf581c4f740 100644
--- a/drivers/mtd/ftl.c
+++ b/drivers/mtd/ftl.c
@@ -1005,6 +1005,29 @@ static int ftl_writesect(struct mtd_blktrans_dev *dev,
return ftl_write((void *)dev, buf, block, 1);
}
+static int ftl_discardsect(struct mtd_blktrans_dev *dev,
+ unsigned long sector, unsigned nr_sects)
+{
+ partition_t *part = (void *)dev;
+ uint32_t bsize = 1 << part->header.EraseUnitSize;
+
+ DEBUG(1, "FTL erase sector %ld for %d sectors\n",
+ sector, nr_sects);
+
+ while (nr_sects) {
+ uint32_t old_addr = part->VirtualBlockMap[sector];
+ if (old_addr != 0xffffffff) {
+ part->VirtualBlockMap[sector] = 0xffffffff;
+ part->EUNInfo[old_addr/bsize].Deleted++;
+ if (set_bam_entry(part, old_addr, 0))
+ return -EIO;
+ }
+ nr_sects--;
+ sector++;
+ }
+
+ return 0;
+}
/*====================================================================*/
static void ftl_freepart(partition_t *part)
@@ -1069,6 +1092,7 @@ static struct mtd_blktrans_ops ftl_tr = {
.blksize = SECTOR_SIZE,
.readsect = ftl_readsect,
.writesect = ftl_writesect,
+ .discard = ftl_discardsect,
.getgeo = ftl_getgeo,
.add_mtd = ftl_add_mtd,
.remove_dev = ftl_remove_dev,