The underlay block storage could work in a stripe-like manner to improve
performance and space efficiency.
EROFS on-disk layout is flexible enough for such use cases.
Cc: Changpeng Liu <changpe...@tencent.com>
Signed-off-by: Gao Xiang <hsiang...@linux.alibaba.com>
---
include/erofs/cache.h | 3 +++
lib/cache.c | 25 ++++++++++++++++++++-----
man/mkfs.erofs.1 | 3 +++
mkfs/main.c | 11 +++++++++++
4 files changed, 37 insertions(+), 5 deletions(-)
diff --git a/include/erofs/cache.h b/include/erofs/cache.h
index d8559a8..6ff80ab 100644
--- a/include/erofs/cache.h
+++ b/include/erofs/cache.h
@@ -67,6 +67,9 @@ struct erofs_bufmgr {
/* last mapped buffer block to accelerate erofs_mapbh() */
struct erofs_buffer_block *last_mapped_block;
+
+ /* align data block addresses to multiples of `dsunit` */
+ unsigned int dsunit;
};
static inline const int get_alignsize(struct erofs_sb_info *sbi, int type,
diff --git a/lib/cache.c b/lib/cache.c
index cb05466..d3e2e62 100644
--- a/lib/cache.c
+++ b/lib/cache.c
@@ -156,10 +156,15 @@ static int erofs_bfind_for_attach(struct erofs_bufmgr
*bmgr,
bb = NULL;
/* try to find a most-fit mapped buffer block first */
- if (size + inline_ext >= blksiz)
+
+ if (__erofs_unlikely(bmgr->dsunit > 1)) {
+ used_before = blksiz - alignsize;
+ } else if (size + inline_ext >= blksiz) {
goto skip_mapped;
+ } else {
+ used_before = rounddown(blksiz - (size + inline_ext),
alignsize);
+ }
- used_before = rounddown(blksiz - (size + inline_ext), alignsize);
for (; used_before; --used_before) {
struct list_head *bt = bmgr->mapped_buckets[type] + used_before;
@@ -181,7 +186,7 @@ static int erofs_bfind_for_attach(struct erofs_bufmgr *bmgr,
ret = __erofs_battach(cur, NULL, size, alignsize,
inline_ext, true);
if (ret < 0) {
- DBG_BUGON(1);
+ DBG_BUGON(!(bmgr->dsunit > 1));
continue;
}
@@ -324,10 +329,20 @@ struct erofs_buffer_head *erofs_battach(struct
erofs_buffer_head *bh,
static void __erofs_mapbh(struct erofs_buffer_block *bb)
{
struct erofs_bufmgr *bmgr = bb->buffers.fsprivate;
- erofs_blk_t blkaddr;
+ erofs_blk_t blkaddr = bmgr->tail_blkaddr;
if (bb->blkaddr == NULL_ADDR) {
- bb->blkaddr = bmgr->tail_blkaddr;
+ bb->blkaddr = blkaddr;
+ if (__erofs_unlikely(bmgr->dsunit > 1) && bb->type == DATA) {
+ struct erofs_buffer_block *pb = list_prev_entry(bb,
list);
+
+ bb->blkaddr = roundup(blkaddr, bmgr->dsunit);
+ if (pb != &bmgr->blkh &&
+ pb->blkaddr + pb->buffers.nblocks >= blkaddr) {
+ DBG_BUGON(pb->blkaddr + pb->buffers.nblocks >
blkaddr);
+ pb->buffers.nblocks = bb->blkaddr - pb->blkaddr;
+ }
+ }
bmgr->last_mapped_block = bb;
erofs_bupdate_mapped(bb);
}
diff --git a/man/mkfs.erofs.1 b/man/mkfs.erofs.1
index 0093839..ee84163 100644
--- a/man/mkfs.erofs.1
+++ b/man/mkfs.erofs.1
@@ -149,6 +149,9 @@ the given primary algorithm, alternative algorithms can be
specified with
are extended regular expressions, matched against absolute paths within
the output filesystem, with no leading /.
.TP
+.BI "\-\-dsunit=" #
+Align all data block addresses to multiples of #.
+.TP
.BI "\-\-exclude-path=" path
Ignore file that matches the exact literal path.
You may give multiple
diff --git a/mkfs/main.c b/mkfs/main.c
index 9ca7dad..1f4b7c6 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -86,6 +86,7 @@ static struct option long_options[] = {
{"all-time", no_argument, NULL, 526},
{"sort", required_argument, NULL, 527},
{"hard-dereference", no_argument, NULL, 528},
+ {"dsunit", required_argument, NULL, 529},
{0, 0, 0, 0},
};
@@ -162,6 +163,7 @@ static void usage(int argc, char **argv)
" --blobdev=X specify an extra device X to store
chunked data\n"
" --chunksize=# generate chunk-based files with #-byte
chunks\n"
" --clean=X run full clean build (default) or:\n"
+ " --dsunit=# align all data block addresses to
multiples of #\n"
" --incremental=X run incremental build\n"
" (X = data|rvsp; data=full data,
rvsp=space is allocated\n"
" and filled with
zeroes)\n"
@@ -243,6 +245,7 @@ static unsigned int rebuild_src_count;
static LIST_HEAD(rebuild_src_list);
static u8 fixeduuid[16];
static bool valid_fixeduuid;
+static unsigned int dsunit;
static int erofs_mkfs_feat_set_legacy_compress(bool en, const char *val,
unsigned int vallen)
@@ -856,6 +859,13 @@ static int mkfs_parse_options_cfg(int argc, char *argv[])
case 528:
cfg.c_hard_dereference = true;
break;
+ case 529:
+ dsunit = strtoul(optarg, &endptr, 0);
+ if (*endptr != '\0') {
+ erofs_err("invalid dsunit %s", optarg);
+ return -EINVAL;
+ }
+ break;
case 'V':
version();
exit(0);
@@ -1318,6 +1328,7 @@ int main(int argc, char **argv)
}
sb_bh = NULL;
}
+ g_sbi.bmgr->dsunit = dsunit;
/* Use the user-defined UUID or generate one for clean builds */
if (valid_fixeduuid)
--
2.43.5
