[PATCH v3] erofs-utils: mkfs: support fragment deduplication
Yue Hu
zbestahu at gmail.com
Wed Nov 30 19:55:34 AEDT 2022
Hi Xiang,
Thanks for your comments.
On Wed, 30 Nov 2022 16:24:09 +0800
Gao Xiang <hsiangkao at linux.alibaba.com> wrote:
> On Tue, Nov 29, 2022 at 06:00:53PM +0800, Yue Hu wrote:
> > From: Yue Hu <huyue2 at coolpad.com>
> >
> > Previously, there's no fragment deduplication when this feature is
> > introduced. Let's support it now.
> >
> > With this patch, for Linux 5.10.1 + 5.10.87 source code:
> >
>
> Please add EROFS -T0 to retest 32 byte inode results.
>
> Also add Squashfs + LZ4HC results as a comparison.
Will do it in v4.
>
> > [before]
> > 32k pcluster + lz4hc,12 + fragment 454M
> > 64k pcluster + lz4hc,12 + fragment 439M
> > 128k pcluster + lz4hc,12 + fragment 431M
> > 32k pcluster + lz4hc,12 + fragment + dedupe 376M
> > 64k pcluster + lz4hc,12 + fragment + dedupe 384M
> > 128k pcluster + lz4hc,12 + fragment + dedupe 399M
> >
> > [after]
> > 32k pcluster + lz4hc,12 + fragment 316M
> > 64k pcluster + lz4hc,12 + fragment 300M
> > 128k pcluster + lz4hc,12 + fragment 292M
> > 32k pcluster + lz4hc,12 + fragment + dedupe 291M
> > 64k pcluster + lz4hc,12 + fragment + dedupe 286M
> > 128k pcluster + lz4hc,12 + fragment + dedupe 283M
> >
> > Suggested-by: Gao Xiang <hsiangkao at linux.alibaba.com>
> > Signed-off-by: Yue Hu <huyue2 at coolpad.com>
> > ---
> > v3:
> > - modify acrroding to Xiang's comments in v2
> > - simplify the logic in vle_compress_one
> > - fix the crash for 1MB pcluster
> >
> > v2: mainly improve the logic in compression
> >
> > include/erofs/fragments.h | 3 +-
> > lib/compress.c | 115 ++++++++++++++++++++----
> > lib/fragments.c | 180 +++++++++++++++++++++++++++++++++++++-
> > 3 files changed, 277 insertions(+), 21 deletions(-)
> >
> > diff --git a/include/erofs/fragments.h b/include/erofs/fragments.h
> > index 5444384..6c51fc9 100644
> > --- a/include/erofs/fragments.h
> > +++ b/include/erofs/fragments.h
> > @@ -15,8 +15,9 @@ extern "C"
> > extern const char *frags_packedname;
> > #define EROFS_PACKED_INODE frags_packedname
> >
> > +int z_erofs_fragments_dedupe(struct erofs_inode *inode, int fd, u32 *crc);
> > int z_erofs_pack_fragments(struct erofs_inode *inode, void *data,
> > - unsigned int len);
> > + unsigned int len, u32 crc);
>
> ^ tofcrc
>
> tail of file crc
Nice.
>
> > struct erofs_inode *erofs_mkfs_build_fragments(void);
> > int erofs_fragments_init(void);
> > void erofs_fragments_exit(void);
> > diff --git a/lib/compress.c b/lib/compress.c
> > index 17b3213..7e01932 100644
> > --- a/lib/compress.c
> > +++ b/lib/compress.c
> > @@ -33,6 +33,10 @@ struct z_erofs_vle_compress_ctx {
> > unsigned int head, tail;
> > erofs_blk_t blkaddr; /* pointing to the next blkaddr */
> > u16 clusterofs;
> > +
> > + u32 crc;
>
> tofcrc;
>
> > + unsigned int pclustersize;
> > + erofs_off_t remaining;
> > };
> >
> > #define Z_EROFS_LEGACY_MAP_HEADER_SIZE \
> > @@ -162,10 +166,10 @@ static void z_erofs_write_indexes(struct z_erofs_vle_compress_ctx *ctx)
> > ctx->clusterofs = clusterofs + count;
> > }
> >
> > -static int z_erofs_compress_dedupe(struct erofs_inode *inode,
> > - struct z_erofs_vle_compress_ctx *ctx,
> > +static int z_erofs_compress_dedupe(struct z_erofs_vle_compress_ctx *ctx,
> > unsigned int *len)
> > {
> > + struct erofs_inode *inode = ctx->inode;
> > int ret = 0;
> >
> > do {
> > @@ -319,30 +323,62 @@ static void tryrecompress_trailing(void *in, unsigned int *insize,
> > *compressedsize = ret;
> > }
> >
> > -static int vle_compress_one(struct z_erofs_vle_compress_ctx *ctx,
> > - bool final)
> > +static void z_erofs_fragments_dedupe_update(struct z_erofs_vle_compress_ctx *ctx,
> > + unsigned int *len)
> > +{
> > + struct erofs_inode *inode = ctx->inode;
> > + const unsigned int remaining = ctx->remaining + *len;
>
> please rename as "new_fragmentsize" for easy understanding.
Okay.
>
> > +
> > + DBG_BUGON(!inode->fragment_size);
> > +
> > + /* try to close the gap if it gets larger (should be rare) */
> > + if (inode->fragment_size < remaining) {
> > + ctx->pclustersize = roundup(remaining - inode->fragment_size,
> > + EROFS_BLKSIZ);
> > + return;
> > + }
> > +
> > + inode->fragmentoff += inode->fragment_size - remaining;
> > + inode->fragment_size = remaining;
> > +
> > + erofs_dbg("Reducing fragment size to %u at %lu",
> > + inode->fragment_size, inode->fragmentoff);
> > +
> > + /* it's ending */
> > + ctx->head += remaining;
> > + ctx->remaining = 0;
> > + *len = 0;
> > +}
> > +
> > +static int vle_compress_one(struct z_erofs_vle_compress_ctx *ctx, bool fixup)
> > {
> > static char dstbuf[EROFS_CONFIG_COMPR_MAX_SZ + EROFS_BLKSIZ];
> > struct erofs_inode *inode = ctx->inode;
> > char *const dst = dstbuf + EROFS_BLKSIZ;
> > struct erofs_compress *const h = &compresshandle;
> > unsigned int len = ctx->tail - ctx->head;
> > + bool final = !ctx->remaining;
> > int ret;
> >
> > while (len) {
> > - unsigned int pclustersize =
> > - z_erofs_get_max_pclusterblks(inode) * EROFS_BLKSIZ;
> > bool may_inline = (cfg.c_ztailpacking && final);
> > bool may_packing = (cfg.c_fragments && final &&
> > !erofs_is_packed_inode(inode));
>
> bool may_xxxx = fixup;
>
> >
> > - if (z_erofs_compress_dedupe(inode, ctx, &len) && !final)
> > + if (z_erofs_compress_dedupe(ctx, &len) && !final)
> > break;
> >
> > - if (len <= pclustersize) {
> > + if (len <= ctx->pclustersize) {
> > if (!final || !len)
> > break;
> > if (may_packing) {
> > + if (inode->fragment_size && !fixup) {
> > + ctx->remaining = inode->fragment_size;
> > + ctx->pclustersize =
> > + roundup(len, EROFS_BLKSIZ);
> > + ctx->e.length = 0;
> > + return -EAGAIN;
> > + }
> > ctx->e.length = len;
> > goto frag_packing;
> > }
> > @@ -353,7 +389,7 @@ static int vle_compress_one(struct z_erofs_vle_compress_ctx *ctx,
> > ctx->e.length = min(len,
> > cfg.c_max_decompressed_extent_bytes);
> > ret = erofs_compress_destsize(h, ctx->queue + ctx->head,
> > - &ctx->e.length, dst, pclustersize,
> > + &ctx->e.length, dst, ctx->pclustersize,
> > !(final && len == ctx->e.length));
> > if (ret <= 0) {
> > if (ret != -EAGAIN) {
> > @@ -385,11 +421,12 @@ nocompression:
> > ctx->e.compressedblks = 1;
> > ctx->e.raw = true;
> > } else if (may_packing && len == ctx->e.length &&
> > - ret < pclustersize) {
> > + ret < ctx->pclustersize && (!inode->fragment_size ||
> > + fixup)) {
> > frag_packing:
> > ret = z_erofs_pack_fragments(inode,
> > ctx->queue + ctx->head,
> > - len);
> > + len, ctx->crc);
> > if (ret < 0)
> > return ret;
> > ctx->e.compressedblks = 0; /* indicate a fragment */
>
> may_xxxx = false;
>
> > @@ -425,6 +462,21 @@ frag_packing:
> > DBG_BUGON(ctx->e.compressedblks * EROFS_BLKSIZ >=
> > ctx->e.length);
> >
> > + /*
> > + * Try to recompress a litte more if there's space left
> > + * for fragment deduplication.
> > + */
> > + if (may_packing && len == ctx->e.length && tailused &&
> > + ctx->tail < sizeof(ctx->queue)) {
> > + DBG_BUGON(!inode->fragment_size);
> > +
> > + ctx->remaining = inode->fragment_size;
> > + ctx->pclustersize =
> > + ctx->e.compressedblks * EROFS_BLKSIZ;
> > + ctx->e.length = 0;
> > + return -EAGAIN;
> > + }
> > +
> > /* zero out garbage trailing data for non-0padding */
> > if (!erofs_sb_has_lz4_0padding())
> > memset(dst + ret, 0,
> > @@ -454,6 +506,9 @@ frag_packing:
> > ctx->head += ctx->e.length;
> > len -= ctx->e.length;
> >
> > + if (fixup && ctx->e.compressedblks)
>
> if (may_xxxx)
Okay.
>
> > + z_erofs_fragments_dedupe_update(ctx, &len);
> > +
> > if (!final && ctx->head >= EROFS_CONFIG_COMPR_MAX_SZ) {
> > const unsigned int qh_aligned =
> > round_down(ctx->head, EROFS_BLKSIZ);
> > @@ -736,10 +791,9 @@ int erofs_write_compressed_file(struct erofs_inode *inode, int fd)
> > {
> > struct erofs_buffer_head *bh;
> > static struct z_erofs_vle_compress_ctx ctx;
> > - erofs_off_t remaining;
> > erofs_blk_t blkaddr, compressed_blocks;
> > unsigned int legacymetasize;
> > - int ret;
> > + int ret = 0;
> > u8 *compressmeta = malloc(vle_compressmeta_capacity(inode->i_size));
> >
> > if (!compressmeta)
> > @@ -775,6 +829,16 @@ int erofs_write_compressed_file(struct erofs_inode *inode, int fd)
> > inode->idata_size = 0;
> > inode->fragment_size = 0;
> >
> > + /*
> > + * Dedupe fragments before compression to avoid writing duplicate parts
> > + * into packed inode.
> > + */
> > + if (cfg.c_fragments && !erofs_is_packed_inode(inode)) {
> > + ret = z_erofs_fragments_dedupe(inode, fd, &ctx.crc);
> > + if (ret < 0)
> > + goto err_bdrop;
> > + }
> > +
> > blkaddr = erofs_mapbh(bh->block); /* start_blkaddr */
> > ctx.inode = inode;
> > ctx.blkaddr = blkaddr;
> > @@ -782,22 +846,25 @@ int erofs_write_compressed_file(struct erofs_inode *inode, int fd)
> > ctx.head = ctx.tail = 0;
> > ctx.clusterofs = 0;
> > ctx.e.length = 0;
> > - remaining = inode->i_size;
> > + ctx.e.compressedblks = 0;
> > + ctx.pclustersize = z_erofs_get_max_pclusterblks(inode) * EROFS_BLKSIZ;
> > + ctx.remaining = inode->i_size - inode->fragment_size;
> >
> > - while (remaining) {
> > - const u64 readcount = min_t(u64, remaining,
> > + while (ctx.remaining) {
> > + const u64 readcount = min_t(u64, ctx.remaining,
> > sizeof(ctx.queue) - ctx.tail);
> > + bool fixup = ret < 0;
>
> drop this one;
>
> >
> > ret = read(fd, ctx.queue + ctx.tail, readcount);
> > if (ret != readcount) {
> > ret = -errno;
> > goto err_bdrop;
> > }
> > - remaining -= readcount;
> > + ctx.remaining -= readcount;
> > ctx.tail += readcount;
> >
> > - ret = vle_compress_one(&ctx, !remaining);
>
> ret == -EAGAIN
Just move 'fixup' in 'ctx'?
>
> > - if (ret)
> > + ret = vle_compress_one(&ctx, fixup);
> > + if (ret && ret != -EAGAIN)
> > goto err_free_idata;
> > }
> > DBG_BUGON(ctx.head != ctx.tail);
> > @@ -807,6 +874,16 @@ int erofs_write_compressed_file(struct erofs_inode *inode, int fd)
> > DBG_BUGON(compressed_blocks < !!inode->idata_size);
> > compressed_blocks -= !!inode->idata_size;
> >
> > + if (inode->fragment_size && ctx.e.compressedblks) {
>
> why not moving into z_erofs_fragments_dedupe_update()?
I consider this before, it's a bit awkward for me due to non updating case.
Let me reconsider.
>
> Thanks,
> Gao Xiang
>
> > + z_erofs_write_indexes(&ctx);
> > +
> > + inode->z_advise |= Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
> > + ctx.e.length = inode->fragment_size;
> > + ctx.e.compressedblks = 0;
> > + ctx.e.raw = true;
> > + ctx.e.partial = false;
> > + ctx.e.blkaddr = ctx.blkaddr;
> > + }
> > z_erofs_write_indexes(&ctx);
> > z_erofs_write_indexes_final(&ctx);
> > legacymetasize = ctx.metacur - compressmeta;
> > diff --git a/lib/fragments.c b/lib/fragments.c
> > index b8c37d5..48c133f 100644
> > --- a/lib/fragments.c
> > +++ b/lib/fragments.c
> > @@ -10,14 +10,183 @@
> > #include "erofs/inode.h"
> > #include "erofs/compress.h"
> > #include "erofs/print.h"
> > +#include "erofs/internal.h"
> > #include "erofs/fragments.h"
> >
> > +struct erofs_fragment_dedupe_item {
> > + struct list_head list;
> > + unsigned int length, nr_dup;
> > + erofs_off_t pos;
> > + u8 data[];
> > +};
> > +
> > +#define FRAGMENT_HASHTABLE_SIZE 65536
> > +#define FRAGMENT_HASH(crc) (crc & (FRAGMENT_HASHTABLE_SIZE - 1))
> > +
> > +static struct list_head dupli_frags[FRAGMENT_HASHTABLE_SIZE];
> > +static unsigned int len_to_hash; /* the fragment length for crc32 hash */
> > +
> > static FILE *packedfile;
> > const char *frags_packedname = "packed_file";
> >
> > +static int z_erofs_fragments_dedupe_find(struct erofs_inode *inode, int fd,
> > + u32 crc)
> > +{
> > + struct erofs_fragment_dedupe_item *cur, *di = NULL;
> > + struct list_head *head;
> > + u8 *data;
> > + unsigned int length;
> > + int ret;
> > +
> > + head = &dupli_frags[FRAGMENT_HASH(crc)];
> > + if (list_empty(head))
> > + return 0;
> > +
> > + /* XXX: no need to read so much for smaller? */
> > + if (inode->i_size < 2 * EROFS_CONFIG_COMPR_MAX_SZ)
> > + length = inode->i_size;
> > + else
> > + length = 2 * EROFS_CONFIG_COMPR_MAX_SZ;
> > +
> > + data = malloc(length);
> > + if (!data)
> > + return -ENOMEM;
> > +
> > + ret = lseek(fd, inode->i_size - length, SEEK_SET);
> > + if (ret == -1) {
> > + ret = -errno;
> > + goto out;
> > + }
> > +
> > + ret = read(fd, data, length);
> > + if (ret != length) {
> > + ret = -errno;
> > + goto out;
> > + }
> > +
> > + list_for_each_entry(cur, head, list) {
> > + unsigned int e1, e2, i = 0;
> > +
> > + DBG_BUGON(cur->length < len_to_hash + 1);
> > + DBG_BUGON(length < len_to_hash + 1);
> > +
> > + e1 = cur->length - len_to_hash - 1;
> > + e2 = length - len_to_hash - 1;
> > +
> > + if (memcmp(cur->data + e1 + 1, data + e2 + 1, len_to_hash))
> > + continue;
> > +
> > + while (i <= min(e1, e2) && cur->data[e1 - i] == data[e2 - i])
> > + i++;
> > +
> > + if (i && (!di || i + len_to_hash > di->nr_dup)) {
> > + cur->nr_dup = i + len_to_hash;
> > + di = cur;
> > +
> > + /* full match */
> > + if (i == min(e1, e2) + 1)
> > + break;
> > + }
> > + }
> > + if (!di)
> > + goto out;
> > +
> > + DBG_BUGON(di->length < di->nr_dup);
> > +
> > + inode->fragment_size = di->nr_dup;
> > + inode->fragmentoff = di->pos + di->length - di->nr_dup;
> > +
> > + erofs_dbg("Dedupe %u fragment data at %lu", inode->fragment_size,
> > + inode->fragmentoff);
> > +out:
> > + free(data);
> > + return ret;
> > +}
> > +
> > +
> > +int z_erofs_fragments_dedupe(struct erofs_inode *inode, int fd, u32 *crc_ret)
> > +{
> > + u8 data_to_hash[len_to_hash];
> > + u32 crc;
> > + int ret;
> > +
> > + if (inode->i_size <= len_to_hash)
> > + return 0;
> > +
> > + ret = lseek(fd, inode->i_size - len_to_hash, SEEK_SET);
> > + if (ret == -1)
> > + return -errno;
> > +
> > + ret = read(fd, data_to_hash, len_to_hash);
> > + if (ret != len_to_hash)
> > + return -errno;
> > +
> > + crc = erofs_crc32c(~0, data_to_hash, len_to_hash);
> > + *crc_ret = crc;
> > +
> > + ret = z_erofs_fragments_dedupe_find(inode, fd, crc);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = lseek(fd, 0, SEEK_SET);
> > + if (ret == -1)
> > + return -errno;
> > + return 0;
> > +}
> > +
> > +static int z_erofs_fragments_dedupe_insert(void *data, unsigned int len,
> > + erofs_off_t pos, u32 crc)
> > +{
> > + struct erofs_fragment_dedupe_item *di;
> > +
> > + if (len <= len_to_hash)
> > + return 0;
> > +
> > + di = malloc(sizeof(*di) + len);
> > + if (!di)
> > + return -ENOMEM;
> > +
> > + memcpy(di->data, data, len);
> > + di->length = len;
> > + di->pos = pos;
> > + di->nr_dup = 0;
> > +
> > + list_add_tail(&di->list, &dupli_frags[FRAGMENT_HASH(crc)]);
> > + return 0;
> > +}
> > +
> > +static inline void z_erofs_fragments_dedupe_init(unsigned int clen)
> > +{
> > + unsigned int i;
> > +
> > + for (i = 0; i < FRAGMENT_HASHTABLE_SIZE; ++i)
> > + init_list_head(&dupli_frags[i]);
> > +
> > + len_to_hash = clen;
> > +}
> > +
> > +static void z_erofs_fragments_dedupe_exit(void)
> > +{
> > + struct erofs_fragment_dedupe_item *di, *n;
> > + struct list_head *head;
> > + unsigned int i;
> > +
> > + for (i = 0; i < FRAGMENT_HASHTABLE_SIZE; ++i) {
> > + head = &dupli_frags[i];
> > +
> > + if (list_empty(head))
> > + continue;
> > +
> > + list_for_each_entry_safe(di, n, head, list)
> > + free(di);
> > + }
> > +}
> > +
> > int z_erofs_pack_fragments(struct erofs_inode *inode, void *data,
> > - unsigned int len)
> > + unsigned int len, u32 crc)
> > {
> > + int ret;
> > +
> > inode->z_advise |= Z_EROFS_ADVISE_FRAGMENT_PCLUSTER;
> > inode->fragmentoff = ftell(packedfile);
> > inode->fragment_size = len;
> > @@ -35,6 +204,11 @@ int z_erofs_pack_fragments(struct erofs_inode *inode, void *data,
> >
> > erofs_dbg("Recording %u fragment data at %lu", inode->fragment_size,
> > inode->fragmentoff);
> > +
> > + ret = z_erofs_fragments_dedupe_insert(data, len, inode->fragmentoff,
> > + crc);
> > + if (ret)
> > + return ret;
> > return len;
> > }
> >
> > @@ -50,6 +224,8 @@ void erofs_fragments_exit(void)
> > {
> > if (packedfile)
> > fclose(packedfile);
> > +
> > + z_erofs_fragments_dedupe_exit();
> > }
> >
> > int erofs_fragments_init(void)
> > @@ -61,5 +237,7 @@ int erofs_fragments_init(void)
> > #endif
> > if (!packedfile)
> > return -ENOMEM;
> > +
> > + z_erofs_fragments_dedupe_init(16);
> > return 0;
> > }
> > --
> > 2.17.1
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