[PATCH] erofs-utils: lib: introduce diskbuf
Gao Xiang
hsiangkao at linux.alibaba.com
Wed Sep 20 13:35:28 AEST 2023
On 2023/9/20 11:32, Jingbo Xu wrote:
>
>
> On 9/15/23 11:29 PM, Gao Xiang wrote:
>> Previously, each tar data file will be kept as a temporary file before
>> landing to the target image since the input stream may be non-seekable.
>>
>> It's somewhat ineffective. Let's introduce a new diskbuf approach to
>> manage those buffers. Laterly, each stream can be redirected to blob
>> files for external reference.
>>
>> Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
>> ---
>> include/erofs/diskbuf.h | 30 ++++++++
>> include/erofs/internal.h | 8 ++-
>> lib/Makefile.am | 3 +-
>> lib/diskbuf.c | 147 +++++++++++++++++++++++++++++++++++++++
>> lib/inode.c | 33 +++++----
>> lib/io.c | 1 +
>> lib/tar.c | 21 ++++--
>> mkfs/main.c | 10 +++
>> 8 files changed, 230 insertions(+), 23 deletions(-)
>> create mode 100644 include/erofs/diskbuf.h
>> create mode 100644 lib/diskbuf.c
>>
>> diff --git a/include/erofs/diskbuf.h b/include/erofs/diskbuf.h
>> new file mode 100644
>> index 0000000..29d9fe2
>> --- /dev/null
>> +++ b/include/erofs/diskbuf.h
>> @@ -0,0 +1,30 @@
>> +/* SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0 */
>> +#ifndef __EROFS_DISKBUF_H
>> +#define __EROFS_DISKBUF_H
>> +
>> +#ifdef __cplusplus
>> +extern "C"
>> +{
>> +#endif
>> +
>> +#include "erofs/defs.h"
>> +
>> +struct erofs_diskbuf {
>> + void *sp; /* internal stream pointer */
>> + u64 offset; /* internal offset */
>> +};
>> +
>> +int erofs_diskbuf_getfd(struct erofs_diskbuf *db, u64 *off);
>> +
>> +int erofs_diskbuf_reserve(struct erofs_diskbuf *db, int sid, u64 *off);
>> +void erofs_diskbuf_commit(struct erofs_diskbuf *db, u64 len);
>> +void erofs_diskbuf_close(struct erofs_diskbuf *db);
>> +
>> +int erofs_diskbuf_init(unsigned int nstrms);
>> +void erofs_diskbuf_exit(void);
>> +
>> +#ifdef __cplusplus
>> +}
>> +#endif
>> +
>> +#endif
>> diff --git a/include/erofs/internal.h b/include/erofs/internal.h
>> index 19b912b..a3c6fcd 100644
>> --- a/include/erofs/internal.h
>> +++ b/include/erofs/internal.h
>> @@ -107,7 +107,7 @@ struct erofs_sb_info {
>> u8 xattr_prefix_count;
>> struct erofs_xattr_prefix_item *xattr_prefixes;
>>
>> - int devfd;
>> + int devfd, devblksz;
>> u64 devsz;
>> dev_t dev;
>> unsigned int nblobs;
>> @@ -150,6 +150,8 @@ EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
>> #define EROFS_I_EA_INITED (1 << 0)
>> #define EROFS_I_Z_INITED (1 << 1)
>>
>> +struct erofs_diskbuf;
>> +
>> struct erofs_inode {
>> struct list_head i_hash, i_subdirs, i_xattrs;
>>
>> @@ -189,7 +191,7 @@ struct erofs_inode {
>> char *i_srcpath;
>> union {
>> char *i_link;
>> - FILE *i_tmpfile;
>> + struct erofs_diskbuf *i_diskbuf;
>> };
>> unsigned char datalayout;
>> unsigned char inode_isize;
>> @@ -197,7 +199,7 @@ struct erofs_inode {
>> unsigned short idata_size;
>> bool compressed_idata;
>> bool lazy_tailblock;
>> - bool with_tmpfile;
>> + bool with_diskbuf;
>> bool opaque;
>> /* OVL: non-merge dir that may contain whiteout entries */
>> bool whiteouts;
>> diff --git a/lib/Makefile.am b/lib/Makefile.am
>> index 8a45bd6..483d410 100644
>> --- a/lib/Makefile.am
>> +++ b/lib/Makefile.am
>> @@ -9,6 +9,7 @@ noinst_HEADERS = $(top_srcdir)/include/erofs_fs.h \
>> $(top_srcdir)/include/erofs/config.h \
>> $(top_srcdir)/include/erofs/decompress.h \
>> $(top_srcdir)/include/erofs/defs.h \
>> + $(top_srcdir)/include/erofs/diskbuf.h \
>> $(top_srcdir)/include/erofs/err.h \
>> $(top_srcdir)/include/erofs/exclude.h \
>> $(top_srcdir)/include/erofs/flex-array.h \
>> @@ -33,7 +34,7 @@ liberofs_la_SOURCES = config.c io.c cache.c super.c inode.c xattr.c exclude.c \
>> namei.c data.c compress.c compressor.c zmap.c decompress.c \
>> compress_hints.c hashmap.c sha256.c blobchunk.c dir.c \
>> fragments.c rb_tree.c dedupe.c uuid_unparse.c uuid.c tar.c \
>> - block_list.c xxhash.c rebuild.c
>> + block_list.c xxhash.c rebuild.c diskbuf.c
>>
>> liberofs_la_CFLAGS = -Wall ${libuuid_CFLAGS} -I$(top_srcdir)/include
>> if ENABLE_LZ4
>> diff --git a/lib/diskbuf.c b/lib/diskbuf.c
>> new file mode 100644
>> index 0000000..004b1c0
>> --- /dev/null
>> +++ b/lib/diskbuf.c
>> @@ -0,0 +1,147 @@
>> +// SPDX-License-Identifier: GPL-2.0+ OR Apache-2.0
>> +#include "erofs/diskbuf.h"
>> +#include "erofs/internal.h"
>> +#include "erofs/print.h"
>> +#include <stdio.h>
>> +#include <errno.h>
>> +#include <sys/stat.h>
>> +#include <unistd.h>
>> +#include <stdlib.h>
>> +
>> +/* A simple approach to avoid creating too many temporary files */
>> +static struct erofs_diskbufstrm {
>> + u64 count;
>> + u64 tailoffset, devpos;
>> + int fd;
>> + unsigned int alignsize;
>> + bool locked;
>> +} *dbufstrm;
>> +
>> +int erofs_diskbuf_getfd(struct erofs_diskbuf *db, u64 *fpos)
>> +{
>> + const struct erofs_diskbufstrm *strm = db->sp;
>> + u64 offset;
>> +
>> + if (!strm)
>> + return -1;
>> + offset = db->offset + strm->devpos;
>> + if (lseek(strm->fd, offset, SEEK_SET) != offset)
>> + return -E2BIG;
>> + if (fpos)
>> + *fpos = offset;
>> + return strm->fd;
>> +}
>> +
>> +int erofs_diskbuf_reserve(struct erofs_diskbuf *db, int sid, u64 *off)
>> +{
>> + struct erofs_diskbufstrm *strm = dbufstrm + sid;
>> +
>> + if (strm->tailoffset & (strm->alignsize - 1)) {
>> + strm->tailoffset = round_up(strm->tailoffset, strm->alignsize);
>> + if (lseek(strm->fd, strm->tailoffset + strm->devpos,
>> + SEEK_SET) != strm->tailoffset + strm->devpos)
>> + return -EIO;
>> + }
>> + if (*off)
>> + *off = db->offset + strm->devpos;
>
>
> if (off)
> *off = db->offset + strm->devpos;
Thanks, fixed.
>
> ?
>
>> + db->offset = strm->tailoffset;
>> + db->sp = strm;
>> + ++strm->count;
>> + strm->locked = true; /* TODO: need a real lock for MT */
>> + return strm->fd;
>> +}
>> +
>> +void erofs_diskbuf_commit(struct erofs_diskbuf *db, u64 len)
>> +{
>> + struct erofs_diskbufstrm *strm = db->sp;
>> +
>> + DBG_BUGON(!strm);
>> + DBG_BUGON(!strm->locked);
>> + DBG_BUGON(strm->tailoffset != db->offset);
>> + strm->tailoffset += len;
>> +}
>> +
>> +void erofs_diskbuf_close(struct erofs_diskbuf *db)
>> +{
>> + struct erofs_diskbufstrm *strm = db->sp;
>> +
>> + DBG_BUGON(!strm);
>> + DBG_BUGON(strm->count <= 1);
>> + --strm->count;
>> + db->sp = NULL;
>> +}
>> +
>> +int erofs_tmpfile(void)
>> +{
>> +#define TRAILER "tmp.XXXXXXXXXX"
>> + char buf[PATH_MAX];
>> + int fd;
>> + umode_t u;
>> +
>> + (void)snprintf(buf, sizeof(buf), "%s/" TRAILER,
>> + getenv("TMPDIR") ?: "/tmp");
>> +
>> + fd = mkstemp(buf);
>> + if (fd < 0)
>> + return -errno;
>> +
>> + unlink(buf);
>> + u = umask(0);
>> + (void)umask(u);
>> + (void)fchmod(fd, 0666 & ~u);
>> + return fd;
>> +}
>> +
>> +int erofs_diskbuf_init(unsigned int nstrms)
>> +{
>> + struct erofs_diskbufstrm *strm;
>> +
>> + strm = calloc(nstrms + 1, sizeof(*strm));
>> + if (!strm)
>> + return -ENOMEM;
>> + strm[nstrms].fd = -1;
>> + dbufstrm = strm;
>> +
>> + for (; strm < dbufstrm + nstrms; ++strm) {
>> + struct stat st;
>> +
>> + /* try to use the devfd for regfiles on stream 0 */
>> + if (strm == dbufstrm && sbi.devsz == INT64_MAX) {
>> + strm->devpos = 1ULL << 40;
>> + if (!ftruncate(sbi.devfd, strm->devpos << 1)) {
>> + strm->fd = dup(sbi.devfd);
>> + if (lseek(strm->fd, strm->devpos,
>> + SEEK_SET) != strm->devpos)
>> + return -EIO;
>> + goto setupone;
>> + }
>> + }
>> + strm->devpos = 0;
>> + strm->fd = erofs_tmpfile();
>> + if (strm->fd < 0)
>> + return -ENOSPC;
>> +setupone:
>> + strm->tailoffset = 0;
>> + strm->count = 1;
>> + if (fstat(strm->fd, &st))
>> + return -errno;
>> + strm->alignsize = max_t(u32, st.st_blksize, getpagesize());
>> + ++strm;
>> + }
>> + return 0;
>> +}
>> +
>> +void erofs_diskbuf_exit(void)
>> +{
>> + struct erofs_diskbufstrm *strm;
>> +
>> + if (!dbufstrm)
>> + return;
>> +
>> + for (strm = dbufstrm; strm->fd >= 0; ++strm) {
>> + DBG_BUGON(strm->count != 1);
>> +
>> + close(strm->fd);
>> + strm->fd = -1;
>> + }
>> +}
>> diff --git a/lib/inode.c b/lib/inode.c
>> index 37aa79e..4dc8260 100644
>> --- a/lib/inode.c
>> +++ b/lib/inode.c
>> @@ -16,6 +16,7 @@
>> #endif
>> #include <dirent.h>
>> #include "erofs/print.h"
>> +#include "erofs/diskbuf.h"
>> #include "erofs/inode.h"
>> #include "erofs/cache.h"
>> #include "erofs/io.h"
>> @@ -121,10 +122,12 @@ unsigned int erofs_iput(struct erofs_inode *inode)
>> list_del(&inode->i_hash);
>> if (inode->i_srcpath)
>> free(inode->i_srcpath);
>> - if (inode->with_tmpfile)
>> - fclose(inode->i_tmpfile);
>> - else if (inode->i_link)
>> + if (inode->with_diskbuf) {
>> + erofs_diskbuf_close(inode->i_diskbuf);
>> + free(inode->i_diskbuf);
>> + } else if (inode->i_link) {
>> free(inode->i_link);
>> + }
>> free(inode);
>> return 0;
>> }
>> @@ -454,12 +457,11 @@ static int write_uncompressed_file_from_fd(struct erofs_inode *inode, int fd)
>> return 0;
>> }
>>
>> -int erofs_write_file(struct erofs_inode *inode, int fd)
>> +int erofs_write_file(struct erofs_inode *inode, int fd, u64 fpos)
>> {
>> int ret;
>>
>> - if (!inode->i_size)
>> - return 0;
>> + DBG_BUGON(!inode->i_size);
>>
>> if (cfg.c_chunkbits) {
>> inode->u.chunkbits = cfg.c_chunkbits;
>> @@ -475,7 +477,7 @@ int erofs_write_file(struct erofs_inode *inode, int fd)
>> if (!ret || ret != -ENOSPC)
>> return ret;
>>
>> - ret = lseek(fd, 0, SEEK_SET);
>> + ret = lseek(fd, fpos, SEEK_SET);
>> if (ret < 0)
>> return -errno;
>> }
>
>
> It seems that erofs_blob_write_chunked_file() has not been adapted to
> the new erofs_diskbuf API?
I have no idea why it needs to be adapted, doesn't it work?
Thanks,
Gao Xiang
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