From 2a8b3fdf37d30bd4e0bec834168dd4fd9d8b4f58 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Wed, 13 Nov 2013 06:40:41 +0000 Subject: [PATCH] db: separate out straight buffer IO from map based IO. Libxfs has two different interfaces for getting and reading buffers. The first is a block/length interface for reading contiguous regions, and the second is based on extent based xfs_buf_map arrays for discontiguous regions. The xfs-db code is solely based on a basic block array interface regardless of the type of region being read, and so doesn't match to either libxfs interface. As a first step to converting xfs_db to the libxfs interfaces, add a simple block/length buffer API and implement it using pread/pwrite. Then remove the single region conditionals from the basic block array based interfaces, and convert all the contiguous block read cases to use the new API. This new API is temporary - it will be replaced by the equivalent libxfs interface calls once all the infrastructure preparation for the changeover has been completed. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Rich Johnston --- db/init.c | 7 ++- db/io.c | 125 +++++++++++++++++++++++++++++++++++++++++++----------- db/io.h | 5 +-- 3 files changed, 104 insertions(+), 33 deletions(-) diff --git a/db/init.c b/db/init.c index d73d5490d..489c9fbcb 100644 --- a/db/init.c +++ b/db/init.c @@ -55,7 +55,7 @@ init( char **argv) { xfs_sb_t *sbp; - void *bufp = NULL; + char bufp[BBSIZE]; int c; setlocale(LC_ALL, ""); @@ -115,15 +115,14 @@ init( exit(1); } - if (read_bbs(XFS_SB_DADDR, 1, &bufp, NULL)) { + if (read_buf(XFS_SB_DADDR, 1, bufp)) { fprintf(stderr, _("%s: %s is invalid (cannot read first 512 " "bytes)\n"), progname, fsdevice); exit(1); } /* copy SB from buffer to in-core, converting architecture as we go */ - libxfs_sb_from_disk(&xmount.m_sb, bufp); - xfree(bufp); + libxfs_sb_from_disk(&xmount.m_sb, (struct xfs_dsb *)bufp); sbp = &xmount.m_sb; if (sbp->sb_magicnum != XFS_SB_MAGIC) { diff --git a/db/io.c b/db/io.c index 39a1827cf..fa1164635 100644 --- a/db/io.c +++ b/db/io.c @@ -417,8 +417,61 @@ ring_add(void) } } - int +read_buf( + xfs_daddr_t bbno, + int count, + void *bufp) +{ + int err; + + err = pread64(x.dfd, bufp, BBTOB(count), BBTOB(bbno)); + if (err < 0) + err = errno; + else if (err < count) + err = -1; + return err; +} + +static int +write_buf( + xfs_daddr_t bbno, + int count, + void *bufp) +{ + int err; + + err = pwrite64(x.dfd, bufp, BBTOB(count), BBTOB(bbno)); + if (err < 0) + err = errno; + else if (err < count) + err = -1; + return err; +} + +static void +write_cur_buf(void) +{ + int ret; + + ret = write_buf(iocur_top->bb, iocur_top->blen, iocur_top->buf); + + if (ret == -1) + dbprintf(_("incomplete write, block: %lld\n"), + (iocur_base + iocur_sp)->bb); + else if (ret != 0) + dbprintf(_("write error: %s\n"), strerror(ret)); + + /* re-read buffer from disk */ + ret = read_buf(iocur_top->bb, iocur_top->blen, iocur_top->buf); + if (ret == -1) + dbprintf(_("incomplete read, block: %lld\n"), + (iocur_base + iocur_sp)->bb); + else if (ret != 0) + dbprintf(_("read error: %s\n"), strerror(ret)); +} + +static int write_bbs( __int64_t bbno, int count, @@ -430,15 +483,14 @@ write_bbs( int j; int rval = EINVAL; /* initialize for zero `count' case */ - for (j = 0; j < count; j += bbmap ? 1 : count) { - if (bbmap) - bbno = bbmap->b[j]; + for (j = 0; j < count; j++) { + bbno = bbmap->b[j]; if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) { rval = errno; dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno); return rval; } - c = BBTOB(bbmap ? 1 : count); + c = BBTOB(1); i = (int)write(x.dfd, (char *)bufp + BBTOB(j), c); if (i < 0) { rval = errno; @@ -452,7 +504,7 @@ write_bbs( return rval; } -int +static int read_bbs( __int64_t bbno, int count, @@ -473,9 +525,8 @@ read_bbs( buf = xmalloc(c); else buf = *bufp; - for (j = 0; j < count; j += bbmap ? 1 : count) { - if (bbmap) - bbno = bbmap->b[j]; + for (j = 0; j < count; j++) { + bbno = bbmap->b[j]; if (lseek64(x.dfd, bbno << BBSHIFT, SEEK_SET) < 0) { rval = errno; dbprintf(_("can't seek in filesystem at bb %lld\n"), bbno); @@ -483,7 +534,7 @@ read_bbs( xfree(buf); buf = NULL; } else { - c = BBTOB(bbmap ? 1 : count); + c = BBTOB(1); i = (int)read(x.dfd, (char *)buf + BBTOB(j), c); if (i < 0) { rval = errno; @@ -506,22 +557,19 @@ read_bbs( return rval; } -void -write_cur(void) +static void +write_cur_bbs(void) { int ret; - if (iocur_sp < 0) { - dbprintf(_("nothing to write\n")); - return; - } ret = write_bbs(iocur_top->bb, iocur_top->blen, iocur_top->buf, - iocur_top->use_bbmap ? &iocur_top->bbmap : NULL); + &iocur_top->bbmap); if (ret == -1) dbprintf(_("incomplete write, block: %lld\n"), (iocur_base + iocur_sp)->bb); else if (ret != 0) dbprintf(_("write error: %s\n"), strerror(ret)); + /* re-read buffer from disk */ ret = read_bbs(iocur_top->bb, iocur_top->blen, &iocur_top->buf, iocur_top->use_bbmap ? &iocur_top->bbmap : NULL); @@ -532,6 +580,20 @@ write_cur(void) dbprintf(_("read error: %s\n"), strerror(ret)); } +void +write_cur(void) +{ + if (iocur_sp < 0) { + dbprintf(_("nothing to write\n")); + return; + } + + if (iocur_top->use_bbmap) + write_cur_bbs(); + else + write_cur_buf(); +} + void set_cur( const typ_t *t, @@ -549,17 +611,32 @@ set_cur( return; } -#ifdef DEBUG - if (bbmap) - printf(_("xfs_db got a bbmap for %lld\n"), (long long)d); -#endif ino = iocur_top->ino; dirino = iocur_top->dirino; mode = iocur_top->mode; pop_cur(); push_cur(); - if (read_bbs(d, c, &iocur_top->buf, bbmap)) - return; + + if (bbmap) { +#ifdef DEBUG + printf(_("xfs_db got a bbmap for %lld\n"), (long long)d); +#endif + + if (read_bbs(d, c, &iocur_top->buf, bbmap)) + return; + iocur_top->bbmap = *bbmap; + iocur_top->use_bbmap = 1; + } else { + if (!iocur_top->buf) { + iocur_top->buf = malloc(BBTOB(c)); + if (!iocur_top->buf) + return; + } + if (read_buf(d, c, iocur_top->buf)) + return; + iocur_top->use_bbmap = 0; + } + iocur_top->bb = d; iocur_top->blen = c; iocur_top->boff = 0; @@ -570,8 +647,6 @@ set_cur( iocur_top->ino = ino; iocur_top->dirino = dirino; iocur_top->mode = mode; - if ((iocur_top->use_bbmap = (bbmap != NULL))) - iocur_top->bbmap = *bbmap; /* store location in ring */ if (ring_flag) diff --git a/db/io.h b/db/io.h index 549aad915..9ea622389 100644 --- a/db/io.h +++ b/db/io.h @@ -52,10 +52,7 @@ extern void off_cur(int off, int len); extern void pop_cur(void); extern void print_iocur(char *tag, iocur_t *ioc); extern void push_cur(void); -extern int read_bbs(__int64_t daddr, int count, void **bufp, - bbmap_t *bbmap); -extern int write_bbs(__int64_t daddr, int count, void *bufp, - bbmap_t *bbmap); +extern int read_buf(__int64_t daddr, int count, void *bufp); extern void write_cur(void); extern void set_cur(const struct typ *t, __int64_t d, int c, int ring_add, bbmap_t *bbmap); -- 2.47.2