On 2/12/16 1:03 PM, Bill O'Donnell wrote:
> Optimize secondary sb search, using similar method to find
> fs geometry as that of xfs_mkfs. If this faster method fails
> in finding a secondary sb, fall back to original brute force
> slower search.
Hey Bill, looks like this is pretty much there. I do have a few
comments, things which I really should have seen earlier, so I'm
very sorry about that. Inline below.
I think you can just send a V5 in reply to this one to keep it in
the thread.
Dave's up to V6 on his latest patchset so don't feel too bad. :D
-Eric
> Signed-off-by: Bill O'Donnell <billodo@xxxxxxxxxx>
> ---
> Makefile | 2 +-
> include/libxcmd.h | 6 +++++-
> libxcmd/topology.c | 27 +++++++++++++++++++++++++++
> repair/Makefile | 4 ++--
> repair/sb.c | 49 +++++++++++++++++++++++++++++++++++++++++--------
> 5 files changed, 76 insertions(+), 12 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index fca0a42..1d60d9c 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -80,7 +80,7 @@ fsr: libhandle
> growfs: libxcmd
> io: libxcmd libhandle
> quota: libxcmd
> -repair: libxlog
> +repair: libxlog libxcmd
> copy: libxlog
>
> ifeq ($(HAVE_BUILDDEFS), yes)
> diff --git a/include/libxcmd.h b/include/libxcmd.h
> index a912534..eb16cd5 100644
> --- a/include/libxcmd.h
> +++ b/include/libxcmd.h
> @@ -51,6 +51,10 @@ extern int
> check_overwrite(
> char *device);
>
> -
> +extern int
> +guess_default_geometry(
> + __uint64_t *agsize,
> + __uint64_t *agcount,
> + libxfs_init_t x);
This function is only used in repair/sb.c, so it can just
be a static in that function, no need to have it in the library.
But more importantly, passing the libxfs_init_t structure by
value is pretty unusual; it works in this case because it's
not modified, but it would be safer and make more sense to
pass in a pointer.
> #endif /* __LIBXCMD_H__ */
> diff --git a/libxcmd/topology.c b/libxcmd/topology.c
> index 4cbe4b1..ec9695c 100644
> --- a/libxcmd/topology.c
> +++ b/libxcmd/topology.c
> @@ -339,3 +339,30 @@ get_topology(
> &lsectorsize, &psectorsize, force_overwrite);
> }
> }
> +
> +int
> +guess_default_geometry(
> + __uint64_t *agsize,
> + __uint64_t *agcount,
> + libxfs_init_t x)
+ __uint64_t *agsize,
+ __uint64_t *agcount,
+ libxfs_init_t *x)
tab out to match below, and take pointer for x
> +{
> + struct fs_topology ft;
> + int blocklog;
> + __uint64_t dblocks;
> + int multidisk;
> +
> + memset(&ft, 0, sizeof(ft));
> + get_topology(&x, &ft, 1);
+ get_topology(x, &ft,1);
> +
> + /*
> + * get geometry from get_topology result.
> + * Use default block size (2^12)
> + */
> + blocklog = 12;
> + multidisk = ft.dswidth | ft.dsunit;
> + dblocks = x.dsize >> (blocklog - BBSHIFT);
+ dblocks = x->dsize >> (blocklog - BBSHIFT);
> + calc_default_ag_geometry(blocklog, dblocks, multidisk,
> + agsize, agcount);
> +
> + return blocklog;
> +}
> diff --git a/repair/Makefile b/repair/Makefile
> index 251722b..d24ab1f 100644
> --- a/repair/Makefile
> +++ b/repair/Makefile
> @@ -20,8 +20,8 @@ CFILES = agheader.c attr_repair.c avl.c avl64.c bmap.c btree.c \
> progress.c prefetch.c rt.c sb.c scan.c threads.c \
> versions.c xfs_repair.c
>
> -LLDLIBS = $(LIBXFS) $(LIBXLOG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD)
> -LTDEPENDENCIES = $(LIBXFS) $(LIBXLOG)
> +LLDLIBS = $(LIBBLKID) $(LIBXFS) $(LIBXLOG) $(LIBUUID) $(LIBRT) $(LIBPTHREAD) $(LIBXCMD)
> +LTDEPENDENCIES = $(LIBXFS) $(LIBXLOG) $(LIBXCMD)
> LLDFLAGS = -static-libtool-libs
>
> default: depend $(LTCOMMAND)
> diff --git a/repair/sb.c b/repair/sb.c
> index 4eef14a..8dcad5f 100644
> --- a/repair/sb.c
> +++ b/repair/sb.c
> @@ -17,6 +17,7 @@
> */
>
> #include "libxfs.h"
> +#include "libxcmd.h"
> #include "libxlog.h"
> #include "agheader.h"
> #include "globals.h"
> @@ -85,10 +86,15 @@ copy_sb(xfs_sb_t *source, xfs_sb_t *dest)
> }
>
> /*
> - * find a secondary superblock, copy it into the sb buffer
> + * find a secondary superblock, copy it into the sb buffer.
> + * start is the point to begin reading BSIZE bytes.
> + * skip contains a byte-count of how far to advance for next read.
> */
> -int
> -find_secondary_sb(xfs_sb_t *rsb)
> +static int
> +__find_secondary_sb(
> + xfs_sb_t *rsb,
> + __uint64_t start,
> + __uint64_t skip)
again, tab those out to match:
+ xfs_sb_t *rsb,
+ __uint64_t start,
+ __uint64_t skip)
> {
> xfs_off_t off;
> xfs_sb_t *sb;
> @@ -101,7 +107,6 @@ find_secondary_sb(xfs_sb_t *rsb)
> int bsize;
>
> do_warn(_("\nattempting to find secondary superblock...\n"));
> -
No good reason to remove this line, really; sometimes we clean up
whitespace if it makes sense and we're in the area, but this hunk
is nothing but a line removal; generally don't want unrelated whitespace
changes to sneak in.
> sb = (xfs_sb_t *)memalign(libxfs_device_alignment(), BSIZE);
> if (!sb) {
> do_error(
> @@ -117,7 +122,7 @@ find_secondary_sb(xfs_sb_t *rsb)
> /*
> * skip first sector since we know that's bad
> */
> - for (done = 0, off = XFS_AG_MIN_BYTES; !done ; off += bsize) {
> + for (done = 0, off = start; !done ; off += skip) {
> /*
> * read disk 1 MByte at a time.
> */
> @@ -128,9 +133,7 @@ find_secondary_sb(xfs_sb_t *rsb)
> if (!done && (bsize = read(x.dfd, sb, BSIZE)) <= 0) {
> done = 1;
> }
> -
> do_warn(".");
> -
While we're at it - no reason to remove these lines, it makes the
dot-generator stand out a little more. ;)
> /*
> * check the buffer 512 bytes at a time since
> * we don't know how big the sectors really are.
> @@ -166,7 +169,37 @@ find_secondary_sb(xfs_sb_t *rsb)
> }
>
> free(sb);
> - return(retval);
> + return retval;
> +}
You can put guess_default_geometry() here, as a static
function.
> +
> +int
> +find_secondary_sb(xfs_sb_t *rsb)
> +{
> + int retval;
> + __uint64_t agcount;
> + __uint64_t agsize;
> + __uint64_t skip;
> + int blocklog;
> +
> + /*
> + * Attempt to find secondary sb with a coarse approach,
> + * using a large skip (agsize in bytes). Failing that,
"using a large start and skip," I guess.
> + * fallback to the fine-grained approach using min agsize.
"fallback to the fine-grained approach, starting at min agsize."
(it's not using min agsize for skip, so just to keep that clear)
> + */
> + blocklog = guess_default_geometry(&agsize, &agcount, x);
> +
> + /*
> + * use found ag geometry to quickly find secondary sb
> + */
> + skip = agsize << blocklog;
> + retval = __find_secondary_sb(rsb, skip, skip);
> + if (!retval) {
> + /*
> + * fallback: use minimum agsize for skipsize
actually that's the start, not skip; so
"fallback: Start at min agsize and scan all blocks"
> + */
> + retval = __find_secondary_sb(rsb, XFS_AG_MIN_BYTES, BSIZE);
> + }
> + return retval;
> }
>
> /*
>
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