131 lines
4.0 KiB
Diff
131 lines
4.0 KiB
Diff
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Chunwei Chen <david.chen@nutanix.com>
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Date: Thu, 1 Feb 2018 16:19:36 -0800
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Subject: [PATCH] Fix zdb -R decompression
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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There are some issues in the zdb -R decompression implementation.
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The first is that ZLE can easily decompress non-ZLE streams. So we add
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ZDB_NO_ZLE env to make zdb skip ZLE.
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The second is the random bytes appended to pabd, pbuf2 stuff. This serve
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no purpose at all, those bytes shouldn't be read during decompression
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anyway. Instead, we randomize lbuf2, so that we can make sure
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decompression fill exactly to lsize by bcmp lbuf and lbuf2.
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The last one is the condition to detect fail is wrong.
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Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
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Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
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Signed-off-by: Chunwei Chen <david.chen@nutanix.com>
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Closes #7099
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Closes #4984
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(cherry picked from commit 18c662b84566cd34e6f6fb982d6a01a415a4e3cd)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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cmd/zdb/zdb.c | 38 ++++++++++++++++++--------------------
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man/man8/zdb.8 | 4 +++-
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2 files changed, 21 insertions(+), 21 deletions(-)
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diff --git a/cmd/zdb/zdb.c b/cmd/zdb/zdb.c
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index 0cc1656a8..2d80589ca 100644
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--- a/cmd/zdb/zdb.c
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+++ b/cmd/zdb/zdb.c
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@@ -3895,13 +3895,6 @@ name:
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return (NULL);
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}
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-/* ARGSUSED */
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-static int
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-random_get_pseudo_bytes_cb(void *buf, size_t len, void *unused)
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-{
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- return (random_get_pseudo_bytes(buf, len));
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-}
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-
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/*
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* Read a block from a pool and print it out. The syntax of the
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* block descriptor is:
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@@ -4064,17 +4057,8 @@ zdb_read_block(char *thing, spa_t *spa)
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* every decompress function at every inflated blocksize.
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*/
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enum zio_compress c;
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- void *pbuf2 = umem_alloc(SPA_MAXBLOCKSIZE, UMEM_NOFAIL);
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void *lbuf2 = umem_alloc(SPA_MAXBLOCKSIZE, UMEM_NOFAIL);
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- abd_copy_to_buf(pbuf2, pabd, psize);
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-
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- VERIFY0(abd_iterate_func(pabd, psize, SPA_MAXBLOCKSIZE - psize,
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- random_get_pseudo_bytes_cb, NULL));
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-
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- VERIFY0(random_get_pseudo_bytes((uint8_t *)pbuf2 + psize,
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- SPA_MAXBLOCKSIZE - psize));
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-
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/*
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* XXX - On the one hand, with SPA_MAXBLOCKSIZE at 16MB,
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* this could take a while and we should let the user know
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@@ -4084,13 +4068,29 @@ zdb_read_block(char *thing, spa_t *spa)
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for (lsize = psize + SPA_MINBLOCKSIZE;
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lsize <= SPA_MAXBLOCKSIZE; lsize += SPA_MINBLOCKSIZE) {
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for (c = 0; c < ZIO_COMPRESS_FUNCTIONS; c++) {
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+ /*
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+ * ZLE can easily decompress non zle stream.
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+ * So have an option to disable it.
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+ */
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+ if (c == ZIO_COMPRESS_ZLE &&
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+ getenv("ZDB_NO_ZLE"))
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+ continue;
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+
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(void) fprintf(stderr,
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"Trying %05llx -> %05llx (%s)\n",
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(u_longlong_t)psize, (u_longlong_t)lsize,
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zio_compress_table[c].ci_name);
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+
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+ /*
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+ * We randomize lbuf2, and decompress to both
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+ * lbuf and lbuf2. This way, we will know if
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+ * decompression fill exactly to lsize.
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+ */
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+ VERIFY0(random_get_pseudo_bytes(lbuf2, lsize));
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+
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if (zio_decompress_data(c, pabd,
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lbuf, psize, lsize) == 0 &&
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- zio_decompress_data_buf(c, pbuf2,
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+ zio_decompress_data(c, pabd,
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lbuf2, psize, lsize) == 0 &&
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bcmp(lbuf, lbuf2, lsize) == 0)
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break;
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@@ -4098,11 +4098,9 @@ zdb_read_block(char *thing, spa_t *spa)
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if (c != ZIO_COMPRESS_FUNCTIONS)
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break;
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}
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-
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- umem_free(pbuf2, SPA_MAXBLOCKSIZE);
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umem_free(lbuf2, SPA_MAXBLOCKSIZE);
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- if (lsize <= psize) {
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+ if (lsize > SPA_MAXBLOCKSIZE) {
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(void) printf("Decompress of %s failed\n", thing);
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goto out;
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}
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diff --git a/man/man8/zdb.8 b/man/man8/zdb.8
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index 4e47de7be..d991aae4c 100644
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--- a/man/man8/zdb.8
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+++ b/man/man8/zdb.8
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@@ -246,7 +246,9 @@ and, optionally,
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.It Sy b Ar offset
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Print block pointer
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.It Sy d
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-Decompress the block
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+Decompress the block. Set environment variable
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+.Nm ZBD_NO_ZLE
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+to skip zle when guessing.
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.It Sy e
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Byte swap the block
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.It Sy g
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--
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2.14.2
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