[PATCH 16/38] ubifs: introduce scan for ubifs-utils
Dongsheng Yang
yangds.fnst at cn.fujitsu.com
Mon Dec 21 00:41:39 PST 2015
It's a lib to scan a leb.
Signed-off-by: Dongsheng Yang <yangds.fnst at cn.fujitsu.com>
---
ubifs-utils/include/scan.h | 8 ++
ubifs-utils/lib/scan.c | 318 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 326 insertions(+)
create mode 100644 ubifs-utils/include/scan.h
create mode 100644 ubifs-utils/lib/scan.c
diff --git a/ubifs-utils/include/scan.h b/ubifs-utils/include/scan.h
new file mode 100644
index 0000000..8447adf
--- /dev/null
+++ b/ubifs-utils/include/scan.h
@@ -0,0 +1,8 @@
+#ifndef __UBIFS_SCAN_H__
+#define __UBIFS_SCAN_H__
+
+struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
+ int offs, void *sbuf, int quiet);
+
+void ubifs_scan_destroy(struct ubifs_scan_leb *sleb);
+#endif
diff --git a/ubifs-utils/lib/scan.c b/ubifs-utils/lib/scan.c
new file mode 100644
index 0000000..69c84d1
--- /dev/null
+++ b/ubifs-utils/lib/scan.c
@@ -0,0 +1,318 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * Copied from kernel
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/*
+ * This file implements the scan which is a general-purpose function for
+ * determining what nodes are in an eraseblock. The scan is used to replay the
+ * journal, to do garbage collection. for the TNC in-the-gaps method, and by
+ * debugging functions.
+ */
+#include "ubifs_common.h"
+
+#include "ubifs.h"
+#define PROGRAM_NAME "ubifs_scan"
+#include "common.h"
+#include "key.h"
+#include "io.h"
+#include "scan.h"
+
+/**
+ * scan_padding_bytes - scan for padding bytes.
+ * @buf: buffer to scan
+ * @len: length of buffer
+ *
+ * This function returns the number of padding bytes on success and
+ * %SCANNED_GARBAGE on failure.
+ */
+static int scan_padding_bytes(void *buf, int len)
+{
+ int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
+ int *p = buf;
+
+ while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
+ pad_len += 1;
+
+ if (!pad_len || (pad_len & 7)) {
+ return SCANNED_GARBAGE;
+ }
+
+ return pad_len;
+}
+
+/**
+ * ubifs_scan_a_node - scan for a node or padding.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to scan
+ * @len: length of buffer
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ * @quiet: print no messages
+ *
+ * This function returns a scanning code to indicate what was scanned.
+ */
+int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len,
+ int lnum __attribute__((unused)), int offs,
+ int quiet __attribute__((unused)))
+{
+ struct ubifs_ch *ch = buf;
+ uint32_t magic;
+
+ magic = le32_to_cpu(ch->magic);
+
+ if (magic == 0xFFFFFFFF)
+ return SCANNED_EMPTY_SPACE;
+
+ if (magic != UBIFS_NODE_MAGIC)
+ return scan_padding_bytes(buf, len);
+
+ if (len < UBIFS_CH_SZ) {
+ return SCANNED_GARBAGE;
+ }
+
+ if (ch->node_type == UBIFS_PAD_NODE) {
+ struct ubifs_pad_node *pad = buf;
+ int pad_len = le32_to_cpu(pad->pad_len);
+ int node_len = le32_to_cpu(ch->len);
+
+ /* Validate the padding node */
+ if (pad_len < 0 ||
+ offs + node_len + pad_len > c->leb_size) {
+ return SCANNED_A_BAD_PAD_NODE;
+ }
+
+ /* Make the node pads to 8-byte boundary */
+ if ((node_len + pad_len) & 7) {
+ return SCANNED_A_BAD_PAD_NODE;
+ }
+
+ return node_len + pad_len;
+ }
+
+ return SCANNED_A_NODE;
+}
+
+/**
+ * ubifs_start_scan - create LEB scanning information at start of scan.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ * @sbuf: scan buffer (must be c->leb_size)
+ *
+ * This function returns the scanned information on success and a negative error
+ * code on failure.
+ */
+struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
+ int offs, void *sbuf)
+{
+ struct ubifs_scan_leb *sleb;
+ int err;
+
+ sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
+ if (!sleb)
+ return ERR_PTR(-ENOMEM);
+
+ sleb->lnum = lnum;
+ INIT_LIST_HEAD(&sleb->nodes);
+ sleb->buf = sbuf;
+
+ err = ubifs_read(lnum * c->leb_size + offs, c->leb_size - offs, sbuf + offs);
+ if (err && err != -EBADMSG) {
+ kfree(sleb);
+ return ERR_PTR(err);
+ }
+
+ /*
+ * Note, we ignore integrity errors (EBASMSG) because all the nodes are
+ * protected by CRC checksums.
+ */
+ return sleb;
+}
+
+/**
+ * ubifs_end_scan - update LEB scanning information at end of scan.
+ * @c: UBIFS file-system description object
+ * @sleb: scanning information
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ */
+void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+ int lnum, int offs)
+{
+ lnum = lnum;
+ ubifs_assert(offs % c->min_io_size == 0);
+
+ sleb->endpt = ALIGN(offs, c->min_io_size);
+}
+
+/**
+ * ubifs_add_snod - add a scanned node to LEB scanning information.
+ * @c: UBIFS file-system description object
+ * @sleb: scanning information
+ * @buf: buffer containing node
+ * @offs: offset of node on flash
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+ void *buf, int offs)
+{
+ struct ubifs_ch *ch = buf;
+ struct ubifs_ino_node *ino = buf;
+ struct ubifs_scan_node *snod;
+
+ snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
+ if (!snod)
+ return -ENOMEM;
+
+ snod->sqnum = le64_to_cpu(ch->sqnum);
+ snod->type = ch->node_type;
+ snod->offs = offs;
+ snod->len = le32_to_cpu(ch->len);
+ snod->node = buf;
+
+ switch (ch->node_type) {
+ case UBIFS_INO_NODE:
+ case UBIFS_DENT_NODE:
+ case UBIFS_XENT_NODE:
+ case UBIFS_DATA_NODE:
+ /*
+ * The key is in the same place in all keyed
+ * nodes.
+ */
+ key_read(c, &ino->key, &snod->key);
+ break;
+ default:
+ invalid_key_init(c, &snod->key);
+ break;
+ }
+ list_add_tail(&snod->list, &sleb->nodes);
+ sleb->nodes_cnt += 1;
+ return 0;
+}
+
+/**
+ * ubifs_scan - scan a logical eraseblock.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
+ * @quiet: print no messages
+ *
+ * This function scans LEB number @lnum and returns complete information about
+ * its contents. Returns the scanned information in case of success and,
+ * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
+ * of failure.
+ *
+ * If @quiet is non-zero, this function does not print large and scary
+ * error messages and flash dumps in case of errors.
+ */
+struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
+ int offs, void *sbuf, int quiet)
+{
+ void *buf = sbuf + offs;
+ int err, len = c->leb_size - offs;
+ struct ubifs_scan_leb *sleb;
+
+ sleb = ubifs_start_scan(c, lnum, offs, sbuf);
+ if (IS_ERR(sleb))
+ return sleb;
+
+ while (len >= 8) {
+ struct ubifs_ch *ch = buf;
+ int node_len, ret;
+
+ cond_resched();
+
+ ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
+ if (ret > 0) {
+ /* Padding bytes or a valid padding node */
+ offs += ret;
+ buf += ret;
+ len -= ret;
+ continue;
+ }
+
+ if (ret == SCANNED_EMPTY_SPACE)
+ /* Empty space is checked later */
+ break;
+
+ switch (ret) {
+ case SCANNED_GARBAGE:
+ if (offs == 0)
+ break;
+ goto corrupted;
+ case SCANNED_A_NODE:
+ break;
+ case SCANNED_A_CORRUPT_NODE:
+ case SCANNED_A_BAD_PAD_NODE:
+ goto corrupted;
+ default:
+ err = -EINVAL;
+ goto error;
+ }
+
+ err = ubifs_add_snod(c, sleb, buf, offs);
+ if (err)
+ goto error;
+
+ node_len = ALIGN(le32_to_cpu(ch->len), 8);
+ offs += node_len;
+ buf += node_len;
+ len -= node_len;
+ }
+
+ if (offs % c->min_io_size) {
+ goto corrupted;
+ }
+
+ ubifs_end_scan(c, sleb, lnum, offs);
+
+ for (; len > 2; offs += 2, buf = buf + 2, len -= 2)
+ if ((*(const uint8_t *)buf) != 0xff)
+ goto corrupted;
+
+ return sleb;
+
+corrupted:
+ err = -EUCLEAN;
+ ubifs_scan_destroy(sleb);
+ return ERR_PTR(err);
+
+error:
+ ubifs_scan_destroy(sleb);
+ return ERR_PTR(err);
+}
+
+/**
+ * ubifs_scan_destroy - destroy LEB scanning information.
+ * @sleb: scanning information to free
+ */
+void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
+{
+ struct ubifs_scan_node *node;
+ struct list_head *head;
+
+ head = &sleb->nodes;
+ while (!list_empty(head)) {
+ node = list_entry(head->next, struct ubifs_scan_node, list);
+ list_del(&node->list);
+ kfree(node);
+ }
+ kfree(sleb);
+}
--
1.8.4.2
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