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366 lines
8.9 KiB
366 lines
8.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* This file is part of UBIFS. |
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* |
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* Copyright (C) 2006-2008 Nokia Corporation |
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* |
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* Authors: Adrian Hunter |
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* Artem Bityutskiy (Битюцкий Артём) |
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*/ |
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/* |
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* This file implements the scan which is a general-purpose function for |
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* determining what nodes are in an eraseblock. The scan is used to replay the |
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* journal, to do garbage collection. for the TNC in-the-gaps method, and by |
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* debugging functions. |
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*/ |
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#include "ubifs.h" |
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/** |
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* scan_padding_bytes - scan for padding bytes. |
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* @buf: buffer to scan |
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* @len: length of buffer |
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* |
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* This function returns the number of padding bytes on success and |
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* %SCANNED_GARBAGE on failure. |
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*/ |
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static int scan_padding_bytes(void *buf, int len) |
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{ |
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int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len); |
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uint8_t *p = buf; |
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dbg_scan("not a node"); |
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while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE) |
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pad_len += 1; |
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if (!pad_len || (pad_len & 7)) |
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return SCANNED_GARBAGE; |
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dbg_scan("%d padding bytes", pad_len); |
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return pad_len; |
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} |
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/** |
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* ubifs_scan_a_node - scan for a node or padding. |
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* @c: UBIFS file-system description object |
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* @buf: buffer to scan |
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* @len: length of buffer |
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* @lnum: logical eraseblock number |
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* @offs: offset within the logical eraseblock |
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* @quiet: print no messages |
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* |
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* This function returns a scanning code to indicate what was scanned. |
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*/ |
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int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum, |
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int offs, int quiet) |
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{ |
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struct ubifs_ch *ch = buf; |
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uint32_t magic; |
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magic = le32_to_cpu(ch->magic); |
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if (magic == 0xFFFFFFFF) { |
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dbg_scan("hit empty space at LEB %d:%d", lnum, offs); |
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return SCANNED_EMPTY_SPACE; |
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} |
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if (magic != UBIFS_NODE_MAGIC) |
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return scan_padding_bytes(buf, len); |
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if (len < UBIFS_CH_SZ) |
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return SCANNED_GARBAGE; |
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dbg_scan("scanning %s at LEB %d:%d", |
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dbg_ntype(ch->node_type), lnum, offs); |
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if (ubifs_check_node(c, buf, lnum, offs, quiet, 1)) |
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return SCANNED_A_CORRUPT_NODE; |
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if (ch->node_type == UBIFS_PAD_NODE) { |
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struct ubifs_pad_node *pad = buf; |
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int pad_len = le32_to_cpu(pad->pad_len); |
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int node_len = le32_to_cpu(ch->len); |
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/* Validate the padding node */ |
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if (pad_len < 0 || |
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offs + node_len + pad_len > c->leb_size) { |
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if (!quiet) { |
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ubifs_err(c, "bad pad node at LEB %d:%d", |
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lnum, offs); |
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ubifs_dump_node(c, pad); |
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} |
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return SCANNED_A_BAD_PAD_NODE; |
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} |
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/* Make the node pads to 8-byte boundary */ |
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if ((node_len + pad_len) & 7) { |
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if (!quiet) |
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ubifs_err(c, "bad padding length %d - %d", |
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offs, offs + node_len + pad_len); |
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return SCANNED_A_BAD_PAD_NODE; |
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} |
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dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len, |
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lnum, offs, ALIGN(offs + node_len + pad_len, 8)); |
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return node_len + pad_len; |
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} |
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return SCANNED_A_NODE; |
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} |
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/** |
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* ubifs_start_scan - create LEB scanning information at start of scan. |
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* @c: UBIFS file-system description object |
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* @lnum: logical eraseblock number |
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* @offs: offset to start at (usually zero) |
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* @sbuf: scan buffer (must be c->leb_size) |
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* |
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* This function returns the scanned information on success and a negative error |
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* code on failure. |
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*/ |
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struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum, |
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int offs, void *sbuf) |
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{ |
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struct ubifs_scan_leb *sleb; |
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int err; |
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dbg_scan("scan LEB %d:%d", lnum, offs); |
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sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS); |
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if (!sleb) |
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return ERR_PTR(-ENOMEM); |
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sleb->lnum = lnum; |
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INIT_LIST_HEAD(&sleb->nodes); |
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sleb->buf = sbuf; |
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err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0); |
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if (err && err != -EBADMSG) { |
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ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d", |
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c->leb_size - offs, lnum, offs, err); |
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kfree(sleb); |
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return ERR_PTR(err); |
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} |
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/* |
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* Note, we ignore integrity errors (EBASMSG) because all the nodes are |
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* protected by CRC checksums. |
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*/ |
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return sleb; |
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} |
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/** |
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* ubifs_end_scan - update LEB scanning information at end of scan. |
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* @c: UBIFS file-system description object |
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* @sleb: scanning information |
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* @lnum: logical eraseblock number |
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* @offs: offset to start at (usually zero) |
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*/ |
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void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb, |
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int lnum, int offs) |
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{ |
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dbg_scan("stop scanning LEB %d at offset %d", lnum, offs); |
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ubifs_assert(c, offs % c->min_io_size == 0); |
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sleb->endpt = ALIGN(offs, c->min_io_size); |
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} |
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/** |
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* ubifs_add_snod - add a scanned node to LEB scanning information. |
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* @c: UBIFS file-system description object |
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* @sleb: scanning information |
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* @buf: buffer containing node |
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* @offs: offset of node on flash |
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* |
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* This function returns %0 on success and a negative error code on failure. |
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*/ |
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int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb, |
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void *buf, int offs) |
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{ |
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struct ubifs_ch *ch = buf; |
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struct ubifs_ino_node *ino = buf; |
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struct ubifs_scan_node *snod; |
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snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS); |
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if (!snod) |
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return -ENOMEM; |
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snod->sqnum = le64_to_cpu(ch->sqnum); |
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snod->type = ch->node_type; |
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snod->offs = offs; |
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snod->len = le32_to_cpu(ch->len); |
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snod->node = buf; |
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switch (ch->node_type) { |
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case UBIFS_INO_NODE: |
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case UBIFS_DENT_NODE: |
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case UBIFS_XENT_NODE: |
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case UBIFS_DATA_NODE: |
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/* |
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* The key is in the same place in all keyed |
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* nodes. |
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*/ |
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key_read(c, &ino->key, &snod->key); |
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break; |
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default: |
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invalid_key_init(c, &snod->key); |
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break; |
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} |
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list_add_tail(&snod->list, &sleb->nodes); |
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sleb->nodes_cnt += 1; |
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return 0; |
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} |
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/** |
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* ubifs_scanned_corruption - print information after UBIFS scanned corruption. |
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* @c: UBIFS file-system description object |
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* @lnum: LEB number of corruption |
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* @offs: offset of corruption |
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* @buf: buffer containing corruption |
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*/ |
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void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs, |
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void *buf) |
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{ |
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int len; |
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ubifs_err(c, "corruption at LEB %d:%d", lnum, offs); |
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len = c->leb_size - offs; |
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if (len > 8192) |
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len = 8192; |
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ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs); |
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print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1); |
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} |
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/** |
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* ubifs_scan - scan a logical eraseblock. |
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* @c: UBIFS file-system description object |
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* @lnum: logical eraseblock number |
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* @offs: offset to start at (usually zero) |
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* @sbuf: scan buffer (must be of @c->leb_size bytes in size) |
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* @quiet: print no messages |
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* |
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* This function scans LEB number @lnum and returns complete information about |
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* its contents. Returns the scanned information in case of success and, |
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* %-EUCLEAN if the LEB neads recovery, and other negative error codes in case |
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* of failure. |
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* |
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* If @quiet is non-zero, this function does not print large and scary |
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* error messages and flash dumps in case of errors. |
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*/ |
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struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum, |
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int offs, void *sbuf, int quiet) |
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{ |
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void *buf = sbuf + offs; |
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int err, len = c->leb_size - offs; |
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struct ubifs_scan_leb *sleb; |
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sleb = ubifs_start_scan(c, lnum, offs, sbuf); |
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if (IS_ERR(sleb)) |
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return sleb; |
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while (len >= 8) { |
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struct ubifs_ch *ch = buf; |
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int node_len, ret; |
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dbg_scan("look at LEB %d:%d (%d bytes left)", |
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lnum, offs, len); |
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cond_resched(); |
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ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet); |
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if (ret > 0) { |
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/* Padding bytes or a valid padding node */ |
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offs += ret; |
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buf += ret; |
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len -= ret; |
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continue; |
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} |
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if (ret == SCANNED_EMPTY_SPACE) |
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/* Empty space is checked later */ |
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break; |
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switch (ret) { |
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case SCANNED_GARBAGE: |
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ubifs_err(c, "garbage"); |
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goto corrupted; |
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case SCANNED_A_NODE: |
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break; |
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case SCANNED_A_CORRUPT_NODE: |
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case SCANNED_A_BAD_PAD_NODE: |
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ubifs_err(c, "bad node"); |
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goto corrupted; |
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default: |
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ubifs_err(c, "unknown"); |
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err = -EINVAL; |
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goto error; |
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} |
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err = ubifs_add_snod(c, sleb, buf, offs); |
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if (err) |
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goto error; |
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node_len = ALIGN(le32_to_cpu(ch->len), 8); |
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offs += node_len; |
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buf += node_len; |
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len -= node_len; |
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} |
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if (offs % c->min_io_size) { |
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if (!quiet) |
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ubifs_err(c, "empty space starts at non-aligned offset %d", |
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offs); |
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goto corrupted; |
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} |
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ubifs_end_scan(c, sleb, lnum, offs); |
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for (; len > 4; offs += 4, buf = buf + 4, len -= 4) |
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if (*(uint32_t *)buf != 0xffffffff) |
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break; |
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for (; len; offs++, buf++, len--) |
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if (*(uint8_t *)buf != 0xff) { |
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if (!quiet) |
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ubifs_err(c, "corrupt empty space at LEB %d:%d", |
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lnum, offs); |
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goto corrupted; |
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} |
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return sleb; |
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corrupted: |
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if (!quiet) { |
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ubifs_scanned_corruption(c, lnum, offs, buf); |
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ubifs_err(c, "LEB %d scanning failed", lnum); |
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} |
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err = -EUCLEAN; |
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ubifs_scan_destroy(sleb); |
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return ERR_PTR(err); |
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error: |
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ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err); |
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ubifs_scan_destroy(sleb); |
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return ERR_PTR(err); |
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} |
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/** |
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* ubifs_scan_destroy - destroy LEB scanning information. |
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* @sleb: scanning information to free |
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*/ |
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void ubifs_scan_destroy(struct ubifs_scan_leb *sleb) |
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{ |
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struct ubifs_scan_node *node; |
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struct list_head *head; |
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head = &sleb->nodes; |
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while (!list_empty(head)) { |
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node = list_entry(head->next, struct ubifs_scan_node, list); |
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list_del(&node->list); |
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kfree(node); |
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} |
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kfree(sleb); |
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}
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