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-rw-r--r--fs/ubifs/tnc.c283
1 files changed, 283 insertions, 0 deletions
diff --git a/fs/ubifs/tnc.c b/fs/ubifs/tnc.c
index ba13c92fdf6..d279012d8dd 100644
--- a/fs/ubifs/tnc.c
+++ b/fs/ubifs/tnc.c
@@ -1492,6 +1492,289 @@ out:
}
/**
+ * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
+ * @c: UBIFS file-system description object
+ * @bu: bulk-read parameters and results
+ *
+ * Lookup consecutive data node keys for the same inode that reside
+ * consecutively in the same LEB.
+ */
+int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
+{
+ int n, err = 0, lnum = -1, uninitialized_var(offs);
+ int uninitialized_var(len);
+ unsigned int block = key_block(c, &bu->key);
+ struct ubifs_znode *znode;
+
+ bu->cnt = 0;
+ bu->blk_cnt = 0;
+ bu->eof = 0;
+
+ mutex_lock(&c->tnc_mutex);
+ /* Find first key */
+ err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
+ if (err < 0)
+ goto out;
+ if (err) {
+ /* Key found */
+ len = znode->zbranch[n].len;
+ /* The buffer must be big enough for at least 1 node */
+ if (len > bu->buf_len) {
+ err = -EINVAL;
+ goto out;
+ }
+ /* Add this key */
+ bu->zbranch[bu->cnt++] = znode->zbranch[n];
+ bu->blk_cnt += 1;
+ lnum = znode->zbranch[n].lnum;
+ offs = ALIGN(znode->zbranch[n].offs + len, 8);
+ }
+ while (1) {
+ struct ubifs_zbranch *zbr;
+ union ubifs_key *key;
+ unsigned int next_block;
+
+ /* Find next key */
+ err = tnc_next(c, &znode, &n);
+ if (err)
+ goto out;
+ zbr = &znode->zbranch[n];
+ key = &zbr->key;
+ /* See if there is another data key for this file */
+ if (key_inum(c, key) != key_inum(c, &bu->key) ||
+ key_type(c, key) != UBIFS_DATA_KEY) {
+ err = -ENOENT;
+ goto out;
+ }
+ if (lnum < 0) {
+ /* First key found */
+ lnum = zbr->lnum;
+ offs = ALIGN(zbr->offs + zbr->len, 8);
+ len = zbr->len;
+ if (len > bu->buf_len) {
+ err = -EINVAL;
+ goto out;
+ }
+ } else {
+ /*
+ * The data nodes must be in consecutive positions in
+ * the same LEB.
+ */
+ if (zbr->lnum != lnum || zbr->offs != offs)
+ goto out;
+ offs += ALIGN(zbr->len, 8);
+ len = ALIGN(len, 8) + zbr->len;
+ /* Must not exceed buffer length */
+ if (len > bu->buf_len)
+ goto out;
+ }
+ /* Allow for holes */
+ next_block = key_block(c, key);
+ bu->blk_cnt += (next_block - block - 1);
+ if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
+ goto out;
+ block = next_block;
+ /* Add this key */
+ bu->zbranch[bu->cnt++] = *zbr;
+ bu->blk_cnt += 1;
+ /* See if we have room for more */
+ if (bu->cnt >= UBIFS_MAX_BULK_READ)
+ goto out;
+ if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
+ goto out;
+ }
+out:
+ if (err == -ENOENT) {
+ bu->eof = 1;
+ err = 0;
+ }
+ bu->gc_seq = c->gc_seq;
+ mutex_unlock(&c->tnc_mutex);
+ if (err)
+ return err;
+ /*
+ * An enormous hole could cause bulk-read to encompass too many
+ * page cache pages, so limit the number here.
+ */
+ if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
+ bu->blk_cnt = UBIFS_MAX_BULK_READ;
+ /*
+ * Ensure that bulk-read covers a whole number of page cache
+ * pages.
+ */
+ if (UBIFS_BLOCKS_PER_PAGE == 1 ||
+ !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
+ return 0;
+ if (bu->eof) {
+ /* At the end of file we can round up */
+ bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
+ return 0;
+ }
+ /* Exclude data nodes that do not make up a whole page cache page */
+ block = key_block(c, &bu->key) + bu->blk_cnt;
+ block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
+ while (bu->cnt) {
+ if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
+ break;
+ bu->cnt -= 1;
+ }
+ return 0;
+}
+
+/**
+ * read_wbuf - bulk-read from a LEB with a wbuf.
+ * @wbuf: wbuf that may overlap the read
+ * @buf: buffer into which to read
+ * @len: read length
+ * @lnum: LEB number from which to read
+ * @offs: offset from which to read
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
+ int offs)
+{
+ const struct ubifs_info *c = wbuf->c;
+ int rlen, overlap;
+
+ dbg_io("LEB %d:%d, length %d", lnum, offs, len);
+ ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+ ubifs_assert(!(offs & 7) && offs < c->leb_size);
+ ubifs_assert(offs + len <= c->leb_size);
+
+ spin_lock(&wbuf->lock);
+ overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
+ if (!overlap) {
+ /* We may safely unlock the write-buffer and read the data */
+ spin_unlock(&wbuf->lock);
+ return ubi_read(c->ubi, lnum, buf, offs, len);
+ }
+
+ /* Don't read under wbuf */
+ rlen = wbuf->offs - offs;
+ if (rlen < 0)
+ rlen = 0;
+
+ /* Copy the rest from the write-buffer */
+ memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
+ spin_unlock(&wbuf->lock);
+
+ if (rlen > 0)
+ /* Read everything that goes before write-buffer */
+ return ubi_read(c->ubi, lnum, buf, offs, rlen);
+
+ return 0;
+}
+
+/**
+ * validate_data_node - validate data nodes for bulk-read.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing data node to validate
+ * @zbr: zbranch of data node to validate
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int validate_data_node(struct ubifs_info *c, void *buf,
+ struct ubifs_zbranch *zbr)
+{
+ union ubifs_key key1;
+ struct ubifs_ch *ch = buf;
+ int err, len;
+
+ if (ch->node_type != UBIFS_DATA_NODE) {
+ ubifs_err("bad node type (%d but expected %d)",
+ ch->node_type, UBIFS_DATA_NODE);
+ goto out_err;
+ }
+
+ err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0);
+ if (err) {
+ ubifs_err("expected node type %d", UBIFS_DATA_NODE);
+ goto out;
+ }
+
+ len = le32_to_cpu(ch->len);
+ if (len != zbr->len) {
+ ubifs_err("bad node length %d, expected %d", len, zbr->len);
+ goto out_err;
+ }
+
+ /* Make sure the key of the read node is correct */
+ key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
+ if (!keys_eq(c, &zbr->key, &key1)) {
+ ubifs_err("bad key in node at LEB %d:%d",
+ zbr->lnum, zbr->offs);
+ dbg_tnc("looked for key %s found node's key %s",
+ DBGKEY(&zbr->key), DBGKEY1(&key1));
+ goto out_err;
+ }
+
+ return 0;
+
+out_err:
+ err = -EINVAL;
+out:
+ ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
+ dbg_dump_node(c, buf);
+ dbg_dump_stack();
+ return err;
+}
+
+/**
+ * ubifs_tnc_bulk_read - read a number of data nodes in one go.
+ * @c: UBIFS file-system description object
+ * @bu: bulk-read parameters and results
+ *
+ * This functions reads and validates the data nodes that were identified by the
+ * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
+ * -EAGAIN to indicate a race with GC, or another negative error code on
+ * failure.
+ */
+int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
+{
+ int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
+ struct ubifs_wbuf *wbuf;
+ void *buf;
+
+ len = bu->zbranch[bu->cnt - 1].offs;
+ len += bu->zbranch[bu->cnt - 1].len - offs;
+ if (len > bu->buf_len) {
+ ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
+ return -EINVAL;
+ }
+
+ /* Do the read */
+ wbuf = ubifs_get_wbuf(c, lnum);
+ if (wbuf)
+ err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
+ else
+ err = ubi_read(c->ubi, lnum, bu->buf, offs, len);
+
+ /* Check for a race with GC */
+ if (maybe_leb_gced(c, lnum, bu->gc_seq))
+ return -EAGAIN;
+
+ if (err && err != -EBADMSG) {
+ ubifs_err("failed to read from LEB %d:%d, error %d",
+ lnum, offs, err);
+ dbg_dump_stack();
+ dbg_tnc("key %s", DBGKEY(&bu->key));
+ return err;
+ }
+
+ /* Validate the nodes read */
+ buf = bu->buf;
+ for (i = 0; i < bu->cnt; i++) {
+ err = validate_data_node(c, buf, &bu->zbranch[i]);
+ if (err)
+ return err;
+ buf = buf + ALIGN(bu->zbranch[i].len, 8);
+ }
+
+ return 0;
+}
+
+/**
* do_lookup_nm- look up a "hashed" node.
* @c: UBIFS file-system description object
* @key: node key to lookup
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-28 06:34:12 +0000