UBIFS: Implement read-only UBIFS support in U-Boot
The U-Boot UBIFS implementation is largely a direct copy from the current
Linux version (2.6.29-rc6). As already done in the UBI version we have an
"abstraction layer" to redefine or remove some OS calls (e.g. mutex_lock()
...). This makes it possible to use the original Linux code with very
little changes. And by this we can better update to later Linux versions.
I removed some of the Linux features that are not used in the U-Boot
version (e.g. garbage-collection, write support).
Signed-off-by: Stefan Roese <sr@denx.de>
CC: Artem Bityutskiy <dedekind@infradead.org>
CC: Adrian Hunter <ext-Adrian.Hunter@nokia.com>
diff --git a/fs/ubifs/misc.h b/fs/ubifs/misc.h
new file mode 100644
index 0000000..b745d86
--- /dev/null
+++ b/fs/ubifs/misc.h
@@ -0,0 +1,310 @@
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * 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
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ * Adrian Hunter
+ */
+
+/*
+ * This file contains miscellaneous helper functions.
+ */
+
+#ifndef __UBIFS_MISC_H__
+#define __UBIFS_MISC_H__
+
+/**
+ * ubifs_zn_dirty - check if znode is dirty.
+ * @znode: znode to check
+ *
+ * This helper function returns %1 if @znode is dirty and %0 otherwise.
+ */
+static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
+{
+ return !!test_bit(DIRTY_ZNODE, &znode->flags);
+}
+
+/**
+ * ubifs_wake_up_bgt - wake up background thread.
+ * @c: UBIFS file-system description object
+ */
+static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
+{
+ if (c->bgt && !c->need_bgt) {
+ c->need_bgt = 1;
+ wake_up_process(c->bgt);
+ }
+}
+
+/**
+ * ubifs_tnc_find_child - find next child in znode.
+ * @znode: znode to search at
+ * @start: the zbranch index to start at
+ *
+ * This helper function looks for znode child starting at index @start. Returns
+ * the child or %NULL if no children were found.
+ */
+static inline struct ubifs_znode *
+ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
+{
+ while (start < znode->child_cnt) {
+ if (znode->zbranch[start].znode)
+ return znode->zbranch[start].znode;
+ start += 1;
+ }
+
+ return NULL;
+}
+
+/**
+ * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
+ * @inode: the VFS 'struct inode' pointer
+ */
+static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
+{
+ return container_of(inode, struct ubifs_inode, vfs_inode);
+}
+
+/**
+ * ubifs_compr_present - check if compressor was compiled in.
+ * @compr_type: compressor type to check
+ *
+ * This function returns %1 of compressor of type @compr_type is present, and
+ * %0 if not.
+ */
+static inline int ubifs_compr_present(int compr_type)
+{
+ ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
+ return !!ubifs_compressors[compr_type]->capi_name;
+}
+
+/**
+ * ubifs_compr_name - get compressor name string by its type.
+ * @compr_type: compressor type
+ *
+ * This function returns compressor type string.
+ */
+static inline const char *ubifs_compr_name(int compr_type)
+{
+ ubifs_assert(compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
+ return ubifs_compressors[compr_type]->name;
+}
+
+/**
+ * ubifs_wbuf_sync - synchronize write-buffer.
+ * @wbuf: write-buffer to synchronize
+ *
+ * This is the same as as 'ubifs_wbuf_sync_nolock()' but it does not assume
+ * that the write-buffer is already locked.
+ */
+static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
+{
+ int err;
+
+ mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+ err = ubifs_wbuf_sync_nolock(wbuf);
+ mutex_unlock(&wbuf->io_mutex);
+ return err;
+}
+
+/**
+ * ubifs_leb_unmap - unmap an LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to unmap
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static inline int ubifs_leb_unmap(const struct ubifs_info *c, int lnum)
+{
+ int err;
+
+ if (c->ro_media)
+ return -EROFS;
+ err = ubi_leb_unmap(c->ubi, lnum);
+ if (err) {
+ ubifs_err("unmap LEB %d failed, error %d", lnum, err);
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * ubifs_leb_write - write to a LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to write
+ * @buf: buffer to write from
+ * @offs: offset within LEB to write to
+ * @len: length to write
+ * @dtype: data type
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static inline int ubifs_leb_write(const struct ubifs_info *c, int lnum,
+ const void *buf, int offs, int len, int dtype)
+{
+ int err;
+
+ if (c->ro_media)
+ return -EROFS;
+ err = ubi_leb_write(c->ubi, lnum, buf, offs, len, dtype);
+ if (err) {
+ ubifs_err("writing %d bytes at %d:%d, error %d",
+ len, lnum, offs, err);
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * ubifs_leb_change - atomic LEB change.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to write
+ * @buf: buffer to write from
+ * @len: length to write
+ * @dtype: data type
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static inline int ubifs_leb_change(const struct ubifs_info *c, int lnum,
+ const void *buf, int len, int dtype)
+{
+ int err;
+
+ if (c->ro_media)
+ return -EROFS;
+ err = ubi_leb_change(c->ubi, lnum, buf, len, dtype);
+ if (err) {
+ ubifs_err("changing %d bytes in LEB %d, error %d",
+ len, lnum, err);
+ return err;
+ }
+
+ return 0;
+}
+
+/**
+ * ubifs_add_dirt - add dirty space to LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to add dirty space for
+ * @dirty: dirty space to add
+ *
+ * This is a helper function which increased amount of dirty LEB space. Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
+{
+ return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
+}
+
+/**
+ * ubifs_return_leb - return LEB to lprops.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to return
+ *
+ * This helper function cleans the "taken" flag of a logical eraseblock in the
+ * lprops. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
+{
+ return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+ LPROPS_TAKEN, 0);
+}
+
+/**
+ * ubifs_idx_node_sz - return index node size.
+ * @c: the UBIFS file-system description object
+ * @child_cnt: number of children of this index node
+ */
+static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
+{
+ return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len) * child_cnt;
+}
+
+/**
+ * ubifs_idx_branch - return pointer to an index branch.
+ * @c: the UBIFS file-system description object
+ * @idx: index node
+ * @bnum: branch number
+ */
+static inline
+struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
+ const struct ubifs_idx_node *idx,
+ int bnum)
+{
+ return (struct ubifs_branch *)((void *)idx->branches +
+ (UBIFS_BRANCH_SZ + c->key_len) * bnum);
+}
+
+/**
+ * ubifs_idx_key - return pointer to an index key.
+ * @c: the UBIFS file-system description object
+ * @idx: index node
+ */
+static inline void *ubifs_idx_key(const struct ubifs_info *c,
+ const struct ubifs_idx_node *idx)
+{
+ return (void *)((struct ubifs_branch *)idx->branches)->key;
+}
+
+/**
+ * ubifs_tnc_lookup - look up a file-system node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ *
+ * This function look up and reads node with key @key. The caller has to make
+ * sure the @node buffer is large enough to fit the node. Returns zero in case
+ * of success, %-ENOENT if the node was not found, and a negative error code in
+ * case of failure.
+ */
+static inline int ubifs_tnc_lookup(struct ubifs_info *c,
+ const union ubifs_key *key, void *node)
+{
+ return ubifs_tnc_locate(c, key, node, NULL, NULL);
+}
+
+/**
+ * ubifs_get_lprops - get reference to LEB properties.
+ * @c: the UBIFS file-system description object
+ *
+ * This function locks lprops. Lprops have to be unlocked by
+ * 'ubifs_release_lprops()'.
+ */
+static inline void ubifs_get_lprops(struct ubifs_info *c)
+{
+ mutex_lock(&c->lp_mutex);
+}
+
+/**
+ * ubifs_release_lprops - release lprops lock.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called after each 'ubifs_get_lprops()' call to
+ * unlock lprops.
+ */
+static inline void ubifs_release_lprops(struct ubifs_info *c)
+{
+ ubifs_assert(mutex_is_locked(&c->lp_mutex));
+ ubifs_assert(c->lst.empty_lebs >= 0 &&
+ c->lst.empty_lebs <= c->main_lebs);
+ mutex_unlock(&c->lp_mutex);
+}
+
+#endif /* __UBIFS_MISC_H__ */