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Message-ID: <20240607042615.2069840-68-chengzhihao1@huawei.com>
Date: Fri, 7 Jun 2024 12:25:32 +0800
From: Zhihao Cheng <chengzhihao1@...wei.com>
To: <richard@....at>, <david.oberhollenzer@...ma-star.at>,
<miquel.raynal@...tlin.com>, <yi.zhang@...wei.com>, <xiangyang3@...wei.com>,
<huangxiaojia2@...wei.com>
CC: <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: [RFC PATCH mtd-utils 067/110] fsck.ubifs: rebuild_fs: Extract reachable directory entries tree
This is the 5/12 step of rebuilding. Extract reachable directory entries
tree. Make sure that all files can be searched from '/', unreachable
file is deleted. So, all files can be accessible in userspace after
reparing.
Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
---
ubifs-utils/fsck.ubifs/extract_files.c | 94 ++++++++++++++++++++++++++++++++++
ubifs-utils/fsck.ubifs/fsck.ubifs.h | 6 +++
ubifs-utils/fsck.ubifs/rebuild_fs.c | 44 ++++++++++++++++
3 files changed, 144 insertions(+)
diff --git a/ubifs-utils/fsck.ubifs/extract_files.c b/ubifs-utils/fsck.ubifs/extract_files.c
index 772e3003..dd5cb310 100644
--- a/ubifs-utils/fsck.ubifs/extract_files.c
+++ b/ubifs-utils/fsck.ubifs/extract_files.c
@@ -525,6 +525,7 @@ static int update_file(struct ubifs_info *c, struct scanned_file *file,
{
struct scanned_dent_node *dent = (struct scanned_dent_node *)sn;
+ dent->file = file;
err = insert_file_dentry(file, dent);
break;
}
@@ -888,3 +889,96 @@ check_dent_node:
return true;
}
+
+static bool dentry_is_reachable(struct ubifs_info *c,
+ struct scanned_dent_node *dent_node,
+ struct list_head *path_list,
+ struct rb_root *file_tree)
+{
+ struct scanned_file *parent_file = NULL;
+ struct scanned_dent_node *dn, *parent_dent;
+ struct rb_node *p;
+
+ /* Check whether the path is cyclical. */
+ list_for_each_entry(dn, path_list, list) {
+ if (dn == dent_node)
+ return false;
+ }
+
+ /* Quick path, dentry has already been checked as reachable. */
+ if (dent_node->can_be_found)
+ return true;
+
+ dent_node->can_be_found = true;
+ list_add(&dent_node->list, path_list);
+
+ parent_file = lookup_file(file_tree, key_inum(c, &dent_node->key));
+ /* Parent dentry is not found, unreachable. */
+ if (!parent_file)
+ return false;
+
+ /* Parent dentry is '/', reachable. */
+ if (parent_file->inum == UBIFS_ROOT_INO)
+ return true;
+
+ p = rb_first(&parent_file->dent_nodes);
+ if (!p)
+ return false;
+ parent_dent = rb_entry(p, struct scanned_dent_node, rb);
+
+ return dentry_is_reachable(c, parent_dent, path_list, file_tree);
+}
+
+/**
+ * file_is_reachable - whether the file can be found from '/'.
+ * @c: UBIFS file-system description object
+ * @file: file object
+ * @file_tree: tree of all scanned files
+ *
+ * This function iterates all directory entries in given @file and checks
+ * whether each dentry is reachable. All unreachable directory entries will
+ * be removed.
+ */
+bool file_is_reachable(struct ubifs_info *c, struct scanned_file *file,
+ struct rb_root *file_tree)
+{
+ struct rb_node *node;
+ struct scanned_dent_node *dent_node;
+
+ if (file->inum == UBIFS_ROOT_INO)
+ goto reachable;
+
+retry:
+ for (node = rb_first(&file->dent_nodes); node; node = rb_next(node)) {
+ LIST_HEAD(path_list);
+
+ dent_node = rb_entry(node, struct scanned_dent_node, rb);
+
+ if (dentry_is_reachable(c, dent_node, &path_list, file_tree))
+ continue;
+
+ while (!list_empty(&path_list)) {
+ dent_node = list_entry(path_list.next,
+ struct scanned_dent_node, list);
+
+ dbg_fsck("remove unreachable dentry %s, in %s",
+ c->encrypted && !file->ino.is_xattr ?
+ "<encrypted>" : dent_node->name, c->dev_name);
+ list_del(&dent_node->list);
+ rb_erase(&dent_node->rb, &dent_node->file->dent_nodes);
+ kfree(dent_node);
+ }
+
+ /* Since dentry node is removed from rb-tree, rescan rb-tree. */
+ goto retry;
+ }
+
+ if (!rb_first(&file->dent_nodes)) {
+ dbg_fsck("file %lu is unreachable, in %s", file->inum, c->dev_name);
+ return false;
+ }
+
+reachable:
+ dbg_fsck("file %lu is reachable, in %s", file->inum, c->dev_name);
+ return true;
+}
diff --git a/ubifs-utils/fsck.ubifs/fsck.ubifs.h b/ubifs-utils/fsck.ubifs/fsck.ubifs.h
index 3885d138..d378a06c 100644
--- a/ubifs-utils/fsck.ubifs/fsck.ubifs.h
+++ b/ubifs-utils/fsck.ubifs/fsck.ubifs.h
@@ -39,6 +39,8 @@ enum { NORMAL_MODE = 0, SAFE_MODE, DANGER_MODE0,
/* Types of inconsistent problems */
enum { SB_CORRUPTED = 0 };
+struct scanned_file;
+
/**
* scanned_node - common header node.
* @exist: whether the node is found by scanning
@@ -92,6 +94,7 @@ struct scanned_ino_node {
* @nlen: name length
* @name: dentry name
* @inum: target inode number
+ * @file: corresponding file
* @rb: link in the trees of:
* 1) valid dentry nodes or deleted dentry node
* 2) all scanned dentry nodes from same file
@@ -105,6 +108,7 @@ struct scanned_dent_node {
unsigned int nlen;
char name[UBIFS_MAX_NLEN + 1];
ino_t inum;
+ struct scanned_file *file;
struct rb_node rb;
struct list_head list;
};
@@ -266,6 +270,8 @@ void destroy_file_tree(struct ubifs_info *c, struct rb_root *file_tree);
struct scanned_file *lookup_file(struct rb_root *file_tree, ino_t inum);
bool file_is_valid(struct ubifs_info *c, struct scanned_file *file,
struct rb_root *file_tree);
+bool file_is_reachable(struct ubifs_info *c, struct scanned_file *file,
+ struct rb_root *file_tree);
/* rebuild_fs.c */
int ubifs_rebuild_filesystem(struct ubifs_info *c);
diff --git a/ubifs-utils/fsck.ubifs/rebuild_fs.c b/ubifs-utils/fsck.ubifs/rebuild_fs.c
index 31f1b3ba..669b61d1 100644
--- a/ubifs-utils/fsck.ubifs/rebuild_fs.c
+++ b/ubifs-utils/fsck.ubifs/rebuild_fs.c
@@ -588,6 +588,46 @@ static void filter_invalid_files(struct ubifs_info *c)
}
/**
+ * extract_dentry_tree - extract reachable directory entries.
+ * @c: UBIFS file-system description object
+ *
+ * This function iterates all directory entries and remove those
+ * unreachable ones. 'Unreachable' means that a directory entry can
+ * not be searched from '/'.
+ */
+static void extract_dentry_tree(struct ubifs_info *c)
+{
+ struct rb_node *node;
+ struct scanned_file *file;
+ struct rb_root *tree = &FSCK(c)->rebuild->scanned_files;
+ LIST_HEAD(unreachable);
+
+ for (node = rb_first(tree); node; node = rb_next(node)) {
+ file = rb_entry(node, struct scanned_file, rb);
+
+ /*
+ * Since all xattr files are already attached to corresponding
+ * host file, there are only non-xattr files in the file tree.
+ */
+ ubifs_assert(c, !file->ino.is_xattr);
+ if (!file_is_reachable(c, file, tree))
+ list_add(&file->list, &unreachable);
+ }
+
+ /* Remove unreachable files. */
+ while (!list_empty(&unreachable)) {
+ file = list_entry(unreachable.next, struct scanned_file, list);
+
+ dbg_fsck("remove unreachable file %lu, in %s",
+ file->inum, c->dev_name);
+ list_del(&file->list);
+ destroy_file_content(c, file);
+ rb_erase(&file->rb, tree);
+ kfree(file);
+ }
+}
+
+/**
* ubifs_rebuild_filesystem - Rebuild filesystem.
* @c: UBIFS file-system description object
*
@@ -633,6 +673,10 @@ int ubifs_rebuild_filesystem(struct ubifs_info *c)
log_out(c, "Filter invalid files");
filter_invalid_files(c);
+ /* Step 5: Extract reachable directory entries. */
+ log_out(c, "Extract reachable files");
+ extract_dentry_tree(c);
+
out:
destroy_scanned_info(c, &si);
destroy_rebuild_info(c);
--
2.13.6
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