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-rw-r--r--fs/efs/dir.c103
1 files changed, 103 insertions, 0 deletions
diff --git a/fs/efs/dir.c b/fs/efs/dir.c
new file mode 100644
index 0000000000..f892ac7c2a
--- /dev/null
+++ b/fs/efs/dir.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * dir.c
+ *
+ * Copyright (c) 1999 Al Smith
+ */
+
+#include <linux/buffer_head.h>
+#include "efs.h"
+
+static int efs_readdir(struct file *, struct dir_context *);
+
+const struct file_operations efs_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate_shared = efs_readdir,
+};
+
+const struct inode_operations efs_dir_inode_operations = {
+ .lookup = efs_lookup,
+};
+
+static int efs_readdir(struct file *file, struct dir_context *ctx)
+{
+ struct inode *inode = file_inode(file);
+ efs_block_t block;
+ int slot;
+
+ if (inode->i_size & (EFS_DIRBSIZE-1))
+ pr_warn("%s(): directory size not a multiple of EFS_DIRBSIZE\n",
+ __func__);
+
+ /* work out where this entry can be found */
+ block = ctx->pos >> EFS_DIRBSIZE_BITS;
+
+ /* each block contains at most 256 slots */
+ slot = ctx->pos & 0xff;
+
+ /* look at all blocks */
+ while (block < inode->i_blocks) {
+ struct efs_dir *dirblock;
+ struct buffer_head *bh;
+
+ /* read the dir block */
+ bh = sb_bread(inode->i_sb, efs_bmap(inode, block));
+
+ if (!bh) {
+ pr_err("%s(): failed to read dir block %d\n",
+ __func__, block);
+ break;
+ }
+
+ dirblock = (struct efs_dir *) bh->b_data;
+
+ if (be16_to_cpu(dirblock->magic) != EFS_DIRBLK_MAGIC) {
+ pr_err("%s(): invalid directory block\n", __func__);
+ brelse(bh);
+ break;
+ }
+
+ for (; slot < dirblock->slots; slot++) {
+ struct efs_dentry *dirslot;
+ efs_ino_t inodenum;
+ const char *nameptr;
+ int namelen;
+
+ if (dirblock->space[slot] == 0)
+ continue;
+
+ dirslot = (struct efs_dentry *) (((char *) bh->b_data) + EFS_SLOTAT(dirblock, slot));
+
+ inodenum = be32_to_cpu(dirslot->inode);
+ namelen = dirslot->namelen;
+ nameptr = dirslot->name;
+ pr_debug("%s(): block %d slot %d/%d: inode %u, name \"%s\", namelen %u\n",
+ __func__, block, slot, dirblock->slots-1,
+ inodenum, nameptr, namelen);
+ if (!namelen)
+ continue;
+ /* found the next entry */
+ ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
+
+ /* sanity check */
+ if (nameptr - (char *) dirblock + namelen > EFS_DIRBSIZE) {
+ pr_warn("directory entry %d exceeds directory block\n",
+ slot);
+ continue;
+ }
+
+ /* copy filename and data in dirslot */
+ if (!dir_emit(ctx, nameptr, namelen, inodenum, DT_UNKNOWN)) {
+ brelse(bh);
+ return 0;
+ }
+ }
+ brelse(bh);
+
+ slot = 0;
+ block++;
+ }
+ ctx->pos = (block << EFS_DIRBSIZE_BITS) | slot;
+ return 0;
+}