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Subject[RFC v2 48/83] Dir: Readdir operation.
Date
From: Andiry Xu <jix024@cs.ucsd.edu>

NOVA reads the directory by traversing the log and reports
the valid dentries. Valid dentris have inode number greater than zero,
meaning it's a create dentry.

Signed-off-by: Andiry Xu <jix024@cs.ucsd.edu>
---
fs/nova/dir.c | 153 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/nova/inode.c | 2 +
fs/nova/nova.h | 1 +
3 files changed, 156 insertions(+)

diff --git a/fs/nova/dir.c b/fs/nova/dir.c
index 377d2da..35a66f9 100644
--- a/fs/nova/dir.c
+++ b/fs/nova/dir.c
@@ -221,3 +221,156 @@ int nova_append_dir_init_entries(struct super_block *sb,

return 0;
}
+
+static u64 nova_find_next_dentry_addr(struct super_block *sb,
+ struct nova_inode_info_header *sih, u64 pos)
+{
+ struct nova_sb_info *sbi = NOVA_SB(sb);
+ struct nova_file_write_entry *entry = NULL;
+ struct nova_file_write_entry *entries[1];
+ int nr_entries;
+ u64 addr = 0;
+
+ nr_entries = radix_tree_gang_lookup(&sih->tree,
+ (void **)entries, pos, 1);
+ if (nr_entries == 1) {
+ entry = entries[0];
+ addr = nova_get_addr_off(sbi, entry);
+ }
+
+ return addr;
+}
+
+static int nova_readdir(struct file *file, struct dir_context *ctx)
+{
+ struct inode *inode = file_inode(file);
+ struct super_block *sb = inode->i_sb;
+ struct nova_inode *pidir;
+ struct nova_inode_info *si = NOVA_I(inode);
+ struct nova_inode_info_header *sih = &si->header;
+ struct nova_inode *child_pi;
+ struct nova_inode *prev_child_pi = NULL;
+ struct nova_dentry *entry = NULL;
+ struct nova_dentry *prev_entry = NULL;
+ unsigned short de_len;
+ u64 pi_addr;
+ unsigned long pos = 0;
+ ino_t ino;
+ void *addr;
+ u64 curr_p;
+ u8 type;
+ int ret = 0;
+ timing_t readdir_time;
+
+ NOVA_START_TIMING(readdir_t, readdir_time);
+ pidir = nova_get_inode(sb, inode);
+ nova_dbgv("%s: ino %llu, size %llu, pos 0x%llx\n",
+ __func__, (u64)inode->i_ino,
+ pidir->i_size, ctx->pos);
+
+ if (sih->log_head == 0) {
+ nova_err(sb, "Dir %lu log is NULL!\n", inode->i_ino);
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ pos = ctx->pos;
+
+ if (pos == 0)
+ curr_p = sih->log_head;
+ else if (pos == READDIR_END)
+ goto out;
+ else {
+ curr_p = nova_find_next_dentry_addr(sb, sih, pos);
+ if (curr_p == 0)
+ goto out;
+ }
+
+ while (curr_p != sih->log_tail) {
+ if (goto_next_page(sb, curr_p))
+ curr_p = next_log_page(sb, curr_p);
+
+
+ if (curr_p == 0) {
+ nova_err(sb, "Dir %lu log is NULL!\n", inode->i_ino);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ addr = (void *)nova_get_block(sb, curr_p);
+ type = nova_get_entry_type(addr);
+ switch (type) {
+ case SET_ATTR:
+ curr_p += sizeof(struct nova_setattr_logentry);
+ continue;
+ case LINK_CHANGE:
+ curr_p += sizeof(struct nova_link_change_entry);
+ continue;
+ case DIR_LOG:
+ break;
+ default:
+ nova_err(sb, "%s: unknown type %d, 0x%llx\n",
+ __func__, type, curr_p);
+ ret = -EINVAL;
+ goto out;
+ }
+
+ entry = (struct nova_dentry *)nova_get_block(sb, curr_p);
+ nova_dbgv("curr_p: 0x%llx, type %d, ino %llu, name %s, namelen %u, rec len %u\n",
+ curr_p, entry->entry_type, le64_to_cpu(entry->ino),
+ entry->name, entry->name_len,
+ le16_to_cpu(entry->de_len));
+
+ de_len = le16_to_cpu(entry->de_len);
+ if (entry->ino > 0 && entry->invalid == 0
+ && entry->reassigned == 0) {
+ ino = __le64_to_cpu(entry->ino);
+ pos = BKDRHash(entry->name, entry->name_len);
+
+ ret = nova_get_inode_address(sb, ino,
+ &pi_addr, 0);
+ if (ret) {
+ nova_dbg("%s: get child inode %lu address failed %d\n",
+ __func__, ino, ret);
+ ctx->pos = READDIR_END;
+ goto out;
+ }
+
+ child_pi = nova_get_block(sb, pi_addr);
+ nova_dbgv("ctx: ino %llu, name %s, name_len %u, de_len %u\n",
+ (u64)ino, entry->name, entry->name_len,
+ entry->de_len);
+ if (prev_entry && !dir_emit(ctx, prev_entry->name,
+ prev_entry->name_len, ino,
+ IF2DT(le16_to_cpu(prev_child_pi->i_mode)))) {
+ nova_dbgv("Here: pos %llu\n", ctx->pos);
+ ret = 0;
+ goto out;
+ }
+ prev_entry = entry;
+
+ prev_child_pi = child_pi;
+ }
+ ctx->pos = pos;
+ curr_p += de_len;
+ }
+
+ if (prev_entry && !dir_emit(ctx, prev_entry->name,
+ prev_entry->name_len, ino,
+ IF2DT(le16_to_cpu(prev_child_pi->i_mode))))
+ return 0;
+
+ ctx->pos = READDIR_END;
+ ret = 0;
+out:
+ NOVA_END_TIMING(readdir_t, readdir_time);
+ nova_dbgv("%s return\n", __func__);
+ return ret;
+}
+
+const struct file_operations nova_dir_operations = {
+ .llseek = generic_file_llseek,
+ .read = generic_read_dir,
+ .iterate = nova_readdir,
+ .fsync = noop_fsync,
+};
diff --git a/fs/nova/inode.c b/fs/nova/inode.c
index 15517cc..41417e3 100644
--- a/fs/nova/inode.c
+++ b/fs/nova/inode.c
@@ -181,6 +181,7 @@ static int nova_read_inode(struct super_block *sb, struct inode *inode,
case S_IFREG:
break;
case S_IFDIR:
+ inode->i_fop = &nova_dir_operations;
break;
case S_IFLNK:
break;
@@ -625,6 +626,7 @@ struct inode *nova_new_vfs_inode(enum nova_new_inode_type type,
inode->i_mapping->a_ops = &nova_aops_dax;
break;
case TYPE_MKDIR:
+ inode->i_fop = &nova_dir_operations;
inode->i_mapping->a_ops = &nova_aops_dax;
set_nlink(inode, 2);
break;
diff --git a/fs/nova/nova.h b/fs/nova/nova.h
index a94f44d..ed269fe 100644
--- a/fs/nova/nova.h
+++ b/fs/nova/nova.h
@@ -447,6 +447,7 @@ nova_get_blocknr(struct super_block *sb, u64 block, unsigned short btype)
/* ====================================================== */

/* dir.c */
+extern const struct file_operations nova_dir_operations;
int nova_insert_dir_radix_tree(struct super_block *sb,
struct nova_inode_info_header *sih, const char *name,
int namelen, struct nova_dentry *direntry);
--
2.7.4
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