--- /dev/null
+From aa282f628e4ad75eea7f8ee1b26dea920c238241 Mon Sep 17 00:00:00 2001
+From: Shaun Tancheff <stancheff@cray.com>
+Date: Tue, 6 Aug 2019 17:00:55 -0500
+Subject: [PATCH] + linux-5.3/ext4-kill-dx-root
+
+---
+ fs/ext4/namei.c | 111 +++++++++++++++++++++++++++++---------------------------
+ 1 file changed, 58 insertions(+), 53 deletions(-)
+
+--- a/fs/ext4/namei.c
++++ b/fs/ext4/namei.c
+@@ -219,22 +219,13 @@ struct dx_entry
+ * hash version mod 4 should never be 0. Sincerely, the paranoia department.
+ */
+
+-struct dx_root
++struct dx_root_info
+ {
+- struct fake_dirent dot;
+- char dot_name[4];
+- struct fake_dirent dotdot;
+- char dotdot_name[4];
+- struct dx_root_info
+- {
+- __le32 reserved_zero;
+- u8 hash_version;
+- u8 info_length; /* 8 */
+- u8 indirect_levels;
+- u8 unused_flags;
+- }
+- info;
+- struct dx_entry entries[];
++ __le32 reserved_zero;
++ u8 hash_version;
++ u8 info_length; /* 8 */
++ u8 indirect_levels;
++ u8 unused_flags;
+ };
+
+ struct dx_node
+@@ -536,6 +527,16 @@ ext4_next_entry(struct ext4_dir_entry_2
+ * Future: use high four bits of block for coalesce-on-delete flags
+ * Mask them off for now.
+ */
++struct dx_root_info *dx_get_dx_info(struct ext4_dir_entry_2 *de)
++{
++ /* get dotdot first */
++ de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(1));
++
++ /* dx root info is after dotdot entry */
++ de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(2));
++
++ return (struct dx_root_info *)de;
++}
+
+ static inline ext4_lblk_t dx_get_block(struct dx_entry *entry)
+ {
+@@ -760,7 +761,7 @@ dx_probe(struct ext4_filename *fname, st
+ {
+ unsigned count, indirect;
+ struct dx_entry *at, *entries, *p, *q, *m;
+- struct dx_root *root;
++ struct dx_root_info *info;
+ struct dx_frame *frame = frame_in;
+ struct dx_frame *ret_err = ERR_PTR(ERR_BAD_DX_DIR);
+ u32 hash;
+@@ -769,18 +770,17 @@ dx_probe(struct ext4_filename *fname, st
+ frame->bh = ext4_read_dirblock(dir, 0, INDEX);
+ if (IS_ERR(frame->bh))
+ return (struct dx_frame *) frame->bh;
+-
+- root = (struct dx_root *) frame->bh->b_data;
+- if (root->info.hash_version != DX_HASH_TEA &&
+- root->info.hash_version != DX_HASH_HALF_MD4 &&
+- root->info.hash_version != DX_HASH_LEGACY) {
+- ext4_warning_inode(dir, "Unrecognised inode hash code %u for directory "
+- "%lu", root->info.hash_version, dir->i_ino);
++ info = dx_get_dx_info((struct ext4_dir_entry_2 *)frame->bh->b_data);
++ if (info->hash_version != DX_HASH_TEA &&
++ info->hash_version != DX_HASH_HALF_MD4 &&
++ info->hash_version != DX_HASH_LEGACY) {
++ ext4_warning(dir->i_sb, "Unrecognised inode hash code %d for directory "
++ "#%lu", info->hash_version, dir->i_ino);
+ goto fail;
+ }
+ if (fname)
+ hinfo = &fname->hinfo;
+- hinfo->hash_version = root->info.hash_version;
++ hinfo->hash_version = info->hash_version;
+ if (hinfo->hash_version <= DX_HASH_TEA)
+ hinfo->hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
+ hinfo->seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+@@ -788,13 +788,13 @@ dx_probe(struct ext4_filename *fname, st
+ ext4fs_dirhash(dir, fname_name(fname), fname_len(fname), hinfo);
+ hash = hinfo->hash;
+
+- if (root->info.unused_flags & 1) {
++ if (info->unused_flags & 1) {
+ ext4_warning_inode(dir, "Unimplemented hash flags: %#06x",
+- root->info.unused_flags);
++ info->unused_flags);
+ goto fail;
+ }
+
+- indirect = root->info.indirect_levels;
++ indirect = info->indirect_levels;
+ if (indirect >= ext4_dir_htree_level(dir->i_sb)) {
+ ext4_warning(dir->i_sb,
+ "Directory (ino: %lu) htree depth %#06x exceed"
+@@ -807,14 +807,13 @@ dx_probe(struct ext4_filename *fname, st
+ goto fail;
+ }
+
+- entries = (struct dx_entry *)(((char *)&root->info) +
+- root->info.info_length);
++ entries = (struct dx_entry *)(((char *)info) + info->info_length);
+
+ if (dx_get_limit(entries) != dx_root_limit(dir,
+- root->info.info_length)) {
++ info->info_length)) {
+ ext4_warning_inode(dir, "dx entry: limit %u != root limit %u",
+ dx_get_limit(entries),
+- dx_root_limit(dir, root->info.info_length));
++ dx_root_limit(dir, info->info_length));
+ goto fail;
+ }
+
+@@ -899,7 +898,7 @@ static void dx_release(struct dx_frame *
+ if (frames[0].bh == NULL)
+ return;
+
+- info = &((struct dx_root *)frames[0].bh->b_data)->info;
++ info = dx_get_dx_info((struct ext4_dir_entry_2 *)frames[0].bh->b_data);
+ /* save local copy, "info" may be freed after brelse() */
+ indirect_levels = info->indirect_levels;
+ for (i = 0; i <= indirect_levels; i++) {
+@@ -2072,16 +2071,15 @@ static int make_indexed_dir(handle_t *ha
+ struct inode *inode, struct buffer_head *bh)
+ {
+ struct buffer_head *bh2;
+- struct dx_root *root;
+ struct dx_frame frames[EXT4_HTREE_LEVEL], *frame;
+ struct dx_entry *entries;
+- struct ext4_dir_entry_2 *de, *de2;
++ struct ext4_dir_entry_2 *de, *de2, *dot_de, *dotdot_de;
+ char *data2, *top;
+ unsigned len;
+ int retval;
+ unsigned blocksize;
+ ext4_lblk_t block;
+- struct fake_dirent *fde;
++ struct dx_root_info *dx_info;
+ int csum_size = 0;
+
+ if (ext4_has_metadata_csum(inode->i_sb))
+@@ -2096,18 +2094,19 @@ static int make_indexed_dir(handle_t *ha
+ brelse(bh);
+ return retval;
+ }
+- root = (struct dx_root *) bh->b_data;
++
++ dot_de = (struct ext4_dir_entry_2 *)bh->b_data;
++ dotdot_de = ext4_next_entry(dot_de, blocksize);
+
+ /* The 0th block becomes the root, move the dirents out */
+- fde = &root->dotdot;
+- de = (struct ext4_dir_entry_2 *)((char *)fde +
+- ext4_rec_len_from_disk(fde->rec_len, blocksize));
+- if ((char *) de >= (((char *) root) + blocksize)) {
++ de = (struct ext4_dir_entry_2 *)((char *)dotdot_de +
++ ext4_rec_len_from_disk(dotdot_de->rec_len, blocksize));
++ if ((char *)de >= (((char *)dot_de) + blocksize)) {
+ EXT4_ERROR_INODE(dir, "invalid rec_len for '..'");
+ brelse(bh);
+ return -EFSCORRUPTED;
+ }
+- len = ((char *) root) + (blocksize - csum_size) - (char *) de;
++ len = ((char *)dot_de) + (blocksize - csum_size) - (char *)de;
+
+ /* Allocate new block for the 0th block's dirents */
+ bh2 = ext4_append(handle, dir, &block);
+@@ -2130,19 +2129,24 @@ static int make_indexed_dir(handle_t *ha
+ ext4_initialize_dirent_tail(bh2, blocksize);
+
+ /* Initialize the root; the dot dirents already exist */
+- de = (struct ext4_dir_entry_2 *) (&root->dotdot);
+- de->rec_len = ext4_rec_len_to_disk(blocksize - EXT4_DIR_REC_LEN(2),
+- blocksize);
+- memset (&root->info, 0, sizeof(root->info));
+- root->info.info_length = sizeof(root->info);
+- root->info.hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
+- entries = root->entries;
++ dotdot_de->rec_len =
++ ext4_rec_len_to_disk(blocksize - le16_to_cpu(dot_de->rec_len),
++ blocksize);
++
++ /* initialize hashing info */
++ dx_info = dx_get_dx_info(dot_de);
++ memset(dx_info, 0, sizeof(*dx_info));
++ dx_info->info_length = sizeof(*dx_info);
++ dx_info->hash_version = EXT4_SB(dir->i_sb)->s_def_hash_version;
++
++ entries = (void *)dx_info + sizeof(*dx_info);
++
+ dx_set_block(entries, 1);
+ dx_set_count(entries, 1);
+- dx_set_limit(entries, dx_root_limit(dir, sizeof(root->info)));
++ dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
+
+ /* Initialize as for dx_probe */
+- fname->hinfo.hash_version = root->info.hash_version;
++ fname->hinfo.hash_version = dx_info->hash_version;
+ if (fname->hinfo.hash_version <= DX_HASH_TEA)
+ fname->hinfo.hash_version += EXT4_SB(dir->i_sb)->s_hash_unsigned;
+ fname->hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
+@@ -2506,7 +2510,7 @@ again:
+ goto journal_error;
+ }
+ } else {
+- struct dx_root *dxroot;
++ struct dx_root_info *info;
+ memcpy((char *) entries2, (char *) entries,
+ icount * sizeof(struct dx_entry));
+ dx_set_limit(entries2, dx_node_limit(dir));
+@@ -2514,8 +2518,9 @@ again:
+ /* Set up root */
+ dx_set_count(entries, 1);
+ dx_set_block(entries + 0, newblock);
+- dxroot = (struct dx_root *)frames[0].bh->b_data;
+- dxroot->info.indirect_levels += 1;
++ info = dx_get_dx_info((struct ext4_dir_entry_2 *)
++ frames[0].bh->b_data);
++ info->indirect_levels = 1;
+ dxtrace(printk(KERN_DEBUG
+ "Creating %d level index...\n",
+ dxroot->info.indirect_levels));
git://git.whamcloud.com / fs / lustre-release.git / blobdiff