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Message-ID: <20250712181249.434530-3-tytso@mit.edu>
Date: Sat, 12 Jul 2025 14:12:49 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: linux-hardening@...r.kernel.org, ethan@...ancedwards.com,
"Theodore Ts'o" <tytso@....edu>
Subject: [PATCH 3/3] ext4: refactor the inline directory conversion and new directory codepaths
There was a lot of common code in the codepaths used to convert an
inline directory and to creaet a new directory. To address this,
rename ext4_init_dot_dotdot() to ext4_init_dirblock() and then move
common code into that function.
This reduces the lines of code count in fs/ext4/inline.c and
fs/ext4/namei.c, as well as reducing the size of their object files.
Signed-off-by: Theodore Ts'o <tytso@....edu>
---
fs/ext4/ext4.h | 9 ++++----
fs/ext4/inline.c | 60 ++++++++++--------------------------------------
fs/ext4/namei.c | 56 ++++++++++++++++++++++++--------------------
3 files changed, 48 insertions(+), 77 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 18373de980f2..4d1d3eff2418 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3612,6 +3612,7 @@ extern loff_t ext4_llseek(struct file *file, loff_t offset, int origin);
extern int ext4_get_max_inline_size(struct inode *inode);
extern int ext4_find_inline_data_nolock(struct inode *inode);
extern int ext4_destroy_inline_data(handle_t *handle, struct inode *inode);
+extern void ext4_update_final_de(void *de_buf, int old_size, int new_size);
int ext4_readpage_inline(struct inode *inode, struct folio *folio);
extern int ext4_try_to_write_inline_data(struct address_space *mapping,
@@ -3671,10 +3672,10 @@ static inline int ext4_has_inline_data(struct inode *inode)
extern const struct inode_operations ext4_dir_inode_operations;
extern const struct inode_operations ext4_special_inode_operations;
extern struct dentry *ext4_get_parent(struct dentry *child);
-extern struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
- struct ext4_dir_entry_2 *de,
- int blocksize, int csum_size,
- unsigned int parent_ino, int dotdot_real_len);
+extern int ext4_init_dirblock(handle_t *handle, struct inode *inode,
+ struct buffer_head *dir_block,
+ unsigned int parent_ino, void *inline_buf,
+ int inline_size);
extern void ext4_initialize_dirent_tail(struct buffer_head *bh,
unsigned int blocksize);
extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index eeee007251e0..4ad3255e45cb 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -995,7 +995,7 @@ static void *ext4_get_inline_xattr_pos(struct inode *inode,
}
/* Set the final de to cover the whole block. */
-static void ext4_update_final_de(void *de_buf, int old_size, int new_size)
+void ext4_update_final_de(void *de_buf, int old_size, int new_size)
{
struct ext4_dir_entry_2 *de, *prev_de;
void *limit;
@@ -1059,51 +1059,6 @@ static void ext4_restore_inline_data(handle_t *handle, struct inode *inode,
ext4_set_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA);
}
-static int ext4_finish_convert_inline_dir(handle_t *handle,
- struct inode *inode,
- struct buffer_head *dir_block,
- void *buf,
- int inline_size)
-{
- int err, csum_size = 0, header_size = 0;
- struct ext4_dir_entry_2 *de;
- void *target = dir_block->b_data;
-
- /*
- * First create "." and ".." and then copy the dir information
- * back to the block.
- */
- de = target;
- de = ext4_init_dot_dotdot(inode, de,
- inode->i_sb->s_blocksize, csum_size,
- le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode), 1);
- header_size = (void *)de - target;
-
- memcpy((void *)de, buf + EXT4_INLINE_DOTDOT_SIZE,
- inline_size - EXT4_INLINE_DOTDOT_SIZE);
-
- if (ext4_has_feature_metadata_csum(inode->i_sb))
- csum_size = sizeof(struct ext4_dir_entry_tail);
-
- inode->i_size = inode->i_sb->s_blocksize;
- i_size_write(inode, inode->i_sb->s_blocksize);
- EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
- ext4_update_final_de(dir_block->b_data,
- inline_size - EXT4_INLINE_DOTDOT_SIZE + header_size,
- inode->i_sb->s_blocksize - csum_size);
-
- if (csum_size)
- ext4_initialize_dirent_tail(dir_block,
- inode->i_sb->s_blocksize);
- set_buffer_uptodate(dir_block);
- unlock_buffer(dir_block);
- err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
- if (err)
- return err;
- set_buffer_verified(dir_block);
- return ext4_mark_inode_dirty(handle, inode);
-}
-
static int ext4_convert_inline_data_nolock(handle_t *handle,
struct inode *inode,
struct ext4_iloc *iloc)
@@ -1175,8 +1130,17 @@ static int ext4_convert_inline_data_nolock(handle_t *handle,
error = ext4_handle_dirty_metadata(handle,
inode, data_bh);
} else {
- error = ext4_finish_convert_inline_dir(handle, inode, data_bh,
- buf, inline_size);
+ unlock_buffer(data_bh);
+ inode->i_size = inode->i_sb->s_blocksize;
+ i_size_write(inode, inode->i_sb->s_blocksize);
+ EXT4_I(inode)->i_disksize = inode->i_sb->s_blocksize;
+
+ error = ext4_init_dirblock(handle, inode, data_bh,
+ le32_to_cpu(((struct ext4_dir_entry_2 *)buf)->inode),
+ buf + EXT4_INLINE_DOTDOT_SIZE,
+ inline_size - EXT4_INLINE_DOTDOT_SIZE);
+ if (!error)
+ error = ext4_mark_inode_dirty(handle, inode);
}
out_restore:
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 9913a94b6a6d..d83f91b62317 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2915,11 +2915,17 @@ static int ext4_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
return err;
}
-struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
- struct ext4_dir_entry_2 *de,
- int blocksize, int csum_size,
- unsigned int parent_ino, int dotdot_real_len)
+int ext4_init_dirblock(handle_t *handle, struct inode *inode,
+ struct buffer_head *bh, unsigned int parent_ino,
+ void *inline_buf, int inline_size)
{
+ struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *) bh->b_data;
+ size_t blocksize = bh->b_size;
+ int csum_size = 0, header_size;
+
+ if (ext4_has_feature_metadata_csum(inode->i_sb))
+ csum_size = sizeof(struct ext4_dir_entry_tail);
+
de->inode = cpu_to_le32(inode->i_ino);
de->name_len = 1;
de->rec_len = ext4_rec_len_to_disk(ext4_dir_rec_len(de->name_len, NULL),
@@ -2930,18 +2936,29 @@ struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
de = ext4_next_entry(de, blocksize);
de->inode = cpu_to_le32(parent_ino);
de->name_len = 2;
- if (!dotdot_real_len)
- de->rec_len = ext4_rec_len_to_disk(blocksize -
- (csum_size + ext4_dir_rec_len(1, NULL)),
- blocksize);
- else
+ memcpy(de->name, "..", 3);
+ ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+ if (inline_buf) {
de->rec_len = ext4_rec_len_to_disk(
ext4_dir_rec_len(de->name_len, NULL),
blocksize);
- memcpy(de->name, "..", 3);
- ext4_set_de_type(inode->i_sb, de, S_IFDIR);
+ de = ext4_next_entry(de, blocksize);
+ header_size = (char *)de - bh->b_data;
+ memcpy((void *)de, inline_buf, inline_size);
+ ext4_update_final_de(bh->b_data, inline_size + header_size,
+ blocksize - csum_size);
+ } else {
+ de->rec_len = ext4_rec_len_to_disk(blocksize -
+ (csum_size + ext4_dir_rec_len(1, NULL)),
+ blocksize);
+ }
- return ext4_next_entry(de, blocksize);
+ if (csum_size)
+ ext4_initialize_dirent_tail(bh, blocksize);
+ BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
+ set_buffer_uptodate(bh);
+ set_buffer_verified(bh);
+ return ext4_handle_dirty_dirblock(handle, inode, bh);
}
int ext4_init_new_dir(handle_t *handle, struct inode *dir,
@@ -2950,13 +2967,8 @@ int ext4_init_new_dir(handle_t *handle, struct inode *dir,
struct buffer_head *dir_block = NULL;
struct ext4_dir_entry_2 *de;
ext4_lblk_t block = 0;
- unsigned int blocksize = dir->i_sb->s_blocksize;
- int csum_size = 0;
int err;
- if (ext4_has_feature_metadata_csum(dir->i_sb))
- csum_size = sizeof(struct ext4_dir_entry_tail);
-
if (ext4_test_inode_state(inode, EXT4_STATE_MAY_INLINE_DATA)) {
err = ext4_try_create_inline_dir(handle, dir, inode);
if (err < 0 && err != -ENOSPC)
@@ -2965,21 +2977,15 @@ int ext4_init_new_dir(handle_t *handle, struct inode *dir,
goto out;
}
+ set_nlink(inode, 2);
inode->i_size = 0;
dir_block = ext4_append(handle, inode, &block);
if (IS_ERR(dir_block))
return PTR_ERR(dir_block);
de = (struct ext4_dir_entry_2 *)dir_block->b_data;
- ext4_init_dot_dotdot(inode, de, blocksize, csum_size, dir->i_ino, 0);
- set_nlink(inode, 2);
- if (csum_size)
- ext4_initialize_dirent_tail(dir_block, blocksize);
-
- BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
- err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
+ err = ext4_init_dirblock(handle, inode, dir_block, dir->i_ino, NULL, 0);
if (err)
goto out;
- set_buffer_verified(dir_block);
out:
brelse(dir_block);
return err;
--
2.47.2
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