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ext4: rename "dirent_csum" functions to use "dirblock"
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Functions such as ext4_dirent_csum_verify() and ext4_dirent_csum_set()
don't actually operate on a directory entry, but a directory block.
And while they take a struct ext4_dir_entry *dirent as an argument, it
had better be the first directory at the beginning of the direct
block, or things will go very wrong.

Rename the following functions so that things make more sense, and
remove a lot of confusing casts along the way:

   ext4_dirent_csum_verify	 -> ext4_dirblock_csum_verify
   ext4_dirent_csum_set		 -> ext4_dirblock_csum_set
   ext4_dirent_csum		 -> ext4_dirblock_csum
   ext4_handle_dirty_dirent_node -> ext4_handle_dirty_dirblock

Signed-off-by: Theodore Ts'o <[email protected]>
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@tytso
tytso committed Jun 21, 2019
1 parent 4e19d6b commit f036adb
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Showing 4 changed files with 35 additions and 41 deletions.
3 changes: 1 addition & 2 deletions fs/ext4/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -194,8 +194,7 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)

/* Check the checksum */
if (!buffer_verified(bh) &&
!ext4_dirent_csum_verify(inode,
(struct ext4_dir_entry *)bh->b_data)) {
!ext4_dirblock_csum_verify(inode, bh)) {
EXT4_ERROR_FILE(file, 0, "directory fails checksum "
"at offset %llu",
(unsigned long long)ctx->pos);
Expand Down
9 changes: 4 additions & 5 deletions fs/ext4/ext4.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2602,8 +2602,8 @@ extern int ext4_ext_migrate(struct inode *);
extern int ext4_ind_migrate(struct inode *inode);

/* namei.c */
extern int ext4_dirent_csum_verify(struct inode *inode,
struct ext4_dir_entry *dirent);
extern int ext4_dirblock_csum_verify(struct inode *inode,
struct buffer_head *bh);
extern int ext4_orphan_add(handle_t *, struct inode *);
extern int ext4_orphan_del(handle_t *, struct inode *);
extern int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
Expand Down Expand Up @@ -3149,9 +3149,8 @@ extern struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
unsigned int parent_ino, int dotdot_real_len);
extern void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
unsigned int blocksize);
extern int ext4_handle_dirty_dirent_node(handle_t *handle,
struct inode *inode,
struct buffer_head *bh);
extern int ext4_handle_dirty_dirblock(handle_t *handle, struct inode *inode,
struct buffer_head *bh);
extern int ext4_ci_compare(const struct inode *parent,
const struct qstr *fname,
const struct qstr *entry, bool quick);
Expand Down
2 changes: 1 addition & 1 deletion fs/ext4/inline.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1164,7 +1164,7 @@ static int ext4_finish_convert_inline_dir(handle_t *handle,
initialize_dirent_tail(t, inode->i_sb->s_blocksize);
}
set_buffer_uptodate(dir_block);
err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
if (err)
return err;
set_buffer_verified(dir_block);
Expand Down
62 changes: 29 additions & 33 deletions fs/ext4/namei.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -163,7 +163,7 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,
}
}
if (!is_dx_block) {
if (ext4_dirent_csum_verify(inode, dirent))
if (ext4_dirblock_csum_verify(inode, bh))
set_buffer_verified(bh);
else {
ext4_error_inode(inode, func, line, block,
Expand Down Expand Up @@ -304,17 +304,17 @@ void initialize_dirent_tail(struct ext4_dir_entry_tail *t,

/* Walk through a dirent block to find a checksum "dirent" at the tail */
static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
struct ext4_dir_entry *de)
struct buffer_head *bh)
{
struct ext4_dir_entry_tail *t;

#ifdef PARANOID
struct ext4_dir_entry *d, *top;

d = de;
top = (struct ext4_dir_entry *)(((void *)de) +
d = (struct ext4_dir_entry *)bh->b_data;
top = (struct ext4_dir_entry *)(bh->b_data +
(EXT4_BLOCK_SIZE(inode->i_sb) -
sizeof(struct ext4_dir_entry_tail)));
sizeof(struct ext4_dir_entry_tail)));
while (d < top && d->rec_len)
d = (struct ext4_dir_entry *)(((void *)d) +
le16_to_cpu(d->rec_len));
Expand All @@ -324,7 +324,7 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,

t = (struct ext4_dir_entry_tail *)d;
#else
t = EXT4_DIRENT_TAIL(de, EXT4_BLOCK_SIZE(inode->i_sb));
t = EXT4_DIRENT_TAIL(bh->b_data, EXT4_BLOCK_SIZE(inode->i_sb));
#endif

if (t->det_reserved_zero1 ||
Expand All @@ -336,8 +336,7 @@ static struct ext4_dir_entry_tail *get_dirent_tail(struct inode *inode,
return t;
}

static __le32 ext4_dirent_csum(struct inode *inode,
struct ext4_dir_entry *dirent, int size)
static __le32 ext4_dirblock_csum(struct inode *inode, void *dirent, int size)
{
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
struct ext4_inode_info *ei = EXT4_I(inode);
Expand All @@ -357,49 +356,49 @@ static void __warn_no_space_for_csum(struct inode *inode, const char *func,
"No space for directory leaf checksum. Please run e2fsck -D.");
}

int ext4_dirent_csum_verify(struct inode *inode, struct ext4_dir_entry *dirent)
int ext4_dirblock_csum_verify(struct inode *inode, struct buffer_head *bh)
{
struct ext4_dir_entry_tail *t;

if (!ext4_has_metadata_csum(inode->i_sb))
return 1;

t = get_dirent_tail(inode, dirent);
t = get_dirent_tail(inode, bh);
if (!t) {
warn_no_space_for_csum(inode);
return 0;
}

if (t->det_checksum != ext4_dirent_csum(inode, dirent,
(void *)t - (void *)dirent))
if (t->det_checksum != ext4_dirblock_csum(inode, bh->b_data,
(char *)t - bh->b_data))
return 0;

return 1;
}

static void ext4_dirent_csum_set(struct inode *inode,
struct ext4_dir_entry *dirent)
static void ext4_dirblock_csum_set(struct inode *inode,
struct buffer_head *bh)
{
struct ext4_dir_entry_tail *t;

if (!ext4_has_metadata_csum(inode->i_sb))
return;

t = get_dirent_tail(inode, dirent);
t = get_dirent_tail(inode, bh);
if (!t) {
warn_no_space_for_csum(inode);
return;
}

t->det_checksum = ext4_dirent_csum(inode, dirent,
(void *)t - (void *)dirent);
t->det_checksum = ext4_dirblock_csum(inode, bh->b_data,
(char *)t - bh->b_data);
}

int ext4_handle_dirty_dirent_node(handle_t *handle,
struct inode *inode,
struct buffer_head *bh)
int ext4_handle_dirty_dirblock(handle_t *handle,
struct inode *inode,
struct buffer_head *bh)
{
ext4_dirent_csum_set(inode, (struct ext4_dir_entry *)bh->b_data);
ext4_dirblock_csum_set(inode, bh);
return ext4_handle_dirty_metadata(handle, inode, bh);
}

Expand Down Expand Up @@ -1530,8 +1529,7 @@ static struct buffer_head *__ext4_find_entry(struct inode *dir,
if (!buffer_verified(bh) &&
!is_dx_internal_node(dir, block,
(struct ext4_dir_entry *)bh->b_data) &&
!ext4_dirent_csum_verify(dir,
(struct ext4_dir_entry *)bh->b_data)) {
!ext4_dirblock_csum_verify(dir, bh)) {
EXT4_ERROR_INODE(dir, "checksumming directory "
"block %lu", (unsigned long)block);
brelse(bh);
Expand Down Expand Up @@ -1894,7 +1892,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir,
de = de2;
}
dx_insert_block(frame, hash2 + continued, newblock);
err = ext4_handle_dirty_dirent_node(handle, dir, bh2);
err = ext4_handle_dirty_dirblock(handle, dir, bh2);
if (err)
goto journal_error;
err = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
Expand Down Expand Up @@ -2022,7 +2020,7 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
inode_inc_iversion(dir);
ext4_mark_inode_dirty(handle, dir);
BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
err = ext4_handle_dirty_dirent_node(handle, dir, bh);
err = ext4_handle_dirty_dirblock(handle, dir, bh);
if (err)
ext4_std_error(dir->i_sb, err);
return 0;
Expand Down Expand Up @@ -2126,7 +2124,7 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
retval = ext4_handle_dirty_dx_node(handle, dir, frame->bh);
if (retval)
goto out_frames;
retval = ext4_handle_dirty_dirent_node(handle, dir, bh2);
retval = ext4_handle_dirty_dirblock(handle, dir, bh2);
if (retval)
goto out_frames;

Expand Down Expand Up @@ -2512,7 +2510,7 @@ static int ext4_delete_entry(handle_t *handle,
goto out;

BUFFER_TRACE(bh, "call ext4_handle_dirty_metadata");
err = ext4_handle_dirty_dirent_node(handle, dir, bh);
err = ext4_handle_dirty_dirblock(handle, dir, bh);
if (unlikely(err))
goto out;

Expand Down Expand Up @@ -2744,7 +2742,7 @@ static int ext4_init_new_dir(handle_t *handle, struct inode *dir,
}

BUFFER_TRACE(dir_block, "call ext4_handle_dirty_metadata");
err = ext4_handle_dirty_dirent_node(handle, inode, dir_block);
err = ext4_handle_dirty_dirblock(handle, inode, dir_block);
if (err)
goto out;
set_buffer_verified(dir_block);
Expand Down Expand Up @@ -3492,9 +3490,8 @@ static int ext4_rename_dir_finish(handle_t *handle, struct ext4_renament *ent,
ent->inode,
ent->dir_bh);
} else {
retval = ext4_handle_dirty_dirent_node(handle,
ent->inode,
ent->dir_bh);
retval = ext4_handle_dirty_dirblock(handle, ent->inode,
ent->dir_bh);
}
} else {
retval = ext4_mark_inode_dirty(handle, ent->inode);
Expand Down Expand Up @@ -3524,8 +3521,7 @@ static int ext4_setent(handle_t *handle, struct ext4_renament *ent,
ext4_mark_inode_dirty(handle, ent->dir);
BUFFER_TRACE(ent->bh, "call ext4_handle_dirty_metadata");
if (!ent->inlined) {
retval = ext4_handle_dirty_dirent_node(handle,
ent->dir, ent->bh);
retval = ext4_handle_dirty_dirblock(handle, ent->dir, ent->bh);
if (unlikely(retval)) {
ext4_std_error(ent->dir->i_sb, retval);
return retval;
Expand Down

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