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ext4: fix readdir error in the case of inline_data+dir_index 

Zach reported a problem that if inline data is enabled, we don't
tell the difference between the offset of '.' and '..'. And a
getdents will fail if the user only want to get '.' and what's worse,
if there is a conversion happens when the user calls getdents
many times, he/she may get the same entry twice.

In theory, a dir block would also fail if it is converted to a
hashed-index based dir since f_pos will become a hash value, not the
real one, but it doesn't happen.  And a deep investigation shows that
we uses a hash based solution even for a normal dir if the dir_index
feature is enabled.

So this patch just adds a new htree_inlinedir_to_tree for inline dir,
and if we find that the hash index is supported, we will do like what
we do for a dir block.

Reported-by: Zach Brown <zab@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Tao Ma 2013-04-19 17:53:09 -04:00 committed by Theodore Ts'o
parent 28daf4fae8
commit 8af0f08227
4 changed files with 153 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
fs/ext4/dir.c
View File

@ -46,7 +46,8 @@ static int is_dx_dir(struct inode *inode)
if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
EXT4_FEATURE_COMPAT_DIR_INDEX) &&
((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
((inode->i_size >> sb->s_blocksize_bits) == 1)))
((inode->i_size >> sb->s_blocksize_bits) == 1) ||
ext4_has_inline_data(inode)))
return 1;
return 0;
@ -115,14 +116,6 @@ static int ext4_readdir(struct file *filp,
int ret = 0;
int dir_has_error = 0;
if (ext4_has_inline_data(inode)) {
int has_inline_data = 1;
ret = ext4_read_inline_dir(filp, dirent, filldir,
&has_inline_data);
if (has_inline_data)
return ret;
}
if (is_dx_dir(inode)) {
err = ext4_dx_readdir(filp, dirent, filldir);
if (err != ERR_BAD_DX_DIR) {
@ -136,6 +129,15 @@ static int ext4_readdir(struct file *filp,
ext4_clear_inode_flag(file_inode(filp),
EXT4_INODE_INDEX);
}
if (ext4_has_inline_data(inode)) {
int has_inline_data = 1;
ret = ext4_read_inline_dir(filp, dirent, filldir,
&has_inline_data);
if (has_inline_data)
return ret;
}
stored = 0;
offset = filp->f_pos & (sb->s_blocksize - 1);

23
fs/ext4/ext4.h
View File

@ -2518,6 +2518,11 @@ extern int ext4_try_create_inline_dir(handle_t *handle,
extern int ext4_read_inline_dir(struct file *filp,
void *dirent, filldir_t filldir,
int *has_inline_data);
extern int htree_inlinedir_to_tree(struct file *dir_file,
struct inode *dir, ext4_lblk_t block,
struct dx_hash_info *hinfo,
__u32 start_hash, __u32 start_minor_hash,
int *has_inline_data);
extern struct buffer_head *ext4_find_inline_entry(struct inode *dir,
const struct qstr *d_name,
struct ext4_dir_entry_2 **res_dir,
@ -2554,6 +2559,24 @@ extern void initialize_dirent_tail(struct ext4_dir_entry_tail *t,
extern int ext4_handle_dirty_dirent_node(handle_t *handle,
struct inode *inode,
struct buffer_head *bh);
#define S_SHIFT 12
static unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
[S_IFREG >> S_SHIFT] = EXT4_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = EXT4_FT_DIR,
[S_IFCHR >> S_SHIFT] = EXT4_FT_CHRDEV,
[S_IFBLK >> S_SHIFT] = EXT4_FT_BLKDEV,
[S_IFIFO >> S_SHIFT] = EXT4_FT_FIFO,
[S_IFSOCK >> S_SHIFT] = EXT4_FT_SOCK,
[S_IFLNK >> S_SHIFT] = EXT4_FT_SYMLINK,
};
static inline void ext4_set_de_type(struct super_block *sb,
struct ext4_dir_entry_2 *de,
umode_t mode) {
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE))
de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
}
/* symlink.c */
extern const struct inode_operations ext4_symlink_inode_operations;

109
fs/ext4/inline.c
View File

@ -19,7 +19,8 @@
#define EXT4_XATTR_SYSTEM_DATA "data"
#define EXT4_MIN_INLINE_DATA_SIZE ((sizeof(__le32) * EXT4_N_BLOCKS))
#define EXT4_INLINE_DOTDOT_SIZE 4
#define EXT4_INLINE_DOTDOT_OFFSET 2
#define EXT4_INLINE_DOTDOT_SIZE 4
int ext4_get_inline_size(struct inode *inode)
{
@ -1289,6 +1290,112 @@ out:
return ret;
}
/*
* This function fills a red-black tree with information from an
* inlined dir. It returns the number directory entries loaded
* into the tree. If there is an error it is returned in err.
*/
int htree_inlinedir_to_tree(struct file *dir_file,
struct inode *dir, ext4_lblk_t block,
struct dx_hash_info *hinfo,
__u32 start_hash, __u32 start_minor_hash,
int *has_inline_data)
{
int err = 0, count = 0;
unsigned int parent_ino;
int pos;
struct ext4_dir_entry_2 *de;
struct inode *inode = file_inode(dir_file);
int ret, inline_size = 0;
struct ext4_iloc iloc;
void *dir_buf = NULL;
struct ext4_dir_entry_2 fake;
ret = ext4_get_inode_loc(inode, &iloc);
if (ret)
return ret;
down_read(&EXT4_I(inode)->xattr_sem);
if (!ext4_has_inline_data(inode)) {
up_read(&EXT4_I(inode)->xattr_sem);
*has_inline_data = 0;
goto out;
}
inline_size = ext4_get_inline_size(inode);
dir_buf = kmalloc(inline_size, GFP_NOFS);
if (!dir_buf) {
ret = -ENOMEM;
up_read(&EXT4_I(inode)->xattr_sem);
goto out;
}
ret = ext4_read_inline_data(inode, dir_buf, inline_size, &iloc);
up_read(&EXT4_I(inode)->xattr_sem);
if (ret < 0)
goto out;
pos = 0;
parent_ino = le32_to_cpu(((struct ext4_dir_entry_2 *)dir_buf)->inode);
while (pos < inline_size) {
/*
* As inlined dir doesn't store any information about '.' and
* only the inode number of '..' is stored, we have to handle
* them differently.
*/
if (pos == 0) {
fake.inode = cpu_to_le32(inode->i_ino);
fake.name_len = 1;
strcpy(fake.name, ".");
fake.rec_len = ext4_rec_len_to_disk(
EXT4_DIR_REC_LEN(fake.name_len),
inline_size);
ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
de = &fake;
pos = EXT4_INLINE_DOTDOT_OFFSET;
} else if (pos == EXT4_INLINE_DOTDOT_OFFSET) {
fake.inode = cpu_to_le32(parent_ino);
fake.name_len = 2;
strcpy(fake.name, "..");
fake.rec_len = ext4_rec_len_to_disk(
EXT4_DIR_REC_LEN(fake.name_len),
inline_size);
ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
de = &fake;
pos = EXT4_INLINE_DOTDOT_SIZE;
} else {
de = (struct ext4_dir_entry_2 *)(dir_buf + pos);
pos += ext4_rec_len_from_disk(de->rec_len, inline_size);
if (ext4_check_dir_entry(inode, dir_file, de,
iloc.bh, dir_buf,
inline_size, pos)) {
ret = count;
goto out;
}
}
ext4fs_dirhash(de->name, de->name_len, hinfo);
if ((hinfo->hash < start_hash) ||
((hinfo->hash == start_hash) &&
(hinfo->minor_hash < start_minor_hash)))
continue;
if (de->inode == 0)
continue;
err = ext4_htree_store_dirent(dir_file,
hinfo->hash, hinfo->minor_hash, de);
if (err) {
count = err;
goto out;
}
count++;
}
ret = count;
out:
kfree(dir_buf);
brelse(iloc.bh);
return ret;
}
int ext4_read_inline_dir(struct file *filp,
void *dirent, filldir_t filldir,
int *has_inline_data)

29
fs/ext4/namei.c
View File

@ -972,6 +972,17 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
hinfo.hash_version +=
EXT4_SB(dir->i_sb)->s_hash_unsigned;
hinfo.seed = EXT4_SB(dir->i_sb)->s_hash_seed;
if (ext4_has_inline_data(dir)) {
int has_inline_data = 1;
count = htree_inlinedir_to_tree(dir_file, dir, 0,
&hinfo, start_hash,
start_minor_hash,
&has_inline_data);
if (has_inline_data) {
*next_hash = ~0;
return count;
}
}
count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo,
start_hash, start_minor_hash);
*next_hash = ~0;
@ -1456,24 +1467,6 @@ struct dentry *ext4_get_parent(struct dentry *child)
return d_obtain_alias(ext4_iget(child->d_inode->i_sb, ino));
}
#define S_SHIFT 12
static unsigned char ext4_type_by_mode[S_IFMT >> S_SHIFT] = {
[S_IFREG >> S_SHIFT] = EXT4_FT_REG_FILE,
[S_IFDIR >> S_SHIFT] = EXT4_FT_DIR,
[S_IFCHR >> S_SHIFT] = EXT4_FT_CHRDEV,
[S_IFBLK >> S_SHIFT] = EXT4_FT_BLKDEV,
[S_IFIFO >> S_SHIFT] = EXT4_FT_FIFO,
[S_IFSOCK >> S_SHIFT] = EXT4_FT_SOCK,
[S_IFLNK >> S_SHIFT] = EXT4_FT_SYMLINK,
};
static inline void ext4_set_de_type(struct super_block *sb,
struct ext4_dir_entry_2 *de,
umode_t mode) {
if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE))
de->file_type = ext4_type_by_mode[(mode & S_IFMT)>>S_SHIFT];
}
/*
* Move count entries from end of map between two memory locations.
* Returns pointer to last entry moved.