this patch implements feature which allows ext4 fs uses (e.g. Lustre)
store data in ext4 dirent.
data is stored in ext4 dirent after file-name, this space is accounted
in de->rec_len. flag EXT4_DIRENT_LUFID added to d_type if extra data
is present.
Index: b/fs/ext4/dir.c
===================================================================
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -53,11 +53,18 @@ const struct file_operations ext4_dir_op
static unsigned char get_dtype(struct super_block *sb, int filetype)
{
+ int fl_index = filetype & EXT4_FT_MASK;
+
if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FILETYPE) ||
- (filetype >= EXT4_FT_MAX))
+ (fl_index >= EXT4_FT_MAX))
return DT_UNKNOWN;
- return (ext4_filetype_table[filetype]);
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_DIRDATA))
+ return (ext4_filetype_table[fl_index]);
+
+ return (ext4_filetype_table[fl_index]) |
+ (filetype & EXT4_DIRENT_LUFID);
+
}
@@ -69,11 +76,11 @@ int ext4_check_dir_entry (const char * f
const char * error_msg = NULL;
const int rlen = ext4_rec_len_from_disk(de->rec_len);
- if (rlen < EXT4_DIR_REC_LEN(1))
+ if (rlen < __EXT4_DIR_REC_LEN(1))
error_msg = "rec_len is smaller than minimal";
else if (rlen % 4 != 0)
error_msg = "rec_len % 4 != 0";
- else if (rlen < EXT4_DIR_REC_LEN(de->name_len))
+ else if (rlen < EXT4_DIR_REC_LEN(de))
error_msg = "rec_len is too small for name_len";
else if (((char *) de - bh->b_data) + rlen > dir->i_sb->s_blocksize)
error_msg = "directory entry across blocks";
@@ -175,7 +182,7 @@ revalidate:
* failure will be detected in the
* dirent test below. */
if (ext4_rec_len_from_disk(de->rec_len)
- < EXT4_DIR_REC_LEN(1))
+ < __EXT4_DIR_REC_LEN(1))
break;
i += ext4_rec_len_from_disk(de->rec_len);
}
@@ -209,7 +216,6 @@ revalidate:
* during the copy operation.
*/
u64 version = filp->f_version;
-
error = filldir(dirent, de->name,
de->name_len,
filp->f_pos,
@@ -335,12 +341,17 @@ int ext4_htree_store_dirent(struct file
struct fname * fname, *new_fn;
struct dir_private_info *info;
int len;
+ int extra_data = 1;
info = (struct dir_private_info *) dir_file->private_data;
p = &info->root.rb_node;
/* Create and allocate the fname structure */
- len = sizeof(struct fname) + dirent->name_len + 1;
+ if (dirent->file_type & EXT4_DIRENT_LUFID)
+ extra_data = ext4_get_dirent_data_len(dirent);
+
+ len = sizeof(struct fname) + dirent->name_len + extra_data;
+
new_fn = kzalloc(len, GFP_KERNEL);
if (!new_fn)
return -ENOMEM;
@@ -349,7 +360,7 @@ int ext4_htree_store_dirent(struct file
new_fn->inode = le32_to_cpu(dirent->inode);
new_fn->name_len = dirent->name_len;
new_fn->file_type = dirent->file_type;
- memcpy(new_fn->name, dirent->name, dirent->name_len);
+ memcpy(new_fn->name, dirent->name, dirent->name_len + extra_data);
new_fn->name[dirent->name_len] = 0;
while (*p) {
Index: b/fs/ext4/ext4.h
===================================================================
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -771,6 +771,7 @@ static inline int ext4_valid_inum(struct
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
+#define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
#define EXT4_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
#define EXT4_FEATURE_INCOMPAT_SUPP (EXT4_FEATURE_INCOMPAT_FILETYPE| \
@@ -779,7 +780,9 @@ static inline int ext4_valid_inum(struct
EXT4_FEATURE_INCOMPAT_EXTENTS| \
EXT4_FEATURE_INCOMPAT_64BIT| \
EXT4_FEATURE_INCOMPAT_FLEX_BG| \
- EXT4_FEATURE_INCOMPAT_MMP)
+ EXT4_FEATURE_INCOMPAT_MMP| \
+ EXT4_FEATURE_INCOMPAT_DIRDATA)
+
#define EXT4_FEATURE_RO_COMPAT_SUPP (EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT4_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_GDT_CSUM| \
@@ -847,6 +850,44 @@ struct ext4_dir_entry_2 {
#define EXT4_FT_SYMLINK 7
#define EXT4_FT_MAX 8
+#define EXT4_FT_MASK 0xf
+
+
+#if EXT4_FT_MAX > EXT4_FT_MASK
+#error "conflicting EXT4_FT_MAX and EXT4_FT_MASK"
+#endif
+
+/*
+ * d_type has 4 unused bits, so it can hold four types data. these different
+ * type of data (e.g. lustre data, high 32 bits of 64-bit inode number) can be
+ * stored, in flag order, after file-name in ext4 dirent.
+*/
+/*
+ * this flag is added to d_type if ext4 dirent has extra data after
+ * filename. this data length is variable and length is stored in first byte
+ * of data. data start after filename NUL byte.
+ * This is used by Lustre FS.
+ */
+#define EXT4_DIRENT_LUFID 0x10
+
+#define EXT4_LUFID_MAGIC 0xAD200907UL
+struct ext4_dentry_param {
+ __u32 edp_magic; /* EXT4_LUFID_MAGIC */
+ char edp_len; /* size of edp_data in bytes */
+ char edp_data[0]; /* packed array of data */
+} __attribute__((packed));
+
+static inline unsigned char *ext4_dentry_get_data(struct super_block *sb,
+ struct ext4_dentry_param* p)
+
+{
+ if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_DIRDATA))
+ return NULL;
+ if (p && p->edp_magic == EXT4_LUFID_MAGIC)
+ return &p->edp_len;
+ else
+ return NULL;
+}
/*
* EXT4_DIR_PAD defines the directory entries boundaries
@@ -855,8 +896,11 @@ struct ext4_dir_entry_2 {
*/
#define EXT4_DIR_PAD 4
#define EXT4_DIR_ROUND (EXT4_DIR_PAD - 1)
-#define EXT4_DIR_REC_LEN(name_len) (((name_len) + 8 + EXT4_DIR_ROUND) & \
+#define __EXT4_DIR_REC_LEN(name_len) (((name_len) + 8 + EXT4_DIR_ROUND) & \
~EXT4_DIR_ROUND)
+#define EXT4_DIR_REC_LEN(de) (__EXT4_DIR_REC_LEN(de->name_len +\
+ ext4_get_dirent_data_len(de)))
+
#define EXT4_MAX_REC_LEN ((1<<16)-1)
static inline unsigned ext4_rec_len_from_disk(__le16 dlen)
@@ -1155,7 +1199,7 @@ extern struct buffer_head * ext4_find_en
struct ext4_dir_entry_2
** res_dir);
extern int ext4_add_dot_dotdot(handle_t *handle, struct inode *dir,
- struct inode *inode);
+ struct inode *inode, const void *, const void *);
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,
@@ -1345,7 +1389,28 @@ static inline int ext4_is_group_locked(s
return spin_is_locked(ext4_group_lock_ptr(sb, group));
}
-
+/*
+ * Compute the total directory entry data length.
+ * This includes the filename and an implicit NUL terminator (always present),
+ * and optional extensions. Each extension has a bit set in the high 4 bits of
+ * de->file_type, and the extension length is the first byte in each entry.
+ */
+
+static inline int ext4_get_dirent_data_len(struct ext4_dir_entry_2 *de)
+{
+ char *len = de->name + de->name_len + 1 /* NUL terminator */;
+ int dlen = 0;
+ __u8 extra_data_flags = (de->file_type & ~EXT4_FT_MASK) >> 4;
+
+ while (extra_data_flags) {
+ if (extra_data_flags & 1) {
+ dlen += *len + (dlen == 0);
+ len += *len;
+ }
+ extra_data_flags >>= 1;
+ }
+ return dlen;
+}
#endif /* __KERNEL__ */
Index: b/fs/ext4/namei.c
===================================================================
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -171,7 +171,8 @@ static unsigned dx_get_count (struct dx_
static unsigned dx_get_limit (struct dx_entry *entries);
static void dx_set_count (struct dx_entry *entries, unsigned value);
static void dx_set_limit (struct dx_entry *entries, unsigned value);
-static unsigned dx_root_limit (struct inode *dir, unsigned infosize);
+static inline unsigned dx_root_limit(__u32 blocksize,
+ struct ext4_dir_entry_2 *dot_de, unsigned infosize);
static unsigned dx_node_limit (struct inode *dir);
static struct dx_frame *dx_probe(struct dentry *dentry,
struct inode *dir,
@@ -212,11 +213,12 @@ ext4_next_entry(struct ext4_dir_entry_2
*/
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));
+ BUG_ON(de->name_len != 1);
+ /* get dotdot first */
+ de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(de));
- /* dx root info is after dotdot entry */
- de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(2));
+ /* dx root info is after dotdot entry */
+ de = (struct ext4_dir_entry_2 *)((char *)de + EXT4_DIR_REC_LEN(de));
return (struct dx_root_info *) de;
}
@@ -261,16 +263,23 @@ static inline void dx_set_limit (struct
((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
}
-static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
+static inline unsigned dx_root_limit(__u32 blocksize,
+ struct ext4_dir_entry_2 *dot_de, unsigned infosize)
{
- unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
- EXT4_DIR_REC_LEN(2) - infosize;
+ struct ext4_dir_entry_2 *dotdot_de;
+ unsigned entry_space;
+
+ BUG_ON(dot_de->name_len != 1);
+ dotdot_de = ext4_next_entry(dot_de);
+ entry_space = blocksize - EXT4_DIR_REC_LEN(dot_de) -
+ EXT4_DIR_REC_LEN(dotdot_de) - infosize;
+
return entry_space / sizeof(struct dx_entry);
}
static inline unsigned dx_node_limit (struct inode *dir)
{
- unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
+ unsigned entry_space = dir->i_sb->s_blocksize - __EXT4_DIR_REC_LEN(0);
return entry_space / sizeof(struct dx_entry);
}
@@ -317,7 +326,7 @@ static struct stats dx_show_leaf(struct
printk(":%x.%u ", h.hash,
((char *) de - base));
}
- space += EXT4_DIR_REC_LEN(de->name_len);
+ space += EXT4_DIR_REC_LEN(de);
names++;
}
de = ext4_next_entry(de);
@@ -421,7 +430,8 @@ dx_probe(struct dentry *dentry, struct i
entries = (struct dx_entry *) (((char *)info) + info->info_length);
- if (dx_get_limit(entries) != dx_root_limit(dir,
+ if (dx_get_limit(entries) != dx_root_limit(dir->i_sb->s_blocksize,
+ (struct ext4_dir_entry_2*)bh->b_data,
info->info_length)) {
ext4_warning(dir->i_sb, __func__,
"dx entry: limit != root limit");
@@ -611,7 +621,7 @@ static int htree_dirblock_to_tree(struct
de = (struct ext4_dir_entry_2 *) bh->b_data;
top = (struct ext4_dir_entry_2 *) ((char *) de +
dir->i_sb->s_blocksize -
- EXT4_DIR_REC_LEN(0));
+ __EXT4_DIR_REC_LEN(0));
for (; de < top; de = ext4_next_entry(de)) {
if (!ext4_check_dir_entry("htree_dirblock_to_tree", dir, de, bh,
(block<<EXT4_BLOCK_SIZE_BITS(dir->i_sb))
@@ -1020,7 +1030,7 @@ static struct buffer_head * ext4_dx_find
goto errout;
de = (struct ext4_dir_entry_2 *) bh->b_data;
top = (struct ext4_dir_entry_2 *) ((char *) de + sb->s_blocksize -
- EXT4_DIR_REC_LEN(0));
+ __EXT4_DIR_REC_LEN(0));
for (; de < top; de = ext4_next_entry(de)) {
int off = (block << EXT4_BLOCK_SIZE_BITS(sb))
+ ((char *) de - bh->b_data);
@@ -1187,7 +1197,7 @@ dx_move_dirents(char *from, char *to, st
while (count--) {
struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *) (from + map->offs);
- rec_len = EXT4_DIR_REC_LEN(de->name_len);
+ rec_len = EXT4_DIR_REC_LEN(de);
memcpy (to, de, rec_len);
((struct ext4_dir_entry_2 *) to)->rec_len =
ext4_rec_len_to_disk(rec_len);
@@ -1211,7 +1221,7 @@ static struct ext4_dir_entry_2* dx_pack_
while ((char*)de < base + size) {
next = ext4_next_entry(de);
if (de->inode && de->name_len) {
- rec_len = EXT4_DIR_REC_LEN(de->name_len);
+ rec_len = EXT4_DIR_REC_LEN(de);
if (de > to)
memmove(to, de, rec_len);
to->rec_len = ext4_rec_len_to_disk(rec_len);
@@ -1341,10 +1351,17 @@ static int add_dirent_to_buf(handle_t *h
int namelen = dentry->d_name.len;
unsigned long offset = 0;
unsigned short reclen;
- int nlen, rlen, err;
+ int nlen, rlen, err, dlen = 0;
+ unsigned char *data;
char *top;
- reclen = EXT4_DIR_REC_LEN(namelen);
+ data = ext4_dentry_get_data(inode->i_sb,
+ (struct ext4_dentry_param *)
+ dentry->d_fsdata);
+ if (data)
+ dlen = (*data) + 1;
+
+ reclen = __EXT4_DIR_REC_LEN(namelen + dlen);
if (!de) {
de = (struct ext4_dir_entry_2 *)bh->b_data;
top = bh->b_data + dir->i_sb->s_blocksize - reclen;
@@ -1358,7 +1375,7 @@ static int add_dirent_to_buf(handle_t *h
brelse (bh);
return -EEXIST;
}
- nlen = EXT4_DIR_REC_LEN(de->name_len);
+ nlen = EXT4_DIR_REC_LEN(de);
rlen = ext4_rec_len_from_disk(de->rec_len);
if ((de->inode? rlen - nlen: rlen) >= reclen)
break;
@@ -1377,7 +1394,7 @@ static int add_dirent_to_buf(handle_t *h
}
/* By now the buffer is marked for journaling */
- nlen = EXT4_DIR_REC_LEN(de->name_len);
+ nlen = EXT4_DIR_REC_LEN(de);
rlen = ext4_rec_len_from_disk(de->rec_len);
if (de->inode) {
struct ext4_dir_entry_2 *de1 = (struct ext4_dir_entry_2 *)((char *)de + nlen);
@@ -1393,6 +1410,12 @@ static int add_dirent_to_buf(handle_t *h
de->inode = 0;
de->name_len = namelen;
memcpy (de->name, name, namelen);
+ if (data) {
+ de->name[namelen] = 0;
+ memcpy(&de->name[namelen + 1], data, *(char *) data);
+ de->file_type |= EXT4_DIRENT_LUFID;
+ }
+
/*
* XXX shouldn't update any times until successful
* completion of syscall, but too many callers depend
@@ -1482,7 +1505,8 @@ static int make_indexed_dir(handle_t *ha
dx_set_block(entries, 1);
dx_set_count(entries, 1);
- dx_set_limit(entries, dx_root_limit(dir, sizeof(*dx_info)));
+ dx_set_limit(entries, dx_root_limit(dir->i_sb->s_blocksize,
+ dot_de, sizeof(*dx_info)));
/* Initialize as for dx_probe */
hinfo.hash_version = dx_info->hash_version;
@@ -2067,7 +2125,7 @@ static int empty_dir (struct inode * ino
int err = 0;
sb = inode->i_sb;
- if (inode->i_size < EXT4_DIR_REC_LEN(1) + EXT4_DIR_REC_LEN(2) ||
+ if (inode->i_size < __EXT4_DIR_REC_LEN(1) + __EXT4_DIR_REC_LEN(2) ||
!(bh = ext4_bread (NULL, inode, 0, 0, &err))) {
if (err)
ext4_error(inode->i_sb, __func__,