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Message-ID: <20171107185333.GA6233@magnolia>
Date: Tue, 7 Nov 2017 10:53:33 -0800
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: Artem Blagodarenko <artem.blagodarenko@...il.com>
Cc: linux-ext4@...r.kernel.org, adilger.kernel@...ger.ca,
Andreas Dilger <andreas.dilger@...el.com>
Subject: Re: [RFC PATCH v2 1/2] ext4: dirdata feature
On Thu, Nov 02, 2017 at 12:24:54AM +0300, Artem Blagodarenko wrote:
> From: Andreas Dilger <andreas.dilger@...el.com>
>
> This patch implements feature which allows ext4 fs users (e.g. Lustre)
> to 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.
>
> Make use of dentry->d_fsdata to pass fid to ext4. so no
> changes in ext4_add_entry() interface required.
>
> Signed-off-by: Andreas Dilger <andreas.dilger@...el.com>
> Signed-off-by: Artem Blagodarenko <artem.blagodarenko@...il.com>
> ---
> fs/ext4/dir.c | 17 +++++---
> fs/ext4/ext4.h | 85 ++++++++++++++++++++++++++++++++++---
> fs/ext4/inline.c | 18 ++++----
> fs/ext4/namei.c | 126 ++++++++++++++++++++++++++++++++++++++++++-------------
> fs/ext4/super.c | 3 +-
> 5 files changed, 200 insertions(+), 49 deletions(-)
>
> diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
> index b04e882179c6..46fcb8ec47a6 100644
> --- a/fs/ext4/dir.c
> +++ b/fs/ext4/dir.c
> @@ -67,11 +67,11 @@ int __ext4_check_dir_entry(const char *function, unsigned int line,
> const int rlen = ext4_rec_len_from_disk(de->rec_len,
> dir->i_sb->s_blocksize);
>
> - if (unlikely(rlen < EXT4_DIR_REC_LEN(1)))
> + if (unlikely(rlen < __EXT4_DIR_REC_LEN(1)))
> error_msg = "rec_len is smaller than minimal";
> else if (unlikely(rlen % 4 != 0))
> error_msg = "rec_len % 4 != 0";
> - else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len)))
> + else if (unlikely(rlen < EXT4_DIR_REC_LEN(de)))
> error_msg = "rec_len is too small for name_len";
> else if (unlikely(((char *) de - buf) + rlen > size))
> error_msg = "directory entry across range";
> @@ -218,7 +218,8 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
> * failure will be detected in the
> * dirent test below. */
> if (ext4_rec_len_from_disk(de->rec_len,
> - sb->s_blocksize) < EXT4_DIR_REC_LEN(1))
> + sb->s_blocksize) <
> + __EXT4_DIR_REC_LEN(1))
> break;
> i += ext4_rec_len_from_disk(de->rec_len,
> sb->s_blocksize);
> @@ -441,12 +442,18 @@ int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
> struct fname *fname, *new_fn;
> struct dir_private_info *info;
> int len;
> + int extra_data = 0;
>
> info = dir_file->private_data;
> p = &info->root.rb_node;
>
> /* Create and allocate the fname structure */
> - len = sizeof(struct fname) + ent_name->len + 1;
> + if (dirent->file_type & ~EXT4_FT_MASK)
> + extra_data = ext4_get_dirent_data_len(dirent);
> +
> + len = sizeof(struct fname) + dirent->name_len + extra_data + 1;
> +
> +
> new_fn = kzalloc(len, GFP_KERNEL);
> if (!new_fn)
> return -ENOMEM;
> @@ -455,7 +462,7 @@ int ext4_htree_store_dirent(struct file *dir_file, __u32 hash,
> new_fn->inode = le32_to_cpu(dirent->inode);
> new_fn->name_len = ent_name->len;
> new_fn->file_type = dirent->file_type;
> - memcpy(new_fn->name, ent_name->name, ent_name->len);
> + memcpy(new_fn->name, ent_name->name, ent_name->len + extra_data);
> new_fn->name[ent_name->len] = 0;
>
> while (*p) {
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index e2abe01c8c6b..9a9b01b0956a 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1111,6 +1111,7 @@ struct ext4_inode_info {
> * Mount flags set via mount options or defaults
> */
> #define EXT4_MOUNT_NO_MBCACHE 0x00001 /* Do not use mbcache */
> +#define EXT4_MOUNT_DIRDATA 0x00002 /* Data in directory entries*/
> #define EXT4_MOUNT_GRPID 0x00004 /* Create files with directory's group */
> #define EXT4_MOUNT_DEBUG 0x00008 /* Some debugging messages */
> #define EXT4_MOUNT_ERRORS_CONT 0x00010 /* Continue on errors */
> @@ -1804,7 +1805,8 @@ EXT4_FEATURE_INCOMPAT_FUNCS(encrypt, ENCRYPT)
> EXT4_FEATURE_INCOMPAT_INLINE_DATA | \
> EXT4_FEATURE_INCOMPAT_ENCRYPT | \
> EXT4_FEATURE_INCOMPAT_CSUM_SEED | \
> - EXT4_FEATURE_INCOMPAT_LARGEDIR)
> + EXT4_FEATURE_INCOMPAT_LARGEDIR | \
> + 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| \
> @@ -1965,6 +1967,45 @@ struct ext4_dir_entry_tail {
>
> #define EXT4_FT_DIR_CSUM 0xDE
>
> +#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_DIRENT_INODE 0x20
> +#define DIRENT_INODE_LEN 2
Unrelated addition, since large inodes are the next patch?
> +
> +#define EXT4_LUFID_MAGIC 0xAD200907UL
> +struct ext4_dentry_param {
> + __u32 edp_magic; /* EXT4_LUFID_MAGIC */
If this is an on-disk data structure, this field type should be __le32.
> + char edp_len; /* size of edp_data in bytes */
Don't we already have a length byte preceeding edp_magic that tells us
the length of the data? I guess it's necessary for the incore buffer to
track the length of edp_data, but since this gets memcpy'd into the
dirent that means we store redundant size information.
> + char edp_data[0]; /* packed array of data */
(and these should be __u8, not char)
> +} __packed;
> +
> +static inline unsigned char *ext4_dentry_get_data(struct super_block *sb,
> + struct ext4_dentry_param *p)
> +{
> + if (!ext4_has_feature_dirdata(sb))
> + 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
> *
> @@ -1972,8 +2013,11 @@ struct ext4_dir_entry_tail {
> */
> #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)))
Now that we have __EXT4_DIR_REC_LEN and EXT4_DIR_REC_LEN, how about a
comment to describe how they differ from each other?
> +
> #define EXT4_MAX_REC_LEN ((1<<16)-1)
>
> /*
> @@ -2376,7 +2420,10 @@ extern int ext4_find_dest_de(struct inode *dir, struct inode *inode,
> struct buffer_head *bh,
> void *buf, int buf_size,
> struct ext4_filename *fname,
> - struct ext4_dir_entry_2 **dest_de);
> + struct ext4_dir_entry_2 **dest_de,
> + bool is_dotdot,
> + bool *write_short_dotdot,
> + unsigned short dotdot_reclen);
> void ext4_insert_dentry(struct inode *inode,
> struct ext4_dir_entry_2 *de,
> int buf_size,
> @@ -2392,10 +2439,16 @@ static const unsigned char ext4_filetype_table[] = {
>
> static inline unsigned char get_dtype(struct super_block *sb, int filetype)
> {
> - if (!ext4_has_feature_filetype(sb) || filetype >= EXT4_FT_MAX)
> + int fl_index = filetype & EXT4_FT_MASK;
> +
> + if (!ext4_has_feature_filetype(sb) || fl_index >= EXT4_FT_MAX)
> return DT_UNKNOWN;
>
> - return ext4_filetype_table[filetype];
> + if (!test_opt(sb, DIRDATA))
> + return (ext4_filetype_table[fl_index]);
What's the use case for having the incompat feature flag set on disk but
no mount option?
> + return (ext4_filetype_table[fl_index]) |
> + (filetype & ~EXT4_FT_MASK);
So I guess this just overrides DT_*? Is the high nibble of de->filetype
(the new EXT4_DIRENT_* flags) exposed to userspace? It would seem to
be, since the return value is passed to dir_emit(), in which case
userland readdir callers are in for a surprise.
> }
> extern int ext4_check_all_de(struct inode *dir, struct buffer_head *bh,
> void *buf, int buf_size);
> @@ -3271,6 +3324,28 @@ static inline void ext4_clear_io_unwritten_flag(ext4_io_end_t *io_end)
>
> extern const struct iomap_ops ext4_iomap_ops;
>
> +/*
> + * 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;
Ugh, dereferencing an char pointer to get the length. See later rant
about adding struct ext4_dirent_data_header to avoid this raw byte
interpretation stuff.
> + }
> + extra_data_flags >>= 1;
> + }
> + return dlen;
> +}
> +
> #endif /* __KERNEL__ */
>
> #define EFSBADCRC EBADMSG /* Bad CRC detected */
> diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
> index 28c5c3abddb3..ea46735e18c6 100644
> --- a/fs/ext4/inline.c
> +++ b/fs/ext4/inline.c
> @@ -1026,7 +1026,7 @@ static int ext4_add_dirent_to_inline(handle_t *handle,
> struct ext4_dir_entry_2 *de;
>
> err = ext4_find_dest_de(dir, inode, iloc->bh, inline_start,
> - inline_size, fname, &de);
> + inline_size, fname, &de, 0, NULL, 0);
> if (err)
> return err;
>
> @@ -1103,7 +1103,7 @@ static int ext4_update_inline_dir(handle_t *handle, struct inode *dir,
> int old_size = EXT4_I(dir)->i_inline_size - EXT4_MIN_INLINE_DATA_SIZE;
> int new_size = get_max_inline_xattr_value_size(dir, iloc);
>
> - if (new_size - old_size <= EXT4_DIR_REC_LEN(1))
> + if (new_size - old_size <= __EXT4_DIR_REC_LEN(1))
> return -ENOSPC;
>
> ret = ext4_update_inline_data(handle, dir,
> @@ -1384,8 +1384,8 @@ int htree_inlinedir_to_tree(struct file *dir_file,
> 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_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;
> @@ -1394,8 +1394,8 @@ int htree_inlinedir_to_tree(struct file *dir_file,
> 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_DIR_REC_LEN(fake.name_len),
> + inline_size);
Unrelated indenting changes...
> ext4_set_de_type(inode->i_sb, &fake, S_IFDIR);
> de = &fake;
> pos = EXT4_INLINE_DOTDOT_SIZE;
> @@ -1492,8 +1492,8 @@ int ext4_read_inline_dir(struct file *file,
> * So we will use extra_offset and extra_size to indicate them
> * during the inline dir iteration.
> */
> - dotdot_offset = EXT4_DIR_REC_LEN(1);
> - dotdot_size = dotdot_offset + EXT4_DIR_REC_LEN(2);
> + dotdot_offset = __EXT4_DIR_REC_LEN(1);
> + dotdot_size = dotdot_offset + __EXT4_DIR_REC_LEN(2);
> extra_offset = dotdot_size - EXT4_INLINE_DOTDOT_SIZE;
> extra_size = extra_offset + inline_size;
>
> @@ -1528,7 +1528,7 @@ int ext4_read_inline_dir(struct file *file,
> * failure will be detected in the
> * dirent test below. */
> if (ext4_rec_len_from_disk(de->rec_len, extra_size)
> - < EXT4_DIR_REC_LEN(1))
> + < __EXT4_DIR_REC_LEN(1))
> break;
> i += ext4_rec_len_from_disk(de->rec_len,
> extra_size);
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index c1cf020d1889..b09e73100e14 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -249,7 +249,8 @@ static unsigned dx_get_count(struct dx_entry *entries);
> 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 int dx_root_limit(struct inode *dir,
> + struct ext4_dir_entry_2 *dot_de, unsigned int infosize);
> static unsigned dx_node_limit(struct inode *dir);
> static struct dx_frame *dx_probe(struct ext4_filename *fname,
> struct inode *dir,
> @@ -551,10 +552,16 @@ static inline void dx_set_limit(struct dx_entry *entries, unsigned value)
> ((struct dx_countlimit *) entries)->limit = cpu_to_le16(value);
> }
>
> -static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
> +static inline unsigned int dx_root_limit(struct inode *dir,
> + struct ext4_dir_entry_2 *dot_de, unsigned int 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 int entry_space;
> +
> + BUG_ON(dot_de->name_len != 1);
Yikes, this will crash the kernel when someone feeds us malicious
metadata!
> + dotdot_de = ext4_next_entry(dot_de, dir->i_sb->s_blocksize);
> + entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(dot_de) -
> + EXT4_DIR_REC_LEN(dotdot_de) - infosize;
>
> if (ext4_has_metadata_csum(dir->i_sb))
> entry_space -= sizeof(struct dx_tail);
> @@ -563,7 +570,8 @@ static inline unsigned dx_root_limit(struct inode *dir, unsigned infosize)
>
> static inline unsigned dx_node_limit(struct inode *dir)
> {
> - unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
> + unsigned int entry_space = dir->i_sb->s_blocksize -
> + __EXT4_DIR_REC_LEN(0);
>
> if (ext4_has_metadata_csum(dir->i_sb))
> entry_space -= sizeof(struct dx_tail);
> @@ -675,7 +683,7 @@ static struct stats dx_show_leaf(struct inode *dir,
> (unsigned) ((char *) de - base));
> #endif
> }
> - space += EXT4_DIR_REC_LEN(de->name_len);
> + space += EXT4_DIR_REC_LEN(de);
> names++;
> }
> de = ext4_next_entry(de, size);
> @@ -785,10 +793,14 @@ dx_probe(struct ext4_filename *fname, struct inode *dir,
> root->info.info_length);
>
> if (dx_get_limit(entries) != dx_root_limit(dir,
> - root->info.info_length)) {
> + (struct ext4_dir_entry_2 *) frame->bh->b_data,
> + root->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,
> + (struct ext4_dir_entry_2 *)
> + frame->bh->b_data,
> + root->info.info_length));
> goto fail;
> }
>
> @@ -980,7 +992,7 @@ static int htree_dirblock_to_tree(struct file *dir_file,
> 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));
> #ifdef CONFIG_EXT4_FS_ENCRYPTION
> /* Check if the directory is encrypted */
> if (ext4_encrypted_inode(dir)) {
> @@ -1563,6 +1575,7 @@ static struct dentry *ext4_lookup(struct inode *dir, struct dentry *dentry, unsi
> inode = NULL;
> if (bh) {
> __u32 ino = le32_to_cpu(de->inode);
> +
> brelse(bh);
> if (!ext4_valid_inum(dir->i_sb, ino)) {
> EXT4_ERROR_INODE(dir, "bad inode number: %u", ino);
> @@ -1631,7 +1644,7 @@ dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count,
> while (count--) {
> struct ext4_dir_entry_2 *de = (struct ext4_dir_entry_2 *)
> (from + (map->offs<<2));
> - 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, blocksize);
> @@ -1655,7 +1668,7 @@ static struct ext4_dir_entry_2* dx_pack_dirents(char *base, unsigned blocksize)
> while ((char*)de < base + blocksize) {
> next = ext4_next_entry(de, blocksize);
> 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, blocksize);
> @@ -1786,10 +1799,13 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
> struct buffer_head *bh,
> void *buf, int buf_size,
> struct ext4_filename *fname,
> - struct ext4_dir_entry_2 **dest_de)
> + struct ext4_dir_entry_2 **dest_de,
> + bool is_dotdot,
> + bool *write_short_dotdot,
> + unsigned short dotdot_reclen)
> {
> struct ext4_dir_entry_2 *de;
> - unsigned short reclen = EXT4_DIR_REC_LEN(fname_len(fname));
> + unsigned short reclen = __EXT4_DIR_REC_LEN(fname_len(fname));
> int nlen, rlen;
> unsigned int offset = 0;
> char *top;
> @@ -1802,10 +1818,28 @@ int ext4_find_dest_de(struct inode *dir, struct inode *inode,
> return -EFSCORRUPTED;
> if (ext4_match(fname, de))
> 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, buf_size);
> + /* Check first for enough space for the full entry */
> if ((de->inode ? rlen - nlen : rlen) >= reclen)
> break;
> + /* Then for dotdot entries, check for the smaller space
> + * required for just the entry, no FID
> + */
> + if (is_dotdot) {
> + if ((de->inode ? rlen - nlen : rlen) >=
> + dotdot_reclen) {
> + *write_short_dotdot = true;
> + break;
> + }
> + /* The new ".." entry mut be written over the
> + * previous ".." entry, which is the first
> + * entry traversed by this scan. If it doesn't
> + * fit, something is badly wrong, so -EIO.
> + */
> + return -EIO;
> + }
> +
> de = (struct ext4_dir_entry_2 *)((char *)de + rlen);
> offset += rlen;
> }
> @@ -1824,7 +1858,8 @@ void ext4_insert_dentry(struct inode *inode,
>
> int nlen, rlen;
>
> - nlen = EXT4_DIR_REC_LEN(de->name_len);
> + nlen = EXT4_DIR_REC_LEN(de);
> +
> rlen = ext4_rec_len_from_disk(de->rec_len, buf_size);
> if (de->inode) {
> struct ext4_dir_entry_2 *de1 =
> @@ -1848,21 +1883,46 @@ void ext4_insert_dentry(struct inode *inode,
> * space. It will return -ENOSPC if no space is available, and -EIO
> * and -EEXIST if directory entry already exists.
> */
> -static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
> +static int add_dirent_to_buf(handle_t *handle,
> + struct dentry *dentry,
> + struct ext4_filename *fname,
> struct inode *dir,
> struct inode *inode, struct ext4_dir_entry_2 *de,
> struct buffer_head *bh)
> {
> unsigned int blocksize = dir->i_sb->s_blocksize;
> int csum_size = 0;
> - int err;
> + unsigned short reclen, dotdot_reclen = 0;
> + int err, dlen = 0;
> + bool is_dotdot = false, write_short_dotdot = false;
> + unsigned char *data;
> + int namelen = dentry->d_name.len;
>
> if (ext4_has_metadata_csum(inode->i_sb))
> csum_size = sizeof(struct ext4_dir_entry_tail);
>
> + data = ext4_dentry_get_data(inode->i_sb, (struct ext4_dentry_param *)
> + dentry->d_fsdata);
> + if (data)
> + dlen = (*data) + 1;
Ok, now I /really/ want this to be some kind of data structure instead
of raw dereferencing of an unsigned char pointer to find the length.
struct ext4_dirent_data_header {
/* length of this header + the whole data blob */
__u8 ddh_length;
} __packed;
struct ext4_dirent_lufid {
struct ext4_dirent_data_header dl_header; /* 6+ */
__le32 dl_magic; /* 0xAD200907 */
__u8 dl_datalen;
__u8 dl_data[0];
} __packed;
struct ext4_dirent_inohi {
struct ext4_dirent_data_header di_header; /* 5 */
__le32 di_inohi;
} __packed;
...and then:
struct ext4_dirent_lufid *dl = ext4_dentry_get_data(...);
if (dl)
dlen = dl->dl_header.ddh_length + 1;
> +
> + is_dotdot = (namelen == 2 &&
> + memcmp(dentry->d_name.name, "..", 2) == 0);
> +
> + /* dotdot entries must be in the second place in a directory block,
> + * so calculate an alternate length without the dirdata so they can
> + * always be made to fit in the existing slot
> + */
> + if (is_dotdot)
> + dotdot_reclen = __EXT4_DIR_REC_LEN(namelen);
> +
> + reclen = __EXT4_DIR_REC_LEN(namelen + dlen + 3);
> +
> if (!de) {
> err = ext4_find_dest_de(dir, inode, bh, bh->b_data,
> - blocksize - csum_size, fname, &de);
> + blocksize - csum_size, fname, &de,
> + is_dotdot,
> + &write_short_dotdot, dotdot_reclen);
> if (err)
> return err;
> }
> @@ -1876,6 +1936,13 @@ static int add_dirent_to_buf(handle_t *handle, struct ext4_filename *fname,
> /* By now the buffer is marked for journaling */
> ext4_insert_dentry(inode, de, blocksize, fname);
>
> + /* If we're writing short form of "dotdot", don't add data section */
> + if (data && !write_short_dotdot) {
What if we're writing a long dotdot entry and write_short_dotdot is true?
We're not just dropping the LUFID on the floor, are we?
> + de->name[namelen] = 0;
Not sure why we suddenly need this extra null byte in the name; we've
gotten along just fine without it.
> + memcpy(&de->name[namelen + 1], data, *(char *)data);
memcpy(&de->name[namelen + 1], dl, dl->dl_header.ddh_length);
(Endian conversions?)
--D
> + de->file_type |= EXT4_DIRENT_LUFID;
> + }
> +
> /*
> * XXX shouldn't update any times until successful
> * completion of syscall, but too many callers depend
> @@ -1970,7 +2037,7 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
>
> /* 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),
> + 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);
> @@ -1978,7 +2045,8 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
> entries = root->entries;
> 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,
> + fde, sizeof(root->info)));
>
> /* Initialize as for dx_probe */
> fname->hinfo.hash_version = root->info.hash_version;
> @@ -2006,7 +2074,7 @@ static int make_indexed_dir(handle_t *handle, struct ext4_filename *fname,
> goto out_frames;
> }
>
> - retval = add_dirent_to_buf(handle, fname, dir, inode, de, bh2);
> + retval = add_dirent_to_buf(handle, NULL, fname, dir, inode, de, bh2);
> out_frames:
> /*
> * Even if the block split failed, we have to properly write
> @@ -2083,7 +2151,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
> bh = NULL;
> goto out;
> }
> - retval = add_dirent_to_buf(handle, &fname, dir, inode,
> + retval = add_dirent_to_buf(handle, dentry, &fname, dir, inode,
> NULL, bh);
> if (retval != -ENOSPC)
> goto out;
> @@ -2112,7 +2180,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
> initialize_dirent_tail(t, blocksize);
> }
>
> - retval = add_dirent_to_buf(handle, &fname, dir, inode, de, bh);
> + retval = add_dirent_to_buf(handle, dentry, &fname, dir, inode, de, bh);
> out:
> ext4_fname_free_filename(&fname);
> brelse(bh);
> @@ -2154,7 +2222,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
> if (err)
> goto journal_error;
>
> - err = add_dirent_to_buf(handle, fname, dir, inode, NULL, bh);
> + err = add_dirent_to_buf(handle, NULL, fname, dir, inode, NULL, bh);
> if (err != -ENOSPC)
> goto cleanup;
>
> @@ -2279,7 +2347,7 @@ static int ext4_dx_add_entry(handle_t *handle, struct ext4_filename *fname,
> err = PTR_ERR(de);
> goto cleanup;
> }
> - err = add_dirent_to_buf(handle, fname, dir, inode, de, bh);
> + err = add_dirent_to_buf(handle, NULL, fname, dir, inode, de, bh);
> goto cleanup;
>
> journal_error:
> @@ -2545,7 +2613,7 @@ struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
> {
> 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),
> + de->rec_len = ext4_rec_len_to_disk(EXT4_DIR_REC_LEN(de),
> blocksize);
> strcpy(de->name, ".");
> ext4_set_de_type(inode->i_sb, de, S_IFDIR);
> @@ -2555,11 +2623,11 @@ struct ext4_dir_entry_2 *ext4_init_dot_dotdot(struct inode *inode,
> de->name_len = 2;
> if (!dotdot_real_len)
> de->rec_len = ext4_rec_len_to_disk(blocksize -
> - (csum_size + EXT4_DIR_REC_LEN(1)),
> + (csum_size + __EXT4_DIR_REC_LEN(1)),
> blocksize);
> else
> de->rec_len = ext4_rec_len_to_disk(
> - EXT4_DIR_REC_LEN(de->name_len), blocksize);
> + EXT4_DIR_REC_LEN(de), blocksize);
> strcpy(de->name, "..");
> ext4_set_de_type(inode->i_sb, de, S_IFDIR);
>
> @@ -2688,7 +2756,7 @@ bool ext4_empty_dir(struct inode *inode)
> }
>
> 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)) {
> EXT4_ERROR_INODE(inode, "invalid size");
> return true;
> }
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index b0915b734a38..ead9406d9cff 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1339,7 +1339,7 @@ enum {
> Opt_data_err_abort, Opt_data_err_ignore, Opt_test_dummy_encryption,
> Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
> Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_jqfmt_vfsv1, Opt_quota,
> - Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err,
> + Opt_noquota, Opt_barrier, Opt_nobarrier, Opt_err, Opt_dirdata,
> Opt_usrquota, Opt_grpquota, Opt_prjquota, Opt_i_version, Opt_dax,
> Opt_stripe, Opt_delalloc, Opt_nodelalloc, Opt_mblk_io_submit,
> Opt_lazytime, Opt_nolazytime, Opt_debug_want_extra_isize,
> @@ -1400,6 +1400,7 @@ static const match_table_t tokens = {
> {Opt_noquota, "noquota"},
> {Opt_quota, "quota"},
> {Opt_usrquota, "usrquota"},
> + {Opt_dirdata, "dirdata"},
> {Opt_prjquota, "prjquota"},
> {Opt_barrier, "barrier=%u"},
> {Opt_barrier, "barrier"},
> --
> 2.13.5 (Apple Git-94)
>
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