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ocfs2: Add directory block trailers. 

Future ocfs2 features metaecc and indexed directories need to store a
little bit of data in each dirblock.  For compatibility, we place this
in a trailer at the end of the dirblock.  The trailer plays itself as an
empty dirent, so that if the features are turned off, it can be reused
without requiring a tunefs scan.

This code adds the trailer and validates it when the block is read in.

[ Mark is the original author, but I reinserted this code before his
  dir index work.  -- Joel ]

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>
This commit is contained in:
Mark Fasheh 2008-12-10 17:36:25 -08:00
parent 8400897249
commit 87d35a74b1
3 changed files with 215 additions and 14 deletions
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197
fs/ocfs2/dir.c
View File

@ -83,6 +83,63 @@ static int ocfs2_do_extend_dir(struct super_block *sb,
struct ocfs2_alloc_context *meta_ac,
struct buffer_head **new_bh);
/*
* These are distinct checks because future versions of the file system will
* want to have a trailing dirent structure independent of indexing.
*/
static int ocfs2_dir_has_trailer(struct inode *dir)
{
if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
return 0;
return ocfs2_meta_ecc(OCFS2_SB(dir->i_sb));
}
static int ocfs2_supports_dir_trailer(struct ocfs2_super *osb)
{
return ocfs2_meta_ecc(osb);
}
static inline unsigned int ocfs2_dir_trailer_blk_off(struct super_block *sb)
{
return sb->s_blocksize - sizeof(struct ocfs2_dir_block_trailer);
}
#define ocfs2_trailer_from_bh(_bh, _sb) ((struct ocfs2_dir_block_trailer *) ((_bh)->b_data + ocfs2_dir_trailer_blk_off((_sb))))
/*
* XXX: This is executed once on every dirent. We should consider optimizing
* it.
*/
static int ocfs2_skip_dir_trailer(struct inode *dir,
struct ocfs2_dir_entry *de,
unsigned long offset,
unsigned long blklen)
{
unsigned long toff = blklen - sizeof(struct ocfs2_dir_block_trailer);
if (!ocfs2_dir_has_trailer(dir))
return 0;
if (offset != toff)
return 0;
return 1;
}
static void ocfs2_init_dir_trailer(struct inode *inode,
struct buffer_head *bh)
{
struct ocfs2_dir_block_trailer *trailer;
trailer = ocfs2_trailer_from_bh(bh, inode->i_sb);
strcpy(trailer->db_signature, OCFS2_DIR_TRAILER_SIGNATURE);
trailer->db_compat_rec_len =
cpu_to_le16(sizeof(struct ocfs2_dir_block_trailer));
trailer->db_parent_dinode = cpu_to_le64(OCFS2_I(inode)->ip_blkno);
trailer->db_blkno = cpu_to_le64(bh->b_blocknr);
}
/*
* bh passed here can be an inode block or a dir data block, depending
* on the inode inline data flag.
@ -232,16 +289,60 @@ static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
{
int rc = 0;
struct buffer_head *tmp = *bh;
struct ocfs2_dir_block_trailer *trailer;
rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, flags,
ocfs2_validate_dir_block);
if (rc)
if (rc) {
mlog_errno(rc);
goto out;
}
/*
* We check the trailer here rather than in
* ocfs2_validate_dir_block() because that function doesn't have
* the inode to test.
*/
if (!(flags & OCFS2_BH_READAHEAD) &&
ocfs2_dir_has_trailer(inode)) {
trailer = ocfs2_trailer_from_bh(tmp, inode->i_sb);
if (!OCFS2_IS_VALID_DIR_TRAILER(trailer)) {
rc = -EINVAL;
ocfs2_error(inode->i_sb,
"Invalid dirblock #%llu: "
"signature = %.*s\n",
(unsigned long long)tmp->b_blocknr, 7,
trailer->db_signature);
goto out;
}
if (le64_to_cpu(trailer->db_blkno) != tmp->b_blocknr) {
rc = -EINVAL;
ocfs2_error(inode->i_sb,
"Directory block #%llu has an invalid "
"db_blkno of %llu",
(unsigned long long)tmp->b_blocknr,
(unsigned long long)le64_to_cpu(trailer->db_blkno));
goto out;
}
if (le64_to_cpu(trailer->db_parent_dinode) !=
OCFS2_I(inode)->ip_blkno) {
rc = -EINVAL;
ocfs2_error(inode->i_sb,
"Directory block #%llu on dinode "
"#%llu has an invalid parent_dinode "
"of %llu",
(unsigned long long)tmp->b_blocknr,
(unsigned long long)OCFS2_I(inode)->ip_blkno,
(unsigned long long)le64_to_cpu(trailer->db_blkno));
goto out;
}
}
/* If ocfs2_read_virt_blocks() got us a new bh, pass it up. */
if (!rc && !*bh)
if (!*bh)
*bh = tmp;
out:
return rc ? -EIO : 0;
}
@ -581,6 +682,16 @@ int __ocfs2_add_entry(handle_t *handle,
goto bail;
}
/* We're guaranteed that we should have space, so we
* can't possibly have hit the trailer...right? */
mlog_bug_on_msg(ocfs2_skip_dir_trailer(dir, de, offset, size),
"Hit dir trailer trying to insert %.*s "
"(namelen %d) into directory %llu. "
"offset is %lu, trailer offset is %d\n",
namelen, name, namelen,
(unsigned long long)parent_fe_bh->b_blocknr,
offset, ocfs2_dir_trailer_blk_off(dir->i_sb));
if (ocfs2_dirent_would_fit(de, rec_len)) {
dir->i_mtime = dir->i_ctime = CURRENT_TIME;
retval = ocfs2_mark_inode_dirty(handle, dir, parent_fe_bh);
@ -622,6 +733,7 @@ int __ocfs2_add_entry(handle_t *handle,
retval = 0;
goto bail;
}
offset += le16_to_cpu(de->rec_len);
de = (struct ocfs2_dir_entry *) ((char *) de + le16_to_cpu(de->rec_len));
}
@ -1059,9 +1171,15 @@ int ocfs2_empty_dir(struct inode *inode)
return !priv.seen_other;
}
static void ocfs2_fill_initial_dirents(struct inode *inode,
struct inode *parent,
char *start, unsigned int size)
/*
* Fills "." and ".." dirents in a new directory block. Returns dirent for
* "..", which might be used during creation of a directory with a trailing
* header. It is otherwise safe to ignore the return code.
*/
static struct ocfs2_dir_entry *ocfs2_fill_initial_dirents(struct inode *inode,
struct inode *parent,
char *start,
unsigned int size)
{
struct ocfs2_dir_entry *de = (struct ocfs2_dir_entry *)start;
@ -1078,6 +1196,8 @@ static void ocfs2_fill_initial_dirents(struct inode *inode,
de->name_len = 2;
strcpy(de->name, "..");
ocfs2_set_de_type(de, S_IFDIR);
return de;
}
/*
@ -1130,10 +1250,15 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
struct ocfs2_alloc_context *data_ac)
{
int status;
unsigned int size = osb->sb->s_blocksize;
struct buffer_head *new_bh = NULL;
struct ocfs2_dir_entry *de;
mlog_entry_void();
if (ocfs2_supports_dir_trailer(osb))
size = ocfs2_dir_trailer_blk_off(parent->i_sb);
status = ocfs2_do_extend_dir(osb->sb, handle, inode, fe_bh,
data_ac, NULL, &new_bh);
if (status < 0) {
@ -1151,8 +1276,9 @@ static int ocfs2_fill_new_dir_el(struct ocfs2_super *osb,
}
memset(new_bh->b_data, 0, osb->sb->s_blocksize);
ocfs2_fill_initial_dirents(inode, parent, new_bh->b_data,
osb->sb->s_blocksize);
de = ocfs2_fill_initial_dirents(inode, parent, new_bh->b_data, size);
if (ocfs2_supports_dir_trailer(osb))
ocfs2_init_dir_trailer(inode, new_bh);
status = ocfs2_journal_dirty(handle, new_bh);
if (status < 0) {
@ -1193,13 +1319,27 @@ int ocfs2_fill_new_dir(struct ocfs2_super *osb,
data_ac);
}
/*
* Expand rec_len of the rightmost dirent in a directory block so that it
* contains the end of our valid space for dirents. We do this during
* expansion from an inline directory to one with extents. The first dir block
* in that case is taken from the inline data portion of the inode block.
*
* We add the dir trailer if this filesystem wants it.
*/
static void ocfs2_expand_last_dirent(char *start, unsigned int old_size,
unsigned int new_size)
struct super_block *sb)
{
struct ocfs2_dir_entry *de;
struct ocfs2_dir_entry *prev_de;
char *de_buf, *limit;
unsigned int bytes = new_size - old_size;
unsigned int new_size = sb->s_blocksize;
unsigned int bytes;
if (ocfs2_supports_dir_trailer(OCFS2_SB(sb)))
new_size = ocfs2_dir_trailer_blk_off(sb);
bytes = new_size - old_size;
limit = start + old_size;
de_buf = start;
@ -1316,8 +1456,9 @@ static int ocfs2_expand_inline_dir(struct inode *dir, struct buffer_head *di_bh,
memcpy(dirdata_bh->b_data, di->id2.i_data.id_data, i_size_read(dir));
memset(dirdata_bh->b_data + i_size_read(dir), 0,
sb->s_blocksize - i_size_read(dir));
ocfs2_expand_last_dirent(dirdata_bh->b_data, i_size_read(dir),
sb->s_blocksize);
ocfs2_expand_last_dirent(dirdata_bh->b_data, i_size_read(dir), sb);
if (ocfs2_supports_dir_trailer(osb))
ocfs2_init_dir_trailer(dir, dirdata_bh);
ret = ocfs2_journal_dirty(handle, dirdata_bh);
if (ret) {
@ -1604,9 +1745,15 @@ do_extend:
goto bail;
}
memset(new_bh->b_data, 0, sb->s_blocksize);
de = (struct ocfs2_dir_entry *) new_bh->b_data;
de->inode = 0;
de->rec_len = cpu_to_le16(sb->s_blocksize);
if (ocfs2_dir_has_trailer(dir)) {
de->rec_len = cpu_to_le16(ocfs2_dir_trailer_blk_off(sb));
ocfs2_init_dir_trailer(dir, new_bh);
} else {
de->rec_len = cpu_to_le16(sb->s_blocksize);
}
status = ocfs2_journal_dirty(handle, new_bh);
if (status < 0) {
mlog_errno(status);
@ -1648,11 +1795,21 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
unsigned int *blocks_wanted)
{
int ret;
struct super_block *sb = dir->i_sb;
struct ocfs2_dinode *di = (struct ocfs2_dinode *)di_bh->b_data;
struct ocfs2_dir_entry *de, *last_de = NULL;
char *de_buf, *limit;
unsigned long offset = 0;
unsigned int rec_len, new_rec_len;
unsigned int rec_len, new_rec_len, free_space = dir->i_sb->s_blocksize;
/*
* This calculates how many free bytes we'd have in block zero, should
* this function force expansion to an extent tree.
*/
if (ocfs2_supports_dir_trailer(OCFS2_SB(sb)))
free_space = ocfs2_dir_trailer_blk_off(sb) - i_size_read(dir);
else
free_space = dir->i_sb->s_blocksize - i_size_read(dir);
de_buf = di->id2.i_data.id_data;
limit = de_buf + i_size_read(dir);
@ -1669,6 +1826,11 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
ret = -EEXIST;
goto out;
}
/*
* No need to check for a trailing dirent record here as
* they're not used for inline dirs.
*/
if (ocfs2_dirent_would_fit(de, rec_len)) {
/* Ok, we found a spot. Return this bh and let
* the caller actually fill it in. */
@ -1689,7 +1851,7 @@ static int ocfs2_find_dir_space_id(struct inode *dir, struct buffer_head *di_bh,
* dirent can be found.
*/
*blocks_wanted = 1;
new_rec_len = le16_to_cpu(last_de->rec_len) + (dir->i_sb->s_blocksize - i_size_read(dir));
new_rec_len = le16_to_cpu(last_de->rec_len) + free_space;
if (new_rec_len < (rec_len + OCFS2_DIR_REC_LEN(last_de->name_len)))
*blocks_wanted = 2;
@ -1707,6 +1869,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
struct ocfs2_dir_entry *de;
struct super_block *sb = dir->i_sb;
int status;
int blocksize = dir->i_sb->s_blocksize;
status = ocfs2_read_dir_block(dir, 0, &bh, 0);
if (status) {
@ -1748,6 +1911,11 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
status = -EEXIST;
goto bail;
}
if (ocfs2_skip_dir_trailer(dir, de, offset % blocksize,
blocksize))
goto next;
if (ocfs2_dirent_would_fit(de, rec_len)) {
/* Ok, we found a spot. Return this bh and let
* the caller actually fill it in. */
@ -1756,6 +1924,7 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
status = 0;
goto bail;
}
next:
offset += le16_to_cpu(de->rec_len);
de = (struct ocfs2_dir_entry *)((char *) de + le16_to_cpu(de->rec_len));
}

3
fs/ocfs2/ocfs2.h
View File

@ -470,6 +470,9 @@ static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)
#define OCFS2_IS_VALID_XATTR_BLOCK(ptr) \
(!strcmp((ptr)->xb_signature, OCFS2_XATTR_BLOCK_SIGNATURE))
#define OCFS2_IS_VALID_DIR_TRAILER(ptr) \
(!strcmp((ptr)->db_signature, OCFS2_DIR_TRAILER_SIGNATURE))
static inline unsigned long ino_from_blkno(struct super_block *sb,
u64 blkno)
{

29
fs/ocfs2/ocfs2_fs.h
View File

@ -65,6 +65,7 @@
#define OCFS2_EXTENT_BLOCK_SIGNATURE "EXBLK01"
#define OCFS2_GROUP_DESC_SIGNATURE "GROUP01"
#define OCFS2_XATTR_BLOCK_SIGNATURE "XATTR01"
#define OCFS2_DIR_TRAILER_SIGNATURE "DIRTRL1"
/* Compatibility flags */
#define OCFS2_HAS_COMPAT_FEATURE(sb,mask) \
@ -751,6 +752,34 @@ struct ocfs2_dir_entry {
/* Actual on-disk length specified by rec_len */
} __attribute__ ((packed));
/*
* Per-block record for the unindexed directory btree. This is carefully
* crafted so that the rec_len and name_len records of an ocfs2_dir_entry are
* mirrored. That way, the directory manipulation code needs a minimal amount
* of update.
*
* NOTE: Keep this structure aligned to a multiple of 4 bytes.
*/
struct ocfs2_dir_block_trailer {
/*00*/ __le64 db_compat_inode; /* Always zero. Was inode */
__le16 db_compat_rec_len; /* Backwards compatible with
* ocfs2_dir_entry. */
__u8 db_compat_name_len; /* Always zero. Was name_len */
__u8 db_reserved0;
__le16 db_reserved1;
__le16 db_free_rec_len; /* Size of largest empty hole
* in this block. (unused) */
/*10*/ __u8 db_signature[8]; /* Signature for verification */
__le64 db_reserved2;
__le64 db_free_next; /* Next block in list (unused) */
/*20*/ __le64 db_blkno; /* Offset on disk, in blocks */
__le64 db_parent_dinode; /* dinode which owns me, in
blocks */
/*30*/ __le64 db_check; /* Error checking */
/*40*/
};
/*
* On disk allocator group structure for OCFS2
*/