From 87d35a74b15ec703910a63e0667692fb5e267be0 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Wed, 10 Dec 2008 17:36:25 -0800 Subject: [PATCH] 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 Signed-off-by: Mark Fasheh --- fs/ocfs2/dir.c | 197 ++++++++++++++++++++++++++++++++++++++++---- fs/ocfs2/ocfs2.h | 3 + fs/ocfs2/ocfs2_fs.h | 29 +++++++ 3 files changed, 215 insertions(+), 14 deletions(-) diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c index 45e4e03d8f71..1efd0ab680cf 100644 --- a/fs/ocfs2/dir.c +++ b/fs/ocfs2/dir.c @@ -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)); } diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h index bad87d0a03c9..ad5c24a29edd 100644 --- a/fs/ocfs2/ocfs2.h +++ b/fs/ocfs2/ocfs2.h @@ -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) { diff --git a/fs/ocfs2/ocfs2_fs.h b/fs/ocfs2/ocfs2_fs.h index 290fa26fba6e..af0013b9c17f 100644 --- a/fs/ocfs2/ocfs2_fs.h +++ b/fs/ocfs2/ocfs2_fs.h @@ -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 */ -- 2.20.1