From 4b22645477b933f5cf2a972beebef367b628cdc2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 3 Jul 2003 04:54:42 -0700 Subject: Add an asynchronous buffer read-ahead facility. Nobody uses it for now, but I needed it for some tuning tests, and it is potentially useful for others. --- include/linux/buffer_head.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include/linux') diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 22d3ac8efc6b..1f468b0491ed 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -167,6 +167,7 @@ struct buffer_head *__find_get_block(struct block_device *, sector_t, int); struct buffer_head * __getblk(struct block_device *, sector_t, int); void __brelse(struct buffer_head *); void __bforget(struct buffer_head *); +void __breadahead(struct block_device *, sector_t block, int size); struct buffer_head *__bread(struct block_device *, sector_t block, int size); struct buffer_head *alloc_buffer_head(int gfp_flags); void free_buffer_head(struct buffer_head * bh); @@ -241,6 +242,12 @@ sb_bread(struct super_block *sb, sector_t block) return __bread(sb->s_bdev, block, sb->s_blocksize); } +static inline void +sb_breadahead(struct super_block *sb, sector_t block) +{ + __breadahead(sb->s_bdev, block, sb->s_blocksize); +} + static inline struct buffer_head * sb_getblk(struct super_block *sb, sector_t block) { -- cgit v1.2.3 From 9c67eccb82d6ce0fb44a812ef5f76be970eedd1b Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 3 Jul 2003 05:20:52 -0700 Subject: Re-organize "ext3_get_inode_loc()" and make it easier to follow by splitting it into two functions: one that calculates the position, and the other that actually reads the inode block off the disk. --- fs/ext3/inode.c | 101 +++++++++++++++++++++++++----------------------- include/linux/ext3_fs.h | 6 ++- 2 files changed, 57 insertions(+), 50 deletions(-) (limited to 'include/linux') diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index c2b0304b1855..aa632b07899a 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -2290,68 +2290,72 @@ out_stop: ext3_journal_stop(handle); } -/* - * ext3_get_inode_loc returns with an extra refcount against the - * inode's underlying buffer_head on success. - */ - -int ext3_get_inode_loc (struct inode *inode, struct ext3_iloc *iloc) +static unsigned long ext3_get_inode_block(struct super_block *sb, + unsigned long ino, struct ext3_iloc *iloc) { - struct buffer_head *bh = 0; - unsigned long block; - unsigned long block_group; - unsigned long group_desc; - unsigned long desc; - unsigned long offset; + unsigned long desc, group_desc, block_group; + unsigned long offset, block; + struct buffer_head *bh; struct ext3_group_desc * gdp; - if ((inode->i_ino != EXT3_ROOT_INO && - inode->i_ino != EXT3_JOURNAL_INO && - inode->i_ino < EXT3_FIRST_INO(inode->i_sb)) || - inode->i_ino > le32_to_cpu( - EXT3_SB(inode->i_sb)->s_es->s_inodes_count)) { - ext3_error (inode->i_sb, "ext3_get_inode_loc", - "bad inode number: %lu", inode->i_ino); - goto bad_inode; + if ((ino != EXT3_ROOT_INO && + ino != EXT3_JOURNAL_INO && + ino < EXT3_FIRST_INO(sb)) || + ino > le32_to_cpu( + EXT3_SB(sb)->s_es->s_inodes_count)) { + ext3_error (sb, "ext3_get_inode_block", + "bad inode number: %lu", ino); + return 0; } - block_group = (inode->i_ino - 1) / EXT3_INODES_PER_GROUP(inode->i_sb); - if (block_group >= EXT3_SB(inode->i_sb)->s_groups_count) { - ext3_error (inode->i_sb, "ext3_get_inode_loc", + block_group = (ino - 1) / EXT3_INODES_PER_GROUP(sb); + if (block_group >= EXT3_SB(sb)->s_groups_count) { + ext3_error (sb, "ext3_get_inode_block", "group >= groups count"); - goto bad_inode; + return 0; } - group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(inode->i_sb); - desc = block_group & (EXT3_DESC_PER_BLOCK(inode->i_sb) - 1); - bh = EXT3_SB(inode->i_sb)->s_group_desc[group_desc]; + group_desc = block_group >> EXT3_DESC_PER_BLOCK_BITS(sb); + desc = block_group & (EXT3_DESC_PER_BLOCK(sb) - 1); + bh = EXT3_SB(sb)->s_group_desc[group_desc]; if (!bh) { - ext3_error (inode->i_sb, "ext3_get_inode_loc", + ext3_error (sb, "ext3_get_inode_block", "Descriptor not loaded"); - goto bad_inode; + return 0; } gdp = (struct ext3_group_desc *) bh->b_data; /* * Figure out the offset within the block group inode table */ - offset = ((inode->i_ino - 1) % EXT3_INODES_PER_GROUP(inode->i_sb)) * - EXT3_INODE_SIZE(inode->i_sb); + offset = ((ino - 1) % EXT3_INODES_PER_GROUP(sb)) * + EXT3_INODE_SIZE(sb); block = le32_to_cpu(gdp[desc].bg_inode_table) + - (offset >> EXT3_BLOCK_SIZE_BITS(inode->i_sb)); - if (!(bh = sb_bread(inode->i_sb, block))) { - ext3_error (inode->i_sb, "ext3_get_inode_loc", - "unable to read inode block - " - "inode=%lu, block=%lu", inode->i_ino, block); - goto bad_inode; - } - offset &= (EXT3_BLOCK_SIZE(inode->i_sb) - 1); + (offset >> EXT3_BLOCK_SIZE_BITS(sb)); - iloc->bh = bh; - iloc->raw_inode = (struct ext3_inode *) (bh->b_data + offset); iloc->block_group = block_group; + iloc->offset = offset & (EXT3_BLOCK_SIZE(sb) - 1); + return block; +} - return 0; +/* + * ext3_get_inode_loc returns with an extra refcount against the + * inode's underlying buffer_head on success. + */ + +int ext3_get_inode_loc (struct inode *inode, struct ext3_iloc *iloc) +{ + unsigned long block; - bad_inode: + block = ext3_get_inode_block(inode->i_sb, inode->i_ino, iloc); + if (block) { + struct buffer_head *bh = sb_bread(inode->i_sb, block); + if (bh) { + iloc->bh = bh; + return 0; + } + ext3_error (inode->i_sb, "ext3_get_inode_loc", + "unable to read inode block - " + "inode=%lu, block=%lu", inode->i_ino, block); + } return -EIO; } @@ -2388,7 +2392,7 @@ void ext3_read_inode(struct inode * inode) if (ext3_get_inode_loc(inode, &iloc)) goto bad_inode; bh = iloc.bh; - raw_inode = iloc.raw_inode; + raw_inode = ext3_raw_inode(&iloc); inode->i_mode = le16_to_cpu(raw_inode->i_mode); inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); @@ -2454,11 +2458,9 @@ void ext3_read_inode(struct inode * inode) * even on big-endian machines: we do NOT byteswap the block numbers! */ for (block = 0; block < EXT3_N_BLOCKS; block++) - ei->i_data[block] = iloc.raw_inode->i_block[block]; + ei->i_data[block] = raw_inode->i_block[block]; INIT_LIST_HEAD(&ei->i_orphan); - brelse (iloc.bh); - if (S_ISREG(inode->i_mode)) { inode->i_op = &ext3_file_inode_operations; inode->i_fop = &ext3_file_operations; @@ -2476,8 +2478,9 @@ void ext3_read_inode(struct inode * inode) } else { inode->i_op = &ext3_special_inode_operations; init_special_inode(inode, inode->i_mode, - le32_to_cpu(iloc.raw_inode->i_block[0])); + le32_to_cpu(raw_inode->i_block[0])); } + brelse (iloc.bh); ext3_set_inode_flags(inode); return; @@ -2497,7 +2500,7 @@ static int ext3_do_update_inode(handle_t *handle, struct inode *inode, struct ext3_iloc *iloc) { - struct ext3_inode *raw_inode = iloc->raw_inode; + struct ext3_inode *raw_inode = ext3_raw_inode(iloc); struct ext3_inode_info *ei = EXT3_I(inode); struct buffer_head *bh = iloc->bh; int err = 0, rc, block; diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h index f077563bcfc3..c360f84fed3d 100644 --- a/include/linux/ext3_fs.h +++ b/include/linux/ext3_fs.h @@ -636,10 +636,14 @@ struct dx_hash_info struct ext3_iloc { struct buffer_head *bh; - struct ext3_inode *raw_inode; + unsigned long offset; unsigned long block_group; }; +static inline struct ext3_inode *ext3_raw_inode(struct ext3_iloc *iloc) +{ + return (struct ext3_inode *) (iloc->bh->b_data + iloc->offset); +} /* * This structure is stuffed into the struct file's private_data field -- cgit v1.2.3