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nilfs2: add read ahead mode to nilfs_btnode_submit_block

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This adds mode argument to nilfs_btnode_submit_block() function and
allows it to issue a read-ahead request.

An optional submit_ptr argument is also added to store the actual
block address for which bio is sent.  submit_ptr is used for a series
of read-ahead requests, and helps to decide if each requested block is
continous to the previous one on disk.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi 2010-07-18 10:42:23 +09:00
parent f8e6cc013b
commit 26dfdd8e29
4 changed files with 22 additions and 8 deletions
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17
fs/nilfs2/btnode.c
View file

@ -96,7 +96,8 @@ nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
}
int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
sector_t pblocknr, struct buffer_head **pbh)
sector_t pblocknr, int mode,
struct buffer_head **pbh, sector_t *submit_ptr)
{
struct buffer_head *bh;
struct inode *inode = NILFS_BTNC_I(btnc);
@ -127,7 +128,16 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
}
}
}
lock_buffer(bh);
if (mode == READA) {
if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
err = -EBUSY; /* internal code */
brelse(bh);
goto out_locked;
}
} else { /* mode == READ */
lock_buffer(bh);
}
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
err = -EEXIST; /* internal code */
@ -138,8 +148,9 @@ int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
bh->b_blocknr = pblocknr; /* set block address for read */
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(READ, bh);
submit_bh(mode, bh);
bh->b_blocknr = blocknr; /* set back to the given block address */
*submit_ptr = pblocknr;
err = 0;
found:
*pbh = bh;

4
fs/nilfs2/btnode.h
View file

@ -42,8 +42,8 @@ void nilfs_btnode_cache_init(struct address_space *, struct backing_dev_info *);
void nilfs_btnode_cache_clear(struct address_space *);
struct buffer_head *nilfs_btnode_create_block(struct address_space *btnc,
__u64 blocknr);
int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t,
struct buffer_head **);
int nilfs_btnode_submit_block(struct address_space *, __u64, sector_t, int,
struct buffer_head **, sector_t *);
void nilfs_btnode_delete(struct buffer_head *);
int nilfs_btnode_prepare_change_key(struct address_space *,
struct nilfs_btnode_chkey_ctxt *);

3
fs/nilfs2/btree.c
View file

@ -71,9 +71,10 @@ static int nilfs_btree_get_block(const struct nilfs_bmap *btree, __u64 ptr,
{
struct address_space *btnc = &NILFS_BMAP_I(btree)->i_btnode_cache;
struct buffer_head *bh;
sector_t pbn = 0;
int err;
err = nilfs_btnode_submit_block(btnc, ptr, 0, bhp);
err = nilfs_btnode_submit_block(btnc, ptr, pbn, READ, bhp, &pbn);
if (err)
return err == -EEXIST ? 0 : err;

6
fs/nilfs2/gcinode.c
View file

@ -151,8 +151,10 @@ int nilfs_gccache_submit_read_data(struct inode *inode, sector_t blkoff,
int nilfs_gccache_submit_read_node(struct inode *inode, sector_t pbn,
__u64 vbn, struct buffer_head **out_bh)
{
int ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
vbn ? : pbn, pbn, out_bh);
int ret;
ret = nilfs_btnode_submit_block(&NILFS_I(inode)->i_btnode_cache,
vbn ? : pbn, pbn, READ, out_bh, &pbn);
if (ret == -EEXIST) /* internal code (cache hit) */
ret = 0;
return ret;