static int
nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
int mode, struct buffer_head **out_bh)
{
struct buffer_head *bh;
unsigned long blknum = 0;
int ret = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
if (unlikely(!bh))
goto failed;
ret = -EEXIST; /* internal code */
if (buffer_uptodate(bh))
goto out;
if (mode == READA) {
if (!trylock_buffer(bh)) {
ret = -EBUSY;
goto failed_bh;
}
} else /* mode == READ */
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
goto out;
}
if (!buffer_mapped(bh)) { /* unused buffer */
ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff,
&blknum);
if (unlikely(ret)) {
unlock_buffer(bh);
goto failed_bh;
}
bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev;
bh->b_blocknr = blknum;
set_buffer_mapped(bh);
}
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(mode, bh);
ret = 0;
out:
get_bh(bh);
*out_bh = bh;
failed_bh:
unlock_page(bh->b_page);
page_cache_release(bh->b_page);
brelse(bh);
failed:
return ret;
}
static int
nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff,
int mode, int mode_flags, struct buffer_head **out_bh)
{
struct buffer_head *bh;
__u64 blknum = 0;
int ret = -ENOMEM;
bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0);
if (unlikely(!bh))
goto failed;
ret = -EEXIST; /* internal code */
if (buffer_uptodate(bh))
goto out;
if (mode_flags & REQ_RAHEAD) {
if (!trylock_buffer(bh)) {
ret = -EBUSY;
goto failed_bh;
}
} else /* mode == READ */
lock_buffer(bh);
if (buffer_uptodate(bh)) {
unlock_buffer(bh);
goto out;
}
ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum);
if (unlikely(ret)) {
unlock_buffer(bh);
goto failed_bh;
}
map_bh(bh, inode->i_sb, (sector_t)blknum);
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
submit_bh(mode, mode_flags, bh);
ret = 0;
trace_nilfs2_mdt_submit_block(inode, inode->i_ino, blkoff, mode);
out:
get_bh(bh);
*out_bh = bh;
failed_bh:
unlock_page(bh->b_page);
put_page(bh->b_page);
brelse(bh);
failed:
return ret;
}
/**
* nilfs_get_block() - get a file block on the filesystem (callback function)
* @inode - inode struct of the target file
* @blkoff - file block number
* @bh_result - buffer head to be mapped on
* @create - indicate whether allocating the block or not when it has not
* been allocated yet.
*
* This function does not issue actual read request of the specified data
* block. It is done by VFS.
* Bulk read for direct-io is not supported yet. (should be supported)
*/
int nilfs_get_block(struct inode *inode, sector_t blkoff,
struct buffer_head *bh_result, int create)
{
struct nilfs_inode_info *ii = NILFS_I(inode);
unsigned long blknum = 0;
int err = 0, ret;
struct inode *dat = nilfs_dat_inode(NILFS_I_NILFS(inode));
/* This exclusion control is a workaround; should be revised */
down_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
ret = nilfs_bmap_lookup(ii->i_bmap, (unsigned long)blkoff, &blknum);
up_read(&NILFS_MDT(dat)->mi_sem); /* XXX */
if (ret == 0) { /* found */
map_bh(bh_result, inode->i_sb, blknum);
goto out;
}
/* data block was not found */
if (ret == -ENOENT && create) {
struct nilfs_transaction_info ti;
bh_result->b_blocknr = 0;
err = nilfs_transaction_begin(inode->i_sb, &ti, 1);
if (unlikely(err))
goto out;
err = nilfs_bmap_insert(ii->i_bmap, (unsigned long)blkoff,
(unsigned long)bh_result);
if (unlikely(err != 0)) {
if (err == -EEXIST) {
/*
* The get_block() function could be called
* from multiple callers for an inode.
* However, the page having this block must
* be locked in this case.
*/
printk(KERN_WARNING
"nilfs_get_block: a race condition "
"while inserting a data block. "
"(inode number=%lu, file block "
"offset=%llu)\n",
inode->i_ino,
(unsigned long long)blkoff);
err = 0;
} else if (err == -EINVAL) {
nilfs_error(inode->i_sb, __func__,
"broken bmap (inode=%lu)\n",
inode->i_ino);
err = -EIO;
}
nilfs_transaction_abort(inode->i_sb);
goto out;
}
nilfs_transaction_commit(inode->i_sb); /* never fails */
/* Error handling should be detailed */
set_buffer_new(bh_result);
map_bh(bh_result, inode->i_sb, 0); /* dbn must be changed
to proper value */
} else if (ret == -ENOENT) {
/* not found is not error (e.g. hole); must return without
the mapped state flag. */
;
} else {
err = ret;
}
out:
return err;
}
