From a8549fb5abb2b372e46d5de0d23ff8b24f4a61af Mon Sep 17 00:00:00 2001 From: Joel Becker Date: Thu, 13 Nov 2008 14:49:20 -0800 Subject: ocfs2: Wrap virtual block reads in ocfs2_read_virt_blocks() The ocfs2_read_dir_block() function really maps an inode's virtual blocks to physical ones before calling ocfs2_read_blocks(). Let's extract that to common code, because other places might want to do that. Other than the block number being virtual, ocfs2_read_virt_blocks() takes the same arguments as ocfs2_read_blocks(). It converts those virtual block numbers to physical before calling ocfs2_read_blocks() directly. If the blocks asked for are discontiguous, this can mean multiple calls to ocfs2_read_blocks(), but this is mostly hidden from the caller. Like ocfs2_read_blocks(), the caller can pass in an existing buffer_head. This is usually done to pick up some readahead I/O. ocfs2_read_virt_blocks() checks the buffer_head's block number against the extent map - it must match. Signed-off-by: Joel Becker Signed-off-by: Mark Fasheh --- fs/ocfs2/extent_map.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) (limited to 'fs/ocfs2/extent_map.c') diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c index 0bd9d9698a24..f2bb1a04d253 100644 --- a/fs/ocfs2/extent_map.c +++ b/fs/ocfs2/extent_map.c @@ -806,3 +806,74 @@ out: return ret; } + +int ocfs2_read_virt_blocks(struct inode *inode, u64 v_block, int nr, + struct buffer_head *bhs[], int flags, + int (*validate)(struct super_block *sb, + struct buffer_head *bh)) +{ + int rc = 0; + u64 p_block, p_count; + int i, count, done = 0; + + mlog_entry("(inode = %p, v_block = %llu, nr = %d, bhs = %p, " + "flags = %x, validate = %p)\n", + inode, (unsigned long long)v_block, nr, bhs, flags, + validate); + + if (((v_block + nr - 1) << inode->i_sb->s_blocksize_bits) >= + i_size_read(inode)) { + BUG_ON(!(flags & OCFS2_BH_READAHEAD)); + goto out; + } + + while (done < nr) { + down_read(&OCFS2_I(inode)->ip_alloc_sem); + rc = ocfs2_extent_map_get_blocks(inode, v_block + done, + &p_block, &p_count, NULL); + up_read(&OCFS2_I(inode)->ip_alloc_sem); + if (rc) { + mlog_errno(rc); + break; + } + + if (!p_block) { + rc = -EIO; + mlog(ML_ERROR, + "Inode #%llu contains a hole at offset %llu\n", + (unsigned long long)OCFS2_I(inode)->ip_blkno, + (unsigned long long)(v_block + done) << + inode->i_sb->s_blocksize_bits); + break; + } + + count = nr - done; + if (p_count < count) + count = p_count; + + /* + * If the caller passed us bhs, they should have come + * from a previous readahead call to this function. Thus, + * they should have the right b_blocknr. + */ + for (i = 0; i < count; i++) { + if (!bhs[done + i]) + continue; + BUG_ON(bhs[done + i]->b_blocknr != (p_block + i)); + } + + rc = ocfs2_read_blocks(inode, p_block, count, bhs + done, + flags, validate); + if (rc) { + mlog_errno(rc); + break; + } + done += count; + } + +out: + mlog_exit(rc); + return rc; +} + + -- cgit v1.2.1