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authorJoel Becker <joel.becker@oracle.com>2008-11-13 14:49:20 -0800
committerMark Fasheh <mfasheh@suse.com>2009-01-05 08:36:54 -0800
commita8549fb5abb2b372e46d5de0d23ff8b24f4a61af (patch)
treeb35c565519fec6827b4bd76938dcfd39e762caf4
parent970e4936d7d15f35d00fd15a14f5343ba78b2fc8 (diff)
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 <joel.becker@oracle.com> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
-rw-r--r--fs/ocfs2/extent_map.c71
-rw-r--r--fs/ocfs2/extent_map.h24
2 files changed, 95 insertions, 0 deletions
diff --git a/fs/ocfs2/extent_map.c b/fs/ocfs2/extent_map.c
index 0bd9d9698a2..f2bb1a04d25 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;
+}
+
+
diff --git a/fs/ocfs2/extent_map.h b/fs/ocfs2/extent_map.h
index 1c4aa8b06f3..b7dd9731b46 100644
--- a/fs/ocfs2/extent_map.h
+++ b/fs/ocfs2/extent_map.h
@@ -57,4 +57,28 @@ int ocfs2_xattr_get_clusters(struct inode *inode, u32 v_cluster,
u32 *p_cluster, u32 *num_clusters,
struct ocfs2_extent_list *el);
+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));
+static inline int ocfs2_read_virt_block(struct inode *inode, u64 v_block,
+ struct buffer_head **bh,
+ int (*validate)(struct super_block *sb,
+ struct buffer_head *bh))
+{
+ int status = 0;
+
+ if (bh == NULL) {
+ printk("ocfs2: bh == NULL\n");
+ status = -EINVAL;
+ goto bail;
+ }
+
+ status = ocfs2_read_virt_blocks(inode, v_block, 1, bh, 0, validate);
+
+bail:
+ return status;
+}
+
+
#endif /* _EXTENT_MAP_H */