ext4: lookup block mapping in extent status tree

After tracking all extent status, we already have a extent cache in
memory.  Every time we want to lookup a block mapping, we can first
try to lookup it in extent status tree to avoid a potential disk I/O.

A new function called ext4_es_lookup_extent is defined to finish this
work.  When we try to lookup a block mapping, we always call
ext4_map_blocks and/or ext4_da_map_blocks.  So in these functions we
first try to lookup a block mapping in extent status tree.

A new flag EXT4_GET_BLOCKS_NO_PUT_HOLE is used in ext4_da_map_blocks
in order not to put a hole into extent status tree because this hole
will be converted to delayed extent in the tree immediately.

Signed-off-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Jan kara <jack@suse.cz>

1 files changed, 56 insertions, 0 deletions

diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index c121cdf55ab3..1e590b68cec4 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -2199,6 +2199,62 @@ TRACE_EVENT(ext4_es_find_delayed_extent_exit,
                   __entry->pblk, __entry->status)
 );
 
+TRACE_EVENT(ext4_es_lookup_extent_enter,
+        TP_PROTO(struct inode *inode, ext4_lblk_t lblk),
+
+        TP_ARGS(inode, lblk),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,          dev             )
+                __field(        ino_t,          ino             )
+                __field(        ext4_lblk_t,    lblk            )
+        ),
+
+        TP_fast_assign(
+                __entry->dev    = inode->i_sb->s_dev;
+                __entry->ino    = inode->i_ino;
+                __entry->lblk   = lblk;
+        ),
+
+        TP_printk("dev %d,%d ino %lu lblk %u",
+                  MAJOR(__entry->dev), MINOR(__entry->dev),
+                  (unsigned long) __entry->ino, __entry->lblk)
+);
+
+TRACE_EVENT(ext4_es_lookup_extent_exit,
+        TP_PROTO(struct inode *inode, struct extent_status *es,
+                 int found),
+
+        TP_ARGS(inode, es, found),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,          dev             )
+                __field(        ino_t,          ino             )
+                __field(        ext4_lblk_t,    lblk            )
+                __field(        ext4_lblk_t,    len             )
+                __field(        ext4_fsblk_t,   pblk            )
+                __field(        unsigned long long,     status  )
+                __field(        int,            found           )
+        ),
+
+        TP_fast_assign(
+                __entry->dev    = inode->i_sb->s_dev;
+                __entry->ino    = inode->i_ino;
+                __entry->lblk   = es->es_lblk;
+                __entry->len    = es->es_len;
+                __entry->pblk   = ext4_es_pblock(es);
+                __entry->status = ext4_es_status(es);
+                __entry->found  = found;
+        ),
+
+        TP_printk("dev %d,%d ino %lu found %d [%u/%u) %llu %llx",
+                  MAJOR(__entry->dev), MINOR(__entry->dev),
+                  (unsigned long) __entry->ino, __entry->found,
+                  __entry->lblk, __entry->len,
+                  __entry->found ? __entry->pblk : 0,
+                  __entry->found ? __entry->status : 0)
+);
+
 #endif /* _TRACE_EXT4_H */
 
 /* This part must be outside protection */