From: Zhang Yi <yi.zhang@xxxxxxxxxx>
Introduce a new helper ext4_es_skip_hole_extent() to skip all hole
extents in a search range, return the valid lblk of next not hole extent
entry. It's useful to estimate and limit the length of a potential hole
returned when querying mapping status in ext4_map_blocks().
Signed-off-by: Zhang Yi <yi.zhang@xxxxxxxxxx>
---
fs/ext4/extents_status.c | 32 ++++++++++++++++++++++++++++++++
fs/ext4/extents_status.h | 2 ++
include/trace/events/ext4.h | 28 ++++++++++++++++++++++++++++
3 files changed, 62 insertions(+)
diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 6f7de14c0fa8..1b1b1a8848a8 100644
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -944,6 +944,38 @@ void ext4_es_cache_extent(struct inode *inode, ext4_lblk_t lblk,
write_unlock(&EXT4_I(inode)->i_es_lock);
}
+/*
+ * ext4_es_skip_hole_extent() skip hole extents and loops up the next
+ * delayed/unwritten/mapped extent in extent status tree from lblk to
+ * end.
+ */
+ext4_lblk_t ext4_es_skip_hole_extent(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len)
+{
+ struct extent_status *es = NULL;
+ ext4_lblk_t next_lblk;
+ struct rb_node *node;
+
+ read_lock(&EXT4_I(inode)->i_es_lock);
+ es = __es_tree_search(&EXT4_I(inode)->i_es_tree.root, lblk);
+
+ while (es && es->es_lblk < lblk + len) {
+ if (!ext4_es_is_hole(es))
+ break;
+ node = rb_next(&es->rb_node);
+ es = rb_entry(node, struct extent_status, rb_node);
+ }
+ if (!es || es->es_lblk >= lblk + len)
+ next_lblk = lblk + len;
+ else
+ next_lblk = es->es_lblk;
+
+ trace_ext4_es_skip_hole_extent(inode, lblk, len, next_lblk);
+ read_unlock(&EXT4_I(inode)->i_es_lock);
+
+ return next_lblk;
+}
+
/*
* ext4_es_lookup_extent() looks up an extent in extent status tree.
*
diff --git a/fs/ext4/extents_status.h b/fs/ext4/extents_status.h
index d9847a4a25db..4f69322dd626 100644
--- a/fs/ext4/extents_status.h
+++ b/fs/ext4/extents_status.h
@@ -139,6 +139,8 @@ extern void ext4_es_find_extent_range(struct inode *inode,
int (*match_fn)(struct extent_status *es),
ext4_lblk_t lblk, ext4_lblk_t end,
struct extent_status *es);
+ext4_lblk_t ext4_es_skip_hole_extent(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len);
extern int ext4_es_lookup_extent(struct inode *inode, ext4_lblk_t lblk,
ext4_lblk_t *next_lblk,
struct extent_status *es);
diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
index 65029dfb92fb..84421cecec0b 100644
--- a/include/trace/events/ext4.h
+++ b/include/trace/events/ext4.h
@@ -2291,6 +2291,34 @@ TRACE_EVENT(ext4_es_find_extent_range_exit,
__entry->pblk, show_extent_status(__entry->status))
);
+TRACE_EVENT(ext4_es_skip_hole_extent,
+ TP_PROTO(struct inode *inode, ext4_lblk_t lblk,
+ ext4_lblk_t len, ext4_lblk_t next_lblk),
+
+ TP_ARGS(inode, lblk, len, next_lblk),
+
+ TP_STRUCT__entry(
+ __field( dev_t, dev )
+ __field( ino_t, ino )
+ __field( ext4_lblk_t, lblk )
+ __field( ext4_lblk_t, len )
+ __field( ext4_lblk_t, next )
+ ),
+
+ TP_fast_assign(
+ __entry->dev = inode->i_sb->s_dev;
+ __entry->ino = inode->i_ino;
+ __entry->lblk = lblk;
+ __entry->len = len;
+ __entry->next = next_lblk;
+ ),
+
+ TP_printk("dev %d,%d ino %lu [%u/%u) next_lblk %u",
+ MAJOR(__entry->dev), MINOR(__entry->dev),
+ (unsigned long) __entry->ino, __entry->lblk,
+ __entry->len, __entry->next)
+);
+
TRACE_EVENT(ext4_es_lookup_extent_enter,
TP_PROTO(struct inode *inode, ext4_lblk_t lblk),
--
2.39.2
