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Btrfs: Fix hole insertion corner cases

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There were a few places that could cause duplicate extent insertion,
this adjusts the code that creates holes to avoid it.

lookup_extent_map is changed to correctly return all of the extents in a
range, even when there are none matching at the start of the range.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason
2008-01-22 16:47:59 -05:00
parent c1e32da616
commit 5f56406aab
4 changed files with 127 additions and 14 deletions
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47
fs/btrfs/extent_map.c
View File

@@ -204,10 +204,12 @@ static struct rb_node *tree_insert(struct rb_root *root, u64 offset,
}
static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
struct rb_node **prev_ret)
struct rb_node **prev_ret,
struct rb_node **next_ret)
{
struct rb_node * n = root->rb_node;
struct rb_node *prev = NULL;
struct rb_node *orig_prev = NULL;
struct tree_entry *entry;
struct tree_entry *prev_entry = NULL;
@@ -223,13 +225,25 @@ static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
else
return n;
}
if (!prev_ret)
return NULL;
while(prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
if (prev_ret) {
orig_prev = prev;
while(prev && offset > prev_entry->end) {
prev = rb_next(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*prev_ret = prev;
prev = orig_prev;
}
if (next_ret) {
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
while(prev && offset < prev_entry->start) {
prev = rb_prev(prev);
prev_entry = rb_entry(prev, struct tree_entry, rb_node);
}
*next_ret = prev;
}
*prev_ret = prev;
return NULL;
}
@@ -237,7 +251,7 @@ static inline struct rb_node *tree_search(struct rb_root *root, u64 offset)
{
struct rb_node *prev;
struct rb_node *ret;
ret = __tree_search(root, offset, &prev);
ret = __tree_search(root, offset, &prev, NULL);
if (!ret)
return prev;
return ret;
@@ -248,7 +262,7 @@ static int tree_delete(struct rb_root *root, u64 offset)
struct rb_node *node;
struct tree_entry *entry;
node = __tree_search(root, offset, NULL);
node = __tree_search(root, offset, NULL, NULL);
if (!node)
return -ENOENT;
entry = rb_entry(node, struct tree_entry, rb_node);
@@ -314,9 +328,21 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
{
struct extent_map *em;
struct rb_node *rb_node;
struct rb_node *prev = NULL;
struct rb_node *next = NULL;
read_lock_irq(&tree->lock);
rb_node = tree_search(&tree->map, start);
rb_node = __tree_search(&tree->map, start, &prev, &next);
if (!rb_node && prev) {
em = rb_entry(prev, struct extent_map, rb_node);
if (em->start <= end && em->end >= start)
goto found;
}
if (!rb_node && next) {
em = rb_entry(next, struct extent_map, rb_node);
if (em->start <= end && em->end >= start)
goto found;
}
if (!rb_node) {
em = NULL;
goto out;
@@ -330,6 +356,7 @@ struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
em = NULL;
goto out;
}
found:
atomic_inc(&em->refs);
out:
read_unlock_irq(&tree->lock);