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kernfs: fix a subdir count leak

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Currently kernfs_link_sibling() increates parent->dir.subdirs before
adding the node into parent's chidren rb tree.

Because it is possible that kernfs_link_sibling() couldn't find
a suitable slot and bail out, this leads to a mismatch between
elevated subdir count with actual children node numbers.

This patches fix this problem, by moving the subdir accouting
after the actual addtion happening.

Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jianyu Zhan 2014-04-17 17:52:10 +08:00 committed by Greg Kroah-Hartman
parent a798c10faf
commit c1befb8859
1 changed files with 6 additions and 3 deletions
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9
fs/kernfs/dir.c
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@ -232,9 +232,6 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
struct rb_node **node = &kn->parent->dir.children.rb_node; struct rb_node **node = &kn->parent->dir.children.rb_node;
struct rb_node *parent = NULL; struct rb_node *parent = NULL;
if (kernfs_type(kn) == KERNFS_DIR)
kn->parent->dir.subdirs++;
while (*node) { while (*node) {
struct kernfs_node *pos; struct kernfs_node *pos;
int result; int result;
@ -249,9 +246,15 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
else else
return -EEXIST; return -EEXIST;
} }
/* add new node and rebalance the tree */ /* add new node and rebalance the tree */
rb_link_node(&kn->rb, parent, node); rb_link_node(&kn->rb, parent, node);
rb_insert_color(&kn->rb, &kn->parent->dir.children); rb_insert_color(&kn->rb, &kn->parent->dir.children);
/* successfully added, account subdir number */
if (kernfs_type(kn) == KERNFS_DIR)
kn->parent->dir.subdirs++;
return 0; return 0;
} }