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ext4: use RCU API in debug_print_tree 

struct ext4_sb_info.system_blks was marked __rcu.
But access the pointer without using RCU lock and dereference.
Sparse warning with __rcu notation:

block_validity.c:139:29: warning: incorrect type in argument 1 (different address spaces)
block_validity.c:139:29:    expected struct rb_root const *
block_validity.c:139:29:    got struct rb_root [noderef] <asn:4> *

Link: https://lore.kernel.org/r/20191213153306.30744-1-tranmanphong@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Phong Tran <tranmanphong@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Phong Tran 2019-12-13 22:33:07 +07:00 committed by Theodore Ts'o
parent 9803387c55
commit 69000d82ee
1 changed files with 5 additions and 1 deletions
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6
fs/ext4/block_validity.c
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@ -133,10 +133,13 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
{
struct rb_node *node;
struct ext4_system_zone *entry;
struct ext4_system_blocks *system_blks;
int first = 1;
printk(KERN_INFO "System zones: ");
node = rb_first(&sbi->system_blks->root);
rcu_read_lock();
system_blks = rcu_dereference(sbi->system_blks);
node = rb_first(&system_blks->root);
while (node) {
entry = rb_entry(node, struct ext4_system_zone, node);
printk(KERN_CONT "%s%llu-%llu", first ? "" : ", ",
@ -144,6 +147,7 @@ static void debug_print_tree(struct ext4_sb_info *sbi)
first = 0;
node = rb_next(node);
}
rcu_read_unlock();
printk(KERN_CONT "\n");
}