From: Yongpeng Yang <[email protected]>
f2fs_destroy_extent_node() does not set FI_NO_EXTENT before clearing
extent nodes. When called from f2fs_drop_inode() with I_SYNC set,
concurrent kworker writeback can insert new extent nodes into the same
extent tree, racing with the destroy and triggering f2fs_bug_on() in
__destroy_extent_node(). The scenario is as follows:
drop inode writeback
- iput
- f2fs_drop_inode // I_SYNC set
- f2fs_destroy_extent_node
- __destroy_extent_node
- while (node_cnt) {
write_lock(&et->lock)
__free_extent_tree
write_unlock(&et->lock)
- __writeback_single_inode
- f2fs_outplace_write_data
- f2fs_update_read_extent_cache
- __update_extent_tree_range
// FI_NO_EXTENT not set,
// insert new extent node
} // node_cnt == 0, exit while
- f2fs_bug_on(node_cnt) // node_cnt > 0
Additionally, __update_extent_tree_range() only checks FI_NO_EXTENT for
EX_READ type, leaving EX_BLOCK_AGE updates completely unprotected.
This patch set FI_NO_EXTENT under et->lock in __destroy_extent_node(),
consistent with other callers (__update_extent_tree_range and
__drop_extent_tree) and check FI_NO_EXTENT for both EX_READ and
EX_BLOCK_AGE tree.
Fixes: 3fc5d5a182f6 ("f2fs: fix to shrink read extent node in batches")
Cc: [email protected]
Signed-off-by: Yongpeng Yang <[email protected]>
---
fs/f2fs/extent_cache.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 0ed84cc065a7..87169fd29d89 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -119,9 +119,10 @@ static bool __may_extent_tree(struct inode *inode, enum
extent_type type)
if (!__init_may_extent_tree(inode, type))
return false;
+ if (is_inode_flag_set(inode, FI_NO_EXTENT))
+ return false;
+
if (type == EX_READ) {
- if (is_inode_flag_set(inode, FI_NO_EXTENT))
- return false;
if (is_inode_flag_set(inode, FI_COMPRESSED_FILE) &&
!f2fs_sb_has_readonly(F2FS_I_SB(inode)))
return false;
@@ -644,6 +645,8 @@ static unsigned int __destroy_extent_node(struct inode
*inode,
while (atomic_read(&et->node_cnt)) {
write_lock(&et->lock);
+ if (!is_inode_flag_set(inode, FI_NO_EXTENT))
+ set_inode_flag(inode, FI_NO_EXTENT);
node_cnt += __free_extent_tree(sbi, et, nr_shrink);
write_unlock(&et->lock);
}
@@ -688,12 +691,12 @@ static void __update_extent_tree_range(struct inode
*inode,
write_lock(&et->lock);
- if (type == EX_READ) {
- if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
- write_unlock(&et->lock);
- return;
- }
+ if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
+ write_unlock(&et->lock);
+ return;
+ }
+ if (type == EX_READ) {
prev = et->largest;
dei.len = 0;
--
2.43.0
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