[PATCH AUTOSEL 4.19 139/146] f2fs: avoid sleeping under spin_lock

Sasha Levin
2018-10-31T23:41:56Z

From: Zhikang Zhang <zhangzhikang1@huawei.com>

[ Upstream commit b430f7263673eab1dc40e662ae3441a9619d16b8 ]

In the call trace below, we might sleep in function dput().

So in order to avoid sleeping under spin_lock, we remove f2fs_mark_inode_dirty_sync
from __try_update_largest_extent && __drop_largest_extent.

BUG: sleeping function called from invalid context at fs/dcache.c:796
Call trace:
dump_backtrace+0x0/0x3f4
show_stack+0x24/0x30
dump_stack+0xe0/0x138
___might_sleep+0x2a8/0x2c8
__might_sleep+0x78/0x10c
dput+0x7c/0x750
block_dump___mark_inode_dirty+0x120/0x17c
__mark_inode_dirty+0x344/0x11f0
f2fs_mark_inode_dirty_sync+0x40/0x50
__insert_extent_tree+0x2e0/0x2f4
f2fs_update_extent_tree_range+0xcf4/0xde8
f2fs_update_extent_cache+0x114/0x12c
f2fs_update_data_blkaddr+0x40/0x50
write_data_page+0x150/0x314
do_write_data_page+0x648/0x2318
__write_data_page+0xdb4/0x1640
f2fs_write_cache_pages+0x768/0xafc
__f2fs_write_data_pages+0x590/0x1218
f2fs_write_data_pages+0x64/0x74
do_writepages+0x74/0xe4
__writeback_single_inode+0xdc/0x15f0
writeback_sb_inodes+0x574/0xc98
__writeback_inodes_wb+0x190/0x204
wb_writeback+0x730/0xf14
wb_check_old_data_flush+0x1bc/0x1c8
wb_workfn+0x554/0xf74
process_one_work+0x440/0x118c
worker_thread+0xac/0x974
kthread+0x1a0/0x1c8
ret_from_fork+0x10/0x1c

Signed-off-by: Zhikang Zhang <zhangzhikang1@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/f2fs/extent_cache.c | 51 ++++++++++++++++++++++++++----------------
fs/f2fs/f2fs.h | 7 +++---
2 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 231b77ef5a53..a70cd2580eae 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -308,14 +308,13 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,
return count - atomic_read(&et->node_cnt);
}

-static void __drop_largest_extent(struct inode *inode,
+static void __drop_largest_extent(struct extent_tree *et,
pgoff_t fofs, unsigned int len)
{
- struct extent_info *largest = &F2FS_I(inode)->extent_tree->largest;
-
- if (fofs < largest->fofs + largest->len && fofs + len > largest->fofs) {
- largest->len = 0;
- f2fs_mark_inode_dirty_sync(inode, true);
+ if (fofs < et->largest.fofs + et->largest.len &&
+ fofs + len > et->largest.fofs) {
+ et->largest.len = 0;
+ et->largest_updated = true;
}
}

@@ -416,12 +415,11 @@ static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
return ret;
}

-static struct extent_node *__try_merge_extent_node(struct inode *inode,
+static struct extent_node *__try_merge_extent_node(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei,
struct extent_node *prev_ex,
struct extent_node *next_ex)
{
- struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_node *en = NULL;

if (prev_ex && __is_back_mergeable(ei, &prev_ex->ei)) {
@@ -443,7 +441,7 @@ static struct extent_node *__try_merge_extent_node(struct inode *inode,
if (!en)
return NULL;

- __try_update_largest_extent(inode, et, en);
+ __try_update_largest_extent(et, en);

spin_lock(&sbi->extent_lock);
if (!list_empty(&en->list)) {
@@ -454,12 +452,11 @@ static struct extent_node *__try_merge_extent_node(struct inode *inode,
return en;
}

-static struct extent_node *__insert_extent_tree(struct inode *inode,
+static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
struct extent_tree *et, struct extent_info *ei,
struct rb_node **insert_p,
struct rb_node *insert_parent)
{
- struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct rb_node **p;
struct rb_node *parent = NULL;
struct extent_node *en = NULL;
@@ -476,7 +473,7 @@ static struct extent_node *__insert_extent_tree(struct inode *inode,
if (!en)
return NULL;

- __try_update_largest_extent(inode, et, en);
+ __try_update_largest_extent(et, en);

/* update in global extent list */
spin_lock(&sbi->extent_lock);
@@ -497,6 +494,7 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
struct rb_node **insert_p = NULL, *insert_parent = NULL;
unsigned int end = fofs + len;
unsigned int pos = (unsigned int)fofs;
+ bool updated = false;

if (!et)
return;
@@ -517,7 +515,7 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
* drop largest extent before lookup, in case it's already
* been shrunk from extent tree
*/
- __drop_largest_extent(inode, fofs, len);
+ __drop_largest_extent(et, fofs, len);

/* 1. lookup first extent node in range [fofs, fofs + len - 1] */
en = (struct extent_node *)f2fs_lookup_rb_tree_ret(&et->root,
@@ -550,7 +548,7 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
set_extent_info(&ei, end,
end - dei.fofs + dei.blk,
org_end - end);
- en1 = __insert_extent_tree(inode, et, &ei,
+ en1 = __insert_extent_tree(sbi, et, &ei,
NULL, NULL);
next_en = en1;
} else {
@@ -570,7 +568,7 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
}

if (parts)
- __try_update_largest_extent(inode, et, en);
+ __try_update_largest_extent(et, en);
else
__release_extent_node(sbi, et, en);

@@ -590,15 +588,16 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
if (blkaddr) {

set_extent_info(&ei, fofs, blkaddr, len);
- if (!__try_merge_extent_node(inode, et, &ei, prev_en, next_en))
- __insert_extent_tree(inode, et, &ei,
+ if (!__try_merge_extent_node(sbi, et, &ei, prev_en, next_en))
+ __insert_extent_tree(sbi, et, &ei,
insert_p, insert_parent);

/* give up extent_cache, if split and small updates happen */
if (dei.len >= 1 &&
prev.len < F2FS_MIN_EXTENT_LEN &&
et->largest.len < F2FS_MIN_EXTENT_LEN) {
- __drop_largest_extent(inode, 0, UINT_MAX);
+ et->largest.len = 0;
+ et->largest_updated = true;
set_inode_flag(inode, FI_NO_EXTENT);
}
}
@@ -606,7 +605,15 @@ static void f2fs_update_extent_tree_range(struct inode *inode,
if (is_inode_flag_set(inode, FI_NO_EXTENT))
__free_extent_tree(sbi, et);

+ if (et->largest_updated) {
+ et->largest_updated = false;
+ updated = true;
+ }
+
write_unlock(&et->lock);
+
+ if (updated)
+ f2fs_mark_inode_dirty_sync(inode, true);
}

unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)
@@ -705,6 +712,7 @@ void f2fs_drop_extent_tree(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
+ bool updated = false;

if (!f2fs_may_extent_tree(inode))
return;
@@ -713,8 +721,13 @@ void f2fs_drop_extent_tree(struct inode *inode)

write_lock(&et->lock);
__free_extent_tree(sbi, et);
- __drop_largest_extent(inode, 0, UINT_MAX);
+ if (et->largest.len) {
+ et->largest.len = 0;
+ updated = true;
+ }
write_unlock(&et->lock);
+ if (updated)
+ f2fs_mark_inode_dirty_sync(inode, true);
}

void f2fs_destroy_extent_tree(struct inode *inode)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index abf925664d9c..e146e6c443e8 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -572,6 +572,7 @@ struct extent_tree {
struct list_head list; /* to be used by sbi->zombie_list */
rwlock_t lock; /* protect extent info rb-tree */
atomic_t node_cnt; /* # of extent node in rb-tree*/
+ bool largest_updated; /* largest extent updated */
};

/*
@@ -754,12 +755,12 @@ static inline bool __is_front_mergeable(struct extent_info *cur,
}

extern void f2fs_mark_inode_dirty_sync(struct inode *inode, bool sync);
-static inline void __try_update_largest_extent(struct inode *inode,
- struct extent_tree *et, struct extent_node *en)
+static inline void __try_update_largest_extent(struct extent_tree *et,
+ struct extent_node *en)
{
if (en->ei.len > et->largest.len) {
et->largest = en->ei;
- f2fs_mark_inode_dirty_sync(inode, true);
+ et->largest_updated = true;
}
}

--
2.17.1