[PATCH 4.18 180/350] f2fs: avoid sleeping under spin_lock

11 Nov 2018

4.18-stable review patch.  If anyone has any objections, please let me know.
------------------
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
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
---
 fs/f2fs/extent_cache.c |   51 ++++++++++++++++++++++++++++++-------------------
 fs/f2fs/f2fs.h         |    7 +++---
 2 files changed, 36 insertions(+), 22 deletions(-)

--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -308,14 +308,13 @@ static unsigned int __free_extent_tree(s
    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 @@ out:
    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_e
    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_e
    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 @@ do_insert:
    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_rang
    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_rang
     * 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_rang
    			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_rang
    	}
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_rang
    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_rang
    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
 {
    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
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)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -556,6 +556,7 @@ 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 */
 };
/*
@@ -736,12 +737,12 @@ static inline bool __is_front_mergeable(
 }
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;
    }
 }

    

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[PATCH 4.18 180/350] f2fs: avoid sleeping under spin_lock