From b3d83066cbebc76dbac8a5fca931f64b4c6fff34 Mon Sep 17 00:00:00 2001
From: Chao Yu <chao@kernel.org>
Date: Fri, 30 Dec 2022 23:43:32 +0800
Subject: [PATCH 1/5] f2fs: fix to avoid NULL pointer dereference in
 f2fs_issue_flush()

With below two cases, it will cause NULL pointer dereference when
accessing SM_I(sbi)->fcc_info in f2fs_issue_flush().

a) If kthread_run() fails in f2fs_create_flush_cmd_control(), it will
release SM_I(sbi)->fcc_info,

- mount -o noflush_merge /dev/vda /mnt/f2fs
- mount -o remount,flush_merge /dev/vda /mnt/f2fs  -- kthread_run() fails
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync

b) we will never allocate memory for SM_I(sbi)->fcc_info w/ below
testcase,

- mount -o ro /dev/vda /mnt/f2fs
- mount -o rw,remount /dev/vda /mnt/f2fs
- dd if=/dev/zero of=/mnt/f2fs/file bs=4k count=1 conv=fsync

In order to fix this issue, let change as below:
- fix error path handling in f2fs_create_flush_cmd_control().
- allocate SM_I(sbi)->fcc_info even if readonly is on.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 25ddea478fc1..c3f8c8208eec 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -663,8 +663,7 @@ init_thread:
 	if (IS_ERR(fcc->f2fs_issue_flush)) {
 		int err = PTR_ERR(fcc->f2fs_issue_flush);
 
-		kfree(fcc);
-		SM_I(sbi)->fcc_info = NULL;
+		fcc->f2fs_issue_flush = NULL;
 		return err;
 	}
 
@@ -5138,11 +5137,9 @@ int f2fs_build_segment_manager(struct f2fs_sb_info *sbi)
 
 	init_f2fs_rwsem(&sm_info->curseg_lock);
 
-	if (!f2fs_readonly(sbi->sb)) {
-		err = f2fs_create_flush_cmd_control(sbi);
-		if (err)
-			return err;
-	}
+	err = f2fs_create_flush_cmd_control(sbi);
+	if (err)
+		return err;
 
 	err = create_discard_cmd_control(sbi);
 	if (err)

From fe59109ae5c0b34a8c7c07f693fc501b12b57787 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 16 Dec 2022 14:05:44 -0800
Subject: [PATCH 2/5] f2fs: initialize extent_cache parameter

This can avoid confusing tracepoint values.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/data.c         | 2 +-
 fs/f2fs/extent_cache.c | 2 +-
 fs/f2fs/file.c         | 2 +-
 fs/f2fs/segment.c      | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 6e43e19c7d1c..97e816590cd9 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2183,7 +2183,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct bio **bio_ret,
 	sector_t last_block_in_file;
 	const unsigned blocksize = blks_to_bytes(inode, 1);
 	struct decompress_io_ctx *dic = NULL;
-	struct extent_info ei = {0, };
+	struct extent_info ei = {};
 	bool from_dnode = true;
 	int i;
 	int ret = 0;
diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 1bd38a78ebba..3aa2f8296045 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -938,7 +938,7 @@ out:
 
 static void __update_extent_cache(struct dnode_of_data *dn, enum extent_type type)
 {
-	struct extent_info ei;
+	struct extent_info ei = {};
 
 	if (!__may_extent_tree(dn->inode, type))
 		return;
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a6c401279886..ecbc8c135b49 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2559,7 +2559,7 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi,
 	struct f2fs_map_blocks map = { .m_next_extent = NULL,
 					.m_seg_type = NO_CHECK_TYPE,
 					.m_may_create = false };
-	struct extent_info ei = {0, };
+	struct extent_info ei = {};
 	pgoff_t pg_start, pg_end, next_pgofs;
 	unsigned int blk_per_seg = sbi->blocks_per_seg;
 	unsigned int total = 0, sec_num;
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index c3f8c8208eec..ae3c4e5474ef 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3160,7 +3160,7 @@ static int __get_segment_type_4(struct f2fs_io_info *fio)
 static int __get_age_segment_type(struct inode *inode, pgoff_t pgofs)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
-	struct extent_info ei;
+	struct extent_info ei = {};
 
 	if (f2fs_lookup_age_extent_cache(inode, pgofs, &ei)) {
 		if (!ei.age)

From ed2724765e58e3310d3de48f4a1761631b3dd640 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 16 Dec 2022 14:41:54 -0800
Subject: [PATCH 3/5] f2fs: don't mix to use union values in extent_info

Let's explicitly use the defined values in block_age case only.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/extent_cache.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 3aa2f8296045..cc3fed04dd6f 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -881,7 +881,8 @@ static unsigned long long __calculate_block_age(unsigned long long new,
 }
 
 /* This returns a new age and allocated blocks in ei */
-static int __get_new_block_age(struct inode *inode, struct extent_info *ei)
+static int __get_new_block_age(struct inode *inode, struct extent_info *ei,
+						block_t blkaddr)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	loff_t f_size = i_size_read(inode);
@@ -894,7 +895,7 @@ static int __get_new_block_age(struct inode *inode, struct extent_info *ei)
 	 * block here.
 	 */
 	if ((f_size >> PAGE_SHIFT) == ei->fofs && f_size & (PAGE_SIZE - 1) &&
-			ei->blk == NEW_ADDR)
+			blkaddr == NEW_ADDR)
 		return -EINVAL;
 
 	if (__lookup_extent_tree(inode, ei->fofs, ei, EX_BLOCK_AGE)) {
@@ -915,14 +916,14 @@ static int __get_new_block_age(struct inode *inode, struct extent_info *ei)
 		return 0;
 	}
 
-	f2fs_bug_on(sbi, ei->blk == NULL_ADDR);
+	f2fs_bug_on(sbi, blkaddr == NULL_ADDR);
 
 	/* the data block was allocated for the first time */
-	if (ei->blk == NEW_ADDR)
+	if (blkaddr == NEW_ADDR)
 		goto out;
 
-	if (__is_valid_data_blkaddr(ei->blk) &&
-			!f2fs_is_valid_blkaddr(sbi, ei->blk, DATA_GENERIC_ENHANCE)) {
+	if (__is_valid_data_blkaddr(blkaddr) &&
+	    !f2fs_is_valid_blkaddr(sbi, blkaddr, DATA_GENERIC_ENHANCE)) {
 		f2fs_bug_on(sbi, 1);
 		return -EINVAL;
 	}
@@ -953,8 +954,7 @@ static void __update_extent_cache(struct dnode_of_data *dn, enum extent_type typ
 		else
 			ei.blk = dn->data_blkaddr;
 	} else if (type == EX_BLOCK_AGE) {
-		ei.blk = dn->data_blkaddr;
-		if (__get_new_block_age(dn->inode, &ei))
+		if (__get_new_block_age(dn->inode, &ei, dn->data_blkaddr))
 			return;
 	}
 	__update_extent_tree_range(dn->inode, &ei, type);

From 22a341b43036415718f2d50f5f98b2f891fe17e9 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Fri, 16 Dec 2022 16:36:36 -0800
Subject: [PATCH 4/5] f2fs: should use a temp extent_info for lookup

Otherwise, __lookup_extent_tree() will override the given extent_info which will
be used by caller.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/extent_cache.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index cc3fed04dd6f..7b191ff65631 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -888,6 +888,7 @@ static int __get_new_block_age(struct inode *inode, struct extent_info *ei,
 	loff_t f_size = i_size_read(inode);
 	unsigned long long cur_blocks =
 				atomic64_read(&sbi->allocated_data_blocks);
+	struct extent_info tei = *ei;	/* only fofs and len are valid */
 
 	/*
 	 * When I/O is not aligned to a PAGE_SIZE, update will happen to the last
@@ -898,17 +899,17 @@ static int __get_new_block_age(struct inode *inode, struct extent_info *ei,
 			blkaddr == NEW_ADDR)
 		return -EINVAL;
 
-	if (__lookup_extent_tree(inode, ei->fofs, ei, EX_BLOCK_AGE)) {
+	if (__lookup_extent_tree(inode, ei->fofs, &tei, EX_BLOCK_AGE)) {
 		unsigned long long cur_age;
 
-		if (cur_blocks >= ei->last_blocks)
-			cur_age = cur_blocks - ei->last_blocks;
+		if (cur_blocks >= tei.last_blocks)
+			cur_age = cur_blocks - tei.last_blocks;
 		else
 			/* allocated_data_blocks overflow */
-			cur_age = ULLONG_MAX - ei->last_blocks + cur_blocks;
+			cur_age = ULLONG_MAX - tei.last_blocks + cur_blocks;
 
-		if (ei->age)
-			ei->age = __calculate_block_age(cur_age, ei->age);
+		if (tei.age)
+			ei->age = __calculate_block_age(cur_age, tei.age);
 		else
 			ei->age = cur_age;
 		ei->last_blocks = cur_blocks;

From df9d44b645b83fffccfb4e28c1f93376585fdec8 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Wed, 21 Dec 2022 16:14:10 -0800
Subject: [PATCH 5/5] f2fs: let's avoid panic if extent_tree is not created

This patch avoids the below panic.

pc : __lookup_extent_tree+0xd8/0x760
lr : f2fs_do_write_data_page+0x104/0x87c
sp : ffffffc010cbb3c0
x29: ffffffc010cbb3e0 x28: 0000000000000000
x27: ffffff8803e7f020 x26: ffffff8803e7ed40
x25: ffffff8803e7f020 x24: ffffffc010cbb460
x23: ffffffc010cbb480 x22: 0000000000000000
x21: 0000000000000000 x20: ffffffff22e90900
x19: 0000000000000000 x18: ffffffc010c5d080
x17: 0000000000000000 x16: 0000000000000020
x15: ffffffdb1acdbb88 x14: ffffff888759e2b0
x13: 0000000000000000 x12: ffffff802da49000
x11: 000000000a001200 x10: ffffff8803e7ed40
x9 : ffffff8023195800 x8 : ffffff802da49078
x7 : 0000000000000001 x6 : 0000000000000000
x5 : 0000000000000006 x4 : ffffffc010cbba28
x3 : 0000000000000000 x2 : ffffffc010cbb480
x1 : 0000000000000000 x0 : ffffff8803e7ed40
Call trace:
 __lookup_extent_tree+0xd8/0x760
 f2fs_do_write_data_page+0x104/0x87c
 f2fs_write_single_data_page+0x420/0xb60
 f2fs_write_cache_pages+0x418/0xb1c
 __f2fs_write_data_pages+0x428/0x58c
 f2fs_write_data_pages+0x30/0x40
 do_writepages+0x88/0x190
 __writeback_single_inode+0x48/0x448
 writeback_sb_inodes+0x468/0x9e8
 __writeback_inodes_wb+0xb8/0x2a4
 wb_writeback+0x33c/0x740
 wb_do_writeback+0x2b4/0x400
 wb_workfn+0xe4/0x34c
 process_one_work+0x24c/0x5bc
 worker_thread+0x3e8/0xa50
 kthread+0x150/0x1b4

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/extent_cache.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 7b191ff65631..342af24b2f8c 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -546,7 +546,8 @@ static bool __lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
 	struct extent_node *en;
 	bool ret = false;
 
-	f2fs_bug_on(sbi, !et);
+	if (!et)
+		return false;
 
 	trace_f2fs_lookup_extent_tree_start(inode, pgofs, type);