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Date: Thu, 9 Feb 2023 10:18:19 -0800
From: Daeho Jeong <daeho43@...il.com>
To: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net, kernel-team@...roid.com
Cc: Daeho Jeong <daehojeong@...gle.com>,
syzbot+823000d23b3400619f7c@...kaller.appspotmail.com
Subject: [PATCH] f2fs: synchronize atomic write aborts
From: Daeho Jeong <daehojeong@...gle.com>
To fix a race condition between atomic write aborts, I use the inode
lock and make COW inode to be re-usable thoroughout the whole
atomic file inode lifetime.
Reported-by: syzbot+823000d23b3400619f7c@...kaller.appspotmail.com
Fixes: 3db1de0e582c ("f2fs: change the current atomic write way")
Signed-off-by: Daeho Jeong <daehojeong@...gle.com>
---
fs/f2fs/file.c | 44 +++++++++++++++++++++++++++++---------------
fs/f2fs/inode.c | 11 +++++++++--
fs/f2fs/segment.c | 3 ---
fs/f2fs/super.c | 2 --
4 files changed, 38 insertions(+), 22 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 300eae8b5415..6436c52e7913 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1863,7 +1863,10 @@ static int f2fs_release_file(struct inode *inode, struct file *filp)
atomic_read(&inode->i_writecount) != 1)
return 0;
+ inode_lock(inode);
f2fs_abort_atomic_write(inode, true);
+ inode_unlock(inode);
+
return 0;
}
@@ -1878,8 +1881,12 @@ static int f2fs_file_flush(struct file *file, fl_owner_t id)
* before dropping file lock, it needs to do in ->flush.
*/
if (F2FS_I(inode)->atomic_write_task == current &&
- (current->flags & PF_EXITING))
+ (current->flags & PF_EXITING)) {
+ inode_lock(inode);
f2fs_abort_atomic_write(inode, true);
+ inode_unlock(inode);
+ }
+
return 0;
}
@@ -2085,19 +2092,28 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
goto out;
}
- /* Create a COW inode for atomic write */
- pinode = f2fs_iget(inode->i_sb, fi->i_pino);
- if (IS_ERR(pinode)) {
- f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
- ret = PTR_ERR(pinode);
- goto out;
- }
+ /* Check if the inode already has a COW inode */
+ if (fi->cow_inode == NULL) {
+ /* Create a COW inode for atomic write */
+ pinode = f2fs_iget(inode->i_sb, fi->i_pino);
+ if (IS_ERR(pinode)) {
+ f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+ ret = PTR_ERR(pinode);
+ goto out;
+ }
- ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode);
- iput(pinode);
- if (ret) {
- f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
- goto out;
+ ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode);
+ iput(pinode);
+ if (ret) {
+ f2fs_up_write(&fi->i_gc_rwsem[WRITE]);
+ goto out;
+ }
+
+ set_inode_flag(fi->cow_inode, FI_COW_FILE);
+ clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
+ } else {
+ /* Reuse the already created COW inode */
+ f2fs_do_truncate_blocks(fi->cow_inode, 0, true);
}
f2fs_write_inode(inode, NULL);
@@ -2105,8 +2121,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate)
stat_inc_atomic_inode(inode);
set_inode_flag(inode, FI_ATOMIC_FILE);
- set_inode_flag(fi->cow_inode, FI_COW_FILE);
- clear_inode_flag(fi->cow_inode, FI_INLINE_DATA);
isize = i_size_read(inode);
fi->original_i_size = isize;
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index 28c9c72dda2a..7bf660d4cad9 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -777,11 +777,18 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc)
void f2fs_evict_inode(struct inode *inode)
{
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
- nid_t xnid = F2FS_I(inode)->i_xattr_nid;
+ struct f2fs_inode_info *fi = F2FS_I(inode);
+ nid_t xnid = fi->i_xattr_nid;
int err = 0;
f2fs_abort_atomic_write(inode, true);
+ if (fi->cow_inode) {
+ clear_inode_flag(fi->cow_inode, FI_COW_FILE);
+ iput(fi->cow_inode);
+ fi->cow_inode = NULL;
+ }
+
trace_f2fs_evict_inode(inode);
truncate_inode_pages_final(&inode->i_data);
@@ -866,7 +873,7 @@ void f2fs_evict_inode(struct inode *inode)
stat_dec_inline_inode(inode);
stat_dec_compr_inode(inode);
stat_sub_compr_blocks(inode,
- atomic_read(&F2FS_I(inode)->i_compr_blocks));
+ atomic_read(&fi->i_compr_blocks));
if (likely(!f2fs_cp_error(sbi) &&
!is_sbi_flag_set(sbi, SBI_CP_DISABLED)))
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index ead3f35f501d..719329c1808c 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -192,9 +192,6 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean)
if (!f2fs_is_atomic_file(inode))
return;
- clear_inode_flag(fi->cow_inode, FI_COW_FILE);
- iput(fi->cow_inode);
- fi->cow_inode = NULL;
release_atomic_write_cnt(inode);
clear_inode_flag(inode, FI_ATOMIC_COMMITTED);
clear_inode_flag(inode, FI_ATOMIC_REPLACE);
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index c11a161ba5be..aa55dc12aff2 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1427,8 +1427,6 @@ static int f2fs_drop_inode(struct inode *inode)
atomic_inc(&inode->i_count);
spin_unlock(&inode->i_lock);
- f2fs_abort_atomic_write(inode, true);
-
/* should remain fi->extent_tree for writepage */
f2fs_destroy_extent_node(inode);
--
2.39.1.581.gbfd45094c4-goog
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