[PATCH 6.1] fs/ntfs3: Additional check in ntfs_file_release

[PATCH 6.1] fs/ntfs3: Additional check in ntfs_file_release

[Bin Lan]

From: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

[ Upstream commit 031d6f608290c847ba6378322d0986d08d1a645a ]

Reported-by: syzbot+8c652f14a0fde76ff11d@syzkaller.appspotmail.com
Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
---
 fs/ntfs3/file.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
index aedd4f5f459e..70b38465aee3 100644
--- a/fs/ntfs3/file.c
+++ b/fs/ntfs3/file.c
@@ -1214,8 +1214,16 @@ static int ntfs_file_release(struct inode *inode, struct file *file)
 	int err = 0;
 
 	/* If we are last writer on the inode, drop the block reservation. */
-	if (sbi->options->prealloc && ((file->f_mode & FMODE_WRITE) &&
-				      atomic_read(&inode->i_writecount) == 1)) {
+	if (sbi->options->prealloc &&
+	    ((file->f_mode & FMODE_WRITE) &&
+	     atomic_read(&inode->i_writecount) == 1)
+	   /*
+	    * The only file when inode->i_fop = &ntfs_file_operations and
+	    * init_rwsem(&ni->file.run_lock) is not called explicitly is MFT.
+	    *
+	    * Add additional check here.
+	    */
+	    && inode->i_ino != MFT_REC_MFT) {
 		ni_lock(ni);
 		down_write(&ni->file.run_lock);
 
-- 
2.43.0

Re: [PATCH 6.1] fs/ntfs3: Additional check in ntfs_file_release

[Sasha Levin]

[ Sasha's backport helper bot ]

Hi,

The upstream commit SHA1 provided is correct: 031d6f608290c847ba6378322d0986d08d1a645a

WARNING: Author mismatch between patch and upstream commit:
Backport author: Bin Lan <bin.lan.cn@windriver.com>
Commit author: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>

Note: The patch differs from the upstream commit:
---
--- -	2024-11-17 21:38:25.916310313 -0500
+++ /tmp/tmp.zOVCh2qWVm	2024-11-17 21:38:25.910015113 -0500
@@ -1,18 +1,24 @@
+[ Upstream commit 031d6f608290c847ba6378322d0986d08d1a645a ]
+
 Reported-by: syzbot+8c652f14a0fde76ff11d@syzkaller.appspotmail.com
 Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
+Signed-off-by: Bin Lan <bin.lan.cn@windriver.com>
 ---
- fs/ntfs3/file.c | 9 ++++++++-
- 1 file changed, 8 insertions(+), 1 deletion(-)
+ fs/ntfs3/file.c | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
 
 diff --git a/fs/ntfs3/file.c b/fs/ntfs3/file.c
-index 4fdcb5177ea17..eb935d4180c0a 100644
+index aedd4f5f459e..70b38465aee3 100644
 --- a/fs/ntfs3/file.c
 +++ b/fs/ntfs3/file.c
-@@ -1314,7 +1314,14 @@ static int ntfs_file_release(struct inode *inode, struct file *file)
+@@ -1214,8 +1214,16 @@ static int ntfs_file_release(struct inode *inode, struct file *file)
+ 	int err = 0;
+ 
  	/* If we are last writer on the inode, drop the block reservation. */
- 	if (sbi->options->prealloc &&
- 	    ((file->f_mode & FMODE_WRITE) &&
--	     atomic_read(&inode->i_writecount) == 1)) {
+-	if (sbi->options->prealloc && ((file->f_mode & FMODE_WRITE) &&
+-				      atomic_read(&inode->i_writecount) == 1)) {
++	if (sbi->options->prealloc &&
++	    ((file->f_mode & FMODE_WRITE) &&
 +	     atomic_read(&inode->i_writecount) == 1)
 +	   /*
 +	    * The only file when inode->i_fop = &ntfs_file_operations and
@@ -24,3 +30,6 @@
  		ni_lock(ni);
  		down_write(&ni->file.run_lock);
  
+-- 
+2.43.0
+
---

Results of testing on various branches:

| Branch                    | Patch Apply | Build Test |
|---------------------------|-------------|------------|
| stable/linux-6.1.y        |  Success    |  Success   |