linux.git/fs/exfat, branch v6.5

vfs: get rid of old '->iterate' directory operation

2023-08-06T13:08:35+00:00

All users now just use '->iterate_shared()', which only takes the
directory inode lock for reading.

Filesystems that never got convered to shared mode now instead use a
wrapper that drops the lock, re-takes it in write mode, calls the old
function, and then downgrades the lock back to read mode.

This way the VFS layer and other callers no longer need to care about
filesystems that never got converted to the modern era.

The filesystems that use the new wrapper are ceph, coda, exfat, jfs,
ntfs, ocfs2, overlayfs, and vboxsf.

Honestly, several of them look like they really could just iterate their
directories in shared mode and skip the wrapper entirely, but the point
of this change is to not change semantics or fix filesystems that
haven't been fixed in the last 7+ years, but to finally get rid of the
dual iterators.

Signed-off-by: Linus Torvalds 
Signed-off-by: Christian Brauner

exfat: release s_lock before calling dir_emit()

2023-07-14T23:34:19+00:00

There is a potential deadlock reported by syzbot as below:

======================================================
WARNING: possible circular locking dependency detected
6.4.0-next-20230707-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor330/5073 is trying to acquire lock:
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock_killable include/linux/mmap_lock.h:151 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: get_mmap_lock_carefully mm/memory.c:5293 [inline]
ffff8880218527a0 (&mm->mmap_lock){++++}-{3:3}, at: lock_mm_and_find_vma+0x369/0x510 mm/memory.c:5344
but task is already holding lock:
ffff888019f760e0 (&sbi->s_lock){+.+.}-{3:3}, at: exfat_iterate+0x117/0xb50 fs/exfat/dir.c:232

which lock already depends on the new lock.

Chain exists of:
  &mm->mmap_lock --> mapping.invalidate_lock#3 --> &sbi->s_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&sbi->s_lock);
                               lock(mapping.invalidate_lock#3);
                               lock(&sbi->s_lock);
  rlock(&mm->mmap_lock);

Let's try to avoid above potential deadlock condition by moving dir_emit*()
out of sbi->s_lock coverage.

Fixes: ca06197382bd ("exfat: add directory operations")
Cc: stable@vger.kernel.org #v5.7+
Reported-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Link: https://lore.kernel.org/lkml/00000000000078ee7e060066270b@google.com/T/#u
Tested-by: syzbot+1741a5d9b79989c10bdc@syzkaller.appspotmail.com
Signed-off-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

exfat: check if filename entries exceeds max filename length

2023-07-13T13:02:25+00:00

exfat_extract_uni_name copies characters from a given file name entry into
the 'uniname' variable. This variable is actually defined on the stack of
the exfat_readdir() function. According to the definition of
the 'exfat_uni_name' type, the file name should be limited 255 characters
(+ null teminator space), but the exfat_get_uniname_from_ext_entry()
function can write more characters because there is no check if filename
entries exceeds max filename length. This patch add the check not to copy
filename characters when exceeding max filename length.

Cc: stable@vger.kernel.org
Cc: Yuezhang Mo 
Reported-by: Maxim Suhanov 
Reviewed-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

exfat: use kvmalloc_array/kvfree instead of kmalloc_array/kfree

2023-07-11T12:33:20+00:00

The call stack shown below is a scenario in the Linux 4.19 kernel.
Allocating memory failed where exfat fs use kmalloc_array due to
system memory fragmentation, while the u-disk was inserted without
recognition.
Devices such as u-disk using the exfat file system are pluggable and
may be insert into the system at any time.
However, long-term running systems cannot guarantee the continuity of
physical memory. Therefore, it's necessary to address this issue.

Binder:2632_6: page allocation failure: order:4,
 mode:0x6040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
Call trace:
[242178.097582]  dump_backtrace+0x0/0x4
[242178.097589]  dump_stack+0xf4/0x134
[242178.097598]  warn_alloc+0xd8/0x144
[242178.097603]  __alloc_pages_nodemask+0x1364/0x1384
[242178.097608]  kmalloc_order+0x2c/0x510
[242178.097612]  kmalloc_order_trace+0x40/0x16c
[242178.097618]  __kmalloc+0x360/0x408
[242178.097624]  load_alloc_bitmap+0x160/0x284
[242178.097628]  exfat_fill_super+0xa3c/0xe7c
[242178.097635]  mount_bdev+0x2e8/0x3a0
[242178.097638]  exfat_fs_mount+0x40/0x50
[242178.097643]  mount_fs+0x138/0x2e8
[242178.097649]  vfs_kern_mount+0x90/0x270
[242178.097655]  do_mount+0x798/0x173c
[242178.097659]  ksys_mount+0x114/0x1ac
[242178.097665]  __arm64_sys_mount+0x24/0x34
[242178.097671]  el0_svc_common+0xb8/0x1b8
[242178.097676]  el0_svc_handler+0x74/0x90
[242178.097681]  el0_svc+0x8/0x340

By analyzing the exfat code,we found that continuous physical memory
is not required here,so kvmalloc_array is used can solve this problem.

Cc: stable@vger.kernel.org
Signed-off-by: gaoming 
Signed-off-by: Namjae Jeon

splice: Use filemap_splice_read() instead of generic_file_splice_read()

2023-05-24T14:42:17+00:00

Replace pointers to generic_file_splice_read() with calls to
filemap_splice_read().

Signed-off-by: David Howells 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Christian Brauner 
cc: Jens Axboe 
cc: Al Viro 
cc: David Hildenbrand 
cc: John Hubbard 
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-29-dhowells@redhat.com
Signed-off-by: Jens Axboe

Merge tag 'exfat-for-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat

2023-03-01T16:42:27+00:00

Pull exfat updates from Namjae Jeon:

 - Handle vendor extension and allocation entries as unrecognized benign
   secondary entries

 - Fix wrong ->i_blocks on devices with non-512 byte sector

 - Add the check to avoid returning -EIO from exfat_readdir() at current
   position exceeding the directory size

 - Fix a bug that reach the end of the directory stream at a position
   not aligned with the dentry size

 - Redefine DIR_DELETED as 0xFFFFFFF7, the bad cluster number

 - Two cleanup fixes and fix cluster leakage in error handling

* tag 'exfat-for-6.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/linkinjeon/exfat:
  exfat: fix the newly allocated clusters are not freed in error handling
  exfat: don't print error log in normal case
  exfat: remove unneeded code from exfat_alloc_cluster()
  exfat: handle unreconized benign secondary entries
  exfat: fix inode->i_blocks for non-512 byte sector size device
  exfat: redefine DIR_DELETED as the bad cluster number
  exfat: fix reporting fs error when reading dir beyond EOF
  exfat: fix unexpected EOF while reading dir

exfat: fix the newly allocated clusters are not freed in error handling

2023-02-28T11:01:40+00:00

In error handling 'free_cluster', before num_alloc clusters allocated,
p_chain->size will not updated and always 0, thus the newly allocated
clusters are not freed.

Signed-off-by: Yuezhang Mo 
Reviewed-by: Andy Wu 
Reviewed-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

exfat: don't print error log in normal case

2023-02-28T11:01:36+00:00

When allocating a new cluster, exFAT first allocates from the
next cluster of the last cluster of the file. If the last cluster
of the file is the last cluster of the volume, allocate from the
first cluster. This is a normal case, but the following error log
will be printed. It makes users confused, so this commit removes
the error log.

[1960905.181545] exFAT-fs (sdb1): hint_cluster is invalid (262130)

Signed-off-by: Yuezhang Mo 
Reviewed-by: Andy Wu 
Reviewed-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

exfat: remove unneeded code from exfat_alloc_cluster()

2023-02-28T11:01:22+00:00

In the removed code, num_clusters is 0, nothing is done in
exfat_chain_cont_cluster(), so it is unneeded, remove it.

Signed-off-by: Yuezhang Mo 
Reviewed-by: Andy Wu 
Reviewed-by: Sungjong Seo 
Signed-off-by: Namjae Jeon

exfat: handle unreconized benign secondary entries

2023-02-27T12:14:46+00:00

Sony PXW-Z280 camera add vendor allocation entries to directory of
pictures. Currently, linux exfat does not support it and the file is
not visible. This patch handle vendor extension and allocation entries
as unreconized benign secondary entries. As described in the specification,
it is recognized but ignored, and when deleting directory entry set,
the associated clusters allocation are removed as well as benign secondary
directory entries.

Reported-by: Barócsi Dénes 
Reviewed-by: Sungjong Seo 
Reviewed-by: Yuezhang Mo 
Signed-off-by: Namjae Jeon