* FAILED: patch "[PATCH] btrfs: do not overwrite NODATASUM flag when removing" failed to apply to 5.10-stable tree
@ 2026-09-03 13:24 gregkh
2026-09-07 16:04 ` [PATCH 5.10.y 1/3] btrfs: move btrfs_is_empty_uuid() from ioctl.c into fs.c Sasha Levin
0 siblings, 1 reply; 4+ messages in thread
From: gregkh @ 2026-09-03 13:24 UTC (permalink / raw)
To: wqu; +Cc: stable
The patch below does not apply to the 5.10-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.10.y
git checkout FETCH_HEAD
git cherry-pick -x 15f7c86215e8d5f14b24127fa88af6c79363d50e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090331-audibly-scallop-6a11@gregkh' --subject-prefix 'PATCH 5.10.y' 'HEAD^..'
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 15f7c86215e8d5f14b24127fa88af6c79363d50e Mon Sep 17 00:00:00 2001
From: Qu Wenruo <wqu@suse.com>
Date: Tue, 9 Jun 2026 08:43:34 +0930
Subject: [PATCH] btrfs: do not overwrite NODATASUM flag when removing
NODATACOW flag
[TEST FAILURE]
The test case generic/628 will fail if MOUNT_OPTIONS is set to
"-o nodatasum":
FSTYP -- btrfs
PLATFORM -- Linux/x86_64 btrfs-vm 7.1.0-rc4-custom+ #383 SMP PREEMPT_DYNAMIC Sat May 30 07:35:42 ACST 2026
MKFS_OPTIONS -- -O bgt -K /dev/mapper/test-scratch1
MOUNT_OPTIONS -- -o nodatasum /dev/mapper/test-scratch1 /mnt/scratch
generic/628 1s ... - output mismatch (see /home/adam/xfstests/results//generic/628.out.bad)
--- tests/generic/628.out 2022-05-11 11:25:30.816666664 +0930
+++ /home/adam/xfstests/results//generic/628.out.bad 2026-06-08 18:56:49.878542927 +0930
@@ -8,8 +8,9 @@
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/d
test reflink flag not set iflag
+XFS_IOC_CLONE: Invalid argument
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
-310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/b
+d41d8cd98f00b204e9800998ecf8427e SCRATCH_MNT/b
...
[CAUSE]
The direct cause is that after "chattr +S", the btrfs inode will lose its
NODATASUM flag inherited from the mount option. E.g.:
# mkfs.btrfs -f $dev
# mount $dev $mnt -o nodatasum
# touch $mnt/foobar
# sync
# btrfs ins dump-tree -t 5 $dev | grep "(257 INODE_ITEM 0) itemoff" -A 3
item 4 key (257 INODE_ITEM 0) itemoff 15879 itemsize 160
generation 9 transid 9 size 0 nbytes 0
block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x1(NODATASUM)
^^^^^^^^^ Proper NODATASUM flag
# chattr +S $mnt/foobar
# sync
# btrfs ins dump-tree -t 5 $dev | grep "(257 INODE_ITEM 0) itemoff" -A 3
item 4 key (257 INODE_ITEM 0) itemoff 15879 itemsize 160
generation 9 transid 10 size 0 nbytes 0
block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
sequence 2 flags 0x20(SYNC)
^^^^ Only the new SYNC flag
This makes the inode drop the old NODATASUM flag, while the new reflink
destination will still inherit the NODATASUM flag. The mismatching
NODATASUM flags will cause the reflink to fail.
The root cause is that, inside btrfs_fileattr_set() if no FS_NOCOW_FL is
set, we remove both NODATASUM and NODATACOW flag.
However we should not touch NODATASUM flag, as data COW doesn't require
checksum. Only NODATACOW implies NODATASUM, but DATACOW doesn't imply
DATASUM.
The deeper problems are:
- Fileattr API is too binary
It either clears or sets a flag, there is no "do not change" option.
So that why "chattr +S" implies "chattr -C", and is forcing us to
change NODATACOW along with NODATASUM flag.
- No way to change NODATASUM through fileattr API
In fact NODATASUM can only be modified through mount option.
The deeper problems are much harder to attack.
[FIX]
Remove NODATACOW flag when FS_NOCOW_FL is not set, but only remove
NODATASUM if "nodatasum" mount option is not set.
This allows the existing "chattr +C" then "chattr -C" to remove
both NODATACOW and NODATASUM flags on a default mount.
But for a mount with "nodatasum" option, the NODATASUM inode flag will
persist through either "chattr +C" and "chattr -C".
Fixes: 7e97b8daf634 ("btrfs: allow setting NOCOW for a zero sized file via ioctl")
Cc: stable@vger.kernel.org
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7e97a6aebf9b..32dd7bbd4d63 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -356,14 +356,21 @@ int btrfs_fileattr_set(struct mnt_idmap *idmap,
inode_flags |= BTRFS_INODE_NODATACOW;
}
} else {
- /*
- * Revert back under same assumptions as above
- */
- if (S_ISREG(inode->vfs_inode.i_mode)) {
- if (inode->vfs_inode.i_size == 0)
- inode_flags &= ~(BTRFS_INODE_NODATACOW |
- BTRFS_INODE_NODATASUM);
- } else {
+ /* We can only change NODATACOW for zero-sized regular file. */
+ if (S_ISREG(inode->vfs_inode.i_mode) && (inode->vfs_inode.i_size == 0)) {
+ inode_flags &= ~BTRFS_INODE_NODATACOW;
+ /*
+ * There is currently no way to change NODATASUM flag
+ * through fileattr API. If we unconditionally keep the
+ * current NODATASUM flag, chattr +C then chattr -C will
+ * keep the NODATASUM flag, and no way to remove that
+ * flag.
+ *
+ * So respect the current mount option for NODATASUM flag.
+ */
+ if (!btrfs_test_opt(fs_info, NODATASUM))
+ inode_flags &= ~BTRFS_INODE_NODATASUM;
+ } else if (!S_ISREG(inode->vfs_inode.i_mode)) {
inode_flags &= ~BTRFS_INODE_NODATACOW;
}
}
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 5.10.y 1/3] btrfs: move btrfs_is_empty_uuid() from ioctl.c into fs.c
2026-09-03 13:24 FAILED: patch "[PATCH] btrfs: do not overwrite NODATASUM flag when removing" failed to apply to 5.10-stable tree gregkh
@ 2026-09-07 16:04 ` Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 2/3] btrfs: pass struct btrfs_inode to btrfs_sync_inode_flags_to_i_flags() Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 3/3] btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag Sasha Levin
0 siblings, 2 replies; 4+ messages in thread
From: Sasha Levin @ 2026-09-07 16:04 UTC (permalink / raw)
To: stable
Cc: Filipe Manana, Qu Wenruo, Johannes Thumshirn, David Sterba,
Sasha Levin
From: Filipe Manana <fdmanana@suse.com>
[ Upstream commit a5b3f117daead61c3c9c88cd1159d38fa4ad1362 ]
It's a generic helper not specific to ioctls and used in several places,
so move it out from ioctl.c and into fs.c. While at it change its return
type from int to bool and declare the loop variable in the loop itself.
This also slightly reduces the module's size.
Before this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1781492 161037 16920 1959449 1de619 fs/btrfs/btrfs.ko
After this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1781340 161037 16920 1959297 1de581 fs/btrfs/btrfs.ko
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
text data bss dec hex filename
1781492 161037 16920 1959449 1de619 fs/btrfs/btrfs.ko
After this change:
$ size fs/btrfs/btrfs.ko
text data bss dec hex filename
1781340 161037 16920 1959297 1de581 fs/btrfs/btrfs.ko
[ stable: The fs.c split does not exist in 5.10, so keep the helper in
ioctl.c and instead align btrfs_ioctl_setflags() variable naming with
the target commit's context. This is a behavior-neutral refactor. ]
[ sashal: Reduced backport -- upstream a5b3f117daead touches 4 file(s), this
backport carries 1. Not backported here:
fs/btrfs/fs.c
fs/btrfs/fs.h
fs/btrfs/ioctl.h
This note is generated from the file lists only; see the resolution record
for the reasoning. ]
Stable-dep-of: 15f7c86215e8 ("btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/ioctl.c | 94 ++++++++++++++++++++++++------------------------
1 file changed, 47 insertions(+), 47 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 16c397062809f..f0a9fb928b39e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -195,17 +195,17 @@ static int check_fsflags(unsigned int old_flags, unsigned int flags)
static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
{
- struct inode *inode = file_inode(file);
- struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- struct btrfs_inode *binode = BTRFS_I(inode);
- struct btrfs_root *root = binode->root;
+ struct btrfs_inode *inode = BTRFS_I(file_inode(file));
+ struct inode *vfs_inode = &inode->vfs_inode;
+ struct btrfs_fs_info *fs_info = btrfs_sb(vfs_inode->i_sb);
+ struct btrfs_root *root = inode->root;
struct btrfs_trans_handle *trans;
unsigned int fsflags, old_fsflags;
int ret;
const char *comp = NULL;
- u32 binode_flags;
+ u32 inode_flags;
- if (!inode_owner_or_capable(inode))
+ if (!inode_owner_or_capable(vfs_inode))
return -EPERM;
if (btrfs_root_readonly(root))
@@ -218,11 +218,11 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
if (ret)
return ret;
- inode_lock(inode);
- fsflags = btrfs_mask_fsflags_for_type(inode, fsflags);
- old_fsflags = btrfs_inode_flags_to_fsflags(binode->flags);
+ inode_lock(vfs_inode);
+ fsflags = btrfs_mask_fsflags_for_type(vfs_inode, fsflags);
+ old_fsflags = btrfs_inode_flags_to_fsflags(inode->flags);
- ret = vfs_ioc_setflags_prepare(inode, old_fsflags, fsflags);
+ ret = vfs_ioc_setflags_prepare(vfs_inode, old_fsflags, fsflags);
if (ret)
goto out_unlock;
@@ -230,54 +230,54 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
if (ret)
goto out_unlock;
- binode_flags = binode->flags;
+ inode_flags = inode->flags;
if (fsflags & FS_SYNC_FL)
- binode_flags |= BTRFS_INODE_SYNC;
+ inode_flags |= BTRFS_INODE_SYNC;
else
- binode_flags &= ~BTRFS_INODE_SYNC;
+ inode_flags &= ~BTRFS_INODE_SYNC;
if (fsflags & FS_IMMUTABLE_FL)
- binode_flags |= BTRFS_INODE_IMMUTABLE;
+ inode_flags |= BTRFS_INODE_IMMUTABLE;
else
- binode_flags &= ~BTRFS_INODE_IMMUTABLE;
+ inode_flags &= ~BTRFS_INODE_IMMUTABLE;
if (fsflags & FS_APPEND_FL)
- binode_flags |= BTRFS_INODE_APPEND;
+ inode_flags |= BTRFS_INODE_APPEND;
else
- binode_flags &= ~BTRFS_INODE_APPEND;
+ inode_flags &= ~BTRFS_INODE_APPEND;
if (fsflags & FS_NODUMP_FL)
- binode_flags |= BTRFS_INODE_NODUMP;
+ inode_flags |= BTRFS_INODE_NODUMP;
else
- binode_flags &= ~BTRFS_INODE_NODUMP;
+ inode_flags &= ~BTRFS_INODE_NODUMP;
if (fsflags & FS_NOATIME_FL)
- binode_flags |= BTRFS_INODE_NOATIME;
+ inode_flags |= BTRFS_INODE_NOATIME;
else
- binode_flags &= ~BTRFS_INODE_NOATIME;
+ inode_flags &= ~BTRFS_INODE_NOATIME;
if (fsflags & FS_DIRSYNC_FL)
- binode_flags |= BTRFS_INODE_DIRSYNC;
+ inode_flags |= BTRFS_INODE_DIRSYNC;
else
- binode_flags &= ~BTRFS_INODE_DIRSYNC;
+ inode_flags &= ~BTRFS_INODE_DIRSYNC;
if (fsflags & FS_NOCOW_FL) {
- if (S_ISREG(inode->i_mode)) {
+ if (S_ISREG(inode->vfs_inode.i_mode)) {
/*
* It's safe to turn csums off here, no extents exist.
* Otherwise we want the flag to reflect the real COW
* status of the file and will not set it.
*/
- if (inode->i_size == 0)
- binode_flags |= BTRFS_INODE_NODATACOW |
- BTRFS_INODE_NODATASUM;
+ if (inode->vfs_inode.i_size == 0)
+ inode_flags |= BTRFS_INODE_NODATACOW |
+ BTRFS_INODE_NODATASUM;
} else {
- binode_flags |= BTRFS_INODE_NODATACOW;
+ inode_flags |= BTRFS_INODE_NODATACOW;
}
} else {
/*
* Revert back under same assumptions as above
*/
- if (S_ISREG(inode->i_mode)) {
- if (inode->i_size == 0)
- binode_flags &= ~(BTRFS_INODE_NODATACOW |
- BTRFS_INODE_NODATASUM);
+ if (S_ISREG(inode->vfs_inode.i_mode)) {
+ if (inode->vfs_inode.i_size == 0)
+ inode_flags &= ~(BTRFS_INODE_NODATACOW |
+ BTRFS_INODE_NODATASUM);
} else {
- binode_flags &= ~BTRFS_INODE_NODATACOW;
+ inode_flags &= ~BTRFS_INODE_NODATACOW;
}
}
@@ -287,23 +287,23 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
* things smaller.
*/
if (fsflags & FS_NOCOMP_FL) {
- binode_flags &= ~BTRFS_INODE_COMPRESS;
- binode_flags |= BTRFS_INODE_NOCOMPRESS;
+ inode_flags &= ~BTRFS_INODE_COMPRESS;
+ inode_flags |= BTRFS_INODE_NOCOMPRESS;
} else if (fsflags & FS_COMPR_FL) {
- if (IS_SWAPFILE(inode)) {
+ if (IS_SWAPFILE(vfs_inode)) {
ret = -ETXTBSY;
goto out_unlock;
}
- binode_flags |= BTRFS_INODE_COMPRESS;
- binode_flags &= ~BTRFS_INODE_NOCOMPRESS;
+ inode_flags |= BTRFS_INODE_COMPRESS;
+ inode_flags &= ~BTRFS_INODE_NOCOMPRESS;
comp = btrfs_compress_type2str(fs_info->compress_type);
if (!comp || comp[0] == 0)
comp = btrfs_compress_type2str(BTRFS_COMPRESS_ZLIB);
} else {
- binode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
+ inode_flags &= ~(BTRFS_INODE_COMPRESS | BTRFS_INODE_NOCOMPRESS);
}
/*
@@ -317,14 +317,14 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
}
if (comp) {
- ret = btrfs_set_prop(trans, inode, "btrfs.compression", comp,
+ ret = btrfs_set_prop(trans, vfs_inode, "btrfs.compression", comp,
strlen(comp), 0);
if (ret) {
btrfs_abort_transaction(trans, ret);
goto out_end_trans;
}
} else {
- ret = btrfs_set_prop(trans, inode, "btrfs.compression", NULL,
+ ret = btrfs_set_prop(trans, vfs_inode, "btrfs.compression", NULL,
0, 0);
if (ret && ret != -ENODATA) {
btrfs_abort_transaction(trans, ret);
@@ -332,16 +332,16 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
}
}
- binode->flags = binode_flags;
- btrfs_sync_inode_flags_to_i_flags(inode);
- inode_inc_iversion(inode);
- inode->i_ctime = current_time(inode);
- ret = btrfs_update_inode(trans, root, inode);
+ inode->flags = inode_flags;
+ btrfs_sync_inode_flags_to_i_flags(vfs_inode);
+ inode_inc_iversion(vfs_inode);
+ vfs_inode->i_ctime = current_time(vfs_inode);
+ ret = btrfs_update_inode(trans, root, vfs_inode);
out_end_trans:
btrfs_end_transaction(trans);
out_unlock:
- inode_unlock(inode);
+ inode_unlock(vfs_inode);
mnt_drop_write_file(file);
return ret;
}
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 5.10.y 2/3] btrfs: pass struct btrfs_inode to btrfs_sync_inode_flags_to_i_flags()
2026-09-07 16:04 ` [PATCH 5.10.y 1/3] btrfs: move btrfs_is_empty_uuid() from ioctl.c into fs.c Sasha Levin
@ 2026-09-07 16:04 ` Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 3/3] btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-09-07 16:04 UTC (permalink / raw)
To: stable; +Cc: David Sterba, Sasha Levin
From: David Sterba <dsterba@suse.com>
[ Upstream commit 4f27a693940bcf313d17792ac4ec13a83f71cf25 ]
Pass a struct btrfs_inode to btrfs_sync_inode_flags_to_i_flags() as it's
an internal interface.
Signed-off-by: David Sterba <dsterba@suse.com>
[ sashal: Reduced backport -- upstream 4f27a693940bc touches 4 file(s), this
backport carries 3. Not backported here:
fs/btrfs/ioctl.h
fs/btrfs/verity.c
This note is generated from the file lists only; see the resolution record
for the reasoning. ]
Stable-dep-of: 15f7c86215e8 ("btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/ctree.h | 2 +-
fs/btrfs/inode.c | 4 ++--
fs/btrfs/ioctl.c | 19 +++++++++----------
3 files changed, 12 insertions(+), 13 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index a9926fb10c491..55dfb73d8e323 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3082,7 +3082,7 @@ ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter);
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
int btrfs_ioctl_get_supported_features(void __user *arg);
-void btrfs_sync_inode_flags_to_i_flags(struct inode *inode);
+void btrfs_sync_inode_flags_to_i_flags(struct btrfs_inode *inode);
int __pure btrfs_is_empty_uuid(u8 *uuid);
int btrfs_defrag_file(struct inode *inode, struct file *file,
struct btrfs_ioctl_defrag_range_args *range,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 3c61f540597d2..7451e18e06eeb 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3463,7 +3463,7 @@ static int btrfs_read_locked_inode(struct inode *inode,
break;
}
- btrfs_sync_inode_flags_to_i_flags(inode);
+ btrfs_sync_inode_flags_to_i_flags(BTRFS_I(inode));
return 0;
}
@@ -5976,7 +5976,7 @@ static void btrfs_inherit_iflags(struct inode *inode, struct inode *dir)
BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM;
}
- btrfs_sync_inode_flags_to_i_flags(inode);
+ btrfs_sync_inode_flags_to_i_flags(BTRFS_I(inode));
}
static struct inode *btrfs_new_inode(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index f0a9fb928b39e..86b4137fc3e9e 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -133,23 +133,22 @@ static unsigned int btrfs_inode_flags_to_fsflags(unsigned int flags)
/*
* Update inode->i_flags based on the btrfs internal flags.
*/
-void btrfs_sync_inode_flags_to_i_flags(struct inode *inode)
+void btrfs_sync_inode_flags_to_i_flags(struct btrfs_inode *inode)
{
- struct btrfs_inode *binode = BTRFS_I(inode);
unsigned int new_fl = 0;
- if (binode->flags & BTRFS_INODE_SYNC)
+ if (inode->flags & BTRFS_INODE_SYNC)
new_fl |= S_SYNC;
- if (binode->flags & BTRFS_INODE_IMMUTABLE)
+ if (inode->flags & BTRFS_INODE_IMMUTABLE)
new_fl |= S_IMMUTABLE;
- if (binode->flags & BTRFS_INODE_APPEND)
+ if (inode->flags & BTRFS_INODE_APPEND)
new_fl |= S_APPEND;
- if (binode->flags & BTRFS_INODE_NOATIME)
+ if (inode->flags & BTRFS_INODE_NOATIME)
new_fl |= S_NOATIME;
- if (binode->flags & BTRFS_INODE_DIRSYNC)
+ if (inode->flags & BTRFS_INODE_DIRSYNC)
new_fl |= S_DIRSYNC;
- set_mask_bits(&inode->i_flags,
+ set_mask_bits(&inode->vfs_inode.i_flags,
S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME | S_DIRSYNC,
new_fl);
}
@@ -333,7 +332,7 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
}
inode->flags = inode_flags;
- btrfs_sync_inode_flags_to_i_flags(vfs_inode);
+ btrfs_sync_inode_flags_to_i_flags(inode);
inode_inc_iversion(vfs_inode);
vfs_inode->i_ctime = current_time(vfs_inode);
ret = btrfs_update_inode(trans, root, vfs_inode);
@@ -476,7 +475,7 @@ static int btrfs_ioctl_fssetxattr(struct file *file, void __user *arg)
goto out_unlock;
}
- btrfs_sync_inode_flags_to_i_flags(inode);
+ btrfs_sync_inode_flags_to_i_flags(binode);
inode_inc_iversion(inode);
inode->i_ctime = current_time(inode);
ret = btrfs_update_inode(trans, root, inode);
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH 5.10.y 3/3] btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag
2026-09-07 16:04 ` [PATCH 5.10.y 1/3] btrfs: move btrfs_is_empty_uuid() from ioctl.c into fs.c Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 2/3] btrfs: pass struct btrfs_inode to btrfs_sync_inode_flags_to_i_flags() Sasha Levin
@ 2026-09-07 16:04 ` Sasha Levin
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2026-09-07 16:04 UTC (permalink / raw)
To: stable; +Cc: Qu Wenruo, Filipe Manana, David Sterba, Sasha Levin
From: Qu Wenruo <wqu@suse.com>
[ Upstream commit 15f7c86215e8d5f14b24127fa88af6c79363d50e ]
[TEST FAILURE]
The test case generic/628 will fail if MOUNT_OPTIONS is set to
"-o nodatasum":
FSTYP -- btrfs
PLATFORM -- Linux/x86_64 btrfs-vm 7.1.0-rc4-custom+ #383 SMP PREEMPT_DYNAMIC Sat May 30 07:35:42 ACST 2026
MKFS_OPTIONS -- -O bgt -K /dev/mapper/test-scratch1
MOUNT_OPTIONS -- -o nodatasum /dev/mapper/test-scratch1 /mnt/scratch
generic/628 1s ... - output mismatch (see /home/adam/xfstests/results//generic/628.out.bad)
--- tests/generic/628.out 2022-05-11 11:25:30.816666664 +0930
+++ /home/adam/xfstests/results//generic/628.out.bad 2026-06-08 18:56:49.878542927 +0930
@@ -8,8 +8,9 @@
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/d
test reflink flag not set iflag
+XFS_IOC_CLONE: Invalid argument
310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/a
-310f146ce52077fcd3308dcbe7632bb2 SCRATCH_MNT/b
+d41d8cd98f00b204e9800998ecf8427e SCRATCH_MNT/b
...
[CAUSE]
The direct cause is that after "chattr +S", the btrfs inode will lose its
NODATASUM flag inherited from the mount option. E.g.:
# mkfs.btrfs -f $dev
# mount $dev $mnt -o nodatasum
# touch $mnt/foobar
# sync
# btrfs ins dump-tree -t 5 $dev | grep "(257 INODE_ITEM 0) itemoff" -A 3
item 4 key (257 INODE_ITEM 0) itemoff 15879 itemsize 160
generation 9 transid 9 size 0 nbytes 0
block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
sequence 1 flags 0x1(NODATASUM)
^^^^^^^^^ Proper NODATASUM flag
# chattr +S $mnt/foobar
# sync
# btrfs ins dump-tree -t 5 $dev | grep "(257 INODE_ITEM 0) itemoff" -A 3
item 4 key (257 INODE_ITEM 0) itemoff 15879 itemsize 160
generation 9 transid 10 size 0 nbytes 0
block group 0 mode 100644 links 1 uid 0 gid 0 rdev 0
sequence 2 flags 0x20(SYNC)
^^^^ Only the new SYNC flag
This makes the inode drop the old NODATASUM flag, while the new reflink
destination will still inherit the NODATASUM flag. The mismatching
NODATASUM flags will cause the reflink to fail.
The root cause is that, inside btrfs_fileattr_set() if no FS_NOCOW_FL is
set, we remove both NODATASUM and NODATACOW flag.
However we should not touch NODATASUM flag, as data COW doesn't require
checksum. Only NODATACOW implies NODATASUM, but DATACOW doesn't imply
DATASUM.
The deeper problems are:
- Fileattr API is too binary
It either clears or sets a flag, there is no "do not change" option.
So that why "chattr +S" implies "chattr -C", and is forcing us to
change NODATACOW along with NODATASUM flag.
- No way to change NODATASUM through fileattr API
In fact NODATASUM can only be modified through mount option.
The deeper problems are much harder to attack.
[FIX]
Remove NODATACOW flag when FS_NOCOW_FL is not set, but only remove
NODATASUM if "nodatasum" mount option is not set.
This allows the existing "chattr +C" then "chattr -C" to remove
both NODATACOW and NODATASUM flags on a default mount.
But for a mount with "nodatasum" option, the NODATASUM inode flag will
persist through either "chattr +C" and "chattr -C".
Fixes: 7e97b8daf634 ("btrfs: allow setting NOCOW for a zero sized file via ioctl")
Cc: stable@vger.kernel.org
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/btrfs/ioctl.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 86b4137fc3e9e..97b2c8aa9cd5a 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -268,14 +268,21 @@ static int btrfs_ioctl_setflags(struct file *file, void __user *arg)
inode_flags |= BTRFS_INODE_NODATACOW;
}
} else {
- /*
- * Revert back under same assumptions as above
- */
- if (S_ISREG(inode->vfs_inode.i_mode)) {
- if (inode->vfs_inode.i_size == 0)
- inode_flags &= ~(BTRFS_INODE_NODATACOW |
- BTRFS_INODE_NODATASUM);
- } else {
+ /* We can only change NODATACOW for zero-sized regular file. */
+ if (S_ISREG(inode->vfs_inode.i_mode) && (inode->vfs_inode.i_size == 0)) {
+ inode_flags &= ~BTRFS_INODE_NODATACOW;
+ /*
+ * There is currently no way to change NODATASUM flag
+ * through fileattr API. If we unconditionally keep the
+ * current NODATASUM flag, chattr +C then chattr -C will
+ * keep the NODATASUM flag, and no way to remove that
+ * flag.
+ *
+ * So respect the current mount option for NODATASUM flag.
+ */
+ if (!btrfs_test_opt(fs_info, NODATASUM))
+ inode_flags &= ~BTRFS_INODE_NODATASUM;
+ } else if (!S_ISREG(inode->vfs_inode.i_mode)) {
inode_flags &= ~BTRFS_INODE_NODATACOW;
}
}
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-09-07 16:04 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-09-03 13:24 FAILED: patch "[PATCH] btrfs: do not overwrite NODATASUM flag when removing" failed to apply to 5.10-stable tree gregkh
2026-09-07 16:04 ` [PATCH 5.10.y 1/3] btrfs: move btrfs_is_empty_uuid() from ioctl.c into fs.c Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 2/3] btrfs: pass struct btrfs_inode to btrfs_sync_inode_flags_to_i_flags() Sasha Levin
2026-09-07 16:04 ` [PATCH 5.10.y 3/3] btrfs: do not overwrite NODATASUM flag when removing NODATACOW flag Sasha Levin
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