The patch below does not apply to the 5.4-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(a)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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 3c652c3a71de1d30d72dc82c3bead8deb48eb749
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102030-hurt-surplus-ab8e@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3c652c3a71de1d30d72dc82c3bead8deb48eb749 Mon Sep 17 00:00:00 2001
From: Zhang Yi <yi.zhang(a)huawei.com>
Date: Tue, 16 Sep 2025 17:33:36 +0800
Subject: [PATCH] jbd2: ensure that all ongoing I/O complete before freeing
blocks
When releasing file system metadata blocks in jbd2_journal_forget(), if
this buffer has not yet been checkpointed, it may have already been
written back, currently be in the process of being written back, or has
not yet written back. jbd2_journal_forget() calls
jbd2_journal_try_remove_checkpoint() to check the buffer's status and
add it to the current transaction if it has not been written back. This
buffer can only be reallocated after the transaction is committed.
jbd2_journal_try_remove_checkpoint() attempts to lock the buffer and
check its dirty status while holding the buffer lock. If the buffer has
already been written back, everything proceeds normally. However, there
are two issues. First, the function returns immediately if the buffer is
locked by the write-back process. It does not wait for the write-back to
complete. Consequently, until the current transaction is committed and
the block is reallocated, there is no guarantee that the I/O will
complete. This means that ongoing I/O could write stale metadata to the
newly allocated block, potentially corrupting data. Second, the function
unlocks the buffer as soon as it detects that the buffer is still dirty.
If a concurrent write-back occurs immediately after this unlocking and
before clear_buffer_dirty() is called in jbd2_journal_forget(), data
corruption can theoretically still occur.
Although these two issues are unlikely to occur in practice since the
undergoing metadata writeback I/O does not take this long to complete,
it's better to explicitly ensure that all ongoing I/O operations are
completed.
Fixes: 597599268e3b ("jbd2: discard dirty data when forgetting an un-journalled buffer")
Cc: stable(a)kernel.org
Suggested-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Zhang Yi <yi.zhang(a)huawei.com>
Reviewed-by: Jan Kara <jack(a)suse.cz>
Message-ID: <20250916093337.3161016-2-yi.zhang(a)huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso(a)mit.edu>
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index c7867139af69..3e510564de6e 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1659,6 +1659,7 @@ int jbd2_journal_forget(handle_t *handle, struct buffer_head *bh)
int drop_reserve = 0;
int err = 0;
int was_modified = 0;
+ int wait_for_writeback = 0;
if (is_handle_aborted(handle))
return -EROFS;
@@ -1782,18 +1783,22 @@ int jbd2_journal_forget(handle_t *handle, struct buffer_head *bh)
}
/*
- * The buffer is still not written to disk, we should
- * attach this buffer to current transaction so that the
- * buffer can be checkpointed only after the current
- * transaction commits.
+ * The buffer has not yet been written to disk. We should
+ * either clear the buffer or ensure that the ongoing I/O
+ * is completed, and attach this buffer to current
+ * transaction so that the buffer can be checkpointed only
+ * after the current transaction commits.
*/
clear_buffer_dirty(bh);
+ wait_for_writeback = 1;
__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
spin_unlock(&journal->j_list_lock);
}
drop:
__brelse(bh);
spin_unlock(&jh->b_state_lock);
+ if (wait_for_writeback)
+ wait_on_buffer(bh);
jbd2_journal_put_journal_head(jh);
if (drop_reserve) {
/* no need to reserve log space for this block -bzzz */
The patch below does not apply to the 5.4-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(a)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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 56094ad3eaa21e6621396cc33811d8f72847a834
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102042-tactical-subtract-5775@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 56094ad3eaa21e6621396cc33811d8f72847a834 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Thu, 2 Oct 2025 17:55:07 +0200
Subject: [PATCH] vfs: Don't leak disconnected dentries on umount
When user calls open_by_handle_at() on some inode that is not cached, we
will create disconnected dentry for it. If such dentry is a directory,
exportfs_decode_fh_raw() will then try to connect this dentry to the
dentry tree through reconnect_path(). It may happen for various reasons
(such as corrupted fs or race with rename) that the call to
lookup_one_unlocked() in reconnect_one() will fail to find the dentry we
are trying to reconnect and instead create a new dentry under the
parent. Now this dentry will not be marked as disconnected although the
parent still may well be disconnected (at least in case this
inconsistency happened because the fs is corrupted and .. doesn't point
to the real parent directory). This creates inconsistency in
disconnected flags but AFAICS it was mostly harmless. At least until
commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
which removed adding of most disconnected dentries to sb->s_anon list.
Thus after this commit cleanup of disconnected dentries implicitely
relies on the fact that dput() will immediately reclaim such dentries.
However when some leaf dentry isn't marked as disconnected, as in the
scenario described above, the reclaim doesn't happen and the dentries
are "leaked". Memory reclaim can eventually reclaim them but otherwise
they stay in memory and if umount comes first, we hit infamous "Busy
inodes after unmount" bug. Make sure all dentries created under a
disconnected parent are marked as disconnected as well.
Reported-by: syzbot+1d79ebe5383fc016cf07(a)syzkaller.appspotmail.com
Fixes: f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/fs/dcache.c b/fs/dcache.c
index a067fa0a965a..035cccbc9276 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2557,6 +2557,8 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
spin_lock(&parent->d_lock);
new->d_parent = dget_dlock(parent);
hlist_add_head(&new->d_sib, &parent->d_children);
+ if (parent->d_flags & DCACHE_DISCONNECTED)
+ new->d_flags |= DCACHE_DISCONNECTED;
spin_unlock(&parent->d_lock);
retry:
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(a)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 56094ad3eaa21e6621396cc33811d8f72847a834
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102041-bonus-amid-8eda@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 56094ad3eaa21e6621396cc33811d8f72847a834 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Thu, 2 Oct 2025 17:55:07 +0200
Subject: [PATCH] vfs: Don't leak disconnected dentries on umount
When user calls open_by_handle_at() on some inode that is not cached, we
will create disconnected dentry for it. If such dentry is a directory,
exportfs_decode_fh_raw() will then try to connect this dentry to the
dentry tree through reconnect_path(). It may happen for various reasons
(such as corrupted fs or race with rename) that the call to
lookup_one_unlocked() in reconnect_one() will fail to find the dentry we
are trying to reconnect and instead create a new dentry under the
parent. Now this dentry will not be marked as disconnected although the
parent still may well be disconnected (at least in case this
inconsistency happened because the fs is corrupted and .. doesn't point
to the real parent directory). This creates inconsistency in
disconnected flags but AFAICS it was mostly harmless. At least until
commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
which removed adding of most disconnected dentries to sb->s_anon list.
Thus after this commit cleanup of disconnected dentries implicitely
relies on the fact that dput() will immediately reclaim such dentries.
However when some leaf dentry isn't marked as disconnected, as in the
scenario described above, the reclaim doesn't happen and the dentries
are "leaked". Memory reclaim can eventually reclaim them but otherwise
they stay in memory and if umount comes first, we hit infamous "Busy
inodes after unmount" bug. Make sure all dentries created under a
disconnected parent are marked as disconnected as well.
Reported-by: syzbot+1d79ebe5383fc016cf07(a)syzkaller.appspotmail.com
Fixes: f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/fs/dcache.c b/fs/dcache.c
index a067fa0a965a..035cccbc9276 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2557,6 +2557,8 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
spin_lock(&parent->d_lock);
new->d_parent = dget_dlock(parent);
hlist_add_head(&new->d_sib, &parent->d_children);
+ if (parent->d_flags & DCACHE_DISCONNECTED)
+ new->d_flags |= DCACHE_DISCONNECTED;
spin_unlock(&parent->d_lock);
retry:
The patch below does not apply to the 5.4-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(a)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-5.4.y
git checkout FETCH_HEAD
git cherry-pick -x 4b47a8601b71ad98833b447d465592d847b4dc77
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102009-buckskin-tweet-87b7@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4b47a8601b71ad98833b447d465592d847b4dc77 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Thu, 11 Sep 2025 11:12:06 -0400
Subject: [PATCH] NFSD: Define a proc_layoutcommit for the FlexFiles layout
type
Avoid a crash if a pNFS client should happen to send a LAYOUTCOMMIT
operation on a FlexFiles layout.
Reported-by: Robert Morris <rtm(a)csail.mit.edu>
Closes: https://lore.kernel.org/linux-nfs/152f99b2-ba35-4dec-93a9-4690e625dccd@orac…
Cc: Thomas Haynes <loghyr(a)hammerspace.com>
Cc: stable(a)vger.kernel.org
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c
index c318cf74e388..0f1a35400cd5 100644
--- a/fs/nfsd/flexfilelayout.c
+++ b/fs/nfsd/flexfilelayout.c
@@ -125,6 +125,13 @@ nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
return 0;
}
+static __be32
+nfsd4_ff_proc_layoutcommit(struct inode *inode, struct svc_rqst *rqstp,
+ struct nfsd4_layoutcommit *lcp)
+{
+ return nfs_ok;
+}
+
const struct nfsd4_layout_ops ff_layout_ops = {
.notify_types =
NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
@@ -133,4 +140,5 @@ const struct nfsd4_layout_ops ff_layout_ops = {
.encode_getdeviceinfo = nfsd4_ff_encode_getdeviceinfo,
.proc_layoutget = nfsd4_ff_proc_layoutget,
.encode_layoutget = nfsd4_ff_encode_layoutget,
+ .proc_layoutcommit = nfsd4_ff_proc_layoutcommit,
};
The patch below does not apply to the 5.15-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(a)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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 56094ad3eaa21e6621396cc33811d8f72847a834
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102040-uninstall-uneatable-a789@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 56094ad3eaa21e6621396cc33811d8f72847a834 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Thu, 2 Oct 2025 17:55:07 +0200
Subject: [PATCH] vfs: Don't leak disconnected dentries on umount
When user calls open_by_handle_at() on some inode that is not cached, we
will create disconnected dentry for it. If such dentry is a directory,
exportfs_decode_fh_raw() will then try to connect this dentry to the
dentry tree through reconnect_path(). It may happen for various reasons
(such as corrupted fs or race with rename) that the call to
lookup_one_unlocked() in reconnect_one() will fail to find the dentry we
are trying to reconnect and instead create a new dentry under the
parent. Now this dentry will not be marked as disconnected although the
parent still may well be disconnected (at least in case this
inconsistency happened because the fs is corrupted and .. doesn't point
to the real parent directory). This creates inconsistency in
disconnected flags but AFAICS it was mostly harmless. At least until
commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
which removed adding of most disconnected dentries to sb->s_anon list.
Thus after this commit cleanup of disconnected dentries implicitely
relies on the fact that dput() will immediately reclaim such dentries.
However when some leaf dentry isn't marked as disconnected, as in the
scenario described above, the reclaim doesn't happen and the dentries
are "leaked". Memory reclaim can eventually reclaim them but otherwise
they stay in memory and if umount comes first, we hit infamous "Busy
inodes after unmount" bug. Make sure all dentries created under a
disconnected parent are marked as disconnected as well.
Reported-by: syzbot+1d79ebe5383fc016cf07(a)syzkaller.appspotmail.com
Fixes: f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/fs/dcache.c b/fs/dcache.c
index a067fa0a965a..035cccbc9276 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2557,6 +2557,8 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
spin_lock(&parent->d_lock);
new->d_parent = dget_dlock(parent);
hlist_add_head(&new->d_sib, &parent->d_children);
+ if (parent->d_flags & DCACHE_DISCONNECTED)
+ new->d_flags |= DCACHE_DISCONNECTED;
spin_unlock(&parent->d_lock);
retry:
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(a)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 4b47a8601b71ad98833b447d465592d847b4dc77
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102040-always-thirty-b345@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4b47a8601b71ad98833b447d465592d847b4dc77 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Thu, 11 Sep 2025 11:12:06 -0400
Subject: [PATCH] NFSD: Define a proc_layoutcommit for the FlexFiles layout
type
Avoid a crash if a pNFS client should happen to send a LAYOUTCOMMIT
operation on a FlexFiles layout.
Reported-by: Robert Morris <rtm(a)csail.mit.edu>
Closes: https://lore.kernel.org/linux-nfs/152f99b2-ba35-4dec-93a9-4690e625dccd@orac…
Cc: Thomas Haynes <loghyr(a)hammerspace.com>
Cc: stable(a)vger.kernel.org
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c
index c318cf74e388..0f1a35400cd5 100644
--- a/fs/nfsd/flexfilelayout.c
+++ b/fs/nfsd/flexfilelayout.c
@@ -125,6 +125,13 @@ nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
return 0;
}
+static __be32
+nfsd4_ff_proc_layoutcommit(struct inode *inode, struct svc_rqst *rqstp,
+ struct nfsd4_layoutcommit *lcp)
+{
+ return nfs_ok;
+}
+
const struct nfsd4_layout_ops ff_layout_ops = {
.notify_types =
NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
@@ -133,4 +140,5 @@ const struct nfsd4_layout_ops ff_layout_ops = {
.encode_getdeviceinfo = nfsd4_ff_encode_getdeviceinfo,
.proc_layoutget = nfsd4_ff_proc_layoutget,
.encode_layoutget = nfsd4_ff_encode_layoutget,
+ .proc_layoutcommit = nfsd4_ff_proc_layoutcommit,
};
The patch below does not apply to the 5.15-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(a)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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 4b47a8601b71ad98833b447d465592d847b4dc77
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102023-trade-spud-e81a@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4b47a8601b71ad98833b447d465592d847b4dc77 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Thu, 11 Sep 2025 11:12:06 -0400
Subject: [PATCH] NFSD: Define a proc_layoutcommit for the FlexFiles layout
type
Avoid a crash if a pNFS client should happen to send a LAYOUTCOMMIT
operation on a FlexFiles layout.
Reported-by: Robert Morris <rtm(a)csail.mit.edu>
Closes: https://lore.kernel.org/linux-nfs/152f99b2-ba35-4dec-93a9-4690e625dccd@orac…
Cc: Thomas Haynes <loghyr(a)hammerspace.com>
Cc: stable(a)vger.kernel.org
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c
index c318cf74e388..0f1a35400cd5 100644
--- a/fs/nfsd/flexfilelayout.c
+++ b/fs/nfsd/flexfilelayout.c
@@ -125,6 +125,13 @@ nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
return 0;
}
+static __be32
+nfsd4_ff_proc_layoutcommit(struct inode *inode, struct svc_rqst *rqstp,
+ struct nfsd4_layoutcommit *lcp)
+{
+ return nfs_ok;
+}
+
const struct nfsd4_layout_ops ff_layout_ops = {
.notify_types =
NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
@@ -133,4 +140,5 @@ const struct nfsd4_layout_ops ff_layout_ops = {
.encode_getdeviceinfo = nfsd4_ff_encode_getdeviceinfo,
.proc_layoutget = nfsd4_ff_proc_layoutget,
.encode_layoutget = nfsd4_ff_encode_layoutget,
+ .proc_layoutcommit = nfsd4_ff_proc_layoutcommit,
};
The patch below does not apply to the 6.1-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(a)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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 56094ad3eaa21e6621396cc33811d8f72847a834
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102039-unmasking-zero-2258@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 56094ad3eaa21e6621396cc33811d8f72847a834 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack(a)suse.cz>
Date: Thu, 2 Oct 2025 17:55:07 +0200
Subject: [PATCH] vfs: Don't leak disconnected dentries on umount
When user calls open_by_handle_at() on some inode that is not cached, we
will create disconnected dentry for it. If such dentry is a directory,
exportfs_decode_fh_raw() will then try to connect this dentry to the
dentry tree through reconnect_path(). It may happen for various reasons
(such as corrupted fs or race with rename) that the call to
lookup_one_unlocked() in reconnect_one() will fail to find the dentry we
are trying to reconnect and instead create a new dentry under the
parent. Now this dentry will not be marked as disconnected although the
parent still may well be disconnected (at least in case this
inconsistency happened because the fs is corrupted and .. doesn't point
to the real parent directory). This creates inconsistency in
disconnected flags but AFAICS it was mostly harmless. At least until
commit f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
which removed adding of most disconnected dentries to sb->s_anon list.
Thus after this commit cleanup of disconnected dentries implicitely
relies on the fact that dput() will immediately reclaim such dentries.
However when some leaf dentry isn't marked as disconnected, as in the
scenario described above, the reclaim doesn't happen and the dentries
are "leaked". Memory reclaim can eventually reclaim them but otherwise
they stay in memory and if umount comes first, we hit infamous "Busy
inodes after unmount" bug. Make sure all dentries created under a
disconnected parent are marked as disconnected as well.
Reported-by: syzbot+1d79ebe5383fc016cf07(a)syzkaller.appspotmail.com
Fixes: f1ee616214cb ("VFS: don't keep disconnected dentries on d_anon")
CC: stable(a)vger.kernel.org
Signed-off-by: Jan Kara <jack(a)suse.cz>
Signed-off-by: Christian Brauner <brauner(a)kernel.org>
diff --git a/fs/dcache.c b/fs/dcache.c
index a067fa0a965a..035cccbc9276 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2557,6 +2557,8 @@ struct dentry *d_alloc_parallel(struct dentry *parent,
spin_lock(&parent->d_lock);
new->d_parent = dget_dlock(parent);
hlist_add_head(&new->d_sib, &parent->d_children);
+ if (parent->d_flags & DCACHE_DISCONNECTED)
+ new->d_flags |= DCACHE_DISCONNECTED;
spin_unlock(&parent->d_lock);
retry:
The patch below does not apply to the 6.1-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(a)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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 4b47a8601b71ad98833b447d465592d847b4dc77
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable(a)vger.kernel.org>' --in-reply-to '2025102006-approach-hesitancy-3614@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 4b47a8601b71ad98833b447d465592d847b4dc77 Mon Sep 17 00:00:00 2001
From: Chuck Lever <chuck.lever(a)oracle.com>
Date: Thu, 11 Sep 2025 11:12:06 -0400
Subject: [PATCH] NFSD: Define a proc_layoutcommit for the FlexFiles layout
type
Avoid a crash if a pNFS client should happen to send a LAYOUTCOMMIT
operation on a FlexFiles layout.
Reported-by: Robert Morris <rtm(a)csail.mit.edu>
Closes: https://lore.kernel.org/linux-nfs/152f99b2-ba35-4dec-93a9-4690e625dccd@orac…
Cc: Thomas Haynes <loghyr(a)hammerspace.com>
Cc: stable(a)vger.kernel.org
Fixes: 9b9960a0ca47 ("nfsd: Add a super simple flex file server")
Signed-off-by: Chuck Lever <chuck.lever(a)oracle.com>
diff --git a/fs/nfsd/flexfilelayout.c b/fs/nfsd/flexfilelayout.c
index c318cf74e388..0f1a35400cd5 100644
--- a/fs/nfsd/flexfilelayout.c
+++ b/fs/nfsd/flexfilelayout.c
@@ -125,6 +125,13 @@ nfsd4_ff_proc_getdeviceinfo(struct super_block *sb, struct svc_rqst *rqstp,
return 0;
}
+static __be32
+nfsd4_ff_proc_layoutcommit(struct inode *inode, struct svc_rqst *rqstp,
+ struct nfsd4_layoutcommit *lcp)
+{
+ return nfs_ok;
+}
+
const struct nfsd4_layout_ops ff_layout_ops = {
.notify_types =
NOTIFY_DEVICEID4_DELETE | NOTIFY_DEVICEID4_CHANGE,
@@ -133,4 +140,5 @@ const struct nfsd4_layout_ops ff_layout_ops = {
.encode_getdeviceinfo = nfsd4_ff_encode_getdeviceinfo,
.proc_layoutget = nfsd4_ff_proc_layoutget,
.encode_layoutget = nfsd4_ff_encode_layoutget,
+ .proc_layoutcommit = nfsd4_ff_proc_layoutcommit,
};