* [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume
@ 2021-12-13 8:45 fdmanana
2021-12-13 8:45 ` [PATCH 1/3] btrfs: fix invalid delayed ref after subvolume creation failure fdmanana
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: fdmanana @ 2021-12-13 8:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
The following patches fix an error path when creating a subvolume, exposed
by generic/475.
Filipe Manana (3):
btrfs: fix invalid delayed ref after subvolume creation failure
btrfs: fix warning when freeing leaf after subvolume creation failure
btrfs: skip transaction commit after failure to create subvolume
fs/btrfs/ctree.c | 17 +++++++++--------
fs/btrfs/ctree.h | 7 ++++++-
fs/btrfs/extent-tree.c | 13 +++++++------
fs/btrfs/free-space-tree.c | 4 ++--
fs/btrfs/ioctl.c | 18 ++++++++++--------
fs/btrfs/qgroup.c | 3 ++-
6 files changed, 36 insertions(+), 26 deletions(-)
--
2.33.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/3] btrfs: fix invalid delayed ref after subvolume creation failure
2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
@ 2021-12-13 8:45 ` fdmanana
2021-12-13 8:45 ` [PATCH 2/3] btrfs: fix warning when freeing leaf " fdmanana
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: fdmanana @ 2021-12-13 8:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
When creating a subvolume, at ioctl.c:create_subvol(), if we fail to
insert the new root's root item into the root tree, we are freeing the
metadata extent we reserved for the new root to prevent a metadata
extent leak, as we don't abort the transaction at that point (since
there is nothing at that point that is irreversible).
However we allocated the metadata extent for the new root which we are
creating for the new subvolume, so its delayed reference refers to the
ID of this new root. But when we free the metadata extent we pass the
root of the subvolume where the new subvolume is located to
btrfs_free_tree_block() - this is incorrect because this will generate
a delayed reference that refers to the ID of the parent subvolume's root,
and not to ID of the new root.
This results in a failure when running delayed references that leads to
a transaction abort and a trace like the following:
[ 3868.738042] RIP: 0010:__btrfs_free_extent+0x709/0x950 [btrfs]
[ 3868.739857] Code: 68 0f 85 e6 fb ff (...)
[ 3868.742963] RSP: 0018:ffffb0e9045cf910 EFLAGS: 00010246
[ 3868.743908] RAX: 00000000fffffffe RBX: 00000000fffffffe RCX: 0000000000000002
[ 3868.745312] RDX: 00000000fffffffe RSI: 0000000000000002 RDI: ffff90b0cd793b88
[ 3868.746643] RBP: 000000000e5d8000 R08: 0000000000000000 R09: ffff90b0cd793b88
[ 3868.747979] R10: 0000000000000002 R11: 00014ded97944d68 R12: 0000000000000000
[ 3868.749373] R13: ffff90b09afe4a28 R14: 0000000000000000 R15: ffff90b0cd793b88
[ 3868.750725] FS: 00007f281c4a8b80(0000) GS:ffff90b3ada00000(0000) knlGS:0000000000000000
[ 3868.752275] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3868.753515] CR2: 00007f281c6a5000 CR3: 0000000108a42006 CR4: 0000000000370ee0
[ 3868.754869] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3868.756228] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3868.757803] Call Trace:
[ 3868.758281] <TASK>
[ 3868.758655] ? btrfs_merge_delayed_refs+0x178/0x1c0 [btrfs]
[ 3868.759827] __btrfs_run_delayed_refs+0x2b1/0x1250 [btrfs]
[ 3868.761047] btrfs_run_delayed_refs+0x86/0x210 [btrfs]
[ 3868.762069] ? lock_acquired+0x19f/0x420
[ 3868.762829] btrfs_commit_transaction+0x69/0xb20 [btrfs]
[ 3868.763860] ? _raw_spin_unlock+0x29/0x40
[ 3868.764614] ? btrfs_block_rsv_release+0x1c2/0x1e0 [btrfs]
[ 3868.765870] create_subvol+0x1d8/0x9a0 [btrfs]
[ 3868.766766] btrfs_mksubvol+0x447/0x4c0 [btrfs]
[ 3868.767669] ? preempt_count_add+0x49/0xa0
[ 3868.768444] __btrfs_ioctl_snap_create+0x123/0x190 [btrfs]
[ 3868.769639] ? _copy_from_user+0x66/0xa0
[ 3868.770391] btrfs_ioctl_snap_create_v2+0xbb/0x140 [btrfs]
[ 3868.771495] btrfs_ioctl+0xd1e/0x35c0 [btrfs]
[ 3868.772364] ? __slab_free+0x10a/0x360
[ 3868.773198] ? rcu_read_lock_sched_held+0x12/0x60
[ 3868.774121] ? lock_release+0x223/0x4a0
[ 3868.774863] ? lock_acquired+0x19f/0x420
[ 3868.775634] ? rcu_read_lock_sched_held+0x12/0x60
[ 3868.776530] ? trace_hardirqs_on+0x1b/0xe0
[ 3868.777373] ? _raw_spin_unlock_irqrestore+0x3e/0x60
[ 3868.778280] ? kmem_cache_free+0x321/0x3c0
[ 3868.779011] ? __x64_sys_ioctl+0x83/0xb0
[ 3868.779718] __x64_sys_ioctl+0x83/0xb0
[ 3868.780387] do_syscall_64+0x3b/0xc0
[ 3868.781059] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 3868.781953] RIP: 0033:0x7f281c59e957
[ 3868.782585] Code: 3c 1c 48 f7 d8 4c (...)
[ 3868.785867] RSP: 002b:00007ffe1f83e2b8 EFLAGS: 00000202 ORIG_RAX: 0000000000000010
[ 3868.787198] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281c59e957
[ 3868.788450] RDX: 00007ffe1f83e2c0 RSI: 0000000050009418 RDI: 0000000000000003
[ 3868.789748] RBP: 00007ffe1f83f300 R08: 0000000000000000 R09: 00007ffe1f83fe36
[ 3868.791214] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
[ 3868.792468] R13: 0000000000000003 R14: 00007ffe1f83e2c0 R15: 00000000000003cc
[ 3868.793765] </TASK>
[ 3868.794037] irq event stamp: 0
[ 3868.794548] hardirqs last enabled at (0): [<0000000000000000>] 0x0
[ 3868.795670] hardirqs last disabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040
[ 3868.797086] softirqs last enabled at (0): [<ffffffff98294214>] copy_process+0x934/0x2040
[ 3868.798309] softirqs last disabled at (0): [<0000000000000000>] 0x0
[ 3868.799284] ---[ end trace be24c7002fe27747 ]---
[ 3868.799928] BTRFS info (device dm-0): leaf 241188864 gen 1268 total ptrs 214 free space 469 owner 2
[ 3868.801133] BTRFS info (device dm-0): refs 2 lock_owner 225627 current 225627
[ 3868.802056] item 0 key (237436928 169 0) itemoff 16250 itemsize 33
[ 3868.802863] extent refs 1 gen 1265 flags 2
[ 3868.803447] ref#0: tree block backref root 1610
(...)
[ 3869.064354] item 114 key (241008640 169 0) itemoff 12488 itemsize 33
[ 3869.065421] extent refs 1 gen 1268 flags 2
[ 3869.066115] ref#0: tree block backref root 1689
(...)
[ 3869.403834] BTRFS error (device dm-0): unable to find ref byte nr 241008640 parent 0 root 1622 owner 0 offset 0
[ 3869.405641] BTRFS: error (device dm-0) in __btrfs_free_extent:3076: errno=-2 No such entry
[ 3869.407138] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2159: errno=-2 No such entry
Fix this by passing the new subvolume's root ID to btrfs_free_tree_block().
This requires changing the root argument of btrfs_free_tree_block() from
struct btrfs_root * to a u64, since at this point during the subvolume
creation we have not yet created the struct btrfs_root for the new
subvolume, and btrfs_free_tree_block() only needs a root ID and nothing
else from a struct btrfs_root.
This was triggered by test case generic/475 from fstests.
Fixes: 67addf29004c5b ("btrfs: fix metadata extent leak after failure to create subvolume")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/ctree.c | 17 +++++++++--------
fs/btrfs/ctree.h | 7 ++++++-
fs/btrfs/extent-tree.c | 13 +++++++------
fs/btrfs/free-space-tree.c | 4 ++--
fs/btrfs/ioctl.c | 9 +++++----
fs/btrfs/qgroup.c | 3 ++-
6 files changed, 31 insertions(+), 22 deletions(-)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 781537692a4a..defc494a2d08 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -463,8 +463,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
BUG_ON(ret < 0);
rcu_assign_pointer(root->node, cow);
- btrfs_free_tree_block(trans, root, buf, parent_start,
- last_ref);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
+ parent_start, last_ref);
free_extent_buffer(buf);
add_root_to_dirty_list(root);
} else {
@@ -485,8 +485,8 @@ static noinline int __btrfs_cow_block(struct btrfs_trans_handle *trans,
return ret;
}
}
- btrfs_free_tree_block(trans, root, buf, parent_start,
- last_ref);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
+ parent_start, last_ref);
}
if (unlock_orig)
btrfs_tree_unlock(buf);
@@ -930,7 +930,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
free_extent_buffer(mid);
root_sub_used(root, mid->len);
- btrfs_free_tree_block(trans, root, mid, 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);
/* once for the root ptr */
free_extent_buffer_stale(mid);
return 0;
@@ -989,7 +989,8 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_tree_unlock(right);
del_ptr(root, path, level + 1, pslot + 1);
root_sub_used(root, right->len);
- btrfs_free_tree_block(trans, root, right, 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), right,
+ 0, 1);
free_extent_buffer_stale(right);
right = NULL;
} else {
@@ -1034,7 +1035,7 @@ static noinline int balance_level(struct btrfs_trans_handle *trans,
btrfs_tree_unlock(mid);
del_ptr(root, path, level + 1, pslot);
root_sub_used(root, mid->len);
- btrfs_free_tree_block(trans, root, mid, 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), mid, 0, 1);
free_extent_buffer_stale(mid);
mid = NULL;
} else {
@@ -4156,7 +4157,7 @@ static noinline void btrfs_del_leaf(struct btrfs_trans_handle *trans,
root_sub_used(root, leaf->len);
atomic_inc(&leaf->refs);
- btrfs_free_tree_block(trans, root, leaf, 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), leaf, 0, 1);
free_extent_buffer_stale(leaf);
}
/*
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 02f06ee02e4e..459d00211181 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2269,6 +2269,11 @@ static inline bool btrfs_root_dead(const struct btrfs_root *root)
return (root->root_item.flags & cpu_to_le64(BTRFS_ROOT_SUBVOL_DEAD)) != 0;
}
+static inline u64 btrfs_root_id(const struct btrfs_root *root)
+{
+ return root->root_key.objectid;
+}
+
/* struct btrfs_root_backup */
BTRFS_SETGET_STACK_FUNCS(backup_tree_root, struct btrfs_root_backup,
tree_root, 64);
@@ -2731,7 +2736,7 @@ struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
u64 empty_size,
enum btrfs_lock_nesting nest);
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
+ u64 root_id,
struct extent_buffer *buf,
u64 parent, int last_ref);
int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 8cb67df5acef..d89273c4b6b8 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3290,20 +3290,20 @@ static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
}
void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
- struct btrfs_root *root,
+ u64 root_id,
struct extent_buffer *buf,
u64 parent, int last_ref)
{
- struct btrfs_fs_info *fs_info = root->fs_info;
+ struct btrfs_fs_info *fs_info = trans->fs_info;
struct btrfs_ref generic_ref = { 0 };
int ret;
btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
buf->start, buf->len, parent);
btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
- root->root_key.objectid, 0, false);
+ root_id, 0, false);
- if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
+ if (root_id != BTRFS_TREE_LOG_OBJECTID) {
btrfs_ref_tree_mod(fs_info, &generic_ref);
ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);
BUG_ON(ret); /* -ENOMEM */
@@ -3313,7 +3313,7 @@ void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
struct btrfs_block_group *cache;
bool must_pin = false;
- if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
+ if (root_id != BTRFS_TREE_LOG_OBJECTID) {
ret = check_ref_cleanup(trans, buf->start);
if (!ret) {
btrfs_redirty_list_add(trans->transaction, buf);
@@ -5516,7 +5516,8 @@ static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
goto owner_mismatch;
}
- btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent,
+ wc->refs[level] == 1);
out:
wc->refs[level] = 0;
wc->flags[level] = 0;
diff --git a/fs/btrfs/free-space-tree.c b/fs/btrfs/free-space-tree.c
index a3eb6bce2a4d..655aad0f9e1c 100644
--- a/fs/btrfs/free-space-tree.c
+++ b/fs/btrfs/free-space-tree.c
@@ -1278,8 +1278,8 @@ int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
btrfs_tree_lock(free_space_root->node);
btrfs_clean_tree_block(free_space_root->node);
btrfs_tree_unlock(free_space_root->node);
- btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
- 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(free_space_root),
+ free_space_root->node, 0, 1);
btrfs_put_root(free_space_root);
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 61c90086072d..1a6784e99082 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -643,11 +643,12 @@ static noinline int create_subvol(struct user_namespace *mnt_userns,
* Since we don't abort the transaction in this case, free the
* tree block so that we don't leak space and leave the
* filesystem in an inconsistent state (an extent item in the
- * extent tree without backreferences). Also no need to have
- * the tree block locked since it is not in any tree at this
- * point, so no other task can find it and use it.
+ * extent tree with a backreference for a root that does not
+ * exists). Also no need to have the tree block locked since it
+ * is not in any tree at this point, so no other task can find
+ * it and use it.
*/
- btrfs_free_tree_block(trans, root, leaf, 0, 1);
+ btrfs_free_tree_block(trans, objectid, leaf, 0, 1);
free_extent_buffer(leaf);
goto fail;
}
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index b126cc39ffd4..8928275823a1 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1238,7 +1238,8 @@ int btrfs_quota_disable(struct btrfs_fs_info *fs_info)
btrfs_tree_lock(quota_root->node);
btrfs_clean_tree_block(quota_root->node);
btrfs_tree_unlock(quota_root->node);
- btrfs_free_tree_block(trans, quota_root, quota_root->node, 0, 1);
+ btrfs_free_tree_block(trans, btrfs_root_id(quota_root),
+ quota_root->node, 0, 1);
btrfs_put_root(quota_root);
--
2.33.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/3] btrfs: fix warning when freeing leaf after subvolume creation failure
2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
2021-12-13 8:45 ` [PATCH 1/3] btrfs: fix invalid delayed ref after subvolume creation failure fdmanana
@ 2021-12-13 8:45 ` fdmanana
2021-12-13 8:45 ` [PATCH 3/3] btrfs: skip transaction commit after failure to create subvolume fdmanana
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: fdmanana @ 2021-12-13 8:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
When creating a subvolume, at ioctl.c:create_subvol(), if we fail to
insert the root item for the new subvolume into the root tree, we can
trigger the following warning:
[78961.741046] WARNING: CPU: 0 PID: 4079814 at fs/btrfs/extent-tree.c:3357 btrfs_free_tree_block+0x2af/0x310 [btrfs]
[78961.743344] Modules linked in:
[78961.749440] dm_snapshot dm_thin_pool (...)
[78961.773648] CPU: 0 PID: 4079814 Comm: fsstress Not tainted 5.16.0-rc4-btrfs-next-108 #1
[78961.775198] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[78961.777266] RIP: 0010:btrfs_free_tree_block+0x2af/0x310 [btrfs]
[78961.778398] Code: 17 00 48 85 (...)
[78961.781067] RSP: 0018:ffffaa4001657b28 EFLAGS: 00010202
[78961.781877] RAX: 0000000000000213 RBX: ffff897f8a796910 RCX: 0000000000000000
[78961.782780] RDX: 0000000000000000 RSI: 0000000011004000 RDI: 00000000ffffffff
[78961.783764] RBP: ffff8981f490e800 R08: 0000000000000001 R09: 0000000000000000
[78961.784740] R10: 0000000000000000 R11: 0000000000000001 R12: ffff897fc963fcc8
[78961.785665] R13: 0000000000000001 R14: ffff898063548000 R15: ffff898063548000
[78961.786620] FS: 00007f31283c6b80(0000) GS:ffff8982ace00000(0000) knlGS:0000000000000000
[78961.787717] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[78961.788598] CR2: 00007f31285c3000 CR3: 000000023fcc8003 CR4: 0000000000370ef0
[78961.789568] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[78961.790585] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[78961.791684] Call Trace:
[78961.792082] <TASK>
[78961.792359] create_subvol+0x5d1/0x9a0 [btrfs]
[78961.793054] btrfs_mksubvol+0x447/0x4c0 [btrfs]
[78961.794009] ? preempt_count_add+0x49/0xa0
[78961.794705] __btrfs_ioctl_snap_create+0x123/0x190 [btrfs]
[78961.795712] ? _copy_from_user+0x66/0xa0
[78961.796382] btrfs_ioctl_snap_create_v2+0xbb/0x140 [btrfs]
[78961.797392] btrfs_ioctl+0xd1e/0x35c0 [btrfs]
[78961.798172] ? __slab_free+0x10a/0x360
[78961.798820] ? rcu_read_lock_sched_held+0x12/0x60
[78961.799664] ? lock_release+0x223/0x4a0
[78961.800321] ? lock_acquired+0x19f/0x420
[78961.800992] ? rcu_read_lock_sched_held+0x12/0x60
[78961.801796] ? trace_hardirqs_on+0x1b/0xe0
[78961.802495] ? _raw_spin_unlock_irqrestore+0x3e/0x60
[78961.803358] ? kmem_cache_free+0x321/0x3c0
[78961.804071] ? __x64_sys_ioctl+0x83/0xb0
[78961.804711] __x64_sys_ioctl+0x83/0xb0
[78961.805348] do_syscall_64+0x3b/0xc0
[78961.805969] entry_SYSCALL_64_after_hwframe+0x44/0xae
[78961.806830] RIP: 0033:0x7f31284bc957
[78961.807517] Code: 3c 1c 48 f7 d8 (...)
This is because we are calling btrfs_free_tree_block() on an extent
buffer that is dirty. Fix that by cleaning the extent buffer, with
btrfs_clean_tree_block(), before freeing it.
This was triggered by test case generic/475 from fstests.
Fixes: 67addf29004c5b ("btrfs: fix metadata extent leak after failure to create subvolume")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/ioctl.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 1a6784e99082..7565b667f4fc 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -644,10 +644,11 @@ static noinline int create_subvol(struct user_namespace *mnt_userns,
* tree block so that we don't leak space and leave the
* filesystem in an inconsistent state (an extent item in the
* extent tree with a backreference for a root that does not
- * exists). Also no need to have the tree block locked since it
- * is not in any tree at this point, so no other task can find
- * it and use it.
+ * exists).
*/
+ btrfs_tree_lock(leaf);
+ btrfs_clean_tree_block(leaf);
+ btrfs_tree_unlock(leaf);
btrfs_free_tree_block(trans, objectid, leaf, 0, 1);
free_extent_buffer(leaf);
goto fail;
--
2.33.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 3/3] btrfs: skip transaction commit after failure to create subvolume
2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
2021-12-13 8:45 ` [PATCH 1/3] btrfs: fix invalid delayed ref after subvolume creation failure fdmanana
2021-12-13 8:45 ` [PATCH 2/3] btrfs: fix warning when freeing leaf " fdmanana
@ 2021-12-13 8:45 ` fdmanana
2021-12-13 11:22 ` [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume Nikolay Borisov
2021-12-14 14:39 ` David Sterba
4 siblings, 0 replies; 6+ messages in thread
From: fdmanana @ 2021-12-13 8:45 UTC (permalink / raw)
To: linux-btrfs
From: Filipe Manana <fdmanana@suse.com>
At ioctl.c:create_subvol(), when we fail to create a subvolume we always
commit the transaction. In most cases this is a no-op, since all the error
paths, except for one, abort the transaction - the only exception is when
we fail to insert the new root item into the root tree, in that case we
don't abort the transaction because we didn't do anything that is
irreversible - however we end up committing the transaction which although
is not a functional problem, it adds unnecessary rotation of the backup
roots in the superblock and unnecessary work.
So change that to commit a transaction only when no error happened,
otherwise just call btrfs_end_transaction() to release our reference on
the transaction.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
---
fs/btrfs/ioctl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 7565b667f4fc..a5bd6926f7ff 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -544,7 +544,6 @@ static noinline int create_subvol(struct user_namespace *mnt_userns,
struct timespec64 cur_time = current_time(dir);
struct inode *inode;
int ret;
- int err;
dev_t anon_dev = 0;
u64 objectid;
u64 index = 0;
@@ -724,9 +723,10 @@ static noinline int create_subvol(struct user_namespace *mnt_userns,
trans->bytes_reserved = 0;
btrfs_subvolume_release_metadata(root, &block_rsv);
- err = btrfs_commit_transaction(trans);
- if (err && !ret)
- ret = err;
+ if (ret)
+ btrfs_end_transaction(trans);
+ else
+ ret = btrfs_commit_transaction(trans);
if (!ret) {
inode = btrfs_lookup_dentry(dir, dentry);
--
2.33.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume
2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
` (2 preceding siblings ...)
2021-12-13 8:45 ` [PATCH 3/3] btrfs: skip transaction commit after failure to create subvolume fdmanana
@ 2021-12-13 11:22 ` Nikolay Borisov
2021-12-14 14:39 ` David Sterba
4 siblings, 0 replies; 6+ messages in thread
From: Nikolay Borisov @ 2021-12-13 11:22 UTC (permalink / raw)
To: fdmanana, linux-btrfs
On 13.12.21 г. 10:45, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> The following patches fix an error path when creating a subvolume, exposed
> by generic/475.
>
> Filipe Manana (3):
> btrfs: fix invalid delayed ref after subvolume creation failure
> btrfs: fix warning when freeing leaf after subvolume creation failure
> btrfs: skip transaction commit after failure to create subvolume
>
> fs/btrfs/ctree.c | 17 +++++++++--------
> fs/btrfs/ctree.h | 7 ++++++-
> fs/btrfs/extent-tree.c | 13 +++++++------
> fs/btrfs/free-space-tree.c | 4 ++--
> fs/btrfs/ioctl.c | 18 ++++++++++--------
> fs/btrfs/qgroup.c | 3 ++-
> 6 files changed, 36 insertions(+), 26 deletions(-)
>
For the whole series :
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume
2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
` (3 preceding siblings ...)
2021-12-13 11:22 ` [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume Nikolay Borisov
@ 2021-12-14 14:39 ` David Sterba
4 siblings, 0 replies; 6+ messages in thread
From: David Sterba @ 2021-12-14 14:39 UTC (permalink / raw)
To: fdmanana; +Cc: linux-btrfs
On Mon, Dec 13, 2021 at 08:45:11AM +0000, fdmanana@kernel.org wrote:
> From: Filipe Manana <fdmanana@suse.com>
>
> The following patches fix an error path when creating a subvolume, exposed
> by generic/475.
>
> Filipe Manana (3):
> btrfs: fix invalid delayed ref after subvolume creation failure
> btrfs: fix warning when freeing leaf after subvolume creation failure
> btrfs: skip transaction commit after failure to create subvolume
Added to misc-next, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-12-13 8:45 [PATCH 0/3] btrfs: fixes for an error path when creating a subvolume fdmanana
2021-12-13 8:45 ` [PATCH 1/3] btrfs: fix invalid delayed ref after subvolume creation failure fdmanana
2021-12-13 8:45 ` [PATCH 2/3] btrfs: fix warning when freeing leaf " fdmanana
2021-12-13 8:45 ` [PATCH 3/3] btrfs: skip transaction commit after failure to create subvolume fdmanana
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