[PATCH 6.6 272/396] xfs: fix perag leak when growfs fails

Greg Kroah-Hartman
2024-04-01T16:50:09Z

From: Long Li <leo.lilong@huawei.com>

commit 7823921887750b39d02e6b44faafdd1cc617c651 upstream.

During growfs, if new ag in memory has been initialized, however
sb_agcount has not been updated, if an error occurs at this time it
will cause perag leaks as follows, these new AGs will not been freed
during umount , because of these new AGs are not visible(that is
included in mp->m_sb.sb_agcount).

unreferenced object 0xffff88810be40200 (size 512):
comm "xfs_growfs", pid 857, jiffies 4294909093
hex dump (first 32 bytes):
00 c0 c1 05 81 88 ff ff 04 00 00 00 00 00 00 00 ................
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace (crc 381741e2):
[<ffffffff8191aef6>] __kmalloc+0x386/0x4f0
[<ffffffff82553e65>] kmem_alloc+0xb5/0x2f0
[<ffffffff8238dac5>] xfs_initialize_perag+0xc5/0x810
[<ffffffff824f679c>] xfs_growfs_data+0x9bc/0xbc0
[<ffffffff8250b90e>] xfs_file_ioctl+0x5fe/0x14d0
[<ffffffff81aa5194>] __x64_sys_ioctl+0x144/0x1c0
[<ffffffff83c3d81f>] do_syscall_64+0x3f/0xe0
[<ffffffff83e00087>] entry_SYSCALL_64_after_hwframe+0x62/0x6a
unreferenced object 0xffff88810be40800 (size 512):
comm "xfs_growfs", pid 857, jiffies 4294909093
hex dump (first 32 bytes):
20 00 00 00 00 00 00 00 57 ef be dc 00 00 00 00 .......W.......
10 08 e4 0b 81 88 ff ff 10 08 e4 0b 81 88 ff ff ................
backtrace (crc bde50e2d):
[<ffffffff8191b43a>] __kmalloc_node+0x3da/0x540
[<ffffffff81814489>] kvmalloc_node+0x99/0x160
[<ffffffff8286acff>] bucket_table_alloc.isra.0+0x5f/0x400
[<ffffffff8286bdc5>] rhashtable_init+0x405/0x760
[<ffffffff8238dda3>] xfs_initialize_perag+0x3a3/0x810
[<ffffffff824f679c>] xfs_growfs_data+0x9bc/0xbc0
[<ffffffff8250b90e>] xfs_file_ioctl+0x5fe/0x14d0
[<ffffffff81aa5194>] __x64_sys_ioctl+0x144/0x1c0
[<ffffffff83c3d81f>] do_syscall_64+0x3f/0xe0
[<ffffffff83e00087>] entry_SYSCALL_64_after_hwframe+0x62/0x6a

Factor out xfs_free_unused_perag_range() from xfs_initialize_perag(),
used for freeing unused perag within a specified range in error handling,
included in the error path of the growfs failure.

Fixes: 1c1c6ebcf528 ("xfs: Replace per-ag array with a radix tree")
Signed-off-by: Long Li <leo.lilong@huawei.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/xfs/libxfs/xfs_ag.c | 36 ++++++++++++++++++++++++++----------
fs/xfs/libxfs/xfs_ag.h | 2 ++
fs/xfs/xfs_fsops.c | 5 ++++-
3 files changed, 32 insertions(+), 11 deletions(-)

--- a/fs/xfs/libxfs/xfs_ag.c
+++ b/fs/xfs/libxfs/xfs_ag.c
@@ -332,6 +332,31 @@ xfs_agino_range(
return __xfs_agino_range(mp, xfs_ag_block_count(mp, agno), first, last);
}

+/*
+ * Free perag within the specified AG range, it is only used to free unused
+ * perags under the error handling path.
+ */
+void
+xfs_free_unused_perag_range(
+ struct xfs_mount *mp,
+ xfs_agnumber_t agstart,
+ xfs_agnumber_t agend)
+{
+ struct xfs_perag *pag;
+ xfs_agnumber_t index;
+
+ for (index = agstart; index < agend; index++) {
+ spin_lock(&mp->m_perag_lock);
+ pag = radix_tree_delete(&mp->m_perag_tree, index);
+ spin_unlock(&mp->m_perag_lock);
+ if (!pag)
+ break;
+ xfs_buf_hash_destroy(pag);
+ xfs_defer_drain_free(&pag->pag_intents_drain);
+ kmem_free(pag);
+ }
+}
+
int
xfs_initialize_perag(
struct xfs_mount *mp,
@@ -431,16 +456,7 @@ out_free_pag:
kmem_free(pag);
out_unwind_new_pags:
/* unwind any prior newly initialized pags */
- for (index = first_initialised; index < agcount; index++) {
- spin_lock(&mp->m_perag_lock);
- pag = radix_tree_delete(&mp->m_perag_tree, index);
- spin_unlock(&mp->m_perag_lock);
- if (!pag)
- break;
- xfs_buf_hash_destroy(pag);
- xfs_defer_drain_free(&pag->pag_intents_drain);
- kmem_free(pag);
- }
+ xfs_free_unused_perag_range(mp, first_initialised, agcount);
return error;
}

--- a/fs/xfs/libxfs/xfs_ag.h
+++ b/fs/xfs/libxfs/xfs_ag.h
@@ -133,6 +133,8 @@ __XFS_AG_OPSTATE(prefers_metadata, PREFE
__XFS_AG_OPSTATE(allows_inodes, ALLOWS_INODES)
__XFS_AG_OPSTATE(agfl_needs_reset, AGFL_NEEDS_RESET)

+void xfs_free_unused_perag_range(struct xfs_mount *mp, xfs_agnumber_t agstart,
+ xfs_agnumber_t agend);
int xfs_initialize_perag(struct xfs_mount *mp, xfs_agnumber_t agcount,
xfs_rfsblock_t dcount, xfs_agnumber_t *maxagi);
int xfs_initialize_perag_data(struct xfs_mount *mp, xfs_agnumber_t agno);
--- a/fs/xfs/xfs_fsops.c
+++ b/fs/xfs/xfs_fsops.c
@@ -157,7 +157,7 @@ xfs_growfs_data_private(
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_growdata, -delta, 0,
0, &tp);
if (error)
- return error;
+ goto out_free_unused_perag;

last_pag = xfs_perag_get(mp, oagcount - 1);
if (delta > 0) {
@@ -231,6 +231,9 @@ xfs_growfs_data_private(

out_trans_cancel:
xfs_trans_cancel(tp);
+out_free_unused_perag:
+ if (nagcount > oagcount)
+ xfs_free_unused_perag_range(mp, oagcount, nagcount);
return error;
}