This patch set fix perag leak problems when growfs fails.
Long Li (2): xfs: add lock protection when remove perag from radix tree xfs: fix perag leak when growfs fails
fs/xfs/libxfs/xfs_ag.c | 36 ++++++++++++++++++++++++++++-------- fs/xfs/libxfs/xfs_ag.h | 2 ++ fs/xfs/xfs_fsops.c | 5 ++++- 3 files changed, 34 insertions(+), 9 deletions(-)
maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8RJA8 CVE: NA
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Take mp->m_perag_lock for deletions from the perag radix tree in xfs_initialize_perag to prevent racing with tagging operations. Lookups are fine - they are RCU protected so already deal with the tree changing shape underneath the lookup - but tagging operations require the tree to be stable while the tags are propagated back up to the root.
Right now there's nothing stopping radix tree tagging from operating while a growfs operation is progress and adding/removing new entries into the radix tree.
Hence we can have traversals that require a stable tree occurring at the same time we are removing unused entries from the radix tree which causes the shape of the tree to change.
Likely this hasn't caused a problem in the past because we are only doing append addition and removal so the active AG part of the tree is not changing shape, but that doesn't mean it is safe. Just making the radix tree modifications serialise against each other is obviously correct.
Signed-off-by: Long Li leo.lilong@huawei.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Darrick J. Wong djwong@kernel.org --- fs/xfs/libxfs/xfs_ag.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c index f9f4d694640d..cc10a3ca052f 100644 --- a/fs/xfs/libxfs/xfs_ag.c +++ b/fs/xfs/libxfs/xfs_ag.c @@ -424,13 +424,17 @@ xfs_initialize_perag(
out_remove_pag: xfs_defer_drain_free(&pag->pag_intents_drain); + spin_lock(&mp->m_perag_lock); radix_tree_delete(&mp->m_perag_tree, index); + spin_unlock(&mp->m_perag_lock); 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);
maillist inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I8RJA8 CVE: NA
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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 --- 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(-)
diff --git a/fs/xfs/libxfs/xfs_ag.c b/fs/xfs/libxfs/xfs_ag.c index cc10a3ca052f..18d9bb2ebe8e 100644 --- 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 @@ xfs_initialize_perag( 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; }
diff --git a/fs/xfs/libxfs/xfs_ag.h b/fs/xfs/libxfs/xfs_ag.h index 2e0aef87d633..40d7b6427afb 100644 --- a/fs/xfs/libxfs/xfs_ag.h +++ b/fs/xfs/libxfs/xfs_ag.h @@ -133,6 +133,8 @@ __XFS_AG_OPSTATE(prefers_metadata, PREFERS_METADATA) __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); diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index 7cb75cb6b8e9..55ea34b4a69a 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -153,7 +153,7 @@ 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) { @@ -227,6 +227,9 @@ 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; }
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