[PATCH] xfs: fix the problem of mount failure caused by not refreshing mp->m_sb

[Wu Guanghao <wuguanghao3@huawei.com>]

After testing xfs_growfs + fsstress + fault injection, the following stack appeared
when mounting the filesystem:

[  149.902032] XFS (loop0): xfs_buf_map_verify: daddr 0x200001 out of range, EOFS 0x200000
[  149.902072] WARNING: CPU: 12 PID: 3045 at fs/xfs/xfs_buf.c:535 xfs_buf_get_map+0x5ae/0x650 [xfs]
...
[  149.902473]  xfs_buf_read_map+0x59/0x330 [xfs]
[  149.902621]  ? xlog_recover_items_pass2+0x55/0xd0 [xfs]
[  149.902809]  xlog_recover_buf_commit_pass2+0xff/0x640 [xfs]
[  149.902959]  ? xlog_recover_items_pass2+0x55/0xd0 [xfs]
[  149.903104]  xlog_recover_items_pass2+0x55/0xd0 [xfs]
[  149.903247]  xlog_recover_commit_trans+0x2e0/0x330 [xfs]
[  149.903390]  xlog_recovery_process_trans+0x8e/0xf0 [xfs]
[  149.903531]  xlog_recover_process_data+0x9c/0x130 [xfs]
[  149.903687]  xlog_do_recovery_pass+0x3cc/0x5d0 [xfs]
[  149.903843]  xlog_do_log_recovery+0x5c/0x80 [xfs]
[  149.903984]  xlog_do_recover+0x33/0x1c0 [xfs]
[  149.904125]  xlog_recover+0xdd/0x190 [xfs]
[  149.904265]  xfs_log_mount+0x125/0x2f0 [xfs]
[  149.904410]  xfs_mountfs+0x41a/0x910 [xfs]
[  149.904558]  ? __pfx_xfs_fstrm_free_func+0x10/0x10 [xfs]
[  149.904725]  xfs_fs_fill_super+0x4b7/0x940 [xfs]
[  149.904873]  ? __pfx_xfs_fs_fill_super+0x10/0x10 [xfs]
[  149.905016]  get_tree_bdev+0x19a/0x280
[  149.905020]  vfs_get_tree+0x29/0xd0
[  149.905023]  path_mount+0x69e/0x9b0
[  149.905026]  do_mount+0x7d/0xa0
[  149.905029]  __x64_sys_mount+0xdc/0x100
[  149.905032]  do_syscall_64+0x3e/0x90
[  149.905035]  entry_SYSCALL_64_after_hwframe+0x72/0xdc

The trigger process is as follows:

1. Growfs size from 0x200000 to 0x300000
2. Using the space range of 0x200000~0x300000
3. The above operations have only been written to the log area on disk
4. Fault injection and shutdown filesystem
5. Mount the filesystem and replay the log about growfs, but only modify the
 superblock buffer without modifying the mp->m_sb structure in memory
6. Continuing the log replay, at this point we are replaying operation 2, then
 it was discovered that the blocks used more than mp->m_sb.sb_dblocks

Therefore, during log replay, if there are any modifications made to the
superblock, we should refresh the information recorded in the mp->m_sb.

Signed-off-by: Wu Guanghao <wuguanghao3@huawei.com>
---
 fs/xfs/xfs_buf_item_recover.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c
index 43167f543afc..2ac3d2083188 100644
--- a/fs/xfs/xfs_buf_item_recover.c
+++ b/fs/xfs/xfs_buf_item_recover.c
@@ -22,6 +22,8 @@
 #include "xfs_inode.h"
 #include "xfs_dir2.h"
 #include "xfs_quota.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"

 /*
  * This is the number of entries in the l_buf_cancel_table used during
@@ -969,6 +971,29 @@ xlog_recover_buf_commit_pass2(
                        goto out_release;
        } else {
                xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn);
+               /*
+                * If the superblock buffer is modified, we also need to modify the
+                * content of the mp.
+                */
+               if (bp->b_maps[0].bm_bn == XFS_SB_DADDR && bp->b_ops) {
+                       struct xfs_dsb *sb = bp->b_addr;
+
+                       bp->b_ops->verify_write(bp);
+                       error = bp->b_error;
+                       if (error)
+                               goto out_release;
+
+                       if (be32_to_cpu(sb->sb_agcount) > mp->m_sb.sb_agcount) {
+                               error = xfs_initialize_perag(mp,
+                                                       be32_to_cpu(sb->sb_agcount),
+                                                       be64_to_cpu(sb->sb_dblocks),
+                                                       &mp->m_maxagi);
+                               if (error)
+                                       goto out_release;
+                       }
+
+                       xfs_sb_from_disk(&mp->m_sb, sb);
+               }
        }

        /*
--
2.27.0