From 41e6362183589afd2cd51d653e277d256daab11f Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 29 Mar 2022 18:22:01 -0700 Subject: xfs: xfs_do_force_shutdown needs to block racing shutdowns When we call xfs_forced_shutdown(), the caller often expects the filesystem to be completely shut down when it returns. However, if we have racing xfs_forced_shutdown() calls, the first caller sets the mount shutdown flag then goes to shutdown the log. The second caller sees the mount shutdown flag and returns immediately - it does not wait for the log to be shut down. Unfortunately, xfs_forced_shutdown() is used in some places that expect it to completely shut down the filesystem before it returns (e.g. xfs_trans_log_inode()). As such, returning before the log has been shut down leaves us in a place where the transaction failed to complete correctly but we still call xfs_trans_commit(). This situation arises because xfs_trans_log_inode() does not return an error and instead calls xfs_force_shutdown() to ensure that the transaction being committed is aborted. Unfortunately, we have a race condition where xfs_trans_commit() needs to check xlog_is_shutdown() because it can't abort log items before the log is shut down, but it needs to use xfs_is_shutdown() because xfs_forced_shutdown() does not block waiting for the log to shut down. To fix this conundrum, first we make all calls to xfs_forced_shutdown() block until the log is also shut down. This means we can then safely use xfs_forced_shutdown() as a mechanism that ensures the currently running transaction will be aborted by xfs_trans_commit() regardless of the shutdown check it uses. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong --- fs/xfs/xfs_fsops.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_fsops.c') diff --git a/fs/xfs/xfs_fsops.c b/fs/xfs/xfs_fsops.c index 196e2c51309c..68f74549fa22 100644 --- a/fs/xfs/xfs_fsops.c +++ b/fs/xfs/xfs_fsops.c @@ -17,6 +17,7 @@ #include "xfs_fsops.h" #include "xfs_trans_space.h" #include "xfs_log.h" +#include "xfs_log_priv.h" #include "xfs_ag.h" #include "xfs_ag_resv.h" #include "xfs_trace.h" @@ -518,8 +519,11 @@ xfs_do_force_shutdown( int tag; const char *why; - if (test_and_set_bit(XFS_OPSTATE_SHUTDOWN, &mp->m_opstate)) + + if (test_and_set_bit(XFS_OPSTATE_SHUTDOWN, &mp->m_opstate)) { + xlog_shutdown_wait(mp->m_log); return; + } if (mp->m_sb_bp) mp->m_sb_bp->b_flags |= XBF_DONE; -- cgit v1.2.3