NFS: Fix an ABBA spinlock issue in pnfs_update_layout() (fbf4bcc9) · Commits · 戴 / test

We need to drop the inode spinlock while calling nfs4_select_rw_stateid(), since nfs4_copy_delegation_stateid() could take the delegation lock. Note that it is safe to do this, since all other calls to pnfs_update_layout() for that inode will find themselves blocked by the lock we hold on NFS_LAYOUT_FIRST_LAYOUTGET. Fixes: ("NFS: Beware when dereferencing the delegation cred") Signed-off-by:

Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/pnfs.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2023,6 +2023,7 @@ lookup_again:
		goto lookup_again;
		}

		spin_unlock(&ino->i_lock);
		first = true;
		status = nfs4_select_rw_stateid(ctx->state,
		iomode == IOMODE_RW ? FMODE_WRITE : FMODE_READ,
		@@ -2032,12 +2033,12 @@ lookup_again:
		trace_pnfs_update_layout(ino, pos, count,
		iomode, lo, lseg,
		PNFS_UPDATE_LAYOUT_INVALID_OPEN);
		spin_unlock(&ino->i_lock);
		nfs4_schedule_stateid_recovery(server, ctx->state);
		pnfs_clear_first_layoutget(lo);
		pnfs_put_layout_hdr(lo);
		goto lookup_again;
		}
		spin_lock(&ino->i_lock);
		} else {
		nfs4_stateid_copy(&stateid, &lo->plh_stateid);
		}

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