From: "Yan, Zheng" <[email protected]>
There is deadlock as illustrated bellow. The fix is taking i_mutex
before getting Fw cap reference.
write truncate MDS
--------------------- -------------------- --------------
get Fw cap
lock i_mutex
lock i_mutex (blocked)
request setattr.size ->
<- revoke Fw cap
Signed-off-by: Yan, Zheng <[email protected]>
---
fs/ceph/caps.c | 13 +++++++------
fs/ceph/file.c | 12 ++++++------
2 files changed, 13 insertions(+), 12 deletions(-)
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 0da2e94..8737572 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2058,6 +2058,13 @@ static int try_get_cap_refs(struct ceph_inode_info *ci,
int need, int want,
goto out;
}
+ /* finish pending truncate */
+ while (ci->i_truncate_pending) {
+ spin_unlock(&ci->i_ceph_lock);
+ __ceph_do_pending_vmtruncate(inode, !(need & CEPH_CAP_FILE_WR));
+ spin_lock(&ci->i_ceph_lock);
+ }
+
if (need & CEPH_CAP_FILE_WR) {
if (endoff >= 0 && endoff > (loff_t)ci->i_max_size) {
dout("get_cap_refs %p endoff %llu > maxsize %llu\n",
@@ -2079,12 +2086,6 @@ static int try_get_cap_refs(struct ceph_inode_info *ci,
int need, int want,
}
have = __ceph_caps_issued(ci, &implemented);
- /*
- * disallow writes while a truncate is pending
- */
- if (ci->i_truncate_pending)
- have &= ~CEPH_CAP_FILE_WR;
-
if ((have & need) == need) {
/*
* Look at (implemented & ~have & not) so that we keep waiting
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 546a705..5490598 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -647,7 +647,6 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const
struct iovec *iov,
dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n",
inode, ceph_vinop(inode), pos, (unsigned)len, inode);
again:
- __ceph_do_pending_vmtruncate(inode, true);
if (fi->fmode & CEPH_FILE_MODE_LAZY)
want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
else
@@ -724,7 +723,7 @@ retry_snap:
ret = -ENOSPC;
goto out;
}
- __ceph_do_pending_vmtruncate(inode, true);
+ mutex_lock(&inode->i_mutex);
dout("aio_write %p %llx.%llx %llu~%u getting caps. i_size %llu\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
inode->i_size);
@@ -733,8 +732,10 @@ retry_snap:
else
want = CEPH_CAP_FILE_BUFFER;
ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
- if (ret < 0)
- goto out_put;
+ if (ret < 0) {
+ mutex_unlock(&inode->i_mutex);
+ goto out;
+ }
dout("aio_write %p %llx.%llx %llu~%u got cap refs on %s\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
@@ -744,10 +745,10 @@ retry_snap:
(iocb->ki_filp->f_flags & O_DIRECT) ||
(inode->i_sb->s_flags & MS_SYNCHRONOUS) ||
(fi->flags & CEPH_F_SYNC)) {
+ mutex_unlock(&inode->i_mutex);
ret = ceph_sync_write(file, iov->iov_base, iov->iov_len,
&iocb->ki_pos);
} else {
- mutex_lock(&inode->i_mutex);
ret = __generic_file_aio_write(iocb, iov, nr_segs,
&iocb->ki_pos);
mutex_unlock(&inode->i_mutex);
@@ -762,7 +763,6 @@ retry_snap:
__mark_inode_dirty(inode, dirty);
}
-out_put:
dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n",
inode, ceph_vinop(inode), pos, (unsigned)iov->iov_len,
ceph_cap_string(got));
--
1.7.11.7
--
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