ceph: fetch inline data when getting Fcr cap refs
we can't use getattr to fetch inline data after getting Fcr caps,
because it can cause deadlock. The solution is try bringing inline
data to page cache when not holding any cap, and hope the inline
data page is still there after getting the Fcr caps. If the page
is still there, pin it in page cache for later IO.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 4a3f55f..5d2b88e 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1207,6 +1207,7 @@
struct inode *inode = file_inode(vma->vm_file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_file_info *fi = vma->vm_file->private_data;
+ struct page *pinned_page = NULL;
loff_t off = vmf->pgoff << PAGE_CACHE_SHIFT;
int want, got, ret;
@@ -1218,7 +1219,8 @@
want = CEPH_CAP_FILE_CACHE;
while (1) {
got = 0;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1,
+ &got, &pinned_page);
if (ret == 0)
break;
if (ret != -ERESTARTSYS) {
@@ -1233,6 +1235,8 @@
dout("filemap_fault %p %llu~%zd dropping cap refs on %s ret %d\n",
inode, off, (size_t)PAGE_CACHE_SIZE, ceph_cap_string(got), ret);
+ if (pinned_page)
+ page_cache_release(pinned_page);
ceph_put_cap_refs(ci, got);
return ret;
@@ -1266,7 +1270,8 @@
want = CEPH_CAP_FILE_BUFFER;
while (1) {
got = 0;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, off + len);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
+ &got, NULL);
if (ret == 0)
break;
if (ret != -ERESTARTSYS) {
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 6372eb9..795afe3 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -2057,15 +2057,17 @@
* requested from the MDS.
*/
static int try_get_cap_refs(struct ceph_inode_info *ci, int need, int want,
- int *got, loff_t endoff, int *check_max, int *err)
+ loff_t endoff, int *got, struct page **pinned_page,
+ int *check_max, int *err)
{
struct inode *inode = &ci->vfs_inode;
int ret = 0;
- int have, implemented;
+ int have, implemented, _got = 0;
int file_wanted;
dout("get_cap_refs %p need %s want %s\n", inode,
ceph_cap_string(need), ceph_cap_string(want));
+again:
spin_lock(&ci->i_ceph_lock);
/* make sure file is actually open */
@@ -2075,7 +2077,7 @@
ceph_cap_string(need), ceph_cap_string(file_wanted));
*err = -EBADF;
ret = 1;
- goto out;
+ goto out_unlock;
}
/* finish pending truncate */
@@ -2095,7 +2097,7 @@
*check_max = 1;
ret = 1;
}
- goto out;
+ goto out_unlock;
}
/*
* If a sync write is in progress, we must wait, so that we
@@ -2103,7 +2105,7 @@
*/
if (__ceph_have_pending_cap_snap(ci)) {
dout("get_cap_refs %p cap_snap_pending\n", inode);
- goto out;
+ goto out_unlock;
}
}
@@ -2120,18 +2122,50 @@
inode, ceph_cap_string(have), ceph_cap_string(not),
ceph_cap_string(revoking));
if ((revoking & not) == 0) {
- *got = need | (have & want);
- __take_cap_refs(ci, *got);
+ _got = need | (have & want);
+ __take_cap_refs(ci, _got);
ret = 1;
}
} else {
dout("get_cap_refs %p have %s needed %s\n", inode,
ceph_cap_string(have), ceph_cap_string(need));
}
-out:
+out_unlock:
spin_unlock(&ci->i_ceph_lock);
+
+ if (ci->i_inline_version != CEPH_INLINE_NONE &&
+ (_got & (CEPH_CAP_FILE_CACHE|CEPH_CAP_FILE_LAZYIO)) &&
+ i_size_read(inode) > 0) {
+ int ret1;
+ struct page *page = find_get_page(inode->i_mapping, 0);
+ if (page) {
+ if (PageUptodate(page)) {
+ *pinned_page = page;
+ goto out;
+ }
+ page_cache_release(page);
+ }
+ /*
+ * drop cap refs first because getattr while holding
+ * caps refs can cause deadlock.
+ */
+ ceph_put_cap_refs(ci, _got);
+ _got = 0;
+
+ /* getattr request will bring inline data into page cache */
+ ret1 = __ceph_do_getattr(inode, NULL,
+ CEPH_STAT_CAP_INLINE_DATA, true);
+ if (ret1 >= 0) {
+ ret = 0;
+ goto again;
+ }
+ *err = ret1;
+ ret = 1;
+ }
+out:
dout("get_cap_refs %p ret %d got %s\n", inode,
- ret, ceph_cap_string(*got));
+ ret, ceph_cap_string(_got));
+ *got = _got;
return ret;
}
@@ -2168,8 +2202,8 @@
* due to a small max_size, make sure we check_max_size (and possibly
* ask the mds) so we don't get hung up indefinitely.
*/
-int ceph_get_caps(struct ceph_inode_info *ci, int need, int want, int *got,
- loff_t endoff)
+int ceph_get_caps(struct ceph_inode_info *ci, int need, int want,
+ loff_t endoff, int *got, struct page **pinned_page)
{
int check_max, ret, err;
@@ -2179,8 +2213,8 @@
check_max = 0;
err = 0;
ret = wait_event_interruptible(ci->i_cap_wq,
- try_get_cap_refs(ci, need, want,
- got, endoff,
+ try_get_cap_refs(ci, need, want, endoff,
+ got, pinned_page,
&check_max, &err));
if (err)
ret = err;
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index c03ac4c..861b995 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -805,6 +805,7 @@
size_t len = iocb->ki_nbytes;
struct inode *inode = file_inode(filp);
struct ceph_inode_info *ci = ceph_inode(inode);
+ struct page *pinned_page = NULL;
ssize_t ret;
int want, got = 0;
int checkeof = 0, read = 0;
@@ -817,7 +818,7 @@
want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
else
want = CEPH_CAP_FILE_CACHE;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, &got, -1);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
if (ret < 0)
return ret;
@@ -840,6 +841,10 @@
}
dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n",
inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret);
+ if (pinned_page) {
+ page_cache_release(pinned_page);
+ pinned_page = NULL;
+ }
ceph_put_cap_refs(ci, got);
if (checkeof && ret >= 0) {
@@ -924,7 +929,8 @@
else
want = CEPH_CAP_FILE_BUFFER;
got = 0;
- err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, pos + count);
+ err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, pos + count,
+ &got, NULL);
if (err < 0)
goto out;
@@ -1225,7 +1231,7 @@
else
want = CEPH_CAP_FILE_BUFFER;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, &got, endoff);
+ ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, endoff, &got, NULL);
if (ret < 0)
goto unlock;