ceph: block non-fatal signals for fault/page_mkwrite

Fault and page_mkwrite are supposed to be uninterruptable. But they
call ceph functions that are interruptible. So they should block
signals before calling functions that are interruptible

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 39 insertions, 27 deletions

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index d52e3bcfda7c..3e204b9ff9f7 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1315,6 +1315,17 @@ const struct address_space_operations ceph_aops = {
         .direct_IO = ceph_direct_io,
 };
 
+static void ceph_block_sigs(sigset_t *oldset)
+{
+        sigset_t mask;
+        siginitsetinv(&mask, sigmask(SIGKILL));
+        sigprocmask(SIG_BLOCK, &mask, oldset);
+}
+
+static void ceph_restore_sigs(sigset_t *oldset)
+{
+        sigprocmask(SIG_SETMASK, oldset, NULL);
+}
 
 /*
  * vm ops
@@ -1327,6 +1338,9 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         struct page *pinned_page = NULL;
         loff_t off = vmf->pgoff << PAGE_SHIFT;
         int want, got, ret;
+        sigset_t oldset;
+
+        ceph_block_sigs(&oldset);
 
         dout("filemap_fault %p %llx.%llx %llu~%zd trying to get caps\n",
              inode, ceph_vinop(inode), off, (size_t)PAGE_SIZE);
@@ -1334,16 +1348,12 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                 want = CEPH_CAP_FILE_CACHE | CEPH_CAP_FILE_LAZYIO;
         else
                 want = CEPH_CAP_FILE_CACHE;
-        while (1) {
-                got = 0;
-                ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want,
-                                    -1, &got, &pinned_page);
-                if (ret == 0)
-                        break;
-                if (ret != -ERESTARTSYS) {
-                        WARN_ON(1);
-                        return VM_FAULT_SIGBUS;
-                }
+
+        got = 0;
+        ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
+        if (ret < 0) {
+                ret = VM_FAULT_SIGBUS;
+                goto out_restore;
         }
         dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
              inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got));
@@ -1361,7 +1371,7 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         ceph_put_cap_refs(ci, got);
 
         if (ret != -EAGAIN)
-                return ret;
+                goto out_restore;
 
         /* read inline data */
         if (off >= PAGE_SIZE) {
@@ -1375,7 +1385,7 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                                                 ~__GFP_FS));
                 if (!page) {
                         ret = VM_FAULT_OOM;
-                        goto out;
+                        goto out_inline;
                 }
                 ret1 = __ceph_do_getattr(inode, page,
                                          CEPH_STAT_CAP_INLINE_DATA, true);
@@ -1383,7 +1393,7 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                         unlock_page(page);
                         put_page(page);
                         ret = VM_FAULT_SIGBUS;
-                        goto out;
+                        goto out_inline;
                 }
                 if (ret1 < PAGE_SIZE)
                         zero_user_segment(page, ret1, PAGE_SIZE);
@@ -1392,10 +1402,12 @@ static int ceph_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
                 SetPageUptodate(page);
                 vmf->page = page;
                 ret = VM_FAULT_MAJOR | VM_FAULT_LOCKED;
+out_inline:
+                dout("filemap_fault %p %llu~%zd read inline data ret %d\n",
+                     inode, off, (size_t)PAGE_SIZE, ret);
         }
-out:
-        dout("filemap_fault %p %llu~%zd read inline data ret %d\n",
-             inode, off, (size_t)PAGE_SIZE, ret);
+out_restore:
+        ceph_restore_sigs(&oldset);
         return ret;
 }
 
@@ -1413,11 +1425,14 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
         loff_t size = i_size_read(inode);
         size_t len;
         int want, got, ret;
+        sigset_t oldset;
 
         prealloc_cf = ceph_alloc_cap_flush();
         if (!prealloc_cf)
                 return VM_FAULT_SIGBUS;
 
+        ceph_block_sigs(&oldset);
+
         if (ci->i_inline_version != CEPH_INLINE_NONE) {
                 struct page *locked_page = NULL;
                 if (off == 0) {
@@ -1444,17 +1459,13 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
                 want = CEPH_CAP_FILE_BUFFER | CEPH_CAP_FILE_LAZYIO;
         else
                 want = CEPH_CAP_FILE_BUFFER;
-        while (1) {
-                got = 0;
-                ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
-                                    &got, NULL);
-                if (ret == 0)
-                        break;
-                if (ret != -ERESTARTSYS) {
-                        WARN_ON(1);
-                        ret = VM_FAULT_SIGBUS;
-                        goto out_free;
-                }
+
+        got = 0;
+        ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
+                            &got, NULL);
+        if (ret < 0) {
+                ret = VM_FAULT_SIGBUS;
+                goto out_free;
         }
         dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
              inode, off, len, ceph_cap_string(got));
@@ -1499,6 +1510,7 @@ out:
              inode, off, len, ceph_cap_string(got), ret);
         ceph_put_cap_refs(ci, got);
 out_free:
+        ceph_restore_sigs(&oldset);
         ceph_free_cap_flush(prealloc_cf);
 
         return ret;