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>

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index d52e3bcfda7c0c12f974f89d73dc2833500d05fd..3e204b9ff9f7b118dd045ec6ba7cd9c02b7bf3ff 100644 (file)
--- 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;