[PATCH 05/14] ceph: untangle ceph_filemap_fault

Christoph Hellwig
2018-05-16T05:43:39Z

Streamline the code to have a somewhat natural flow, and separate the
errno values from the VM_FAULT_* values.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/ceph/addr.c | 100 +++++++++++++++++++++++++------------------------
1 file changed, 51 insertions(+), 49 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5f7ad3d0df2e..6e80894ca073 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -1428,15 +1428,18 @@ static void ceph_restore_sigs(sigset_t *oldset)
/*
* vm ops
*/
-static int ceph_filemap_fault(struct vm_fault *vmf)
+static vm_fault_t ceph_filemap_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct inode *inode = file_inode(vma->vm_file);
+ struct address_space *mapping = inode->i_mapping;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_file_info *fi = vma->vm_file->private_data;
- struct page *pinned_page = NULL;
+ struct page *pinned_page = NULL, *page;
loff_t off = vmf->pgoff << PAGE_SHIFT;
- int want, got, ret;
+ int want, got, err = 0;
+ vm_fault_t ret = 0;
+ bool did_fault = false;
sigset_t oldset;

ceph_block_sigs(&oldset);
@@ -1449,9 +1452,9 @@ static int ceph_filemap_fault(struct vm_fault *vmf)
want = CEPH_CAP_FILE_CACHE;

got = 0;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
- if (ret < 0)
- goto out_restore;
+ err = ceph_get_caps(ci, CEPH_CAP_FILE_RD, want, -1, &got, &pinned_page);
+ if (err < 0)
+ goto out_errno;

dout("filemap_fault %p %llu~%zd got cap refs on %s\n",
inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got));
@@ -1462,8 +1465,8 @@ static int ceph_filemap_fault(struct vm_fault *vmf)
ceph_add_rw_context(fi, &rw_ctx);
ret = filemap_fault(vmf);
ceph_del_rw_context(fi, &rw_ctx);
- } else
- ret = -EAGAIN;
+ did_fault = true;
+ }

dout("filemap_fault %p %llu~%zd dropping cap refs on %s ret %d\n",
inode, off, (size_t)PAGE_SIZE, ceph_cap_string(got), ret);
@@ -1471,57 +1474,55 @@ static int ceph_filemap_fault(struct vm_fault *vmf)
put_page(pinned_page);
ceph_put_cap_refs(ci, got);

- if (ret != -EAGAIN)
+ if (did_fault)
goto out_restore;

/* read inline data */
if (off >= PAGE_SIZE) {
/* does not support inline data > PAGE_SIZE */
ret = VM_FAULT_SIGBUS;
+ goto out_restore;
+ }
+
+ page = find_or_create_page(mapping, 0,
+ mapping_gfp_constraint(mapping, ~__GFP_FS));
+ if (!page) {
+ ret = VM_FAULT_OOM;
+ goto out_inline;
+ }
+
+ err = __ceph_do_getattr(inode, page, CEPH_STAT_CAP_INLINE_DATA, true);
+ if (err < 0 || off >= i_size_read(inode)) {
+ unlock_page(page);
+ put_page(page);
+ if (err < 0)
+ goto out_errno;
+ ret = VM_FAULT_SIGBUS;
} else {
- int ret1;
- struct address_space *mapping = inode->i_mapping;
- struct page *page = find_or_create_page(mapping, 0,
- mapping_gfp_constraint(mapping,
- ~__GFP_FS));
- if (!page) {
- ret = VM_FAULT_OOM;
- goto out_inline;
- }
- ret1 = __ceph_do_getattr(inode, page,
- CEPH_STAT_CAP_INLINE_DATA, true);
- if (ret1 < 0 || off >= i_size_read(inode)) {
- unlock_page(page);
- put_page(page);
- if (ret1 < 0)
- ret = ret1;
- else
- ret = VM_FAULT_SIGBUS;
- goto out_inline;
- }
- if (ret1 < PAGE_SIZE)
- zero_user_segment(page, ret1, PAGE_SIZE);
+ if (err < PAGE_SIZE)
+ zero_user_segment(page, err, PAGE_SIZE);
else
flush_dcache_page(page);
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_inline:
+ 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);
- if (ret < 0)
- ret = (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
-
return ret;
+out_errno:
+ ret = (err == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
+ goto out_restore;
}

/*
* Reuse write_begin here for simplicity.
*/
-static int ceph_page_mkwrite(struct vm_fault *vmf)
+static vm_fault_t ceph_page_mkwrite(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct inode *inode = file_inode(vma->vm_file);
@@ -1532,7 +1533,8 @@ static int ceph_page_mkwrite(struct vm_fault *vmf)
loff_t off = page_offset(page);
loff_t size = i_size_read(inode);
size_t len;
- int want, got, ret;
+ int want, got, err = 0;
+ vm_fault_t ret = 0;
sigset_t oldset;

prealloc_cf = ceph_alloc_cap_flush();
@@ -1547,10 +1549,10 @@ static int ceph_page_mkwrite(struct vm_fault *vmf)
lock_page(page);
locked_page = page;
}
- ret = ceph_uninline_data(vma->vm_file, locked_page);
+ err = ceph_uninline_data(vma->vm_file, locked_page);
if (locked_page)
unlock_page(locked_page);
- if (ret < 0)
+ if (err < 0)
goto out_free;
}

@@ -1567,9 +1569,9 @@ static int ceph_page_mkwrite(struct vm_fault *vmf)
want = CEPH_CAP_FILE_BUFFER;

got = 0;
- ret = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
+ err = ceph_get_caps(ci, CEPH_CAP_FILE_WR, want, off + len,
&got, NULL);
- if (ret < 0)
+ if (err < 0)
goto out_free;

dout("page_mkwrite %p %llu~%zd got cap refs on %s\n",
@@ -1587,13 +1589,13 @@ static int ceph_page_mkwrite(struct vm_fault *vmf)
break;
}

- ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
- if (ret >= 0) {
+ err = ceph_update_writeable_page(vma->vm_file, off, len, page);
+ if (err >= 0) {
/* success. we'll keep the page locked. */
set_page_dirty(page);
ret = VM_FAULT_LOCKED;
}
- } while (ret == -EAGAIN);
+ } while (err == -EAGAIN);

if (ret == VM_FAULT_LOCKED ||
ci->i_inline_version != CEPH_INLINE_NONE) {
@@ -1608,13 +1610,13 @@ static int ceph_page_mkwrite(struct vm_fault *vmf)
}

dout("page_mkwrite %p %llu~%zd dropping cap refs on %s ret %d\n",
- inode, off, len, ceph_cap_string(got), ret);
+ inode, off, len, ceph_cap_string(got), err);
ceph_put_cap_refs(ci, got);
out_free:
ceph_restore_sigs(&oldset);
ceph_free_cap_flush(prealloc_cf);
- if (ret < 0)
- ret = (ret == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
+ if (err < 0)
+ ret = (err == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS;
return ret;
}

--
2.17.0