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authorYehuda Sadeh <yehuda@hq.newdream.net>2010-02-09 11:02:51 -0800
committerSage Weil <sage@newdream.net>2010-02-11 11:48:50 -0800
commit4af6b2257ee0eb8f4bf3b1dc8acb643c0e8a887f (patch)
tree6193e59ebd7806d286e16e091a5acf98bceae424 /fs/ceph/addr.c
parent972f0d3ab1a15cb5d790dd8c53903066084b28f2 (diff)
ceph: refactor ceph_write_begin, fix ceph_page_mkwrite
Originally ceph_page_mkwrite called ceph_write_begin, hoping that the returned locked page would be the page that it was requested to mkwrite. Factored out relevant part of ceph_page_mkwrite and we lock the right page anyway. Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net> Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph/addr.c')
-rw-r--r--fs/ceph/addr.c80
1 files changed, 51 insertions, 29 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 92f48215074..89c5ff3b59d 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -907,15 +907,13 @@ static int context_is_writeable_or_written(struct inode *inode,
* We are only allowed to write into/dirty the page if the page is
* clean, or already dirty within the same snap context.
*/
-static int ceph_write_begin(struct file *file, struct address_space *mapping,
- loff_t pos, unsigned len, unsigned flags,
- struct page **pagep, void **fsdata)
+static int ceph_update_writeable_page(struct file *file,
+ loff_t pos, unsigned len,
+ struct page *page)
{
struct inode *inode = file->f_dentry->d_inode;
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
- struct page *page;
- pgoff_t index = pos >> PAGE_CACHE_SHIFT;
loff_t page_off = pos & PAGE_CACHE_MASK;
int pos_in_page = pos & ~PAGE_CACHE_MASK;
int end_in_page = pos_in_page + len;
@@ -923,16 +921,6 @@ static int ceph_write_begin(struct file *file, struct address_space *mapping,
struct ceph_snap_context *snapc;
int r;
- /* get a page*/
-retry:
- page = grab_cache_page_write_begin(mapping, index, 0);
- if (!page)
- return -ENOMEM;
- *pagep = page;
-
- dout("write_begin file %p inode %p page %p %d~%d\n", file,
- inode, page, (int)pos, (int)len);
-
retry_locked:
/* writepages currently holds page lock, but if we change that later, */
wait_on_page_writeback(page);
@@ -964,7 +952,7 @@ retry_locked:
wait_event_interruptible(ci->i_cap_wq,
context_is_writeable_or_written(inode, snapc));
ceph_put_snap_context(snapc);
- goto retry;
+ return -EAGAIN;
}
/* yay, writeable, do it now (without dropping page lock) */
@@ -1022,6 +1010,35 @@ fail_nosnap:
}
/*
+ * We are only allowed to write into/dirty the page if the page is
+ * clean, or already dirty within the same snap context.
+ */
+static int ceph_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct page *page;
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ int r;
+
+ do {
+ /* get a page*/
+ page = grab_cache_page_write_begin(mapping, index, 0);
+ if (!page)
+ return -ENOMEM;
+ *pagep = page;
+
+ dout("write_begin file %p inode %p page %p %d~%d\n", file,
+ inode, page, (int)pos, (int)len);
+
+ r = ceph_update_writeable_page(file, pos, len, page);
+ } while (r == -EAGAIN);
+
+ return r;
+}
+
+/*
* we don't do anything in here that simple_write_end doesn't do
* except adjust dirty page accounting and drop read lock on
* mdsc->snap_rwsem.
@@ -1104,8 +1121,6 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
loff_t off = page->index << PAGE_CACHE_SHIFT;
loff_t size, len;
- struct page *locked_page = NULL;
- void *fsdata = NULL;
int ret;
size = i_size_read(inode);
@@ -1116,23 +1131,30 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
off, len, page, page->index);
- ret = ceph_write_begin(vma->vm_file, inode->i_mapping, off, len, 0,
- &locked_page, &fsdata);
- WARN_ON(page != locked_page);
- if (!ret) {
- /*
- * doing the following, instead of calling
- * ceph_write_end. Note that we keep the
- * page locked
- */
+
+ lock_page(page);
+
+ ret = VM_FAULT_NOPAGE;
+ if ((off > size) ||
+ (page->mapping != inode->i_mapping))
+ goto out;
+
+ ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
+ if (ret == 0) {
+ /* success. we'll keep the page locked. */
set_page_dirty(page);
up_read(&mdsc->snap_rwsem);
- page_cache_release(page);
ret = VM_FAULT_LOCKED;
} else {
- ret = VM_FAULT_SIGBUS;
+ if (ret == -ENOMEM)
+ ret = VM_FAULT_OOM;
+ else
+ ret = VM_FAULT_SIGBUS;
}
+out:
dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
+ if (ret != VM_FAULT_LOCKED)
+ unlock_page(page);
return ret;
}