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authorMark Fasheh <mark.fasheh@oracle.com>2007-05-09 15:16:19 -0700
committerMark Fasheh <mark.fasheh@oracle.com>2007-07-10 17:31:51 -0700
commit7307de80510a70e5e5aa98de1e80ccbb7d90a3a8 (patch)
treeba45bef3e0b875feb67b97aebe8295159852ef97 /fs/ocfs2/mmap.c
parent607d44aa3fa6f40b0facaf1028886ed362b92682 (diff)
downloadlinux-2.6.38-lt-ux500-7307de80510a70e5e5aa98de1e80ccbb7d90a3a8.tar.gz
ocfs2: shared writeable mmap
Implement cluster consistent shared writeable mappings using the ->page_mkwrite() callback. Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'fs/ocfs2/mmap.c')
-rw-r--r--fs/ocfs2/mmap.c167
1 files changed, 143 insertions, 24 deletions
diff --git a/fs/ocfs2/mmap.c b/fs/ocfs2/mmap.c
index af01158b39f..d79aa12137d 100644
--- a/fs/ocfs2/mmap.c
+++ b/fs/ocfs2/mmap.c
@@ -37,11 +37,29 @@
#include "ocfs2.h"
+#include "aops.h"
#include "dlmglue.h"
#include "file.h"
#include "inode.h"
#include "mmap.h"
+static inline int ocfs2_vm_op_block_sigs(sigset_t *blocked, sigset_t *oldset)
+{
+ /* The best way to deal with signals in the vm path is
+ * to block them upfront, rather than allowing the
+ * locking paths to return -ERESTARTSYS. */
+ sigfillset(blocked);
+
+ /* We should technically never get a bad return value
+ * from sigprocmask */
+ return sigprocmask(SIG_BLOCK, blocked, oldset);
+}
+
+static inline int ocfs2_vm_op_unblock_sigs(sigset_t *oldset)
+{
+ return sigprocmask(SIG_SETMASK, oldset, NULL);
+}
+
static struct page *ocfs2_nopage(struct vm_area_struct * area,
unsigned long address,
int *type)
@@ -53,14 +71,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
mlog_entry("(area=%p, address=%lu, type=%p)\n", area, address,
type);
- /* The best way to deal with signals in this path is
- * to block them upfront, rather than allowing the
- * locking paths to return -ERESTARTSYS. */
- sigfillset(&blocked);
-
- /* We should technically never get a bad ret return
- * from sigprocmask */
- ret = sigprocmask(SIG_BLOCK, &blocked, &oldset);
+ ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
if (ret < 0) {
mlog_errno(ret);
goto out;
@@ -68,7 +79,7 @@ static struct page *ocfs2_nopage(struct vm_area_struct * area,
page = filemap_nopage(area, address, type);
- ret = sigprocmask(SIG_SETMASK, &oldset, NULL);
+ ret = ocfs2_vm_op_unblock_sigs(&oldset);
if (ret < 0)
mlog_errno(ret);
out:
@@ -76,28 +87,136 @@ out:
return page;
}
-static struct vm_operations_struct ocfs2_file_vm_ops = {
- .nopage = ocfs2_nopage,
-};
+static int __ocfs2_page_mkwrite(struct inode *inode, struct buffer_head *di_bh,
+ struct page *page)
+{
+ int ret;
+ struct address_space *mapping = inode->i_mapping;
+ loff_t pos = page->index << PAGE_CACHE_SHIFT;
+ unsigned int len = PAGE_CACHE_SIZE;
+ pgoff_t last_index;
+ struct page *locked_page = NULL;
+ void *fsdata;
+ loff_t size = i_size_read(inode);
-int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
+ /*
+ * Another node might have truncated while we were waiting on
+ * cluster locks.
+ */
+ last_index = size >> PAGE_CACHE_SHIFT;
+ if (page->index > last_index) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * The i_size check above doesn't catch the case where nodes
+ * truncated and then re-extended the file. We'll re-check the
+ * page mapping after taking the page lock inside of
+ * ocfs2_write_begin_nolock().
+ */
+ if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Call ocfs2_write_begin() and ocfs2_write_end() to take
+ * advantage of the allocation code there. We pass a write
+ * length of the whole page (chopped to i_size) to make sure
+ * the whole thing is allocated.
+ *
+ * Since we know the page is up to date, we don't have to
+ * worry about ocfs2_write_begin() skipping some buffer reads
+ * because the "write" would invalidate their data.
+ */
+ if (page->index == last_index)
+ len = size & ~PAGE_CACHE_MASK;
+
+ ret = ocfs2_write_begin_nolock(mapping, pos, len, 0, &locked_page,
+ &fsdata, di_bh, page);
+ if (ret) {
+ if (ret != -ENOSPC)
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_write_end_nolock(mapping, pos, len, len, locked_page,
+ fsdata);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
+ BUG_ON(ret != len);
+ ret = 0;
+out:
+ return ret;
+}
+
+static int ocfs2_page_mkwrite(struct vm_area_struct *vma, struct page *page)
{
- int ret = 0, lock_level = 0;
- struct ocfs2_super *osb = OCFS2_SB(file->f_dentry->d_inode->i_sb);
+ struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
+ struct buffer_head *di_bh = NULL;
+ sigset_t blocked, oldset;
+ int ret, ret2;
+
+ ret = ocfs2_vm_op_block_sigs(&blocked, &oldset);
+ if (ret < 0) {
+ mlog_errno(ret);
+ return ret;
+ }
+
+ /*
+ * The cluster locks taken will block a truncate from another
+ * node. Taking the data lock will also ensure that we don't
+ * attempt page truncation as part of a downconvert.
+ */
+ ret = ocfs2_meta_lock(inode, &di_bh, 1);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out;
+ }
/*
- * Only support shared writeable mmap for local mounts which
- * don't know about holes.
+ * The alloc sem should be enough to serialize with
+ * ocfs2_truncate_file() changing i_size as well as any thread
+ * modifying the inode btree.
*/
- if ((!ocfs2_mount_local(osb) || ocfs2_sparse_alloc(osb)) &&
- ((vma->vm_flags & VM_SHARED) || (vma->vm_flags & VM_MAYSHARE)) &&
- ((vma->vm_flags & VM_WRITE) || (vma->vm_flags & VM_MAYWRITE))) {
- mlog(0, "disallow shared writable mmaps %lx\n", vma->vm_flags);
- /* This is -EINVAL because generic_file_readonly_mmap
- * returns it in a similar situation. */
- return -EINVAL;
+ down_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+ ret = ocfs2_data_lock(inode, 1);
+ if (ret < 0) {
+ mlog_errno(ret);
+ goto out_meta_unlock;
}
+ ret = __ocfs2_page_mkwrite(inode, di_bh, page);
+
+ ocfs2_data_unlock(inode, 1);
+
+out_meta_unlock:
+ up_write(&OCFS2_I(inode)->ip_alloc_sem);
+
+ brelse(di_bh);
+ ocfs2_meta_unlock(inode, 1);
+
+out:
+ ret2 = ocfs2_vm_op_unblock_sigs(&oldset);
+ if (ret2 < 0)
+ mlog_errno(ret2);
+
+ return ret;
+}
+
+static struct vm_operations_struct ocfs2_file_vm_ops = {
+ .nopage = ocfs2_nopage,
+ .page_mkwrite = ocfs2_page_mkwrite,
+};
+
+int ocfs2_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ int ret = 0, lock_level = 0;
+
ret = ocfs2_meta_lock_atime(file->f_dentry->d_inode,
file->f_vfsmnt, &lock_level);
if (ret < 0) {