[CIFS] Fix locking problem around some cifs uses of i_size write
Could cause hangs on smp systems in i_size_read on a cifs inode
whose size has been previously simultaneously updated from
different processes.
Thanks to Brian Wang for some great testing/debugging on this
hard problem.
Fixes kernel bugzilla #7903
CC: Shirish Pargoankar <shirishp@us.ibm.com>
CC: Shaggy <shaggy@us.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index a1265c9..c07ff83 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -879,18 +879,19 @@
cifs_stats_bytes_written(pTcon, total_written);
/* since the write may have blocked check these pointers again */
- if (file->f_path.dentry) {
- if (file->f_path.dentry->d_inode) {
- struct inode *inode = file->f_path.dentry->d_inode;
- inode->i_ctime = inode->i_mtime =
- current_fs_time(inode->i_sb);
- if (total_written > 0) {
- if (*poffset > file->f_path.dentry->d_inode->i_size)
- i_size_write(file->f_path.dentry->d_inode,
+ if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
+ struct inode *inode = file->f_path.dentry->d_inode;
+/* Do not update local mtime - server will set its actual value on write
+ * inode->i_ctime = inode->i_mtime =
+ * current_fs_time(inode->i_sb);*/
+ if (total_written > 0) {
+ spin_lock(&inode->i_lock);
+ if (*poffset > file->f_path.dentry->d_inode->i_size)
+ i_size_write(file->f_path.dentry->d_inode,
*poffset);
- }
- mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+ spin_unlock(&inode->i_lock);
}
+ mark_inode_dirty_sync(file->f_path.dentry->d_inode);
}
FreeXid(xid);
return total_written;
@@ -1012,18 +1013,18 @@
cifs_stats_bytes_written(pTcon, total_written);
/* since the write may have blocked check these pointers again */
- if (file->f_path.dentry) {
- if (file->f_path.dentry->d_inode) {
+ if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
/*BB We could make this contingent on superblock ATIME flag too */
-/* file->f_path.dentry->d_inode->i_ctime =
- file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
- if (total_written > 0) {
- if (*poffset > file->f_path.dentry->d_inode->i_size)
- i_size_write(file->f_path.dentry->d_inode,
- *poffset);
- }
- mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+/* file->f_path.dentry->d_inode->i_ctime =
+ file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
+ if (total_written > 0) {
+ spin_lock(&file->f_path.dentry->d_inode->i_lock);
+ if (*poffset > file->f_path.dentry->d_inode->i_size)
+ i_size_write(file->f_path.dentry->d_inode,
+ *poffset);
+ spin_unlock(&file->f_path.dentry->d_inode->i_lock);
}
+ mark_inode_dirty_sync(file->f_path.dentry->d_inode);
}
FreeXid(xid);
return total_written;
@@ -1400,6 +1401,7 @@
xid = GetXid();
cFYI(1, ("commit write for page %p up to position %lld for %d",
page, position, to));
+ spin_lock(&inode->i_lock);
if (position > inode->i_size) {
i_size_write(inode, position);
/* if (file->private_data == NULL) {
@@ -1429,6 +1431,7 @@
cFYI(1, (" SetEOF (commit write) rc = %d", rc));
} */
}
+ spin_unlock(&inode->i_lock);
if (!PageUptodate(page)) {
position = ((loff_t)page->index << PAGE_CACHE_SHIFT) + offset;
/* can not rely on (or let) writepage write this data */