cifs: don't leak -EAGAIN for stat() during reconnect

If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an
error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected
it is possible we will leak -EAGAIN back to the application even for
system calls such as stat() where this is not a valid error.

Fix this by re-trying the operation from within cifs_revalidate_dentry_attr()
if cifs_get_inode_info*() returns -EAGAIN.

This fixes stat() and possibly also other system calls that uses
cifs_revalidate_dentry*().

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
CC: Stable <stable@vger.kernel.org>

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index b5e6635..1c6f659 100644 (file)
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2073,6 +2073,7 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry)
        struct inode *inode = d_inode(dentry);
        struct super_block *sb = dentry->d_sb;
        char *full_path = NULL;
+       int count = 0;
 
        if (inode == NULL)
                return -ENOENT;
@@ -2094,15 +2095,18 @@ int cifs_revalidate_dentry_attr(struct dentry *dentry)
                 full_path, inode, inode->i_count.counter,
                 dentry, cifs_get_time(dentry), jiffies);
 
+again:
        if (cifs_sb_master_tcon(CIFS_SB(sb))->unix_ext)
                rc = cifs_get_inode_info_unix(&inode, full_path, sb, xid);
        else
                rc = cifs_get_inode_info(&inode, full_path, NULL, sb,
                                         xid, NULL);
-
+       if (rc == -EAGAIN && count++ < 10)
+               goto again;
 out:
        kfree(full_path);
        free_xid(xid);
+
        return rc;
 }