Commit fc513fac authored Feb 19, 2020 by Ronnie Sahlberg Committed by Steve French Feb 24, 2020

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>

parent f8788d86

fs/cifs/inode.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}

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