From: Steve French Date: Thu, 15 Aug 2024 23:31:36 +0000 (-0500) Subject: smb3: fix broken cached reads when posix locks X-Git-Tag: v6.11-rc5~10^2~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e4be320eeca842a3d7648258ee3673f1755a5a59;p=thirdparty%2Fkernel%2Fstable.git smb3: fix broken cached reads when posix locks Mandatory locking is enforced for cached reads, which violates default posix semantics, and also it is enforced inconsistently. This affected recent versions of libreoffice, and can be demonstrated by opening a file twice from the same client, locking it from handle one and trying to read from it from handle two (which fails, returning EACCES). There is already a mount option "forcemandatorylock" (which defaults to off), so with this change only when the user intentionally specifies "forcemandatorylock" on mount will we break posix semantics on read to a locked range (ie we will only fail in this case, if the user mounts with "forcemandatorylock"). An earlier patch fixed the write path. Fixes: 85160e03a79e ("CIFS: Implement caching mechanism for mandatory brlocks") Cc: stable@vger.kernel.org Cc: Pavel Shilovsky Reviewed-by: David Howells Reported-by: abartlet@samba.org Reported-by: Kevin Ottens Signed-off-by: Steve French --- diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c index 1fc66bcf49eb4..f9b302cb8233c 100644 --- a/fs/smb/client/file.c +++ b/fs/smb/client/file.c @@ -2912,9 +2912,7 @@ cifs_strict_readv(struct kiocb *iocb, struct iov_iter *to) if (!CIFS_CACHE_READ(cinode)) return netfs_unbuffered_read_iter(iocb, to); - if (cap_unix(tcon->ses) && - (CIFS_UNIX_FCNTL_CAP & le64_to_cpu(tcon->fsUnixInfo.Capability)) && - ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0)) { + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NOPOSIXBRL) == 0) { if (iocb->ki_flags & IOCB_DIRECT) return netfs_unbuffered_read_iter(iocb, to); return netfs_buffered_read_iter(iocb, to);