From 2485bd7557a7edb4520b4072af464f0a08c8efe0 Mon Sep 17 00:00:00 2001 From: Ronnie Sahlberg Date: Thu, 22 Jul 2021 14:53:32 +1000 Subject: [PATCH 1/2] cifs: only write 64kb at a time when fallocating a small region of a file We only allow sending single credit writes through the SMB2_write() synchronous api so split this into smaller chunks. Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation") Signed-off-by: Ronnie Sahlberg Reported-by: Namjae Jeon Signed-off-by: Steve French --- fs/cifs/smb2ops.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index ba3c58e1f725..5cefb5972396 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -3617,7 +3617,7 @@ static int smb3_simple_fallocate_write_range(unsigned int xid, char *buf) { struct cifs_io_parms io_parms = {0}; - int nbytes; + int rc, nbytes; struct kvec iov[2]; io_parms.netfid = cfile->fid.netfid; @@ -3625,13 +3625,25 @@ static int smb3_simple_fallocate_write_range(unsigned int xid, io_parms.tcon = tcon; io_parms.persistent_fid = cfile->fid.persistent_fid; io_parms.volatile_fid = cfile->fid.volatile_fid; - io_parms.offset = off; - io_parms.length = len; - /* iov[0] is reserved for smb header */ - iov[1].iov_base = buf; - iov[1].iov_len = io_parms.length; - return SMB2_write(xid, &io_parms, &nbytes, iov, 1); + while (len) { + io_parms.offset = off; + io_parms.length = len; + if (io_parms.length > SMB2_MAX_BUFFER_SIZE) + io_parms.length = SMB2_MAX_BUFFER_SIZE; + /* iov[0] is reserved for smb header */ + iov[1].iov_base = buf; + iov[1].iov_len = io_parms.length; + rc = SMB2_write(xid, &io_parms, &nbytes, iov, 1); + if (rc) + break; + if (nbytes > len) + return -EINVAL; + buf += nbytes; + off += nbytes; + len -= nbytes; + } + return rc; } static int smb3_simple_fallocate_range(unsigned int xid, -- 2.30.2