Re: cifs hang patch idea - reduce sendtimeo on socket

From: Dave Kleikamp
Date: Wed Feb 22 2006 - 16:33:04 EST


On Thu, 2006-02-16 at 21:56 +0100, Adrian Bunk wrote:
>
> I'm a bit lost now, but I hope this information helps you in finding
> what is going wrong?

Steve and I think we have figured this out. In some cases, CIFSSMBRead
was returning a recently freed buffer.

CIFS: CIFSSMBRead was returning an invalid pointer in buf

Thanks to Adrian Bunk for debugging the problem

Also added a fix for 64K pages we found in loosely-related testing

Signed-off-by: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
Signed-off-by: Steve French <sfrench@xxxxxxxxxx>

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 38ab9f6..9d7bbd2 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1076,13 +1076,14 @@ CIFSSMBRead(const int xid, struct cifsTc
cifs_small_buf_release(iov[0].iov_base);
else if(resp_buf_type == CIFS_LARGE_BUFFER)
cifs_buf_release(iov[0].iov_base);
- } else /* return buffer to caller to free */ /* BB FIXME how do we tell caller if it is not a large buffer */ {
- *buf = iov[0].iov_base;
+ } else if(resp_buf_type != CIFS_NO_BUFFER) {
+ /* return buffer to caller to free */
+ *buf = iov[0].iov_base;
if(resp_buf_type == CIFS_SMALL_BUFFER)
*pbuf_type = CIFS_SMALL_BUFFER;
else if(resp_buf_type == CIFS_LARGE_BUFFER)
*pbuf_type = CIFS_LARGE_BUFFER;
- }
+ } /* else no valid buffer on return - leave as null */

/* Note: On -EAGAIN error only caller can retry on handle based calls
since file handle passed in no longer valid */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 0e1560a..16535b5 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1795,10 +1795,10 @@ cifs_mount(struct super_block *sb, struc
conjunction with 52K kvec constraint on arch with 4K
page size */

- if(cifs_sb->rsize < PAGE_CACHE_SIZE) {
- cifs_sb->rsize = PAGE_CACHE_SIZE;
- /* Windows ME does this */
- cFYI(1,("Attempt to set readsize for mount to less than one page (4096)"));
+ if(cifs_sb->rsize < 2048) {
+ cifs_sb->rsize = 2048;
+ /* Windows ME may prefer this */
+ cFYI(1,("readsize set to minimum 2048"));
}
cifs_sb->mnt_uid = volume_info.linux_uid;
cifs_sb->mnt_gid = volume_info.linux_gid;

--
David Kleikamp
IBM Linux Technology Center

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