Attachment 15866 Details for Bug 14237 – Patch for 4.11 backported from master

[patch] Patch for 4.11 backported from master

bug14237-v411.patch (text/plain), 2.03 KB, created by Ralph Böhme on 2020-03-16 13:49:41 UTC

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Creator: Ralph Böhme

Created: 2020-03-16 13:49:41 UTC

Size: 2.03 KB

patch

obsolete

>From 446cf8b5c2c74179f1e74a01f270cdf28263fff3 Mon Sep 17 00:00:00 2001
>From: Ralph Boehme <slow@samba.org>
>Date: Fri, 17 Jan 2020 10:56:00 +0100
>Subject: [PATCH] smbd: avoid calling vfs_file_id_from_sbuf() if statinfo is
> not valid
>
>When we're about to create a file, the stat info will be all zero, so
>vfs_file_id_from_sbuf() would return a bogus file_id. This is normally not a
>problem, as open_file() itself also calls vfs_file_id_from_sbuf() after having
>created the file.
>
>This is however a problem when using the VFS module fileid, as that is doing
>caching of /etc/mtab and failing to find smb_fname->st.st_ex_dev (all zero in
>this case when creating a new file) in the mtab cache will trigger a mtab reload
>which can be *very* expensive.
>
>Copying many small files to a Samba server in this situation will result in
>abysimal performance.
>
>BUG: https://bugzilla.samba.org/show_bug.cgi?id=14237
>
>Pair-Programmed-With: Jeremy Allison <jra@samba.org>
>Signed-off-by: Ralph Boehme <slow@samba.org>
>
>Autobuild-User(master): Jeremy Allison <jra@samba.org>
>Autobuild-Date(master): Fri Jan 17 22:38:14 UTC 2020 on sn-devel-184
>
>(backported from commit 7606800b798a31d62e69f61d441201e5db2f0d8a)
>---
> source3/smbd/open.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
>diff --git a/source3/smbd/open.c b/source3/smbd/open.c
>index 871cc72053f..888e6ad3af7 100644
>--- a/source3/smbd/open.c
>+++ b/source3/smbd/open.c
>@@ -3245,7 +3245,15 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
> 		return NT_STATUS_ACCESS_DENIED;
> 	}
> 
>-	fsp->file_id = vfs_file_id_from_sbuf(conn, &smb_fname->st);
>+	if (VALID_STAT(smb_fname->st)) {
>+		/*
>+		 * Only try and create a file id before open
>+		 * for an existing file. For a file being created
>+		 * this won't do anything useful until the file
>+		 * exists and has a valid stat struct.
>+		 */
>+		fsp->file_id = vfs_file_id_from_sbuf(conn, &smb_fname->st);
>+	}
> 	fsp->share_access = share_access;
> 	fsp->fh->private_options = private_flags;
> 	fsp->access_mask = open_access_mask; /* We change this to the
>-- 
>2.24.1
>

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Attachments on bug 14237: 15866