From: Ralph Boehme <slow@samba.org>
Date: Wed, 20 May 2020 19:46:41 +0000 (+0200)
Subject: vfs_prealloc: implement SMB_VFS_OPENAT()
X-Git-Tag: ldb-2.2.0~383
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d93d73189b5aa447b22b236ab5219a3ebc7b407c;p=thirdparty%2Fsamba.git

vfs_prealloc: implement SMB_VFS_OPENAT()

Signed-off-by: Ralph Boehme <slow@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>
---

diff --git a/source3/modules/vfs_prealloc.c b/source3/modules/vfs_prealloc.c
index 04e77a3412b..cf3019c588a 100644
--- a/source3/modules/vfs_prealloc.c
+++ b/source3/modules/vfs_prealloc.c
@@ -192,6 +192,92 @@ normal_open:
 	return SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
 }
 
+static int prealloc_openat(struct vfs_handle_struct* handle,
+			   const struct files_struct *dirfsp,
+			   const struct smb_filename *smb_fname,
+			   files_struct *fsp,
+			   int flags,
+			   mode_t mode)
+{
+	int fd;
+	off_t size = 0;
+	const char * dot;
+	char fext[10];
+
+	if (!(flags & (O_CREAT|O_TRUNC))) {
+		/* Caller is not intending to rewrite the file. Let's not mess
+		 * with the allocation in this case.
+		 */
+		goto normal_open;
+	}
+
+	*fext = '\0';
+	dot = strrchr(smb_fname->base_name, '.');
+	if (dot && *++dot) {
+		if (strlen(dot) < sizeof(fext)) {
+			strncpy(fext, dot, sizeof(fext));
+			if (!strnorm(fext, CASE_LOWER)) {
+				goto normal_open;
+			}
+		}
+	}
+
+	if (*fext == '\0') {
+		goto normal_open;
+	}
+
+	/* Syntax for specifying preallocation size is:
+	 *	MODULE: <extension> = <size>
+	 * where
+	 *	<extension> is the file extension in lower case
+	 *	<size> is a size like 10, 10K, 10M
+	 */
+	size = conv_str_size(lp_parm_const_string(SNUM(handle->conn), MODULE,
+						    fext, NULL));
+	if (size <= 0) {
+		/* No need to preallocate this file. */
+		goto normal_open;
+	}
+
+	fd = SMB_VFS_NEXT_OPENAT(handle, dirfsp, smb_fname, fsp, flags, mode);
+	if (fd < 0) {
+		return fd;
+	}
+
+	/* Prellocate only if the file is being created or replaced. Note that
+	 * Samba won't ever pass down O_TRUNC, which is why we have to handle
+	 * truncate calls specially.
+	 */
+	if ((flags & O_CREAT) || (flags & O_TRUNC)) {
+		off_t * psize;
+
+		psize = VFS_ADD_FSP_EXTENSION(handle, fsp, off_t, NULL);
+		if (psize == NULL || *psize == -1) {
+			return fd;
+		}
+
+		DEBUG(module_debug,
+			("%s: preallocating %s (fd=%d) to %lld bytes\n",
+			    MODULE, smb_fname_str_dbg(smb_fname), fd,
+			    (long long)size));
+
+		*psize = size;
+		if (preallocate_space(fd, *psize) < 0) {
+			VFS_REMOVE_FSP_EXTENSION(handle, fsp);
+		}
+	}
+
+	return fd;
+
+normal_open:
+	/* We are not creating or replacing a file. Skip the
+	 * preallocation.
+	 */
+	DEBUG(module_debug, ("%s: skipping preallocation for %s\n",
+		MODULE, smb_fname_str_dbg(smb_fname)));
+	return SMB_VFS_NEXT_OPENAT(handle, dirfsp, smb_fname, fsp, flags, mode);
+}
+
 static int prealloc_ftruncate(vfs_handle_struct * handle,
 			files_struct *	fsp,
 			off_t	offset)
@@ -209,6 +295,7 @@ static int prealloc_ftruncate(vfs_handle_struct * handle,
 
 static struct vfs_fn_pointers prealloc_fns = {
 	.open_fn = prealloc_open,
+	.openat_fn = prealloc_openat,
 	.ftruncate_fn = prealloc_ftruncate,
 	.connect_fn = prealloc_connect,
 };