[PATCH AUTOSEL 5.12 35/52] cifs: improve fallocate emulation

[PATCH AUTOSEL 5.12 35/52] cifs: improve fallocate emulation

[Sasha Levin]

From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit 966a3cb7c7db786452a87afdc3b48858fc4d4d6b ]

RHBZ: 1866684

We don't have a real fallocate in the SMB2 protocol so we used to emulate fallocate
by simply switching the file to become non-sparse. But as that could potantially consume
a lot more data than we intended to fallocate (large sparse file and fallocating a thin
slice in the middle) we would only do this IFF the fallocate request was for virtually
the entire file.

This patch improves this and starts allowing us to fallocate smaller chunks of a file by
overwriting the region with 0, for the parts that are unallocated.

The method used is to first query the server for FSCTL_QUERY_ALLOCATED_RANGES to find what
is unallocated in the fallocate range and then to only overwrite-with-zero the unallocated
ranges to fill in the holes.

As overwriting-with-zero is different from just allocating blocks, and potentially much
more expensive, we limit this to only allow fallocate ranges up to 1Mb in size.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Acked-by: Aurelien Aptel <aaptel@suse.com>
Acked-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/smb2ops.c | 133 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 133 insertions(+)

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index e9a530da4255..ea5e958fd6b0 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -3561,6 +3561,119 @@ static long smb3_punch_hole(struct file *file, struct cifs_tcon *tcon,
 	return rc;
 }
 
+static int smb3_simple_fallocate_write_range(unsigned int xid,
+					     struct cifs_tcon *tcon,
+					     struct cifsFileInfo *cfile,
+					     loff_t off, loff_t len,
+					     char *buf)
+{
+	struct cifs_io_parms io_parms = {0};
+	int nbytes;
+	struct kvec iov[2];
+
+	io_parms.netfid = cfile->fid.netfid;
+	io_parms.pid = current->tgid;
+	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);
+}
+
+static int smb3_simple_fallocate_range(unsigned int xid,
+				       struct cifs_tcon *tcon,
+				       struct cifsFileInfo *cfile,
+				       loff_t off, loff_t len)
+{
+	struct file_allocated_range_buffer in_data, *out_data = NULL, *tmp_data;
+	u32 out_data_len;
+	char *buf = NULL;
+	loff_t l;
+	int rc;
+
+	in_data.file_offset = cpu_to_le64(off);
+	in_data.length = cpu_to_le64(len);
+	rc = SMB2_ioctl(xid, tcon, cfile->fid.persistent_fid,
+			cfile->fid.volatile_fid,
+			FSCTL_QUERY_ALLOCATED_RANGES, true,
+			(char *)&in_data, sizeof(in_data),
+			1024 * sizeof(struct file_allocated_range_buffer),
+			(char **)&out_data, &out_data_len);
+	if (rc)
+		goto out;
+	/*
+	 * It is already all allocated
+	 */
+	if (out_data_len == 0)
+		goto out;
+
+	buf = kzalloc(1024 * 1024, GFP_KERNEL);
+	if (buf == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	tmp_data = out_data;
+	while (len) {
+		/*
+		 * The rest of the region is unmapped so write it all.
+		 */
+		if (out_data_len == 0) {
+			rc = smb3_simple_fallocate_write_range(xid, tcon,
+					       cfile, off, len, buf);
+			goto out;
+		}
+
+		if (out_data_len < sizeof(struct file_allocated_range_buffer)) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		if (off < le64_to_cpu(tmp_data->file_offset)) {
+			/*
+			 * We are at a hole. Write until the end of the region
+			 * or until the next allocated data,
+			 * whichever comes next.
+			 */
+			l = le64_to_cpu(tmp_data->file_offset) - off;
+			if (len < l)
+				l = len;
+			rc = smb3_simple_fallocate_write_range(xid, tcon,
+					       cfile, off, l, buf);
+			if (rc)
+				goto out;
+			off = off + l;
+			len = len - l;
+			if (len == 0)
+				goto out;
+		}
+		/*
+		 * We are at a section of allocated data, just skip forward
+		 * until the end of the data or the end of the region
+		 * we are supposed to fallocate, whichever comes first.
+		 */
+		l = le64_to_cpu(tmp_data->length);
+		if (len < l)
+			l = len;
+		off += l;
+		len -= l;
+
+		tmp_data = &tmp_data[1];
+		out_data_len -= sizeof(struct file_allocated_range_buffer);
+	}
+
+ out:
+	kfree(out_data);
+	kfree(buf);
+	return rc;
+}
+
+
 static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 			    loff_t off, loff_t len, bool keep_size)
 {
@@ -3621,6 +3734,26 @@ static long smb3_simple_falloc(struct file *file, struct cifs_tcon *tcon,
 	}
 
 	if ((keep_size == true) || (i_size_read(inode) >= off + len)) {
+		/*
+		 * At this point, we are trying to fallocate an internal
+		 * regions of a sparse file. Since smb2 does not have a
+		 * fallocate command we have two otions on how to emulate this.
+		 * We can either turn the entire file to become non-sparse
+		 * which we only do if the fallocate is for virtually
+		 * the whole file,  or we can overwrite the region with zeroes
+		 * using SMB2_write, which could be prohibitevly expensive
+		 * if len is large.
+		 */
+		/*
+		 * We are only trying to fallocate a small region so
+		 * just write it with zero.
+		 */
+		if (len <= 1024 * 1024) {
+			rc = smb3_simple_fallocate_range(xid, tcon, cfile,
+							 off, len);
+			goto out;
+		}
+
 		/*
 		 * Check if falloc starts within first few pages of file
 		 * and ends within a few pages of the end of file to
-- 
2.30.2

[PATCH AUTOSEL 5.12 36/52] cifs: fix check of dfs interlinks

[Sasha Levin]

From: Paulo Alcantara <pc@cjr.nz>

[ Upstream commit 889c2a700799f3b6f82210925e1faf4a9b833c4a ]

Interlink is a special type of DFS link that resolves to a different
DFS domain-based namespace.  To determine whether it is an interlink
or not, check if ReferralServers and StorageServers bits are set to 1
and 0 respectively in ReferralHeaderFlags, as specified in MS-DFSC
3.1.5.4.5 Determining Whether a Referral Response is an Interlink.

Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/dfs_cache.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
index 098b4bc8da59..d2d686ee10a3 100644
--- a/fs/cifs/dfs_cache.c
+++ b/fs/cifs/dfs_cache.c
@@ -25,8 +25,7 @@
 #define CACHE_HTABLE_SIZE 32
 #define CACHE_MAX_ENTRIES 64
 
-#define IS_INTERLINK_SET(v) ((v) & (DFSREF_REFERRAL_SERVER | \
-				    DFSREF_STORAGE_SERVER))
+#define IS_DFS_INTERLINK(v) (((v) & DFSREF_REFERRAL_SERVER) && !((v) & DFSREF_STORAGE_SERVER))
 
 struct cache_dfs_tgt {
 	char *name;
@@ -170,7 +169,7 @@ static int dfscache_proc_show(struct seq_file *m, void *v)
 				   "cache entry: path=%s,type=%s,ttl=%d,etime=%ld,hdr_flags=0x%x,ref_flags=0x%x,interlink=%s,path_consumed=%d,expired=%s\n",
 				   ce->path, ce->srvtype == DFS_TYPE_ROOT ? "root" : "link",
 				   ce->ttl, ce->etime.tv_nsec, ce->ref_flags, ce->hdr_flags,
-				   IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
+				   IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
 				   ce->path_consumed, cache_entry_expired(ce) ? "yes" : "no");
 
 			list_for_each_entry(t, &ce->tlist, list) {
@@ -239,7 +238,7 @@ static inline void dump_ce(const struct cache_entry *ce)
 		 ce->srvtype == DFS_TYPE_ROOT ? "root" : "link", ce->ttl,
 		 ce->etime.tv_nsec,
 		 ce->hdr_flags, ce->ref_flags,
-		 IS_INTERLINK_SET(ce->hdr_flags) ? "yes" : "no",
+		 IS_DFS_INTERLINK(ce->hdr_flags) ? "yes" : "no",
 		 ce->path_consumed,
 		 cache_entry_expired(ce) ? "yes" : "no");
 	dump_tgts(ce);
-- 
2.30.2

[PATCH AUTOSEL 5.12 37/52] smb3: fix uninitialized value for port in witness protocol move

[Sasha Levin]

From: Steve French <stfrench@microsoft.com>

[ Upstream commit ff93b71a3eff25fe9d4364ef13b6e01d935600c6 ]

Although in practice this can not occur (since IPv4 and IPv6 are the
only two cases currently supported), it is cleaner to avoid uninitialized
variable warnings.

Addresses smatch warning:
  fs/cifs/cifs_swn.c:468 cifs_swn_store_swn_addr() error: uninitialized symbol 'port'.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
CC: Samuel Cabrero <scabrero@suse.de>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/cifs_swn.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/fs/cifs/cifs_swn.c b/fs/cifs/cifs_swn.c
index d829b8bf833e..93b47818c6c2 100644
--- a/fs/cifs/cifs_swn.c
+++ b/fs/cifs/cifs_swn.c
@@ -447,15 +447,13 @@ static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
 				   const struct sockaddr_storage *old,
 				   struct sockaddr_storage *dst)
 {
-	__be16 port;
+	__be16 port = cpu_to_be16(CIFS_PORT);
 
 	if (old->ss_family == AF_INET) {
 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)old;
 
 		port = ipv4->sin_port;
-	}
-
-	if (old->ss_family == AF_INET6) {
+	} else if (old->ss_family == AF_INET6) {
 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)old;
 
 		port = ipv6->sin6_port;
@@ -465,9 +463,7 @@ static int cifs_swn_store_swn_addr(const struct sockaddr_storage *new,
 		struct sockaddr_in *ipv4 = (struct sockaddr_in *)new;
 
 		ipv4->sin_port = port;
-	}
-
-	if (new->ss_family == AF_INET6) {
+	} else if (new->ss_family == AF_INET6) {
 		struct sockaddr_in6 *ipv6 = (struct sockaddr_in6 *)new;
 
 		ipv6->sin6_port = port;
-- 
2.30.2