Samba and Linux OFD locks
Andreas Schneider
asn at samba.org
Wed Jan 30 18:45:30 UTC 2019
Hello,
on newer Linux distributions with glibc >= 2.20 we have OFD file locks
available. Our autobuild hosts are too old!
However if your system supports OFD file locks the
samba3.vfs.fruit_netatalk.nt4 test is failing!
The attached patch has some fixes and adds debug messages and shows a
workaround.
If you look where it fails, we want to unlock a file with fcntl and get:
3163 19:20:18.349723 fcntl(37</home/asn/workspace/projects/samba/st/nt4_dc/
share/vfs_fruit_dir/locking_conflict.txt>, F_OFD_GETLK, {l_type=F_RDLCK,
l_whence=SEEK_SET, l_start=0, l_len=9223372036854775807,
l_pid=18446744073709551615}) = 0 <0.000003>
In contrary to the posix locks, the OFD locks return information in 'struct
flock' and this tells us that we are holding a read lock!
test_netatalk_lock() checks if the return lock is F_UNLCK, but F_RDLCK has
been returned and we fail. We fail because if you look a bit earlier in the
strace we acquired an flock() on that file:
3163 19:20:18.349282 flock(37</home/asn/workspace/projects/samba/st/nt4_dc/
share/vfs_fruit_dir/locking_conflict.txt>, LOCK_MAND|LOCK_READ) = 0 <0.000004>
I think that the OFD lock returns that information and we do not handle it. I
have no idea where this flock() is coming from. Maybe the vfs experts could
chime in and help here.
Thanks,
Andreas
--
Andreas Schneider asn at samba.org
Samba Team www.samba.org
GPG-ID: 8DFF53E18F2ABC8D8F3C92237EE0FC4DCC014E3D
-------------- next part --------------
>From d964ce0c6fc038397155b9596103b42c365b968c Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn at samba.org>
Date: Wed, 30 Jan 2019 18:09:52 +0100
Subject: [PATCH 1/5] s3:vfs: Initialize pid to 0 in test_netatalk_lock()
Signed-off-by: Andreas Schneider <asn at samba.org>
---
source3/modules/vfs_fruit.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/source3/modules/vfs_fruit.c b/source3/modules/vfs_fruit.c
index 9f3fe24e5fc..0a67ad39d8e 100644
--- a/source3/modules/vfs_fruit.c
+++ b/source3/modules/vfs_fruit.c
@@ -2647,7 +2647,7 @@ static bool test_netatalk_lock(files_struct *fsp, off_t in_offset)
off_t offset = in_offset;
off_t len = 1;
int type = F_WRLCK;
- pid_t pid;
+ pid_t pid = 0;
result = SMB_VFS_GETLOCK(fsp, &offset, &len, &type, &pid);
if (result == false) {
--
2.20.1
>From 02d4c954923b0be3950660fa695cce53919c1f24 Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn at samba.org>
Date: Wed, 30 Jan 2019 18:45:34 +0100
Subject: [PATCH 2/5] s3:vfs: Correctly check if OFD locks should be enabled or
not
Also the smb.conf options should only be checked once and a reload of
the config should not switch to a different locking mode.
Signed-off-by: Andreas Schneider <asn at samba.org>
---
source3/include/proto.h | 2 +-
source3/lib/util.c | 7 ++-----
source3/modules/vfs_default.c | 14 ++++----------
source3/smbd/files.c | 9 +++++++++
4 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/source3/include/proto.h b/source3/include/proto.h
index 715bc56e286..9d6192967ba 100644
--- a/source3/include/proto.h
+++ b/source3/include/proto.h
@@ -360,7 +360,7 @@ void set_namearray(name_compare_entry **ppname_array, const char *namelist);
void free_namearray(name_compare_entry *name_array);
bool fcntl_lock(int fd, int op, off_t offset, off_t count, int type);
bool fcntl_getlock(int fd, int op, off_t *poffset, off_t *pcount, int *ptype, pid_t *ppid);
-int map_process_lock_to_ofd_lock(int op, bool *use_ofd_locks);
+int map_process_lock_to_ofd_lock(int op);
bool is_myname(const char *s);
void ra_lanman_string( const char *native_lanman );
const char *get_remote_arch_str(void);
diff --git a/source3/lib/util.c b/source3/lib/util.c
index 5dbd67349fa..7530ea67973 100644
--- a/source3/lib/util.c
+++ b/source3/lib/util.c
@@ -1079,7 +1079,7 @@ bool fcntl_getlock(int fd, int op, off_t *poffset, off_t *pcount, int *ptype, pi
}
#if defined(HAVE_OFD_LOCKS)
-int map_process_lock_to_ofd_lock(int op, bool *use_ofd_locks)
+int map_process_lock_to_ofd_lock(int op)
{
switch (op) {
case F_GETLK:
@@ -1095,16 +1095,13 @@ int map_process_lock_to_ofd_lock(int op, bool *use_ofd_locks)
op = F_OFD_SETLKW;
break;
default:
- *use_ofd_locks = false;
return -1;
}
- *use_ofd_locks = true;
return op;
}
#else /* HAVE_OFD_LOCKS */
-int map_process_lock_to_ofd_lock(int op, bool *use_ofd_locks)
+int map_process_lock_to_ofd_lock(int op)
{
- *use_ofd_locks = false;
return op;
}
#endif /* HAVE_OFD_LOCKS */
diff --git a/source3/modules/vfs_default.c b/source3/modules/vfs_default.c
index a27d33a6bea..cb5537e096e 100644
--- a/source3/modules/vfs_default.c
+++ b/source3/modules/vfs_default.c
@@ -2553,11 +2553,8 @@ static bool vfswrap_lock(vfs_handle_struct *handle, files_struct *fsp, int op, o
START_PROFILE(syscall_fcntl_lock);
- if (fsp->use_ofd_locks || !lp_parm_bool(SNUM(fsp->conn),
- "smbd",
- "force process locks",
- false)) {
- op = map_process_lock_to_ofd_lock(op, &fsp->use_ofd_locks);
+ if (fsp->use_ofd_locks) {
+ op = map_process_lock_to_ofd_lock(op);
}
result = fcntl_lock(fsp->fh->fd, op, offset, count, type);
@@ -2581,11 +2578,8 @@ static bool vfswrap_getlock(vfs_handle_struct *handle, files_struct *fsp, off_t
START_PROFILE(syscall_fcntl_getlock);
- if (fsp->use_ofd_locks || !lp_parm_bool(SNUM(fsp->conn),
- "smbd",
- "force process locks",
- false)) {
- op = map_process_lock_to_ofd_lock(op, &fsp->use_ofd_locks);
+ if (fsp->use_ofd_locks) {
+ op = map_process_lock_to_ofd_lock(op);
}
result = fcntl_getlock(fsp->fh->fd, op, poffset, pcount, ptype, ppid);
diff --git a/source3/smbd/files.c b/source3/smbd/files.c
index 397baea84cb..99b4937c99b 100644
--- a/source3/smbd/files.c
+++ b/source3/smbd/files.c
@@ -51,6 +51,15 @@ NTSTATUS fsp_new(struct connection_struct *conn, TALLOC_CTX *mem_ctx,
goto fail;
}
+#if defined(HAVE_OFD_LOCKS)
+ fsp->use_ofd_locks = true;
+ if (lp_parm_bool(SNUM(conn),
+ "smbd",
+ "force process locks",
+ false)) {
+ fsp->use_ofd_locks = false;
+ }
+#endif
fsp->fh->ref_count = 1;
fsp->fh->fd = -1;
--
2.20.1
>From e9f50120368b731ea921f1d032211ca5e96d1014 Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze at samba.org>
Date: Mon, 28 Jan 2019 11:31:05 +0100
Subject: [PATCH 3/5] DEBUG source3/modules/vfs_fruit.c
---
source3/lib/util.c | 2 ++
source3/modules/vfs_fruit.c | 10 ++++++++++
source3/smbd/files.c | 2 ++
3 files changed, 14 insertions(+)
diff --git a/source3/lib/util.c b/source3/lib/util.c
index 7530ea67973..48b763c7241 100644
--- a/source3/lib/util.c
+++ b/source3/lib/util.c
@@ -1097,11 +1097,13 @@ int map_process_lock_to_ofd_lock(int op)
default:
return -1;
}
+ DBG_ERR("XXXXXX OFD locks supported!\n");
return op;
}
#else /* HAVE_OFD_LOCKS */
int map_process_lock_to_ofd_lock(int op)
{
+ DBG_ERR("XXXXXX OFD locks NOT supported!\n");
return op;
}
#endif /* HAVE_OFD_LOCKS */
diff --git a/source3/modules/vfs_fruit.c b/source3/modules/vfs_fruit.c
index 0a67ad39d8e..425cb69c44f 100644
--- a/source3/modules/vfs_fruit.c
+++ b/source3/modules/vfs_fruit.c
@@ -2650,6 +2650,16 @@ static bool test_netatalk_lock(files_struct *fsp, off_t in_offset)
pid_t pid = 0;
result = SMB_VFS_GETLOCK(fsp, &offset, &len, &type, &pid);
+
+ DBG_ERR("XXXXXX in_offset[0x%016llx] offset[0x%016llx] result[%u] "
+ "len[%llu] type[%d => %d]\n",
+ (unsigned long long)in_offset,
+ (unsigned long long)offset,
+ result,
+ (unsigned long long)len,
+ F_WRLCK,
+ type);
+
if (result == false) {
return true;
}
diff --git a/source3/smbd/files.c b/source3/smbd/files.c
index 99b4937c99b..e4a412f23f7 100644
--- a/source3/smbd/files.c
+++ b/source3/smbd/files.c
@@ -60,6 +60,8 @@ NTSTATUS fsp_new(struct connection_struct *conn, TALLOC_CTX *mem_ctx,
fsp->use_ofd_locks = false;
}
#endif
+ DBG_ERR("XXXXXX OFD locks have been %s\n",
+ fsp->use_ofd_locks ? "enabled" : "disabled");
fsp->fh->ref_count = 1;
fsp->fh->fd = -1;
--
2.20.1
>From 1873c4ae77c4921c2f265a313623560cc99da523 Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn at samba.org>
Date: Wed, 30 Jan 2019 18:47:49 +0100
Subject: [PATCH 4/5] WORKAROUND: Disabling OFD locks with netatalk fixes the
test
make -j8 test TESTS="samba3.vfs.fruit_netatalk.nt4"
---
source3/modules/vfs_fruit.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/source3/modules/vfs_fruit.c b/source3/modules/vfs_fruit.c
index 425cb69c44f..e60b62c2b69 100644
--- a/source3/modules/vfs_fruit.c
+++ b/source3/modules/vfs_fruit.c
@@ -2649,6 +2649,9 @@ static bool test_netatalk_lock(files_struct *fsp, off_t in_offset)
int type = F_WRLCK;
pid_t pid = 0;
+ /* Disable OFD locks for netatalk locks as they don't work */
+ fsp->use_ofd_locks = false;
+
result = SMB_VFS_GETLOCK(fsp, &offset, &len, &type, &pid);
DBG_ERR("XXXXXX in_offset[0x%016llx] offset[0x%016llx] result[%u] "
--
2.20.1
>From adc31f0302c8a5f79f43afbb17695f6bfcd0f338 Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn at samba.org>
Date: Wed, 30 Jan 2019 19:09:50 +0100
Subject: [PATCH 5/5] Revert "WORKAROUND: Disabling OFD locks with netatalk
fixes the test"
This reverts commit 431c67fee7f930f5a43d40031c092be6e252c2e4.
---
source3/modules/vfs_fruit.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/source3/modules/vfs_fruit.c b/source3/modules/vfs_fruit.c
index e60b62c2b69..425cb69c44f 100644
--- a/source3/modules/vfs_fruit.c
+++ b/source3/modules/vfs_fruit.c
@@ -2649,9 +2649,6 @@ static bool test_netatalk_lock(files_struct *fsp, off_t in_offset)
int type = F_WRLCK;
pid_t pid = 0;
- /* Disable OFD locks for netatalk locks as they don't work */
- fsp->use_ofd_locks = false;
-
result = SMB_VFS_GETLOCK(fsp, &offset, &len, &type, &pid);
DBG_ERR("XXXXXX in_offset[0x%016llx] offset[0x%016llx] result[%u] "
--
2.20.1
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