[SCM] Samba Shared Repository - branch v3-6-test updated
Karolin Seeger
kseeger at samba.org
Tue Jun 7 05:08:18 MDT 2011
The branch, v3-6-test has been updated
via f8e1eea Fix bug #8175 - smbd deadlock.
from 6df3ff2 Fix bug 8196 - Many (newer) header files don't have copyright / GPL header comments.
http://gitweb.samba.org/?p=samba.git;a=shortlog;h=v3-6-test
- Log -----------------------------------------------------------------
commit f8e1eea238a332ce503c40108d59862b32f83fee
Author: Jeremy Allison <jra at samba.org>
Date: Wed Jun 1 12:11:53 2011 -0700
Fix bug #8175 - smbd deadlock.
Force the open operation (which is the expensive one anyway) to
acquire and release locks in a way compatible with the more common
do_lock check.
Jeremy.
-----------------------------------------------------------------------
Summary of changes:
source3/smbd/open.c | 98 +++++++++++++++++++++++++++++++++++++--------------
1 files changed, 71 insertions(+), 27 deletions(-)
Changeset truncated at 500 lines:
diff --git a/source3/smbd/open.c b/source3/smbd/open.c
index e537d0f..aea25fe 100644
--- a/source3/smbd/open.c
+++ b/source3/smbd/open.c
@@ -1056,18 +1056,8 @@ static bool delay_for_exclusive_oplocks(files_struct *fsp,
return false;
}
-static bool file_has_brlocks(files_struct *fsp)
-{
- struct byte_range_lock *br_lck;
-
- br_lck = brl_get_locks_readonly(fsp);
- if (!br_lck)
- return false;
-
- return br_lck->num_locks > 0 ? true : false;
-}
-
static void grant_fsp_oplock_type(files_struct *fsp,
+ const struct byte_range_lock *br_lck,
int oplock_request,
bool got_level2_oplock,
bool got_a_none_oplock)
@@ -1085,7 +1075,7 @@ static void grant_fsp_oplock_type(files_struct *fsp,
DEBUG(10,("grant_fsp_oplock_type: oplock type 0x%x on file %s\n",
fsp->oplock_type, fsp_str_dbg(fsp)));
return;
- } else if (lp_locking(fsp->conn->params) && file_has_brlocks(fsp)) {
+ } else if (br_lck && br_lck->num_locks > 0) {
DEBUG(10,("grant_fsp_oplock_type: file %s has byte range locks\n",
fsp_str_dbg(fsp)));
fsp->oplock_type = NO_OPLOCK;
@@ -1563,6 +1553,55 @@ void remove_deferred_open_entry(struct file_id id, uint64_t mid,
}
}
+/****************************************************************
+ Ensure we get the brlock lock followed by the share mode lock
+ in the correct order to prevent deadlocks if other smbd's are
+ using the brlock database on this file simultaneously with this open
+ (that code also gets the locks in brlock -> share mode lock order).
+****************************************************************/
+
+static bool acquire_ordered_locks(TALLOC_CTX *mem_ctx,
+ files_struct *fsp,
+ const struct file_id id,
+ const char *connectpath,
+ const struct smb_filename *smb_fname,
+ const struct timespec *p_old_write_time,
+ struct share_mode_lock **p_lck,
+ struct byte_range_lock **p_br_lck)
+{
+ /* Ordering - we must get the br_lck for this
+ file before the share mode. */
+ if (lp_locking(fsp->conn->params)) {
+ *p_br_lck = brl_get_locks_readonly(fsp);
+ if (*p_br_lck == NULL) {
+ DEBUG(0, ("Could not get br_lock\n"));
+ return false;
+ }
+ /* Note - we don't need to free the returned
+ br_lck explicitly as it was allocated on talloc_tos()
+ and so will be autofreed (and release the lock)
+ once the frame context disappears.
+
+ If it was set to fsp->brlock_rec then it was
+ talloc_move'd to hang off the fsp pointer and
+ in this case is guarenteed to not be holding the
+ lock on the brlock database. */
+ }
+
+ *p_lck = get_share_mode_lock(mem_ctx,
+ id,
+ connectpath,
+ smb_fname,
+ p_old_write_time);
+
+ if (*p_lck == NULL) {
+ DEBUG(0, ("Could not get share mode lock\n"));
+ TALLOC_FREE(*p_br_lck);
+ return false;
+ }
+ return true;
+}
+
/****************************************************************************
Open a file with a share mode. Passed in an already created files_struct *.
****************************************************************************/
@@ -1907,6 +1946,7 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
}
if (file_existed) {
+ struct byte_range_lock *br_lck = NULL;
struct share_mode_entry *batch_entry = NULL;
struct share_mode_entry *exclusive_entry = NULL;
bool got_level2_oplock = false;
@@ -1915,12 +1955,14 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
struct timespec old_write_time = smb_fname->st.st_ex_mtime;
id = vfs_file_id_from_sbuf(conn, &smb_fname->st);
- lck = get_share_mode_lock(talloc_tos(), id,
- conn->connectpath,
- smb_fname, &old_write_time);
-
- if (lck == NULL) {
- DEBUG(0, ("Could not get share mode lock\n"));
+ if (!acquire_ordered_locks(talloc_tos(),
+ fsp,
+ id,
+ conn->connectpath,
+ smb_fname,
+ &old_write_time,
+ &lck,
+ &br_lck)) {
return NT_STATUS_SHARING_VIOLATION;
}
@@ -1974,6 +2016,7 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
}
grant_fsp_oplock_type(fsp,
+ br_lck,
oplock_request,
got_level2_oplock,
got_a_none_oplock);
@@ -2137,6 +2180,7 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
}
if (!file_existed) {
+ struct byte_range_lock *br_lck = NULL;
struct share_mode_entry *batch_entry = NULL;
struct share_mode_entry *exclusive_entry = NULL;
bool got_level2_oplock = false;
@@ -2159,15 +2203,14 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
id = fsp->file_id;
- lck = get_share_mode_lock(talloc_tos(), id,
- conn->connectpath,
- smb_fname, &old_write_time);
-
- if (lck == NULL) {
- DEBUG(0, ("open_file_ntcreate: Could not get share "
- "mode lock for %s\n",
- smb_fname_str_dbg(smb_fname)));
- fd_close(fsp);
+ if (!acquire_ordered_locks(talloc_tos(),
+ fsp,
+ id,
+ conn->connectpath,
+ smb_fname,
+ &old_write_time,
+ &lck,
+ &br_lck)) {
return NT_STATUS_SHARING_VIOLATION;
}
@@ -2238,6 +2281,7 @@ static NTSTATUS open_file_ntcreate(connection_struct *conn,
}
grant_fsp_oplock_type(fsp,
+ br_lck,
oplock_request,
got_level2_oplock,
got_a_none_oplock);
--
Samba Shared Repository
More information about the samba-cvs
mailing list