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authorAl Viro <viro@zeniv.linux.org.uk>2016-03-25 19:56:34 -0400
committerMike Marshall <hubcap@omnibond.com>2016-03-26 07:22:00 -0400
commit45996492e5c85aa0ac93a95d1b2d1ed56851c865 (patch)
tree3ee74b07ce43cdb0b637c3747fadbb1f2ba59eb6
parent6d4c1a30b32a377083900f39c42bcacb633f99a1 (diff)
downloadlinux-sh-45996492e5c85aa0ac93a95d1b2d1ed56851c865.tar.gz
orangefs: fix orangefs_superblock locking
* switch orangefs_remount() to taking ORANGEFS_SB(sb) instead of sb * remove from the list _before_ orangefs_unmount() - request_mutex in the latter will make sure that nothing observed in the loop in ORANGEFS_DEV_REMOUNT_ALL handling will get freed until the end of loop * on removal, keep the forward pointer and zero the back one. That way we can drop and regain the spinlock in the loop body (again, ORANGEFS_DEV_REMOUNT_ALL one) and still be able to get to the rest of the list. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Mike Marshall <hubcap@omnibond.com>
-rw-r--r--fs/orangefs/devorangefs-req.c41
-rw-r--r--fs/orangefs/orangefs-kernel.h34
-rw-r--r--fs/orangefs/super.c30
3 files changed, 47 insertions, 58 deletions
diff --git a/fs/orangefs/devorangefs-req.c b/fs/orangefs/devorangefs-req.c
index 35418d0b77bf..db170beba797 100644
--- a/fs/orangefs/devorangefs-req.c
+++ b/fs/orangefs/devorangefs-req.c
@@ -572,8 +572,7 @@ static long dispatch_ioctl_command(unsigned int command, unsigned long arg)
struct dev_mask_info_s mask_info = { 0 };
struct dev_mask2_info_s mask2_info = { 0, 0 };
int upstream_kmod = 1;
- struct list_head *tmp = NULL;
- struct orangefs_sb_info_s *orangefs_sb = NULL;
+ struct orangefs_sb_info_s *orangefs_sb;
/* mtmoore: add locking here */
@@ -619,26 +618,32 @@ static long dispatch_ioctl_command(unsigned int command, unsigned long arg)
gossip_debug(GOSSIP_DEV_DEBUG,
"%s: priority remount in progress\n",
__func__);
- list_for_each(tmp, &orangefs_superblocks) {
- orangefs_sb =
- list_entry(tmp,
- struct orangefs_sb_info_s,
- list);
- if (orangefs_sb && (orangefs_sb->sb)) {
+ spin_lock(&orangefs_superblocks_lock);
+ list_for_each_entry(orangefs_sb, &orangefs_superblocks, list) {
+ /*
+ * We have to drop the spinlock, so entries can be
+ * removed. They can't be freed, though, so we just
+ * keep the forward pointers and zero the back ones -
+ * that way we can get to the rest of the list.
+ */
+ if (!orangefs_sb->list.prev)
+ continue;
+ gossip_debug(GOSSIP_DEV_DEBUG,
+ "%s: Remounting SB %p\n",
+ __func__,
+ orangefs_sb);
+
+ spin_unlock(&orangefs_superblocks_lock);
+ ret = orangefs_remount(orangefs_sb);
+ spin_lock(&orangefs_superblocks_lock);
+ if (ret) {
gossip_debug(GOSSIP_DEV_DEBUG,
- "%s: Remounting SB %p\n",
- __func__,
+ "SB %p remount failed\n",
orangefs_sb);
-
- ret = orangefs_remount(orangefs_sb->sb);
- if (ret) {
- gossip_debug(GOSSIP_DEV_DEBUG,
- "SB %p remount failed\n",
- orangefs_sb);
- break;
- }
+ break;
}
}
+ spin_unlock(&orangefs_superblocks_lock);
gossip_debug(GOSSIP_DEV_DEBUG,
"%s: priority remount complete\n",
__func__);
diff --git a/fs/orangefs/orangefs-kernel.h b/fs/orangefs/orangefs-kernel.h
index db258d2ccc6a..a9925e296ceb 100644
--- a/fs/orangefs/orangefs-kernel.h
+++ b/fs/orangefs/orangefs-kernel.h
@@ -462,7 +462,7 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
void *data);
void orangefs_kill_sb(struct super_block *sb);
-int orangefs_remount(struct super_block *sb);
+int orangefs_remount(struct orangefs_sb_info_s *);
int fsid_key_table_initialize(void);
void fsid_key_table_finalize(void);
@@ -598,38 +598,6 @@ int service_operation(struct orangefs_kernel_op_s *op,
((ORANGEFS_SB(inode->i_sb)->flags & ORANGEFS_OPT_INTR) ? \
ORANGEFS_OP_INTERRUPTIBLE : 0)
-#define add_orangefs_sb(sb) \
-do { \
- gossip_debug(GOSSIP_SUPER_DEBUG, \
- "Adding SB %p to orangefs superblocks\n", \
- ORANGEFS_SB(sb)); \
- spin_lock(&orangefs_superblocks_lock); \
- list_add_tail(&ORANGEFS_SB(sb)->list, &orangefs_superblocks); \
- spin_unlock(&orangefs_superblocks_lock); \
-} while (0)
-
-#define remove_orangefs_sb(sb) \
-do { \
- struct list_head *tmp = NULL; \
- struct list_head *tmp_safe = NULL; \
- struct orangefs_sb_info_s *orangefs_sb = NULL; \
- \
- spin_lock(&orangefs_superblocks_lock); \
- list_for_each_safe(tmp, tmp_safe, &orangefs_superblocks) { \
- orangefs_sb = list_entry(tmp, \
- struct orangefs_sb_info_s, \
- list); \
- if (orangefs_sb && (orangefs_sb->sb == sb)) { \
- gossip_debug(GOSSIP_SUPER_DEBUG, \
- "Removing SB %p from orangefs superblocks\n", \
- orangefs_sb); \
- list_del(&orangefs_sb->list); \
- break; \
- } \
- } \
- spin_unlock(&orangefs_superblocks_lock); \
-} while (0)
-
#define fill_default_sys_attrs(sys_attr, type, mode) \
do { \
sys_attr.owner = from_kuid(current_user_ns(), current_fsuid()); \
diff --git a/fs/orangefs/super.c b/fs/orangefs/super.c
index 5a89b8083966..b9da9a0281c9 100644
--- a/fs/orangefs/super.c
+++ b/fs/orangefs/super.c
@@ -210,7 +210,7 @@ static int orangefs_remount_fs(struct super_block *sb, int *flags, char *data)
* the client regains all of the mount information from us.
* NOTE: this function assumes that the request_mutex is already acquired!
*/
-int orangefs_remount(struct super_block *sb)
+int orangefs_remount(struct orangefs_sb_info_s *orangefs_sb)
{
struct orangefs_kernel_op_s *new_op;
int ret = -EINVAL;
@@ -221,7 +221,7 @@ int orangefs_remount(struct super_block *sb)
if (!new_op)
return -ENOMEM;
strncpy(new_op->upcall.req.fs_mount.orangefs_config_server,
- ORANGEFS_SB(sb)->devname,
+ orangefs_sb->devname,
ORANGEFS_MAX_SERVER_ADDR_LEN);
gossip_debug(GOSSIP_SUPER_DEBUG,
@@ -244,8 +244,8 @@ int orangefs_remount(struct super_block *sb)
* short-lived mapping that the system interface uses
* to map this superblock to a particular mount entry
*/
- ORANGEFS_SB(sb)->id = new_op->downcall.resp.fs_mount.id;
- ORANGEFS_SB(sb)->mount_pending = 0;
+ orangefs_sb->id = new_op->downcall.resp.fs_mount.id;
+ orangefs_sb->mount_pending = 0;
}
op_release(new_op);
@@ -485,7 +485,12 @@ struct dentry *orangefs_mount(struct file_system_type *fst,
* finally, add this sb to our list of known orangefs
* sb's
*/
- add_orangefs_sb(sb);
+ gossip_debug(GOSSIP_SUPER_DEBUG,
+ "Adding SB %p to orangefs superblocks\n",
+ ORANGEFS_SB(sb));
+ spin_lock(&orangefs_superblocks_lock);
+ list_add_tail(&ORANGEFS_SB(sb)->list, &orangefs_superblocks);
+ spin_unlock(&orangefs_superblocks_lock);
op_release(new_op);
return dget(sb->s_root);
@@ -512,10 +517,21 @@ void orangefs_kill_sb(struct super_block *sb)
* issue the unmount to userspace to tell it to remove the
* dynamic mount info it has for this superblock
*/
- orangefs_unmount_sb(sb);
+ orangefs_unmount_sb(sb);
/* remove the sb from our list of orangefs specific sb's */
- remove_orangefs_sb(sb);
+
+ spin_lock(&orangefs_superblocks_lock);
+ __list_del_entry(&ORANGEFS_SB(sb)->list); /* not list_del_init */
+ ORANGEFS_SB(sb)->list.prev = NULL;
+ spin_unlock(&orangefs_superblocks_lock);
+
+ /*
+ * make sure that ORANGEFS_DEV_REMOUNT_ALL loop that might've seen us
+ * gets completed before we free the dang thing.
+ */
+ mutex_lock(&request_mutex);
+ mutex_unlock(&request_mutex);
/* free the orangefs superblock private data */
kfree(ORANGEFS_SB(sb));