mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 12:11:40 +00:00
172e422ffe
In some setups directories can have many (usually negative) dentries. Hence __fsnotify_update_child_dentry_flags() function can take a significant amount of time. Since the bulk of this function happens under inode->i_lock this causes a significant contention on the lock when we remove the watch from the directory as the __fsnotify_update_child_dentry_flags() call from fsnotify_recalc_mask() races with __fsnotify_update_child_dentry_flags() calls from __fsnotify_parent() happening on children. This can lead upto softlockup reports reported by users. Fix the problem by calling fsnotify_update_children_dentry_flags() to set PARENT_WATCHED flags only when parent starts watching children. When parent stops watching children, clear false positive PARENT_WATCHED flags lazily in __fsnotify_parent() for each accessed child. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Signed-off-by: Jan Kara <jack@suse.cz>
101 lines
2.8 KiB
C
101 lines
2.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __FS_NOTIFY_FSNOTIFY_H_
|
|
#define __FS_NOTIFY_FSNOTIFY_H_
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/fsnotify.h>
|
|
#include <linux/srcu.h>
|
|
#include <linux/types.h>
|
|
|
|
#include "../mount.h"
|
|
|
|
/*
|
|
* fsnotify_connp_t is what we embed in objects which connector can be attached
|
|
* to.
|
|
*/
|
|
typedef struct fsnotify_mark_connector __rcu *fsnotify_connp_t;
|
|
|
|
static inline struct inode *fsnotify_conn_inode(
|
|
struct fsnotify_mark_connector *conn)
|
|
{
|
|
return conn->obj;
|
|
}
|
|
|
|
static inline struct mount *fsnotify_conn_mount(
|
|
struct fsnotify_mark_connector *conn)
|
|
{
|
|
return real_mount(conn->obj);
|
|
}
|
|
|
|
static inline struct super_block *fsnotify_conn_sb(
|
|
struct fsnotify_mark_connector *conn)
|
|
{
|
|
return conn->obj;
|
|
}
|
|
|
|
static inline struct super_block *fsnotify_object_sb(void *obj,
|
|
enum fsnotify_obj_type obj_type)
|
|
{
|
|
switch (obj_type) {
|
|
case FSNOTIFY_OBJ_TYPE_INODE:
|
|
return ((struct inode *)obj)->i_sb;
|
|
case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
|
|
return ((struct vfsmount *)obj)->mnt_sb;
|
|
case FSNOTIFY_OBJ_TYPE_SB:
|
|
return (struct super_block *)obj;
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static inline struct super_block *fsnotify_connector_sb(
|
|
struct fsnotify_mark_connector *conn)
|
|
{
|
|
return fsnotify_object_sb(conn->obj, conn->type);
|
|
}
|
|
|
|
static inline fsnotify_connp_t *fsnotify_sb_marks(struct super_block *sb)
|
|
{
|
|
struct fsnotify_sb_info *sbinfo = fsnotify_sb_info(sb);
|
|
|
|
return sbinfo ? &sbinfo->sb_marks : NULL;
|
|
}
|
|
|
|
/* destroy all events sitting in this groups notification queue */
|
|
extern void fsnotify_flush_notify(struct fsnotify_group *group);
|
|
|
|
/* protects reads of inode and vfsmount marks list */
|
|
extern struct srcu_struct fsnotify_mark_srcu;
|
|
|
|
/* compare two groups for sorting of marks lists */
|
|
extern int fsnotify_compare_groups(struct fsnotify_group *a,
|
|
struct fsnotify_group *b);
|
|
|
|
/* Destroy all marks attached to an object via connector */
|
|
extern void fsnotify_destroy_marks(fsnotify_connp_t *connp);
|
|
/* run the list of all marks associated with inode and destroy them */
|
|
static inline void fsnotify_clear_marks_by_inode(struct inode *inode)
|
|
{
|
|
fsnotify_destroy_marks(&inode->i_fsnotify_marks);
|
|
}
|
|
/* run the list of all marks associated with vfsmount and destroy them */
|
|
static inline void fsnotify_clear_marks_by_mount(struct vfsmount *mnt)
|
|
{
|
|
fsnotify_destroy_marks(&real_mount(mnt)->mnt_fsnotify_marks);
|
|
}
|
|
/* run the list of all marks associated with sb and destroy them */
|
|
static inline void fsnotify_clear_marks_by_sb(struct super_block *sb)
|
|
{
|
|
fsnotify_destroy_marks(fsnotify_sb_marks(sb));
|
|
}
|
|
|
|
/*
|
|
* update the dentry->d_flags of all of inode's children to indicate if inode cares
|
|
* about events that happen to its children.
|
|
*/
|
|
extern void fsnotify_set_children_dentry_flags(struct inode *inode);
|
|
|
|
extern struct kmem_cache *fsnotify_mark_connector_cachep;
|
|
|
|
#endif /* __FS_NOTIFY_FSNOTIFY_H_ */
|