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fsnotify: Remove indirection from mark list addition 

Adding notification mark to object list has been currently done through
fsnotify_add_{inode|vfsmount}_mark() helpers from
fsnotify_add_mark_locked() which call fsnotify_add_mark_list(). Remove
this unnecessary indirection to simplify the code.

Pushing all the locking to fsnotify_add_mark_list() also allows us to
allocate the connector structure with GFP_KERNEL mode.

Reviewed-by: Miklos Szeredi <mszeredi@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2017-03-14 16:11:23 +01:00
parent e911d8af87
commit 755b5bc681
4 changed files with 43 additions and 86 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
fs/notify/fsnotify.h
View File

@ -21,20 +21,6 @@ extern u32 fsnotify_recalc_mask(struct fsnotify_mark_connector *conn);
extern int fsnotify_compare_groups(struct fsnotify_group *a,
struct fsnotify_group *b);
/* Add mark to a proper place in mark list */
extern int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
struct fsnotify_mark *mark,
struct inode *inode, struct vfsmount *mnt,
int allow_dups);
/* add a mark to an inode */
extern int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct inode *inode,
int allow_dups);
/* add a mark to a vfsmount */
extern int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct vfsmount *mnt,
int allow_dups);
/* vfsmount specific destruction of a mark */
extern void fsnotify_destroy_vfsmount_mark(struct fsnotify_mark *mark);
/* inode specific destruction of a mark */

25
fs/notify/inode_mark.c
View File

@ -92,31 +92,6 @@ struct fsnotify_mark *fsnotify_find_inode_mark(struct fsnotify_group *group,
return mark;
}
/*
* Attach an initialized mark to a given inode.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which group and for which inodes. These
* marks are ordered according to priority, highest number first, and then by
* the group's location in memory.
*/
int fsnotify_add_inode_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct inode *inode,
int allow_dups)
{
int ret;
BUG_ON(!mutex_is_locked(&group->mark_mutex));
assert_spin_locked(&mark->lock);
spin_lock(&inode->i_lock);
ret = fsnotify_add_mark_list(&inode->i_fsnotify_marks, mark, inode,
NULL, allow_dups);
inode->i_fsnotify_mask = fsnotify_recalc_mask(inode->i_fsnotify_marks);
spin_unlock(&inode->i_lock);
return ret;
}
/**
* fsnotify_unmount_inodes - an sb is unmounting. handle any watched inodes.
* @sb: superblock being unmounted.

66
fs/notify/mark.c
View File

@ -320,12 +320,13 @@ int fsnotify_compare_groups(struct fsnotify_group *a, struct fsnotify_group *b)
static int fsnotify_attach_connector_to_object(
struct fsnotify_mark_connector **connp,
spinlock_t *lock,
struct inode *inode,
struct vfsmount *mnt)
{
struct fsnotify_mark_connector *conn;
conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_ATOMIC);
conn = kmem_cache_alloc(fsnotify_mark_connector_cachep, GFP_KERNEL);
if (!conn)
return -ENOMEM;
INIT_HLIST_HEAD(&conn->list);
@ -341,7 +342,12 @@ static int fsnotify_attach_connector_to_object(
* lockless_dereference() in fsnotify().
*/
smp_wmb();
*connp = conn;
spin_lock(lock);
if (!*connp)
*connp = conn;
else
kmem_cache_free(fsnotify_mark_connector_cachep, conn);
spin_unlock(lock);
return 0;
}
@ -352,20 +358,35 @@ static int fsnotify_attach_connector_to_object(
* to which group and for which inodes. These marks are ordered according to
* priority, highest number first, and then by the group's location in memory.
*/
int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
struct fsnotify_mark *mark, struct inode *inode,
struct vfsmount *mnt, int allow_dups)
static int fsnotify_add_mark_list(struct fsnotify_mark *mark,
struct inode *inode, struct vfsmount *mnt,
int allow_dups)
{
struct fsnotify_mark *lmark, *last = NULL;
struct fsnotify_mark_connector *conn;
struct fsnotify_mark_connector **connp;
spinlock_t *lock;
int cmp;
int err;
int err = 0;
if (WARN_ON(!inode && !mnt))
return -EINVAL;
if (inode) {
connp = &inode->i_fsnotify_marks;
lock = &inode->i_lock;
} else {
connp = &real_mount(mnt)->mnt_fsnotify_marks;
lock = &mnt->mnt_root->d_lock;
}
if (!*connp) {
err = fsnotify_attach_connector_to_object(connp, inode, mnt);
err = fsnotify_attach_connector_to_object(connp, lock,
inode, mnt);
if (err)
return err;
}
spin_lock(&mark->lock);
spin_lock(lock);
conn = *connp;
/* is mark the first mark? */
@ -380,8 +401,10 @@ int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
hlist_for_each_entry(lmark, &conn->list, obj_list) {
last = lmark;
if ((lmark->group == mark->group) && !allow_dups)
return -EEXIST;
if ((lmark->group == mark->group) && !allow_dups) {
err = -EEXIST;
goto out_err;
}
cmp = fsnotify_compare_groups(lmark->group, mark->group);
if (cmp >= 0) {
@ -395,7 +418,10 @@ int fsnotify_add_mark_list(struct fsnotify_mark_connector **connp,
hlist_add_behind_rcu(&mark->obj_list, &last->obj_list);
added:
mark->connector = conn;
return 0;
out_err:
spin_unlock(lock);
spin_unlock(&mark->lock);
return err;
}
/*
@ -427,22 +453,16 @@ int fsnotify_add_mark_locked(struct fsnotify_mark *mark,
list_add(&mark->g_list, &group->marks_list);
atomic_inc(&group->num_marks);
fsnotify_get_mark(mark); /* for i_list and g_list */
if (inode) {
ret = fsnotify_add_inode_mark(mark, group, inode, allow_dups);
if (ret)
goto err;
} else if (mnt) {
ret = fsnotify_add_vfsmount_mark(mark, group, mnt, allow_dups);
if (ret)
goto err;
} else {
BUG();
}
spin_unlock(&mark->lock);
ret = fsnotify_add_mark_list(mark, inode, mnt, allow_dups);
if (ret)
goto err;
if (inode)
__fsnotify_update_child_dentry_flags(inode);
fsnotify_recalc_inode_mask(inode);
else
fsnotify_recalc_vfsmount_mask(mnt);
return ret;
err:

24
fs/notify/vfsmount_mark.c
View File

@ -80,27 +80,3 @@ struct fsnotify_mark *fsnotify_find_vfsmount_mark(struct fsnotify_group *group,
return mark;
}
/*
* Attach an initialized mark to a given group and vfsmount.
* These marks may be used for the fsnotify backend to determine which
* event types should be delivered to which groups.
*/
int fsnotify_add_vfsmount_mark(struct fsnotify_mark *mark,
struct fsnotify_group *group, struct vfsmount *mnt,
int allow_dups)
{
struct mount *m = real_mount(mnt);
int ret;
BUG_ON(!mutex_is_locked(&group->mark_mutex));
assert_spin_locked(&mark->lock);
spin_lock(&mnt->mnt_root->d_lock);
ret = fsnotify_add_mark_list(&m->mnt_fsnotify_marks, mark, NULL, mnt,
allow_dups);
m->mnt_fsnotify_mask = fsnotify_recalc_mask(m->mnt_fsnotify_marks);
spin_unlock(&mnt->mnt_root->d_lock);
return ret;
}