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fsnotify: count all objects with attached connectors

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Rename s_fsnotify_inode_refs to s_fsnotify_connectors and count all
objects with attached connectors, not only inodes with attached
connectors.

This will be used to optimize fsnotify() calls on sb without any
type of marks.

Link: https://lore.kernel.org/r/20210810151220.285179-4-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Matthew Bobrowski <repnop@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Amir Goldstein 2021-08-10 18:12:19 +03:00 committed by Jan Kara
parent 11fa333b58
commit ec44610fe2
4 changed files with 44 additions and 8 deletions
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6
fs/notify/fsnotify.c
View file

@ -87,15 +87,15 @@ static void fsnotify_unmount_inodes(struct super_block *sb)
if (iput_inode)
iput(iput_inode);
/* Wait for outstanding inode references from connectors */
wait_var_event(&sb->s_fsnotify_inode_refs,
!atomic_long_read(&sb->s_fsnotify_inode_refs));
}
void fsnotify_sb_delete(struct super_block *sb)
{
fsnotify_unmount_inodes(sb);
fsnotify_clear_marks_by_sb(sb);
/* Wait for outstanding object references from connectors */
wait_var_event(&sb->s_fsnotify_connectors,
!atomic_long_read(&sb->s_fsnotify_connectors));
}
/*

15
fs/notify/fsnotify.h
View file

@ -27,6 +27,21 @@ static inline struct super_block *fsnotify_conn_sb(
return container_of(conn->obj, struct super_block, s_fsnotify_marks);
}
static inline struct super_block *fsnotify_connector_sb(
struct fsnotify_mark_connector *conn)
{
switch (conn->type) {
case FSNOTIFY_OBJ_TYPE_INODE:
return fsnotify_conn_inode(conn)->i_sb;
case FSNOTIFY_OBJ_TYPE_VFSMOUNT:
return fsnotify_conn_mount(conn)->mnt.mnt_sb;
case FSNOTIFY_OBJ_TYPE_SB:
return fsnotify_conn_sb(conn);
default:
return NULL;
}
}
/* destroy all events sitting in this groups notification queue */
extern void fsnotify_flush_notify(struct fsnotify_group *group);

24
fs/notify/mark.c
View file

@ -172,7 +172,7 @@ static void fsnotify_connector_destroy_workfn(struct work_struct *work)
static void fsnotify_get_inode_ref(struct inode *inode)
{
ihold(inode);
atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs);
atomic_long_inc(&inode->i_sb->s_fsnotify_connectors);
}
static void fsnotify_put_inode_ref(struct inode *inode)
@ -180,8 +180,24 @@ static void fsnotify_put_inode_ref(struct inode *inode)
struct super_block *sb = inode->i_sb;
iput(inode);
if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs))
wake_up_var(&sb->s_fsnotify_inode_refs);
if (atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
wake_up_var(&sb->s_fsnotify_connectors);
}
static void fsnotify_get_sb_connectors(struct fsnotify_mark_connector *conn)
{
struct super_block *sb = fsnotify_connector_sb(conn);
if (sb)
atomic_long_inc(&sb->s_fsnotify_connectors);
}
static void fsnotify_put_sb_connectors(struct fsnotify_mark_connector *conn)
{
struct super_block *sb = fsnotify_connector_sb(conn);
if (sb && atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
wake_up_var(&sb->s_fsnotify_connectors);
}
static void *fsnotify_detach_connector_from_object(
@ -203,6 +219,7 @@ static void *fsnotify_detach_connector_from_object(
fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;
}
fsnotify_put_sb_connectors(conn);
rcu_assign_pointer(*(conn->obj), NULL);
conn->obj = NULL;
conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
@ -504,6 +521,7 @@ static int fsnotify_attach_connector_to_object(fsnotify_connp_t *connp,
inode = fsnotify_conn_inode(conn);
fsnotify_get_inode_ref(inode);
}
fsnotify_get_sb_connectors(conn);
/*
* cmpxchg() provides the barrier so that readers of *connp can see

7
include/linux/fs.h
View file

@ -1507,8 +1507,11 @@ struct super_block {
/* Number of inodes with nlink == 0 but still referenced */
atomic_long_t s_remove_count;
/* Pending fsnotify inode refs */
atomic_long_t s_fsnotify_inode_refs;
/*
* Number of inode/mount/sb objects that are being watched, note that
* inodes objects are currently double-accounted.
*/
atomic_long_t s_fsnotify_connectors;
/* Being remounted read-only */
int s_readonly_remount;