[patch 6/7] fsnotify: Use sequential fdinfo engine

[Cyrill Gorcunov <gorcunov@openvz.org>]

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Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Pavel Emelyanov <xemul@parallels.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrey Vagin <avagin@openvz.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: James Bottomley <jbottomley@parallels.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Matthew Helsley <matt.helsley@gmail.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 fs/notify/fanotify/fanotify_user.c |    4 
 fs/notify/fdinfo.c                 |  167 +++++++++++++++++++++++--------------
 fs/notify/fdinfo.h                 |   12 --
 fs/notify/inotify/inotify_user.c   |    4 
 4 files changed, 116 insertions(+), 71 deletions(-)

Index: linux-2.6.git/fs/notify/fanotify/fanotify_user.c
===================================================================
--- linux-2.6.git.orig/fs/notify/fanotify/fanotify_user.c
+++ linux-2.6.git/fs/notify/fanotify/fanotify_user.c
@@ -432,7 +432,9 @@ static long fanotify_ioctl(struct file *
 }
 
 static const struct file_operations fanotify_fops = {
-	.show_fdinfo	= fanotify_show_fdinfo,
+#ifdef CONFIG_PROC_FS
+	.fdinfo_op	= &fanotify_fdinfo_op,
+#endif
 	.poll		= fanotify_poll,
 	.read		= fanotify_read,
 	.write		= fanotify_write,
Index: linux-2.6.git/fs/notify/fdinfo.c
===================================================================
--- linux-2.6.git.orig/fs/notify/fdinfo.c
+++ linux-2.6.git/fs/notify/fdinfo.c
@@ -16,25 +16,50 @@
 #include "inotify/inotify.h"
 #include "../fs/mount.h"
 
+#define seq_notify_group(m) ((struct file*)(m)->private)->private_data
+
 #if defined(CONFIG_PROC_FS)
 
 #if defined(CONFIG_INOTIFY_USER) || defined(CONFIG_FANOTIFY)
 
-static int show_fdinfo(struct seq_file *m, struct file *f,
-		       int (*show)(struct seq_file *m, struct fsnotify_mark *mark))
+static void *notify_start(struct seq_file *m, loff_t *pos,
+			  void *(*__start)(struct seq_file *m, loff_t *pos,
+					   struct fsnotify_group *group,
+					   struct fsnotify_mark *mark))
 {
-	struct fsnotify_group *group = f->private_data;
+	struct fsnotify_group *group = seq_notify_group(m);
 	struct fsnotify_mark *mark;
-	int ret = 0;
+	loff_t num = *pos;
 
 	mutex_lock(&group->mark_mutex);
 	list_for_each_entry(mark, &group->marks_list, g_list) {
-		ret = show(m, mark);
-		if (ret)
-			break;
+		if (num-- == 0) {
+			if (__start)
+				return __start(m, pos, group, mark);
+			return mark;
+		}
 	}
+
+	return NULL;
+}
+
+static void notify_stop(struct seq_file *m, void *v)
+{
+	struct fsnotify_group *group = seq_notify_group(m);
 	mutex_unlock(&group->mark_mutex);
-	return ret;
+}
+
+static void *notify_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	struct fsnotify_group *group = seq_notify_group(m);
+	struct fsnotify_mark *mark = p;
+
+	if (!list_is_last(&mark->g_list, &group->marks_list))
+		mark = list_first_entry(&mark->g_list, struct fsnotify_mark, g_list);
+	else
+		mark = NULL;
+	++*pos;
+	return mark;
 }
 
 #if defined(CONFIG_EXPORTFS)
@@ -58,13 +83,13 @@ static int show_mark_fhandle(struct seq_
 	f.handle.handle_type = ret;
 	f.handle.handle_bytes = size * sizeof(u32);
 
-	ret = seq_printf(m, "fhandle-bytes:%x fhandle-type:%x f_handle:",
-			 f.handle.handle_bytes, f.handle.handle_type);
+	seq_printf(m, "fhandle-bytes:%x fhandle-type:%x f_handle:",
+		   f.handle.handle_bytes, f.handle.handle_type);
 
 	for (i = 0; i < f.handle.handle_bytes; i++)
-		ret |= seq_printf(m, "%02x", (int)f.handle.f_handle[i]);
+		seq_printf(m, "%02x", (int)f.handle.f_handle[i]);
 
-	return ret;
+	return 0;
 }
 #else
 static int show_mark_fhandle(struct seq_file *m, struct inode *inode)
@@ -75,11 +100,16 @@ static int show_mark_fhandle(struct seq_
 
 #ifdef CONFIG_INOTIFY_USER
 
-static int inotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
+static void *inotify_start(struct seq_file *m, loff_t *pos)
+{
+	return notify_start(m, pos, NULL);
+}
+
+static int inotify_show(struct seq_file *m, void *v)
 {
 	struct inotify_inode_mark *inode_mark;
+	struct fsnotify_mark *mark = v;
 	struct inode *inode;
-	int ret = 0;
 
 	if (!(mark->flags & (FSNOTIFY_MARK_FLAG_ALIVE | FSNOTIFY_MARK_FLAG_INODE)))
 		return 0;
@@ -87,33 +117,35 @@ static int inotify_fdinfo(struct seq_fil
 	inode_mark = container_of(mark, struct inotify_inode_mark, fsn_mark);
 	inode = igrab(mark->i.inode);
 	if (inode) {
-		ret = seq_printf(m, "inotify wd:%x ino:%lx sdev:%x "
-				 "mask:%x ignored_mask:%x ",
-				 inode_mark->wd, inode->i_ino,
-				 inode->i_sb->s_dev,
-				 mark->mask, mark->ignored_mask);
-		ret |= show_mark_fhandle(m, inode);
-		ret |= seq_putc(m, '\n');
+		seq_printf(m, "inotify wd:%x ino:%lx sdev:%x "
+			   "mask:%x ignored_mask:%x ",
+			   inode_mark->wd, inode->i_ino,
+			   inode->i_sb->s_dev,
+			   mark->mask, mark->ignored_mask);
+		show_mark_fhandle(m, inode);
+		seq_putc(m, '\n');
 		iput(inode);
 	}
 
-	return ret;
+	return 0;
 }
 
-int inotify_show_fdinfo(struct seq_file *m, struct file *f)
-{
-	return show_fdinfo(m, f, inotify_fdinfo);
-}
+struct seq_operations inotify_fdinfo_op = {
+	.start		= inotify_start,
+	.next		= notify_next,
+	.stop		= notify_stop,
+	.show		= inotify_show,
+};
 
 #endif /* CONFIG_INOTIFY_USER */
 
 #ifdef CONFIG_FANOTIFY
 
-static int fanotify_fdinfo(struct seq_file *m, struct fsnotify_mark *mark)
+static int fanotify_show(struct seq_file *m, void *v)
 {
+	struct fsnotify_mark *mark = v;
 	unsigned int mflags = 0;
 	struct inode *inode;
-	int ret = 0;
 
 	if (!(mark->flags & FSNOTIFY_MARK_FLAG_ALIVE))
 		return 0;
@@ -125,53 +157,68 @@ static int fanotify_fdinfo(struct seq_fi
 		inode = igrab(mark->i.inode);
 		if (!inode)
 			goto out;
-		ret = seq_printf(m, "fanotify ino:%lx sdev:%x "
-				 "mflags:%x mask:%x ignored_mask:%x ",
-				 inode->i_ino, inode->i_sb->s_dev,
-				 mflags, mark->mask, mark->ignored_mask);
-		ret |= show_mark_fhandle(m, inode);
-		ret |= seq_putc(m, '\n');
+		seq_printf(m, "fanotify ino:%lx sdev:%x "
+			   "mflags:%x mask:%x ignored_mask:%x ",
+			   inode->i_ino, inode->i_sb->s_dev,
+			   mflags, mark->mask, mark->ignored_mask);
+		show_mark_fhandle(m, inode);
+		seq_putc(m, '\n');
 		iput(inode);
 	} else if (mark->flags & FSNOTIFY_MARK_FLAG_VFSMOUNT) {
 		struct mount *mnt = real_mount(mark->m.mnt);
 
-		ret = seq_printf(m, "fanotify mnt_id:%x mflags:%x mask:%x "
-				 "ignored_mask:%x\n", mnt->mnt_id, mflags,
-				 mark->mask, mark->ignored_mask);
+		seq_printf(m, "fanotify mnt_id:%x mflags:%x mask:%x "
+			   "ignored_mask:%x\n", mnt->mnt_id, mflags,
+			   mark->mask, mark->ignored_mask);
 	}
 out:
-	return ret;
+	return 0;
 }
 
-int fanotify_show_fdinfo(struct seq_file *m, struct file *f)
-{
-	struct fsnotify_group *group = f->private_data;
-	unsigned int flags = 0;
+static void *__fanotify_start(struct seq_file *m, loff_t *pos,
+			      struct fsnotify_group *group,
+			      struct fsnotify_mark *mark)
+{
+	if (*pos == 0) {
+		unsigned int flags = 0;
+
+		switch (group->priority) {
+		case FS_PRIO_0:
+			flags |= FAN_CLASS_NOTIF;
+			break;
+		case FS_PRIO_1:
+			flags |= FAN_CLASS_CONTENT;
+			break;
+		case FS_PRIO_2:
+			flags |= FAN_CLASS_PRE_CONTENT;
+			break;
+		}
 
-	switch (group->priority) {
-	case FS_PRIO_0:
-		flags |= FAN_CLASS_NOTIF;
-		break;
-	case FS_PRIO_1:
-		flags |= FAN_CLASS_CONTENT;
-		break;
-	case FS_PRIO_2:
-		flags |= FAN_CLASS_PRE_CONTENT;
-		break;
-	}
+		if (group->max_events == UINT_MAX)
+			flags |= FAN_UNLIMITED_QUEUE;
 
-	if (group->max_events == UINT_MAX)
-		flags |= FAN_UNLIMITED_QUEUE;
+		if (group->fanotify_data.max_marks == UINT_MAX)
+			flags |= FAN_UNLIMITED_MARKS;
 
-	if (group->fanotify_data.max_marks == UINT_MAX)
-		flags |= FAN_UNLIMITED_MARKS;
+		seq_printf(m, "fanotify flags:%x event-flags:%x\n",
+			   flags, group->fanotify_data.f_flags);
+	}
 
-	seq_printf(m, "fanotify flags:%x event-flags:%x\n",
-		   flags, group->fanotify_data.f_flags);
+	return mark;
+}
 
-	return show_fdinfo(m, f, fanotify_fdinfo);
+static void *fanotify_start(struct seq_file *m, loff_t *pos)
+{
+	return notify_start(m, pos, __fanotify_start);
 }
 
+struct seq_operations fanotify_fdinfo_op = {
+	.start		= fanotify_start,
+	.next		= notify_next,
+	.stop		= notify_stop,
+	.show		= fanotify_show,
+};
+
 #endif /* CONFIG_FANOTIFY */
 
 #endif /* CONFIG_INOTIFY_USER || CONFIG_FANOTIFY */
Index: linux-2.6.git/fs/notify/fdinfo.h
===================================================================
--- linux-2.6.git.orig/fs/notify/fdinfo.h
+++ linux-2.6.git/fs/notify/fdinfo.h
@@ -4,24 +4,18 @@
 #include <linux/errno.h>
 #include <linux/proc_fs.h>
 
-struct seq_file;
-struct file;
+struct seq_operations;
 
 #ifdef CONFIG_PROC_FS
 
 #ifdef CONFIG_INOTIFY_USER
-extern int inotify_show_fdinfo(struct seq_file *m, struct file *f);
+extern struct seq_operations inotify_fdinfo_op;
 #endif
 
 #ifdef CONFIG_FANOTIFY
-extern int fanotify_show_fdinfo(struct seq_file *m, struct file *f);
+extern struct seq_operations fanotify_fdinfo_op;
 #endif
 
-#else /* CONFIG_PROC_FS */
-
-#define inotify_show_fdinfo	NULL
-#define fanotify_show_fdinfo	NULL
-
 #endif /* CONFIG_PROC_FS */
 
 #endif /* __FSNOTIFY_FDINFO_H__ */
Index: linux-2.6.git/fs/notify/inotify/inotify_user.c
===================================================================
--- linux-2.6.git.orig/fs/notify/inotify/inotify_user.c
+++ linux-2.6.git/fs/notify/inotify/inotify_user.c
@@ -327,7 +327,9 @@ static long inotify_ioctl(struct file *f
 }
 
 static const struct file_operations inotify_fops = {
-	.show_fdinfo	= inotify_show_fdinfo,
+#ifdef CONFIG_PROC_FS
+	.fdinfo_op	= &inotify_fdinfo_op,
+#endif
 	.poll		= inotify_poll,
 	.read		= inotify_read,
 	.fasync		= fsnotify_fasync,