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vfs: factor sb iteration out of do_emergency_remount

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The intent is to reduce code duplication with other code
iterating the list.

No functional changes.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Mateusz Guzik 2017-10-03 18:17:40 +02:00 committed by Al Viro
parent 9e66317d3c
commit fa7c1d5080
1 changed files with 36 additions and 25 deletions
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61
fs/super.c
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@ -574,6 +574,28 @@ void drop_super_exclusive(struct super_block *sb)
}
EXPORT_SYMBOL(drop_super_exclusive);
static void __iterate_supers(void (*f)(struct super_block *))
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
f(sb);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
}
/**
* iterate_supers - call function for all active superblocks
* @f: function to call
@ -881,33 +903,22 @@ int do_remount_sb(struct super_block *sb, int sb_flags, void *data, int force)
return retval;
}
static void do_emergency_remount_callback(struct super_block *sb)
{
down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
!sb_rdonly(sb)) {
/*
* What lock protects sb->s_flags??
*/
do_remount_sb(sb, SB_RDONLY, NULL, 1);
}
up_write(&sb->s_umount);
}
static void do_emergency_remount(struct work_struct *work)
{
struct super_block *sb, *p = NULL;
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
!sb_rdonly(sb)) {
/*
* What lock protects sb->s_flags??
*/
do_remount_sb(sb, SB_RDONLY, NULL, 1);
}
up_write(&sb->s_umount);
spin_lock(&sb_lock);
if (p)
__put_super(p);
p = sb;
}
if (p)
__put_super(p);
spin_unlock(&sb_lock);
__iterate_supers(do_emergency_remount_callback);
kfree(work);
printk("Emergency Remount complete\n");
}