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No need to do lock_super() for exclusion in generic_shutdown_super()

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We can't run into contention on it.  All other callers of lock_super()
either hold s_umount (and we have it exclusive) or hold an active
reference to superblock in question, which prevents the call of
generic_shutdown_super() while the reference is held.  So we can
replace lock_super(s) with get_fs_excl() in generic_shutdown_super()
(and corresponding change for unlock_super(), of course).

Since ext4 expects s_lock held for its put_super, take lock_super()
into it.  The rest of filesystems do not care at all.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2009-05-05 22:10:44 -04:00
parent 62c6943b4b
commit a9e220f832
2 changed files with 3 additions and 3 deletions
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2
fs/ext4/super.c
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@ -576,6 +576,7 @@ static void ext4_put_super(struct super_block *sb)
struct ext4_super_block *es = sbi->s_es;
int i, err;
lock_super(sb);
if (sb->s_dirt)
ext4_write_super(sb);
@ -645,7 +646,6 @@ static void ext4_put_super(struct super_block *sb)
unlock_super(sb);
kobject_put(&sbi->s_kobj);
wait_for_completion(&sbi->s_kobj_unregister);
lock_super(sb);
lock_kernel();
kfree(sbi->s_blockgroup_lock);
kfree(sbi);

4
fs/super.c
View File

@ -304,7 +304,7 @@ void generic_shutdown_super(struct super_block *sb)
if (sb->s_root) {
shrink_dcache_for_umount(sb);
sync_filesystem(sb);
lock_super(sb);
get_fs_excl();
sb->s_flags &= ~MS_ACTIVE;
/* bad name - it should be evict_inodes() */
@ -322,7 +322,7 @@ void generic_shutdown_super(struct super_block *sb)
}
unlock_kernel();
unlock_super(sb);
put_fs_excl();
}
spin_lock(&sb_lock);
/* should be initialized for __put_super_and_need_restart() */