From 8f82f840ec6ab873f520364d443ff6fa1b3f8e22 Mon Sep 17 00:00:00 2001 From: Yongqiang Yang Date: Tue, 26 Jul 2011 21:35:44 -0400 Subject: ext4: prevent parallel resizers by atomic bit ops Before this patch, parallel resizers are allowed and protected by a mutex lock, actually, there is no need to support parallel resizer, so this patch prevents parallel resizers by atmoic bit ops, like lock_page() and unlock_page() do. To do this, the patch removed the mutex lock s_resize_lock from struct ext4_sb_info and added a unsigned long field named s_resize_flags which inidicates if there is a resizer. Signed-off-by: Yongqiang Yang Signed-off-by: "Theodore Ts'o" --- fs/ext4/ioctl.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'fs/ext4/ioctl.c') diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 808c554e773..f18bfe37aff 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -202,8 +202,9 @@ setversion_out: struct super_block *sb = inode->i_sb; int err, err2=0; - if (!capable(CAP_SYS_RESOURCE)) - return -EPERM; + err = ext4_resize_begin(sb); + if (err) + return err; if (get_user(n_blocks_count, (__u32 __user *)arg)) return -EFAULT; @@ -221,6 +222,7 @@ setversion_out: if (err == 0) err = err2; mnt_drop_write(filp->f_path.mnt); + ext4_resize_end(sb); return err; } @@ -271,8 +273,9 @@ mext_out: struct super_block *sb = inode->i_sb; int err, err2=0; - if (!capable(CAP_SYS_RESOURCE)) - return -EPERM; + err = ext4_resize_begin(sb); + if (err) + return err; if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg, sizeof(input))) @@ -291,6 +294,7 @@ mext_out: if (err == 0) err = err2; mnt_drop_write(filp->f_path.mnt); + ext4_resize_end(sb); return err; } -- cgit v1.2.3