From 16c8d569f5704a84164f30ff01b29879f3438065 Mon Sep 17 00:00:00 2001 From: piaojun Date: Wed, 31 Jan 2018 16:14:59 -0800 Subject: [PATCH] ocfs2/acl: use 'ip_xattr_sem' to protect getting extended attribute The race between *set_acl and *get_acl will cause getting incomplete xattr data as below: processA processB ocfs2_set_acl ocfs2_xattr_set __ocfs2_xattr_set_handle ocfs2_get_acl_nolock ocfs2_xattr_get_nolock: processB may get incomplete xattr data if processA hasn't set_acl done. So we should use 'ip_xattr_sem' to protect getting extended attribute in ocfs2_get_acl_nolock(), as other processes could be changing it concurrently. Link: http://lkml.kernel.org/r/5A5DDCFF.7030001@huawei.com Signed-off-by: Jun Piao Reviewed-by: Alex Chen Cc: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Cc: Changwei Ge Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ocfs2/acl.c | 6 ++++++ fs/ocfs2/xattr.c | 2 ++ 2 files changed, 8 insertions(+) diff --git a/fs/ocfs2/acl.c b/fs/ocfs2/acl.c index 40b5cc97f7b0..917fadca8a7b 100644 --- a/fs/ocfs2/acl.c +++ b/fs/ocfs2/acl.c @@ -311,7 +311,9 @@ struct posix_acl *ocfs2_iop_get_acl(struct inode *inode, int type) if (had_lock < 0) return ERR_PTR(had_lock); + down_read(&OCFS2_I(inode)->ip_xattr_sem); acl = ocfs2_get_acl_nolock(inode, type, di_bh); + up_read(&OCFS2_I(inode)->ip_xattr_sem); ocfs2_inode_unlock_tracker(inode, 0, &oh, had_lock); brelse(di_bh); @@ -330,7 +332,9 @@ int ocfs2_acl_chmod(struct inode *inode, struct buffer_head *bh) if (!(osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL)) return 0; + down_read(&OCFS2_I(inode)->ip_xattr_sem); acl = ocfs2_get_acl_nolock(inode, ACL_TYPE_ACCESS, bh); + up_read(&OCFS2_I(inode)->ip_xattr_sem); if (IS_ERR(acl) || !acl) return PTR_ERR(acl); ret = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); @@ -361,8 +365,10 @@ int ocfs2_init_acl(handle_t *handle, if (!S_ISLNK(inode->i_mode)) { if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) { + down_read(&OCFS2_I(dir)->ip_xattr_sem); acl = ocfs2_get_acl_nolock(dir, ACL_TYPE_DEFAULT, dir_bh); + up_read(&OCFS2_I(dir)->ip_xattr_sem); if (IS_ERR(acl)) return PTR_ERR(acl); } diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 268619c96b4e..c261c1dfd374 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -638,9 +638,11 @@ int ocfs2_calc_xattr_init(struct inode *dir, si->value_len); if (osb->s_mount_opt & OCFS2_MOUNT_POSIX_ACL) { + down_read(&OCFS2_I(dir)->ip_xattr_sem); acl_len = ocfs2_xattr_get_nolock(dir, dir_bh, OCFS2_XATTR_INDEX_POSIX_ACL_DEFAULT, "", NULL, 0); + up_read(&OCFS2_I(dir)->ip_xattr_sem); if (acl_len > 0) { a_size = ocfs2_xattr_entry_real_size(0, acl_len); if (S_ISDIR(mode)) -- 2.45.2