From dc3d3b810a644dfa329efaa230cd514226f8981d Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Sun, 15 Aug 2010 23:33:57 +0900 Subject: nilfs2: deny write access to inodes in snapshots Snapshots of nilfs are read-only. After super block instances (sb) will be unified, nilfs will need to check write access by a way other than implicit test with IS_RDONLY(inode). This is because IS_RDONLY() refers to MS_RDONLY bit of inode->i_sb->s_flags and it will become inaccurate after the unification of sb. To prepare for the issue, this uses i_op->permission to deny write access to inodes in snapshots. Signed-off-by: Ryusuke Konishi --- fs/nilfs2/inode.c | 11 +++++++++++ fs/nilfs2/namei.c | 1 + fs/nilfs2/nilfs.h | 4 +--- 3 files changed, 13 insertions(+), 3 deletions(-) (limited to 'fs/nilfs2') diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index ca09e4362d66..3efef0ecfa24 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -764,6 +764,17 @@ out_err: return err; } +int nilfs_permission(struct inode *inode, int mask) +{ + struct nilfs_root *root = NILFS_I(inode)->i_root; + + if ((mask & MAY_WRITE) && root && + root->cno != NILFS_CPTREE_CURRENT_CNO) + return -EROFS; /* snapshot is not writable */ + + return generic_permission(inode, mask, NULL); +} + int nilfs_load_inode_block(struct nilfs_sb_info *sbi, struct inode *inode, struct buffer_head **pbh) { diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c index a65f46560fbe..185d1607cb00 100644 --- a/fs/nilfs2/namei.c +++ b/fs/nilfs2/namei.c @@ -588,6 +588,7 @@ const struct inode_operations nilfs_symlink_inode_operations = { .readlink = generic_readlink, .follow_link = page_follow_link_light, .put_link = page_put_link, + .permission = nilfs_permission, }; const struct export_operations nilfs_export_ops = { diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h index 3870c109aba3..cf5507a2a178 100644 --- a/fs/nilfs2/nilfs.h +++ b/fs/nilfs2/nilfs.h @@ -201,12 +201,9 @@ static inline struct inode *nilfs_dat_inode(const struct the_nilfs *nilfs) */ #ifdef CONFIG_NILFS_POSIX_ACL #error "NILFS: not yet supported POSIX ACL" -extern int nilfs_permission(struct inode *, int, struct nameidata *); extern int nilfs_acl_chmod(struct inode *); extern int nilfs_init_acl(struct inode *, struct inode *); #else -#define nilfs_permission NULL - static inline int nilfs_acl_chmod(struct inode *inode) { return 0; @@ -256,6 +253,7 @@ extern void nilfs_update_inode(struct inode *, struct buffer_head *); extern void nilfs_truncate(struct inode *); extern void nilfs_evict_inode(struct inode *); extern int nilfs_setattr(struct dentry *, struct iattr *); +int nilfs_permission(struct inode *inode, int mask); extern int nilfs_load_inode_block(struct nilfs_sb_info *, struct inode *, struct buffer_head **); extern int nilfs_inode_dirty(struct inode *); -- cgit v1.2.3-59-g8ed1b