diff options
| author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2010-08-15 23:33:57 +0900 |
|---|---|---|
| committer | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2010-10-23 09:24:35 +0900 |
| commit | dc3d3b810a644dfa329efaa230cd514226f8981d (patch) | |
| tree | e0a2c2bfb3edb6b1fa4383cb2d1f52adb653c9e2 | |
| parent | fd52202930b7e8db48bee5a6fc6b1f438e822a23 (diff) | |
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 <konishi.ryusuke@lab.ntt.co.jp>
| -rw-r--r-- | fs/nilfs2/inode.c | 11 | ||||
| -rw-r--r-- | fs/nilfs2/namei.c | 1 | ||||
| -rw-r--r-- | fs/nilfs2/nilfs.h | 4 |
3 files changed, 13 insertions, 3 deletions
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index ca09e4362d6..3efef0ecfa2 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 a65f46560fb..185d1607cb0 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 3870c109aba..cf5507a2a17 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 *); |