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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-08-15 23:33:57 +0900
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-10-23 09:24:35 +0900
commitdc3d3b810a644dfa329efaa230cd514226f8981d (patch)
treee0a2c2bfb3edb6b1fa4383cb2d1f52adb653c9e2 /fs/nilfs2/inode.c
parentfd52202930b7e8db48bee5a6fc6b1f438e822a23 (diff)
downloadlinux-dc3d3b810a644dfa329efaa230cd514226f8981d.tar.gz
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>
Diffstat (limited to 'fs/nilfs2/inode.c')
-rw-r--r--fs/nilfs2/inode.c11
1 files changed, 11 insertions, 0 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)
{