[PATCH] r/o bind mounts: monitor zeroing of i_nlink

Some filesystems, instead of simply decrementing i_nlink, simply zero it
during an unlink operation.  We need to catch these in addition to the
decrement operations.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index e21bb46..c149352 100644 (file)
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -638,7 +638,7 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
        dput(ino->dentry);
 
        dentry->d_inode->i_size = 0;
-       dentry->d_inode->i_nlink = 0;
+       clear_nlink(dentry->d_inode);
 
        dir->i_mtime = CURRENT_TIME;
 
@@ -673,7 +673,7 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
        }
        dput(ino->dentry);
        dentry->d_inode->i_size = 0;
-       dentry->d_inode->i_nlink = 0;
+       clear_nlink(dentry->d_inode);
 
        if (dir->i_nlink)
                drop_nlink(dir);

diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 76b7fb3..6b90ef9 100644 (file)
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -818,7 +818,7 @@ int cifs_rmdir(struct inode *inode, struct dentry *direntry)
        if (!rc) {
                drop_nlink(inode);
                i_size_write(direntry->d_inode,0);
-               direntry->d_inode->i_nlink = 0;
+               clear_nlink(direntry->d_inode);
        }
 
        cifsInode = CIFS_I(direntry->d_inode);

diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
index b45c88b..906731a 100644 (file)
--- a/fs/ext3/namei.c
+++ b/fs/ext3/namei.c
@@ -2045,7 +2045,7 @@ static int ext3_rmdir (struct inode * dir, struct dentry *dentry)
                              "empty directory has nlink!=2 (%d)",
                              inode->i_nlink);
        inode->i_version++;
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        /* There's no need to set i_disksize: the fact that i_nlink is
         * zero will ensure that the right thing happens during any
         * recovery. */

diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index f85b2a2..8605155 100644 (file)
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -508,7 +508,7 @@ static int fuse_unlink(struct inode *dir, struct dentry *entry)
                /* Set nlink to zero so the inode can be cleared, if
                    the inode does have more links this will be
                    discovered at the next lookup/getattr */
-               inode->i_nlink = 0;
+               clear_nlink(inode);
                fuse_invalidate_attr(inode);
                fuse_invalidate_attr(dir);
                fuse_invalidate_entry_cache(entry);
@@ -534,7 +534,7 @@ static int fuse_rmdir(struct inode *dir, struct dentry *entry)
        err = req->out.h.error;
        fuse_put_request(fc, req);
        if (!err) {
-               entry->d_inode->i_nlink = 0;
+               clear_nlink(entry->d_inode);
                fuse_invalidate_attr(dir);
                fuse_invalidate_entry_cache(entry);
        } else if (err == -EINTR)

diff --git a/fs/hfs/dir.c b/fs/hfs/dir.c
index cfef6ad..37d681b 100644 (file)
--- a/fs/hfs/dir.c
+++ b/fs/hfs/dir.c
@@ -273,7 +273,7 @@ static int hfs_rmdir(struct inode *dir, struct dentry *dentry)
        res = hfs_cat_delete(inode->i_ino, dir, &dentry->d_name);
        if (res)
                return res;
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        hfs_delete_inode(inode);
        mark_inode_dirty(inode);

diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 99b4ed1..7e30975 100644 (file)
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -348,7 +348,7 @@ static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
                } else
                        inode->i_flags |= S_DEAD;
        } else
-               inode->i_nlink = 0;
+               clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        mark_inode_dirty(inode);
 
@@ -387,7 +387,7 @@ static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry)
        res = hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
        if (res)
                return res;
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        hfsplus_delete_inode(inode);
        mark_inode_dirty(inode);

diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c
index 25dd6f8..2507e73 100644 (file)
--- a/fs/hpfs/namei.c
+++ b/fs/hpfs/namei.c
@@ -495,7 +495,7 @@ static int hpfs_rmdir(struct inode *dir, struct dentry *dentry)
                break;
        default:
                drop_nlink(dir);
-               inode->i_nlink = 0;
+               clear_nlink(inode);
                err = 0;
        }
        goto out;
@@ -590,7 +590,7 @@ static int hpfs_rename(struct inode *old_dir, struct dentry *old_dentry,
                int r;
                if ((r = hpfs_remove_dirent(old_dir, dno, dep, &qbh, 1)) != 2) {
                        if ((nde = map_dirent(new_dir, hpfs_i(new_dir)->i_dno, (char *)new_name, new_len, NULL, &qbh1))) {
-                               new_inode->i_nlink = 0;
+                               clear_nlink(new_inode);
                                copy_de(nde, &de);
                                memcpy(nde->name, new_name, new_len);
                                hpfs_mark_4buffers_dirty(&qbh1);

diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c
index 8cef881..b8d16a6 100644 (file)
--- a/fs/jfs/namei.c
+++ b/fs/jfs/namei.c
@@ -414,7 +414,7 @@ static int jfs_rmdir(struct inode *dip, struct dentry *dentry)
        JFS_IP(ip)->acl.flag = 0;
 
        /* mark the target directory as deleted */
-       ip->i_nlink = 0;
+       clear_nlink(ip);
        mark_inode_dirty(ip);
 
        rc = txCommit(tid, 2, &iplist[0], 0);

diff --git a/fs/msdos/namei.c b/fs/msdos/namei.c
index fa868c7..b0f01b3 100644 (file)
--- a/fs/msdos/namei.c
+++ b/fs/msdos/namei.c
@@ -345,7 +345,7 @@ static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
                goto out;
        drop_nlink(dir);
 
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        fat_detach(inode);
 out:
@@ -430,7 +430,7 @@ static int msdos_unlink(struct inode *dir, struct dentry *dentry)
        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
        if (err)
                goto out;
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        fat_detach(inode);
 out:

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 26eecb8..481f889 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1286,7 +1286,7 @@ static int nfs_rmdir(struct inode *dir, struct dentry *dentry)
        error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
        /* Ensure the VFS deletes this inode */
        if (error == 0 && dentry->d_inode != NULL)
-               dentry->d_inode->i_nlink = 0;
+               clear_nlink(dentry->d_inode);
        nfs_end_data_update(dir);
        unlock_kernel();
 

diff --git a/fs/qnx4/namei.c b/fs/qnx4/namei.c
index ad5afa4..733cdf0 100644 (file)
--- a/fs/qnx4/namei.c
+++ b/fs/qnx4/namei.c
@@ -186,7 +186,7 @@ int qnx4_rmdir(struct inode *dir, struct dentry *dentry)
        memset(de->di_fname, 0, sizeof de->di_fname);
        de->di_mode = 0;
        mark_buffer_dirty(bh);
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        mark_inode_dirty(inode);
        inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
        inode_dec_link_count(dir);

diff --git a/fs/reiserfs/namei.c b/fs/reiserfs/namei.c
index cf92e89..16e9cff 100644 (file)
--- a/fs/reiserfs/namei.c
+++ b/fs/reiserfs/namei.c
@@ -913,7 +913,7 @@ static int reiserfs_rmdir(struct inode *dir, struct dentry *dentry)
                reiserfs_warning(inode->i_sb, "%s: empty directory has nlink "
                                 "!= 2 (%d)", __FUNCTION__, inode->i_nlink);
 
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
        reiserfs_update_sd(&th, inode);
 
@@ -1473,7 +1473,7 @@ static int reiserfs_rename(struct inode *old_dir, struct dentry *old_dentry,
        if (new_dentry_inode) {
                // adjust link number of the victim
                if (S_ISDIR(new_dentry_inode->i_mode)) {
-                       new_dentry_inode->i_nlink = 0;
+                       clear_nlink(new_dentry_inode);
                } else {
                        drop_nlink(new_dentry_inode);
                }

diff --git a/fs/udf/namei.c b/fs/udf/namei.c
index e40c95e..7316332 100644 (file)
--- a/fs/udf/namei.c
+++ b/fs/udf/namei.c
@@ -876,7 +876,7 @@ static int udf_rmdir(struct inode * dir, struct dentry * dentry)
                udf_warning(inode->i_sb, "udf_rmdir",
                        "empty directory has nlink != 2 (%d)",
                        inode->i_nlink);
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_size = 0;
        inode_dec_link_count(inode);
        inode->i_ctime = dir->i_ctime = dir->i_mtime = current_fs_time(dir->i_sb);

diff --git a/fs/vfat/namei.c b/fs/vfat/namei.c
index 5846ba2..edb711f 100644 (file)
--- a/fs/vfat/namei.c
+++ b/fs/vfat/namei.c
@@ -784,7 +784,7 @@ static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
                goto out;
        drop_nlink(dir);
 
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
        fat_detach(inode);
 out:
@@ -808,7 +808,7 @@ static int vfat_unlink(struct inode *dir, struct dentry *dentry)
        err = fat_remove_entries(dir, &sinfo);  /* and releases bh */
        if (err)
                goto out;
-       inode->i_nlink = 0;
+       clear_nlink(inode);
        inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
        fat_detach(inode);
 out:

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6a5267d..3493d28 100644 (file)
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1235,6 +1235,11 @@ static inline void drop_nlink(struct inode *inode)
        inode->i_nlink--;
 }
 
+static inline void clear_nlink(struct inode *inode)
+{
+       inode->i_nlink = 0;
+}
+
 static inline void inode_dec_link_count(struct inode *inode)
 {
        drop_nlink(inode);