From: Sougata Santra <sougata@xxxxxxxxxx> HFS+ resource fork lookup breaks opendir() library function. Since opendir first calls open() with O_DIRECTORY flag set. O_DIRECTORY means "refuse to open if not a directory". The open system call in the kernel does a check for inode->i_op->lookup and returns -ENOTDIR. So if hfsplus_file_lookup is set it allows opendir() for plain files. Also resource fork lookup in HFS+ does not work. Since it is never invoked after VFS permission checking. It will always return with -EACCES. Acked-by: Christoph Hellwig <hch@xxxxxx> Signed-off-by: Sougata Santra <sougata@xxxxxxxxxx> --- When we call opendir() on a file, it does not return NULL. opendir() library call is based on open with O_DIRECTORY flag passed and then layered on top of getdents() system call. O_DIRECTORY means "refuse to open if not a directory". The open() system call in the kernel does a check for: do_sys_open() -->..--> can_lookup() i.e it only checks inode->i_op->lookup and returns ENOTDIR if this function pointer is not set. " In OSX, we can open "file/rsrc" to get the resource fork of "file". This behavior is emulated inside hfsplus on Linux, which means that to some degree every file acts like a directory. That is the reason lookup() inode operations is supported for files, and it is possible to do a lookup on this specific name. As a result of this open succeeds without returning ENOTDIR for HFS+ " Please see the LKML discussion thread on this issue: http://marc.info/?l=linux-fsdevel&m=122823343730412&w=2 I tried to test file/rsrc lookup in HFS+ driver and the feature does not work. >From OSX: $ touch test $ echo "1234" > test/..namedfork/rsrc $ ls -l test..namedfork/rsrc --rw-r--r-- 1 tuxera staff 5 10 dec 12:59 test/..namedfork/rsrc [sougata@ultrabook tmp]$ id uid=1000(sougata) gid=1000(sougata) groups=1000(sougata),5(tty),18(dialout),1001(vboxusers) [sougata@ultrabook tmp]$ mount /dev/sdb1 on /mnt/tmp type hfsplus (rw,relatime,umask=0,uid=1000,gid=1000,nls=utf8) [sougata@ultrabook tmp]$ ls -l test/rsrc ls: cannot access test/rsrc: Permission denied According to this LKML thread it is expected behavior. http://marc.info/?t=121139033800008&r=1&w=4 I guess now that permission checking happens in vfs generic_permission() ? So it turns out that even though the lookup() inode_operation exists for HFS+ files. It cannot really get invoked ?. So if we can disable this feature to make opendir() work for HFS+. Thanks, Sougata fs/hfsplus/inode.c | 59 ------------------------------------------------------ 1 file changed, 59 deletions(-) diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c index 37213d0..3ebda92 100644 --- a/fs/hfsplus/inode.c +++ b/fs/hfsplus/inode.c @@ -178,64 +178,6 @@ const struct dentry_operations hfsplus_dentry_operations = { .d_compare = hfsplus_compare_dentry, }; -static struct dentry *hfsplus_file_lookup(struct inode *dir, - struct dentry *dentry, unsigned int flags) -{ - struct hfs_find_data fd; - struct super_block *sb = dir->i_sb; - struct inode *inode = NULL; - struct hfsplus_inode_info *hip; - int err; - - if (HFSPLUS_IS_RSRC(dir) || strcmp(dentry->d_name.name, "rsrc")) - goto out; - - inode = HFSPLUS_I(dir)->rsrc_inode; - if (inode) - goto out; - - inode = new_inode(sb); - if (!inode) - return ERR_PTR(-ENOMEM); - - hip = HFSPLUS_I(inode); - inode->i_ino = dir->i_ino; - INIT_LIST_HEAD(&hip->open_dir_list); - mutex_init(&hip->extents_lock); - hip->extent_state = 0; - hip->flags = 0; - hip->userflags = 0; - set_bit(HFSPLUS_I_RSRC, &hip->flags); - - err = hfs_find_init(HFSPLUS_SB(sb)->cat_tree, &fd); - if (!err) { - err = hfsplus_find_cat(sb, dir->i_ino, &fd); - if (!err) - err = hfsplus_cat_read_inode(inode, &fd); - hfs_find_exit(&fd); - } - if (err) { - iput(inode); - return ERR_PTR(err); - } - hip->rsrc_inode = dir; - HFSPLUS_I(dir)->rsrc_inode = inode; - igrab(dir); - - /* - * __mark_inode_dirty expects inodes to be hashed. Since we don't - * want resource fork inodes in the regular inode space, we make them - * appear hashed, but do not put on any lists. hlist_del() - * will work fine and require no locking. - */ - hlist_add_fake(&inode->i_hash); - - mark_inode_dirty(inode); -out: - d_add(dentry, inode); - return NULL; -} - static void hfsplus_get_perms(struct inode *inode, struct hfsplus_perm *perms, int dir) { @@ -385,7 +327,6 @@ int hfsplus_file_fsync(struct file *file, loff_t start, loff_t end, } static const struct inode_operations hfsplus_file_inode_operations = { - .lookup = hfsplus_file_lookup, .setattr = hfsplus_setattr, .setxattr = generic_setxattr, .getxattr = generic_getxattr, -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
