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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. 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+. Signed-off-by: Sougata Santra <sougata@tuxera.com> Acked-by: Christoph Hellwig <hch@lst.de> Cc: Vyacheslav Dubeyko <slava@dubeyko.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| acl.h | ||
| attributes.c | ||
| bfind.c | ||
| bitmap.c | ||
| bnode.c | ||
| brec.c | ||
| btree.c | ||
| catalog.c | ||
| dir.c | ||
| extents.c | ||
| hfsplus_fs.h | ||
| hfsplus_raw.h | ||
| inode.c | ||
| ioctl.c | ||
| Kconfig | ||
| Makefile | ||
| options.c | ||
| part_tbl.c | ||
| posix_acl.c | ||
| super.c | ||
| tables.c | ||
| unicode.c | ||
| wrapper.c | ||
| xattr_security.c | ||
| xattr_trusted.c | ||
| xattr_user.c | ||
| xattr.c | ||
| xattr.h | ||