> Could you describe in more details how do you use userspace utilities > for extracting xattr? Of course. I first create a new file on an HFS+ filesystem (case- sensitive, journaling disabled). I then call listxattr() on that file and receive a list of one attribute: osx.com.apple.FinderInfo I call getxattr() with this name as the second argument. Without the patch, getxattr() returns -1 and sets errno to either ENOATTR (ENODATA) if the volume has an attribute tree or EOPNOTSUPP if it doesn't. This behavior is clearly wrong, since listxattr() told me that the attribute existed. In the case where ENOATTR is returned (when an attribute b-tree exists, as it does when any file on the filesystem has a real attribute), the error causes GNU patch 2.7.5 to fail with the error message getting attribute osx.com.apple.FinderInfo of osx.com.apple.FinderInfo: No data available (As shown in the attached typescript.) That's how I originally discovered the problem. I have written a test program to demonstrate the issue. It builds on both Linux and OS X, so that the behaviors can be compared. You can find it at https://github.com/tchebb/xattr-test. After more investigation, however, I must withdraw the initial patch I sent. It is not a correct solution to the entire problem; it's simply a band-aid that fixes this one particular symptom. As you can see from the included typescript, *any* osx-namespaced attribute is given an additional copy of the prefix. I believe I've found a commit from 2014 that introduced this incorrect behavior, and I'll send another patch soon that should resolve the issue entirely. Thanks, -Thomas Hebb typescript --- $ cat >a # Make some test files line 1 line 2 $ cat >b line 1 line 2 line 3 $ diff -u a b | tee patch # Create a diff between them --- a 2015-04-02 17:03:18.000000000 -0400 +++ b 2015-04-02 17:03:30.000000000 -0400 @@ -1,2 +1,3 @@ line 1 line 2 +line 3 $ patch -i patch a # Patch the file. Works fine, for now... patching file a $ ./xattr-test a # But getxattr() still returns EOPNOTSUPP Listing attributes of "a" listxattr() returned 25 List contents: osx.com.apple.FinderInfo Getting attribute "osx.com.apple.FinderInfo" getxattr() returned -1 getxattr() failed: Operation not supported $ cat >a # Let's try again line 1 line 2 $ setfattr -n 'user.test' -v 'abc' a # This time, give the volume an attr tree $ patch -i patch a # And patch fails! patching file a patch: getting attribute osx.com.apple.FinderInfo of osx.com.apple.FinderInfo: No data available $ ./xattr-test a # Because getxattr() returns ENODATA Listing attributes of "a" listxattr() returned 35 List contents: osx.com.apple.FinderInfo user.test Getting attribute "osx.com.apple.FinderInfo" getxattr() returned -1 getxattr() failed: No data available Getting attribute "user.test" getxattr() returned 3 Attribute value: 0x61 0x62 0x63 $ setfattr -n 'osx.test' -v 'def' a # Now, what if we create an attr in the osx namespace? $ ./xattr-test a # Aha, here's the real problem: "osx." is prefixed an extra time! Listing attributes of "a" listxattr() returned 48 List contents: osx.com.apple.FinderInfo osx.osx.test user.test Getting attribute "osx.com.apple.FinderInfo" getxattr() returned -1 getxattr() failed: No data available Getting attribute "osx.osx.test" getxattr() returned -1 getxattr() failed: No data available Getting attribute "user.test" getxattr() returned 3 Attribute value: 0x61 0x62 0x63 $ exit -- 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
