On Fri, 2014-01-31 at 20:24 +0800, Jeff Liu wrote: > On 01/31 2014 18:44 PM, Vyacheslav Dubeyko wrote: > > On Fri, 2014-01-31 at 16:54 +0800, Jeff Liu wrote: > >> Hello, > >> > >> On 01/31 2014 15:40 PM, Sun_Blood wrote: > >>> Hello, > >>> > >>> If I understands it correctly XFS don't have a limit to the size of > >>> extended attributes(EA) but Linux impose a limit at 64k. > >>> What I am trying to do is build a backup server that our Apple computers > >>> will use together with rsync to backup files to. The problem I face is > >>> that Apple HFS+ don't have a limit to EA so it has files with more then > >>> 64k of EA in it. > > > > Technical Note TN1150: > > "In an HFS Plus B-tree, the node size is determined by a field > > (nodeSize) in the header node. The node size must be a power from 512 > > through 32,768." > > > > So, as minimum, xattrs unable to be a larger than node size. > > > > But xattrs' size has limitation anyway: > > > > https://github.com/darwin-on-arm/xnu/blob/master/bsd/hfs/hfs.h#L849 > > > > /* Maximum extended attribute size supported for all extended attributes except > > * resource fork and finder info. > > */ > > #define HFS_XATTR_MAXSIZE (128 * 1024) > > > > So, I need to check and correct slightly HFS+ xattrs support code. > > Because, I used 3082 bytes limitation value. > > I just verified above limits on Mac OS X, that's true. > > sh-3.2# a=`perl -e 'print "A"x131072'` > sh-3.2# xattr -w user.comment ${a} xattr_test > > sh-3.2# a=`perl -e 'print "A"x131073'` > sh-3.2# xattr -w user.comment ${a} xattr_test > xattr: [Errno 7] Argument list too long: 'xattr' > > Hence, that would be a problem to preserve EA with large value size on Linux. > I checked the same under Mac OS X 10.6.8 (Snow Leopard). And I have failed on 3803 bytes size of xattr. So, I suppose that you have Mac OS X Lion. And EAs is larger under Lion yet. What version of Mac OS X have you? Thanks, Vyacheslav Dubeyko. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
