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Diffstat (limited to 'community/gsoc/project_ideas/xattr.mdwn')
-rw-r--r-- | community/gsoc/project_ideas/xattr.mdwn | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/community/gsoc/project_ideas/xattr.mdwn b/community/gsoc/project_ideas/xattr.mdwn new file mode 100644 index 00000000..7178d826 --- /dev/null +++ b/community/gsoc/project_ideas/xattr.mdwn @@ -0,0 +1,47 @@ +[[!meta copyright="Copyright © 2009 Free Software Foundation, Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled +[[GNU Free Documentation License|/fdl]]."]]"""]] + +[[!meta title="Implement xattr Support"]] + +Extended attributes (xattr) are a standardized, generic method for storing +additional metadata along with a file (inode). Most modern UNIX filesystems +support xattrs. + +In general, xattrs should be used sparingly, as they are less transparent than +data stored as explicit file contents; however, there are some cases where they +really make sense. The Hurd's variant of ext2 presently uses some additional +fields in the inode to store Hurd-specific metadata: most notable passive +translator settings. As these fields are Hurd-specific, they can't be accessed +by the standard methods from Linux for example, so it's not possible to fully +work with a Hurd filesystem on GNU/Linux (copy, backup etc.); and also, even +when on Hurd, only tools that explicitly support the Hurd-specific information +can handle them. + +Using extended attributes instead of custom fields for the Hurd-specific +information would be very helpful. + +The most important goal of this project thus is to make the Hurd ext2fs server +able to store and read the Hurd-specific information with extended attributes +instead of the custom fields, so it become accessible from other systems. Being +able to access the information through the standard xattr API instead of +Hurd-specific calls is also desirable. (And in turn requires implementing the +generic xattr API first, which can be useful for other purposes as well.) + +Completing this project will require digging into some parts of the Hurd, but +it should be quite doable without previous Hurd experience. Some experience +with xattrs might help a bit, but shouldn't be really necessary either. + +Some previous work on xattr support is available in [[!GNU_Savannah_patch +5126]], and might serve as a starting point. + +Possible mentors: Samuel Thibault (youpi) + +Exercise: Implement support for different inode sizes (other than 128 bytes) in +Hurd's ext2fs. |