Re: Appending data to the middle of a file using btrfs-specific features

2010-12-07 Thread Nirbheek Chauhan
[I think the mail was sent to just me due to a reply-accident, I've re-added the mailing list for this reply] On Tue, Dec 7, 2010 at 3:50 PM, David Pottage da...@electric-spoon.com wrote: On 06/12/10 12:41, Nirbheek Chauhan wrote: I'd like to know if there has been any discussion about adding

Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Nirbheek Chauhan
Hello, I'd like to know if there has been any discussion about adding a new feature to write (add) data at an offset, but without overwriting existing data, or re-writing the existing data. Essentially, in-place addition/removal of data to a file at a place other than the end of the file. Some

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Chris Mason
Excerpts from Nirbheek Chauhan's message of 2010-12-06 07:41:16 -0500: Hello, I'd like to know if there has been any discussion about adding a new feature to write (add) data at an offset, but without overwriting existing data, or re-writing the existing data. Essentially, in-place

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Nirbheek Chauhan
On Mon, Dec 6, 2010 at 9:35 PM, Chris Mason chris.ma...@oracle.com wrote: Excerpts from Nirbheek Chauhan's message of 2010-12-06 07:41:16 -0500: [snip] Some possible use-cases of such a feature would be: (a) Databases (currently hack around this by allocating sparse files) (b) Delta-patching

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Chris Mason
Excerpts from Nirbheek Chauhan's message of 2010-12-06 14:14:59 -0500: On Mon, Dec 6, 2010 at 9:35 PM, Chris Mason chris.ma...@oracle.com wrote: Excerpts from Nirbheek Chauhan's message of 2010-12-06 07:41:16 -0500: [snip] Some possible use-cases of such a feature would be: (a) Databases

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Freddie Cash
On Mon, Dec 6, 2010 at 11:14 AM, Nirbheek Chauhan nirbheek.chau...@gmail.com wrote: As an aside, my primary motivation for this was that doing an incremental backup of things like git bare repositories and databases using btrfs subvolume snapshots is expensive w.r.t. disk space. Even though

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Nirbheek Chauhan
On Tue, Dec 7, 2010 at 1:05 AM, Freddie Cash fjwc...@gmail.com wrote: On Mon, Dec 6, 2010 at 11:14 AM, Nirbheek Chauhan nirbheek.chau...@gmail.com wrote: As an aside, my primary motivation for this was that doing an incremental backup of things like git bare repositories and databases using

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Freddie Cash
On Mon, Dec 6, 2010 at 12:30 PM, Nirbheek Chauhan nirbheek.chau...@gmail.com wrote: On Tue, Dec 7, 2010 at 1:05 AM, Freddie Cash fjwc...@gmail.com wrote: On Mon, Dec 6, 2010 at 11:14 AM, Nirbheek Chauhan nirbheek.chau...@gmail.com wrote: As an aside, my primary motivation for this was that

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Nirbheek Chauhan
On Tue, Dec 7, 2010 at 2:12 AM, Freddie Cash fjwc...@gmail.com wrote: On Mon, Dec 6, 2010 at 12:30 PM, Nirbheek Chauhan nirbheek.chau...@gmail.com wrote: But the behaviour of --inplace is not entirely to write out *only* the blocks that have changed. From what I could make out, it does the

Re: Appending data to the middle of a file using btrfs-specific features

2010-12-06 Thread Andrey Kuzmin
On Mon, Dec 6, 2010 at 7:05 PM, Chris Mason chris.ma...@oracle.com wrote: Excerpts from Nirbheek Chauhan's message of 2010-12-06 07:41:16 -0500: Hello, I'd like to know if there has been any discussion about adding a new feature to write (add) data at an offset, but without overwriting