extent generation_id

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



hi,
i am new to the email list - and i have a question. Please let me know
if this is not the right forum for this question.

While iterating the extents for a subvolume, btrfs_file_extent_item
returns a generation_id - which is the "transaction id that created
this extent".
Is it safe to assume that every pwrite syscall will endup a generating
new generation id for an extent, regardless if it is over-writing an
existing extent (offset) or writing to a new never written (offset) ?
In other words, can we assume that if we have generation id associated
with all extents of a snapshot (S1) of a volume, then we delete this
snapshot, and then do some i/o(write/discard) to the volume and create
a new snapshot (S2) from this volume, if we iterate over the extents
of this new snapshot (S2) we will see a different generation id
(compared to the one we got from the snapshot (S1)) if the i/o
(write/discard) happened at an offset in that extent ?

Thanks for the help !



[Index of Archives]     [Linux Filesystem Development]     [Linux NFS]     [Linux NILFS]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux