Theodore Ts'o wrote:
On Sat, Apr 30, 2016 at 05:23:58PM +0200, Damien Guibouret wrote:
[...]
For the other case (shrinking the fs) at line 856:
if (last_bg > 1 &&
old_fs->super->s_backup_bgs[1] == old_last_bg)
fs->super->s_backup_bgs[1] = last_bg;
what ensures the location where the new super block backup will be set is a
free block?
This is handled by reserve_sparse2_last_group(). We have to deal this
sort of thing whenever we need to do things like grow the group
descriptors, and we will relocate data blocks as necessary to make
room for blocks that have to be at specific locations. (This means we
have allocate new blocks for the blocks we are moving, copy the data
blocks, and then update the inode(s) to point the new block
locations.)
Cheers,
- Ted
Hello,
Thanks for the feedback.
For the last point, you're right, I did not look deep enough in the remaining
part of the code (and it looks obvious that when shrinking the fs, there is some
need to reallocate blocks).
Regards,
Damien
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