ext4: reduce computation of overhead during resize

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This patch avoids doing an O(n**2)-complexity walk through every flex group.
Instead, it uses the already computed overhead information for the newly
allocated space, and simply adds it to the previously calculated
overhead stored in the superblock.  This drastically reduces the time
taken to resize very large bigalloc filesystems (from 3+ hours for a
64TB fs down to milliseconds).

Signed-off-by: Oleg Kiselev <okiselev@amazon.com>
Link: https://lore.kernel.org/r/CE4F359F-4779-45E6-B6A9-8D67FDFF5AE2@amazon.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

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Kiselev, Oleg 2022-07-20 04:26:22 +00:00 • committed by Theodore Ts'o

parent 4a734f0869

commit 026d0d27c4

1 changed files with 21 additions and 2 deletions

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fs/ext4/resize.c

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