netfs: In readahead, put the folio refs as soon extracted

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netfslib currently defers dropping the ref on the folios it obtains during
readahead to after it has started I/O on the basis that we can do it whilst
we wait for the I/O to complete, but this runs the risk of the I/O
collection racing with this in future.

Furthermore, Matthew Wilcox strongly suggests that the refs should be
dropped immediately, as readahead_folio() does (netfslib is using
__readahead_batch() which doesn't drop the refs).

Fixes: ee4cdf7ba8 ("netfs: Speed up buffered reading")
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/3771538.1728052438@warthog.procyon.org.uk
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

...

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David Howells 2024-10-04 15:33:58 +01:00 • committed by Christian Brauner

parent 8cf0b93919

commit 796a404964

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3 changed files with 16 additions and 34 deletions

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47

fs/netfs/buffered_read.c

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2

fs/netfs/read_collect.c

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1

include/trace/events/netfs.h

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