linux-stable/fs/netfs
David Howells 5e51c627c5 netfs: Fix dodgy maths
Fix the dodgy maths in netfs_rreq_unlock_folios().  start_page could be
inside the folio, in which case the calculation of pgpos will be come up
with a negative number (though for the moment rreq->start is rounded down
earlier and folios would have to get merged whilst locked)

Alter how this works to just frame the tracking in terms of absolute file
positions, rather than offsets from the start of the I/O request.  This
simplifies the maths and makes it easier to follow.

Fix the issue by using folio_pos() and folio_size() to calculate the end
position of the page.

Fixes: 3d3c950467 ("netfs: Provide readahead and readpage netfs helpers")
Reported-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Jingbo Xu <jefflexu@linux.alibaba.com>
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/Y2SJw7w1IsIik3nb@casper.infradead.org/
Link: https://lore.kernel.org/r/166757988611.950645.7626959069846893164.stgit@warthog.procyon.org.uk/ # v2
2022-11-15 16:56:07 +00:00
..
buffered_read.c netfs: Fix dodgy maths 2022-11-15 16:56:07 +00:00
internal.h netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context 2022-06-09 13:55:00 -07:00
io.c netfs: Fix missing xas_retry() calls in xarray iteration 2022-11-15 16:49:06 +00:00
Kconfig netfs: Make CONFIG_NETFS_SUPPORT auto-selected rather than manual 2021-05-25 13:48:04 +01:00
main.c netfs: Split some core bits out into their own file 2022-03-18 09:29:05 +00:00
Makefile netfs: Split some core bits out into their own file 2022-03-18 09:29:05 +00:00
objects.c netfs: Rename the netfs_io_request cleanup op and give it an op pointer 2022-06-10 20:55:21 +01:00
stats.c netfs: Add a netfs inode context 2022-03-18 09:29:05 +00:00