ceph: track read contexts in ceph_file_info

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Previously ceph_read_iter() uses current->journal to pass context info
to ceph_readpages(), so that ceph_readpages() can distinguish read(2)
from readahead(2)/fadvise(2)/madvise(2). The problem is that page fault
can happen when copying data to userspace memory. Page fault may call
other filesystem's page_mkwrite() if the userspace memory is mapped to a
file. The later filesystem may also want to use current->journal.

The fix is define a on-stack data structure in ceph_read_iter(), add it
to context list in ceph_file_info. ceph_readpages() searches the list,
find if there is a context belongs to current thread.

Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

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Yan, Zheng 2017-12-15 11:15:36 +08:00 • committed by Ilya Dryomov

parent 5495c2d04f

commit 5d98830828

3 changed files with 66 additions and 9 deletions

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19

fs/ceph/addr.c

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10

fs/ceph/file.c

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46

fs/ceph/super.h

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