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Andreas Gruenbacher authored
Since commit 64bc06bb ("gfs2: iomap buffered write support"), gfs2 is doing buffered writes by starting a transaction in iomap_begin, writing a range of pages, and ending that transaction in iomap_end. This approach suffers from two problems: (1) Any allocations necessary for the write are done in iomap_begin, so when the data aren't journaled, there is no need for keeping the transaction open until iomap_end. (2) Transactions keep the gfs2 log flush lock held. When iomap_file_buffered_write calls balance_dirty_pages, this can end up calling gfs2_write_inode, which will try to flush the log. This requires taking the log flush lock which is already held, resulting in a deadlock. Fix both of these issues by not keeping transactions open from iomap_begin to iomap_end. Instead, start a small transaction in page_prepare and end it in page_done when necessary. Reported-by:
Edwin Török <edvin.torok@citrix.com> Fixes: 64bc06bb ("gfs2: iomap buffered write support") Signed-off-by:
Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by:
Bob Peterson <rpeterso@redhat.com>
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