Searched hist:d0a22a4b (Results 1 – 2 of 2) sorted by relevance
/openbmc/linux/fs/gfs2/ |
H A D | aops.c | d0a22a4b Mon Apr 29 14:50:30 CDT 2019 Andreas Gruenbacher <agruenba@redhat.com> gfs2: Fix iomap write page reclaim deadlock
Since commit 64bc06bb32ee ("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: 64bc06bb32ee ("gfs2: iomap buffered write support") Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> d0a22a4b Mon Apr 29 14:50:30 CDT 2019 Andreas Gruenbacher <agruenba@redhat.com> gfs2: Fix iomap write page reclaim deadlock Since commit 64bc06bb32ee ("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: 64bc06bb32ee ("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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H A D | bmap.c | d0a22a4b Mon Apr 29 14:50:30 CDT 2019 Andreas Gruenbacher <agruenba@redhat.com> gfs2: Fix iomap write page reclaim deadlock
Since commit 64bc06bb32ee ("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: 64bc06bb32ee ("gfs2: iomap buffered write support") Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> d0a22a4b Mon Apr 29 14:50:30 CDT 2019 Andreas Gruenbacher <agruenba@redhat.com> gfs2: Fix iomap write page reclaim deadlock Since commit 64bc06bb32ee ("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: 64bc06bb32ee ("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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