Users report that an extent map''s list is still linked when it''s actually going to be freed from cache. The story is that a) when we''re going to drop an extent map and may split this large one into smaller ems, and if this large one is flagged as EXTENT_FLAG_LOGGING which means that it''s on the list to be logged, then the smaller ems split from it will also be flagged as EXTENT_FLAG_LOGGING, and this is _not_ expected. b) we''ll keep ems from unlinking the list and freeing when they are flagged with EXTENT_FLAG_LOGGING, because the log code holds one reference. The end result is the warning, but the truth is that we set the flag EXTENT_FLAG_LOGGING only during fsync. So clear flag EXTENT_FLAG_LOGGING for extent maps split from a large one. Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> Reported-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/file.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 83c790d..7bdb47f 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -591,6 +591,7 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, } compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); clear_bit(EXTENT_FLAG_PINNED, &em->flags); + clear_bit(EXTENT_FLAG_LOGGING, &flags); remove_extent_mapping(em_tree, em); if (no_splits) goto next; -- 1.7.7.6 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Mar 15, 2013 at 10:46:39PM +0800, Liu Bo wrote:> Users report that an extent map''s list is still linked when it''s actually > going to be freed from cache. > > The story is that > > a) when we''re going to drop an extent map and may split this large one into > smaller ems, and if this large one is flagged as EXTENT_FLAG_LOGGING which means > that it''s on the list to be logged, then the smaller ems split from it will also > be flagged as EXTENT_FLAG_LOGGING, and this is _not_ expected. > > b) we''ll keep ems from unlinking the list and freeing when they are flagged with > EXTENT_FLAG_LOGGING, because the log code holds one reference. > > The end result is the warning, but the truth is that we set the flag > EXTENT_FLAG_LOGGING only during fsync. > > So clear flag EXTENT_FLAG_LOGGING for extent maps split from a large one. > > Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> > Reported-by: Darrick J. Wong <darrick.wong@oracle.com> > Signed-off-by: Liu Bo <bo.li.liu@oracle.com>This seems to fix my problem, so you can add: Tested-by: Darrick J. Wong <darrick.wong@oracle.com> --D> --- > fs/btrfs/file.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 83c790d..7bdb47f 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -591,6 +591,7 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end, > } > compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags); > clear_bit(EXTENT_FLAG_PINNED, &em->flags); > + clear_bit(EXTENT_FLAG_LOGGING, &flags); > remove_extent_mapping(em_tree, em); > if (no_splits) > goto next; > -- > 1.7.7.6 >-- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoting Liu Bo (2013-03-15 10:46:39)> Users report that an extent map''s list is still linked when it''s actually > going to be freed from cache. > > The story is that > > a) when we''re going to drop an extent map and may split this large one into > smaller ems, and if this large one is flagged as EXTENT_FLAG_LOGGING which means > that it''s on the list to be logged, then the smaller ems split from it will also > be flagged as EXTENT_FLAG_LOGGING, and this is _not_ expected. > > b) we''ll keep ems from unlinking the list and freeing when they are flagged with > EXTENT_FLAG_LOGGING, because the log code holds one reference. > > The end result is the warning, but the truth is that we set the flag > EXTENT_FLAG_LOGGING only during fsync. > > So clear flag EXTENT_FLAG_LOGGING for extent maps split from a large one.Thanks for tracking this down! I''ve got it in my tree now. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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