| Message ID | 20200924163922.2547-5-rgoldwyn@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | BTRFS DIO inode locking/D_SYNC fix | expand |
On Thu, Sep 24, 2020 at 11:39:11AM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > iomap complete routine can deadlock with btrfs_fallocate because of the > call to generic_write_sync(). > > P0 P1 > inode_lock() fallocate(FALLOC_FL_ZERO_RANGE) > __iomap_dio_rw() inode_lock() > <block> > <submits IO> > <completes IO> > inode_unlock() > <gets inode_lock()> > inode_dio_wait() > iomap_dio_complete() > generic_write_sync() > btrfs_file_fsync() > inode_lock() > <deadlock> > > inode_dio_end() is used to notify the end of DIO data in order > to synchronize with truncate. Call inode_dio_end() before calling > generic_write_sync(), so filesystems can lock i_rwsem during a sync. > > This matches the way it is done in fs/direct-io.c:dio_complete(). > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > Reviewed-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Josef Bacik <josef@toxicpanda.com> Looks ok (at least with the fses that use either iomap or ye olde directio) to me... Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> So, uh, do you want me to pull these two iomap patches in for 5.10? --D > --- > fs/iomap/direct-io.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c > index b88dbfe15118..0ea88ae57cb2 100644 > --- a/fs/iomap/direct-io.c > +++ b/fs/iomap/direct-io.c > @@ -118,6 +118,7 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) > dio_warn_stale_pagecache(iocb->ki_filp); > } > > + inode_dio_end(file_inode(iocb->ki_filp)); > /* > * If this is a DSYNC write, make sure we push it to stable storage now > * that we've written data. > @@ -125,7 +126,6 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) > if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) > ret = generic_write_sync(iocb, ret); > > - inode_dio_end(file_inode(iocb->ki_filp)); > kfree(dio); > > return ret; > -- > 2.26.2 >
On Fri, Sep 25, 2020 at 06:51:08PM -0700, Darrick J. Wong wrote: > On Thu, Sep 24, 2020 at 11:39:11AM -0500, Goldwyn Rodrigues wrote: > > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > > iomap complete routine can deadlock with btrfs_fallocate because of the > > call to generic_write_sync(). > > > > P0 P1 > > inode_lock() fallocate(FALLOC_FL_ZERO_RANGE) > > __iomap_dio_rw() inode_lock() > > <block> > > <submits IO> > > <completes IO> > > inode_unlock() > > <gets inode_lock()> > > inode_dio_wait() > > iomap_dio_complete() > > generic_write_sync() > > btrfs_file_fsync() > > inode_lock() > > <deadlock> > > > > inode_dio_end() is used to notify the end of DIO data in order > > to synchronize with truncate. Call inode_dio_end() before calling > > generic_write_sync(), so filesystems can lock i_rwsem during a sync. > > > > This matches the way it is done in fs/direct-io.c:dio_complete(). > > > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > Reviewed-by: Christoph Hellwig <hch@lst.de> > > Reviewed-by: Josef Bacik <josef@toxicpanda.com> > > Looks ok (at least with the fses that use either iomap or ye olde > directio) to me... > > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > So, uh, do you want me to pull these two iomap patches in for 5.10? That would be great, thanks. Once they land in 5.10-rc we'll be able to base the rest on some master snapshot and target 5.11 for release.
On Mon, Sep 28, 2020 at 05:04:19PM +0200, David Sterba wrote: > On Fri, Sep 25, 2020 at 06:51:08PM -0700, Darrick J. Wong wrote: > > On Thu, Sep 24, 2020 at 11:39:11AM -0500, Goldwyn Rodrigues wrote: > > > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > > > > iomap complete routine can deadlock with btrfs_fallocate because of the > > > call to generic_write_sync(). > > > > > > P0 P1 > > > inode_lock() fallocate(FALLOC_FL_ZERO_RANGE) > > > __iomap_dio_rw() inode_lock() > > > <block> > > > <submits IO> > > > <completes IO> > > > inode_unlock() > > > <gets inode_lock()> > > > inode_dio_wait() > > > iomap_dio_complete() > > > generic_write_sync() > > > btrfs_file_fsync() > > > inode_lock() > > > <deadlock> > > > > > > inode_dio_end() is used to notify the end of DIO data in order > > > to synchronize with truncate. Call inode_dio_end() before calling > > > generic_write_sync(), so filesystems can lock i_rwsem during a sync. > > > > > > This matches the way it is done in fs/direct-io.c:dio_complete(). > > > > > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > Reviewed-by: Christoph Hellwig <hch@lst.de> > > > Reviewed-by: Josef Bacik <josef@toxicpanda.com> > > > > Looks ok (at least with the fses that use either iomap or ye olde > > directio) to me... > > > > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > > > So, uh, do you want me to pull these two iomap patches in for 5.10? > > That would be great, thanks. Once they land in 5.10-rc we'll be able to > base the rest on some master snapshot and target 5.11 for release. Ok, done. :) --D
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index b88dbfe15118..0ea88ae57cb2 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -118,6 +118,7 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) dio_warn_stale_pagecache(iocb->ki_filp); } + inode_dio_end(file_inode(iocb->ki_filp)); /* * If this is a DSYNC write, make sure we push it to stable storage now * that we've written data. @@ -125,7 +126,6 @@ ssize_t iomap_dio_complete(struct iomap_dio *dio) if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) ret = generic_write_sync(iocb, ret); - inode_dio_end(file_inode(iocb->ki_filp)); kfree(dio); return ret;