Message ID | 20240503032329.2392931-7-viro@zeniv.linux.org.uk (mailing list archive) |
---|---|
State | New |
Headers | show |
Series | [v2,1/9] bcache_register(): don't bother with set_blocksize() | expand |
On Fri, May 03, 2024 at 04:23:27AM +0100, Al Viro wrote: > btrfs_get_bdev_and_sb() has two callers - btrfs_open_one_device(), > which asks for open to be exclusive and btrfs_get_dev_args_from_path(), > which doesn't. Currently it does set_blocksize() in all cases. > > I'm rather dubious about the need to do set_blocksize() anywhere in btrfs, > to be honest - there's some access to page cache of underlying block > devices in there, but it's nowhere near the hot paths, AFAICT. > > In any case, btrfs_get_dev_args_from_path() only needs to read > the on-disk superblock and copy several fields out of it; all > callers are only interested in devices that are already opened > and brought into per-filesystem set, so setting the block size > is redundant for those and actively harmful if we are given > a pathname of unrelated device. > > So we only need btrfs_get_bdev_and_sb() to call set_blocksize() > when it's asked to open exclusive. > > Reviewed-by: Christoph Hellwig <hch@lst.de> > Reviewed-by: Christian Brauner <brauner@kernel.org> > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index f15591f3e54f..43af5a9fb547 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -482,10 +482,12 @@ btrfs_get_bdev_and_sb(const char *device_path, blk_mode_t flags, void *holder, if (flush) sync_blockdev(bdev); - ret = set_blocksize(bdev, BTRFS_BDEV_BLOCKSIZE); - if (ret) { - fput(*bdev_file); - goto error; + if (holder) { + ret = set_blocksize(bdev, BTRFS_BDEV_BLOCKSIZE); + if (ret) { + fput(*bdev_file); + goto error; + } } invalidate_bdev(bdev); *disk_super = btrfs_read_dev_super(bdev); @@ -498,6 +500,7 @@ btrfs_get_bdev_and_sb(const char *device_path, blk_mode_t flags, void *holder, return 0; error: + *disk_super = NULL; *bdev_file = NULL; return ret; }