| Message ID | 6a5d4240e53b55381d3049f6051d10323d356e95.1725955565.git.wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | btrfs: make extent_range_clear_diryt_for_io() to handle sector size < page size cases | expand |
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index edac499fd83d..d53b9e4ca13e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -902,7 +902,8 @@ static int extent_range_clear_dirty_for_io(struct inode *inode, u64 start, u64 e ret = PTR_ERR(folio); continue; } - folio_clear_dirty_for_io(folio); + btrfs_folio_clamp_clear_dirty(inode_to_fs_info(inode), folio, start, + end + 1 - start); folio_put(folio); } return ret;
For btrfs with sector size < page size (e.g. 4K sector size, 64K page size), and enable the sector perfect compression support, then the following dirty range can lead to problems: 0 32K 64K 96K 128K | |///////||//////| |/| 124K In above case, if we start writeback for that inode, the last dirty range [124K, 128K) will not be submitted and cause reserved space leakage: - Start writeback for page 0 We find the range [32K, 96K) is suitable for compression, and queue it into a workqueue to do the delayed compression and submission. - Compression happens for range [32K, 96K) Function extent_range_clear_diryt_for_io() is called, however it is only doing full page handling, not considering any the extra bitmaps for subpage cases. That function will clear page dirty for both page 0 and page 64K. - Writeback for the inode is done Because page 64K has its dirty flag cleared, it will not be considered as a writeback target. This means the range [124K, 128K) will not be submitted, and reserved space for it will be leaked. Fix this problem by using the subpage helper to clear the dirty flag. Signed-off-by: Qu Wenruo <wqu@suse.com> --- The previous version seems to causing a hang, but it looks very possible that's caused by the double page freeing at the same kernel window. With that double page freeing fix, I haven't hit any lockup on subpage cases with this patch applied anymore. --- fs/btrfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)