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Wong" Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 03/10] iomap: move locking out of iomap_write_delalloc_release Date: Mon, 23 Sep 2024 17:28:17 +0200 Message-ID: <20240923152904.1747117-4-hch@lst.de> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240923152904.1747117-1-hch@lst.de> References: <20240923152904.1747117-1-hch@lst.de> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html XFS (which currently is the only user of iomap_write_delalloc_release) already holds invalidate_lock for most zeroing operations. To be able to avoid a deadlock it needs to stop taking the lock, but doing so in iomap would leak XFS locking details into iomap. To avoid this require the caller to hold invalidate_lock when calling iomap_write_delalloc_release instead of taking it there. Signed-off-by: Christoph Hellwig Reviewed-by: Darrick J. Wong --- fs/iomap/buffered-io.c | 17 ++++++++--------- fs/xfs/xfs_iomap.c | 2 ++ 2 files changed, 10 insertions(+), 9 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 237aeb883166df..232aaa1e86451a 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1211,12 +1211,13 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, loff_t scan_end_byte = min(i_size_read(inode), end_byte); /* - * Lock the mapping to avoid races with page faults re-instantiating - * folios and dirtying them via ->page_mkwrite whilst we walk the - * cache and perform delalloc extent removal. Failing to do this can - * leave dirty pages with no space reservation in the cache. + * The caller must hold invalidate_lock to avoid races with page faults + * re-instantiating folios and dirtying them via ->page_mkwrite whilst + * we walk the cache and perform delalloc extent removal. Failing to do + * this can leave dirty pages with no space reservation in the cache. */ - filemap_invalidate_lock(inode->i_mapping); + lockdep_assert_held_write(&inode->i_mapping->invalidate_lock); + while (start_byte < scan_end_byte) { loff_t data_end; @@ -1233,7 +1234,7 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, if (start_byte == -ENXIO || start_byte == scan_end_byte) break; if (WARN_ON_ONCE(start_byte < 0)) - goto out_unlock; + return; WARN_ON_ONCE(start_byte < punch_start_byte); WARN_ON_ONCE(start_byte > scan_end_byte); @@ -1244,7 +1245,7 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, data_end = mapping_seek_hole_data(inode->i_mapping, start_byte, scan_end_byte, SEEK_HOLE); if (WARN_ON_ONCE(data_end < 0)) - goto out_unlock; + return; /* * If we race with post-direct I/O invalidation of the page cache, @@ -1266,8 +1267,6 @@ void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, if (punch_start_byte < end_byte) punch(inode, punch_start_byte, end_byte - punch_start_byte, iomap); -out_unlock: - filemap_invalidate_unlock(inode->i_mapping); } EXPORT_SYMBOL_GPL(iomap_write_delalloc_release); diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index 30f2530b6d5461..01324da63fcfc7 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -1239,8 +1239,10 @@ xfs_buffered_write_iomap_end( if (start_byte >= end_byte) return 0; + filemap_invalidate_lock(inode->i_mapping); iomap_write_delalloc_release(inode, start_byte, end_byte, flags, iomap, xfs_buffered_write_delalloc_punch); + filemap_invalidate_unlock(inode->i_mapping); return 0; }