btrfs: enhance compression error messages

Add more verbose and specific messages to all main error points in
compression code for all algorithms. Currently there's no way to know
which inode is affected or where in the data errors happened.

The messages follow a common format:

- what happened
- error code if relevant
- root and inode
- additional data like offsets or lengths

There's no helper for the messages as they differ in some details and
that would be cumbersome to generalize to a single function. As all the
errors are "almost never happens" there are the unlikely annotations
done as compression is hot path.

Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 43 insertions, 13 deletions

diff --git a/fs/btrfs/zlib.c b/fs/btrfs/zlib.c
index d9e5c88a0f85..30971dd741e2 100644
--- a/fs/btrfs/zlib.c
+++ b/fs/btrfs/zlib.c
@@ -18,6 +18,7 @@
 #include <linux/pagemap.h>
 #include <linux/bio.h>
 #include <linux/refcount.h>
+#include "btrfs_inode.h"
 #include "compression.h"
 
 /* workspace buffer size for s390 zlib hardware support */
@@ -112,8 +113,13 @@ int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
 	*total_out = 0;
 	*total_in = 0;
 
-	if (Z_OK != zlib_deflateInit(&workspace->strm, workspace->level)) {
-		pr_warn("BTRFS: deflateInit failed\n");
+	ret = zlib_deflateInit(&workspace->strm, workspace->level);
+	if (unlikely(ret != Z_OK)) {
+		struct btrfs_inode *inode = BTRFS_I(mapping->host);
+
+		btrfs_err(inode->root->fs_info,
+	"zlib compression init failed, error %d root %llu inode %llu offset %llu",
+			  ret, btrfs_root_id(inode->root), btrfs_ino(inode), start);
 		ret = -EIO;
 		goto out;
 	}
@@ -182,9 +188,13 @@ int zlib_compress_folios(struct list_head *ws, struct address_space *mapping,
 		}
 
 		ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH);
-		if (ret != Z_OK) {
-			pr_debug("BTRFS: deflate in loop returned %d\n",
-			       ret);
+		if (unlikely(ret != Z_OK)) {
+			struct btrfs_inode *inode = BTRFS_I(mapping->host);
+
+			btrfs_warn(inode->root->fs_info,
+		"zlib compression failed, error %d root %llu inode %llu offset %llu",
+				   ret, btrfs_root_id(inode->root), btrfs_ino(inode),
+				   start);
 			zlib_deflateEnd(&workspace->strm);
 			ret = -EIO;
 			goto out;
@@ -307,9 +317,14 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 		workspace->strm.avail_in -= 2;
 	}
 
-	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
-		pr_warn("BTRFS: inflateInit failed\n");
+	ret = zlib_inflateInit2(&workspace->strm, wbits);
+	if (unlikely(ret != Z_OK)) {
+		struct btrfs_inode *inode = cb->bbio.inode;
+
 		kunmap_local(data_in);
+		btrfs_err(inode->root->fs_info,
+	"zlib decompression init failed, error %d root %llu inode %llu offset %llu",
+			  ret, btrfs_root_id(inode->root), btrfs_ino(inode), cb->start);
 		return -EIO;
 	}
 	while (workspace->strm.total_in < srclen) {
@@ -348,10 +363,15 @@ int zlib_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
 			workspace->strm.avail_in = min(tmp, PAGE_SIZE);
 		}
 	}
-	if (ret != Z_STREAM_END)
+	if (unlikely(ret != Z_STREAM_END)) {
+		btrfs_err(cb->bbio.inode->root->fs_info,
+		"zlib decompression failed, error %d root %llu inode %llu offset %llu",
+			  ret, btrfs_root_id(cb->bbio.inode->root),
+			  btrfs_ino(cb->bbio.inode), cb->start);
 		ret = -EIO;
-	else
+	} else {
 		ret = 0;
+	}
 done:
 	zlib_inflateEnd(&workspace->strm);
 	if (data_in)
@@ -386,8 +406,14 @@ int zlib_decompress(struct list_head *ws, const u8 *data_in,
 		workspace->strm.avail_in -= 2;
 	}
 
-	if (Z_OK != zlib_inflateInit2(&workspace->strm, wbits)) {
-		pr_warn("BTRFS: inflateInit failed\n");
+	ret = zlib_inflateInit2(&workspace->strm, wbits);
+	if (unlikely(ret != Z_OK)) {
+		struct btrfs_inode *inode = BTRFS_I(dest_page->mapping->host);
+
+		btrfs_err(inode->root->fs_info,
+		"zlib decompression init failed, error %d root %llu inode %llu offset %llu",
+			  ret, btrfs_root_id(inode->root), btrfs_ino(inode),
+			  page_offset(dest_page));
 		return -EIO;
 	}
 
@@ -404,8 +430,12 @@ int zlib_decompress(struct list_head *ws, const u8 *data_in,
 
 out:
 	if (unlikely(to_copy != destlen)) {
-		pr_warn_ratelimited("BTRFS: inflate failed, decompressed=%lu expected=%zu\n",
-					to_copy, destlen);
+		struct btrfs_inode *inode = BTRFS_I(dest_page->mapping->host);
+
+		btrfs_err(inode->root->fs_info,
+"zlib decompression failed, error %d root %llu inode %llu offset %llu decompressed %lu expected %zu",
+			  ret, btrfs_root_id(inode->root), btrfs_ino(inode),
+			  page_offset(dest_page), to_copy, destlen);
 		ret = -EIO;
 	} else {
 		ret = 0;