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FAILED: patch "[PATCH] btrfs: do not allow compression on nodatacow files" failed to apply to 5.15-stable tree

PATCH [email protected] 1 participant 1 message May 9, 2022

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The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0e852ab8974cd2b5946766b2d9baf82c78ace03d Mon Sep 17 00:00:00 2001
From: Chung-Chiang Cheng <[email protected]>
Date: Fri, 15 Apr 2022 16:04:06 +0800
Subject: [PATCH] btrfs: do not allow compression on nodatacow files

Compression and nodatacow are mutually exclusive. A similar issue was fixed by commit f37c563bab429 ("btrfs: add missing check for nocow and compression inode flags"). Besides ioctl, there is another way to enable/disable/reset compression directly via xattr. The following steps will result in a invalid combination.

  $ touch bar
  $ chattr +C bar
  $ lsattr bar
  ---------------C-- bar
  $ setfattr -n btrfs.compression -v zstd bar
  $ lsattr bar
  --------c------C-- bar

To align with the logic in check_fsflags, nocompress will also be unacceptable after this patch, to prevent mix any compression-related options with nodatacow.

  $ touch bar
  $ chattr +C bar
  $ lsattr bar
  ---------------C-- bar
  $ setfattr -n btrfs.compression -v zstd bar
  setfattr: bar: Invalid argument
  $ setfattr -n btrfs.compression -v no bar
  setfattr: bar: Invalid argument

When both compression and nodatacow are enabled, then btrfs_run_delalloc_range prefers nodatacow and no compression happens.

Reported-by Jayce Lin <[email protected]>
CC [email protected] # 5.10.x: e6f9d6964802: btrfs: export a helper for compression hard check
CC [email protected] # 5.10.x
Reviewed-by Filipe Manana <[email protected]>
Signed-off-by Chung-Chiang Cheng <[email protected]>
Reviewed-by David Sterba <[email protected]>
Signed-off-by David Sterba <[email protected]>
fs/btrfs/props.c +11 -5
index 1a6d2d5b4b33..5a6f87744c28 100644
@@ -17,7 +17,8 @@ static DEFINE_HASHTABLE(prop_handlers_ht, BTRFS_PROP_HANDLERS_HT_BITS);
 struct prop_handler {
 	struct hlist_node node;
 	const char *xattr_name;
-	int (*validate)(const char *value, size_t len);
+	int (*validate)(const struct btrfs_inode *inode, const char *value,
+			size_t len);
 	int (*apply)(struct inode *inode, const char *value, size_t len);
 	const char *(*extract)(struct inode *inode);
 	int inheritable;

@@ -55,7 +56,8 @@ find_prop_handler(const char *name,
 	return NULL;
 }
 
-int btrfs_validate_prop(const char *name, const char *value, size_t value_len)
+int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
+			const char *value, size_t value_len)
 {
 	const struct prop_handler *handler;
 

@@ -69,7 +71,7 @@ int btrfs_validate_prop(const char *name, const char *value, size_t value_len)
 	if (value_len == 0)
 		return 0;
 
-	return handler->validate(value, value_len);
+	return handler->validate(inode, value, value_len);
 }
 
 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,

@@ -252,8 +254,12 @@ int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path)
 	return ret;
 }
 
-static int prop_compression_validate(const char *value, size_t len)
+static int prop_compression_validate(const struct btrfs_inode *inode,
+				     const char *value, size_t len)
 {
+	if (!btrfs_inode_can_compress(inode))
+		return -EINVAL;
+
 	if (!value)
 		return 0;
 

@@ -364,7 +370,7 @@ static int inherit_props(struct btrfs_trans_handle *trans,
 		 * This is not strictly necessary as the property should be
 		 * valid, but in case it isn't, don't propagate it further.
 		 */
-		ret = h->validate(value, strlen(value));
+		ret = h->validate(BTRFS_I(inode), value, strlen(value));
 		if (ret)
 			continue;
fs/btrfs/props.h +2 -1
index 40b2c65b518c..2b2ac15ab788 100644
@@ -13,7 +13,8 @@ void __init btrfs_props_init(void);
 int btrfs_set_prop(struct btrfs_trans_handle *trans, struct inode *inode,
 		   const char *name, const char *value, size_t value_len,
 		   int flags);
-int btrfs_validate_prop(const char *name, const char *value, size_t value_len);
+int btrfs_validate_prop(const struct btrfs_inode *inode, const char *name,
+			const char *value, size_t value_len);
 
 int btrfs_load_inode_props(struct inode *inode, struct btrfs_path *path);
fs/btrfs/xattr.c +1 -1
index 99abf41b89b9..9632d0ff2038 100644
@@ -403,7 +403,7 @@ static int btrfs_xattr_handler_set_prop(const struct xattr_handler *handler,
 	struct btrfs_root *root = BTRFS_I(inode)->root;
 
 	name = xattr_full_name(handler, name);
-	ret = btrfs_validate_prop(name, value, size);
+	ret = btrfs_validate_prop(BTRFS_I(inode), name, value, size);
 	if (ret)
 		return ret;