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authorDavid Sterba <dsterba@suse.com>2016-04-27 03:07:39 +0200
committerDavid Sterba <dsterba@suse.com>2016-05-10 09:46:16 +0200
commit523567168da04bae0f88802ddef49d00072c5d58 (patch)
tree9e5341242e6becf6a81a0bdea5ac080b3f1797a3 /fs/btrfs/compression.c
parente721e49dd1681d45d71919f0561f5e978a34153c (diff)
downloadlinux-523567168da04bae0f88802ddef49d00072c5d58.tar.gz
btrfs: make find_workspace warn if there are no workspaces
Be verbose if there are no workspaces at all, ie. the module init time
preallocation failed.

Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/compression.c')
-rw-r--r--fs/btrfs/compression.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index c70625560265..658c39b70fba 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -834,7 +834,21 @@ again:
 		 * workspace preallocated for each type and the compression
 		 * time is bounded so we get to a workspace eventually. This
 		 * makes our caller's life easier.
+		 *
+		 * To prevent silent and low-probability deadlocks (when the
+		 * initial preallocation fails), check if there are any
+		 * workspaces at all.
 		 */
+		if (atomic_read(total_ws) == 0) {
+			static DEFINE_RATELIMIT_STATE(_rs,
+					/* once per minute */ 60 * HZ,
+					/* no burst */ 1);
+
+			if (__ratelimit(&_rs)) {
+				printk(KERN_WARNING
+			    "no compression workspaces, low memory, retrying");
+			}
+		}
 		goto again;
 	}
 	return workspace;