1 files changed, 22 insertions, 6 deletions

diff --git a/fs/ubifs/journal.c b/fs/ubifs/journal.c
index 914f1bd89e57..aed25e864227 100644
--- a/fs/ubifs/journal.c
+++ b/fs/ubifs/journal.c
@@ -690,7 +690,7 @@ int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
 {
         struct ubifs_data_node *data;
         int err, lnum, offs, compr_type, out_len;
-        int dlen = UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE * WORST_COMPR_FACTOR;
+        int dlen = COMPRESSED_DATA_NODE_BUF_SZ, allocated = 1;
         struct ubifs_inode *ui = ubifs_inode(inode);
 
         dbg_jnl("ino %lu, blk %u, len %d, key %s",
@@ -698,9 +698,19 @@ int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
                 DBGKEY(key));
         ubifs_assert(len <= UBIFS_BLOCK_SIZE);
 
-        data = kmalloc(dlen, GFP_NOFS);
-        if (!data)
-                return -ENOMEM;
+        data = kmalloc(dlen, GFP_NOFS | __GFP_NOWARN);
+        if (!data) {
+                /*
+                 * Fall-back to the write reserve buffer. Note, we might be
+                 * currently on the memory reclaim path, when the kernel is
+                 * trying to free some memory by writing out dirty pages. The
+                 * write reserve buffer helps us to guarantee that we are
+                 * always able to write the data.
+                 */
+                allocated = 0;
+                mutex_lock(&c->write_reserve_mutex);
+                data = c->write_reserve_buf;
+        }
 
         data->ch.node_type = UBIFS_DATA_NODE;
         key_write(c, key, &data->key);
@@ -736,7 +746,10 @@ int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
                 goto out_ro;
 
         finish_reservation(c);
-        kfree(data);
+        if (!allocated)
+                mutex_unlock(&c->write_reserve_mutex);
+        else
+                kfree(data);
         return 0;
 
 out_release:
@@ -745,7 +758,10 @@ out_ro:
         ubifs_ro_mode(c, err);
         finish_reservation(c);
 out_free:
-        kfree(data);
+        if (!allocated)
+                mutex_unlock(&c->write_reserve_mutex);
+        else
+                kfree(data);
         return err;
 }