From d8eb6cf4482087f473101e32ef02aba5180093ec Mon Sep 17 00:00:00 2001
From: Steve Slaven <bpk@hoopajoo.net>
Date: Tue, 28 Jul 2009 14:19:04 -0700
Subject: This is a workaround for a bug with lseek causing a getattr instead
 of fgetattr on an already opened file, so it reports the wrong file size if
 you use seek_end for whence by reading the on-disk info instead of the
 open-file info


diff --git a/fusearchive.py b/fusearchive.py
index a0cdb18..f3567aa 100755
--- a/fusearchive.py
+++ b/fusearchive.py
@@ -46,6 +46,14 @@ dirty_size = 1024 * 1024 * 1;
 # This is the number of actualy blocks in that size
 dirty_flush = int( dirty_size / magic_blocksize )
 
+# This is a cache of open files by inode, to fix the lseek == size problem
+# this causes a failure in fsx-linux becuase to to lseek(fd,0,seek_end) it
+# apparently does a getattr to find the file length then subtracts the
+# offset from that to pass to write or whatever, since the offset is passed
+# to write and we don't maintain one internally.  xmp.py also fails this
+# test.
+dirty_cache = {}
+
 def flag2mode(flags):
     md = {os.O_RDONLY: 'r', os.O_WRONLY: 'w', os.O_RDWR: 'w+'}
     m = md[flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR)]
@@ -344,11 +352,19 @@ class FuseArchive(Fuse):
         treefile = "./tree" + path
 
         if os.path.isfile( treefile ):
-            logging.debug( "Delegating getattr to FuserArchiveFile" )
-
-            f = self.FuseArchiveFile( path, os.O_RDONLY, 0 )
-            stats = f.fgetattr()
-            f.release( 0 )
+            logging.debug( "Delegating getattr to FuserArchiveFile for " + path )
+
+            # Check in the dirty cache first (to handle lseek and the
+            # relatively broken implmentation in fuse/python)
+            if path in dirty_cache:
+                logging.info( "WORKAROUND: lseek appears to do a gettattr if whence is SEEK_END, using dirty cache object" )
+                f = dirty_cache[ path ]
+                stats = f.fgetattr()
+                # no release, it's still being used
+            else:
+                f = self.FuseArchiveFile( path, os.O_RDONLY, 0 )
+                stats = f.fgetattr()
+                f.release( 0 )
         else:
             logging.debug( "Using os.lstat to get stats" )
             stats = os.lstat( treefile )
@@ -725,6 +741,10 @@ class FuseArchive(Fuse):
 
             logging.debug( "Chunk size is now: " + str(len(self.chunk)) )
             logging.debug( "File size is now: " + str(self.size) )
+
+            # Mark us in the dirty cache
+            dirty_cache[ self.orig_path ] = self
+
             return len(buf)
 
         # BUG: If you cp -a a file then quickly ls -l sometimes it doesn't show
@@ -766,6 +786,10 @@ class FuseArchive(Fuse):
                     'chunk_size': self.chunk_size
                 } )
 
+                # Not dirty anymore
+                if self.orig_path in dirty_cache:
+                    del dirty_cache[ self.orig_path ]
+
 
             logging.debug( "_fflush exit" )
             return 1
@@ -854,6 +878,7 @@ class FuseArchive(Fuse):
             self.modified = True
             self.size = length
             self._load_chunk( 0 )
+            # Don't need to mark dirty cache because we're flushing
             self._fflush()
 
         def lock(self, cmd, owner, **kw):
-- 
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