Ruby

When writing to file in disk using File.open with a block as an argument, if the diskspace is full and IO.write does not flush right away, the block just exits successfully instead of throwing Errno:ENOSPC.

Setup: Drive partition needs to be full

Eg. of a write that will succeed normally with no exception given that the drive is full (this means that the expected failure is being swallowed)

File.open('/full_drive/test.txt','wb') do |file| file.write("test") end #This will complete normally because the "test" data does not get flushed #This will leave a 0kb file on the disk 

Eg. force a flush to see the error

File.open('/full_drive/test.txt','wb') do |file| file.write("test") file.flush end #This will throw Errno::ENOSPC #This will leave a 0kb file on the disk 

Eg. write a large enough data that file.write will flush by itself (most likely it hits the buffer cap)

fills = '1'*1048576 File.open('/full_drive/test.txt','wb') do |file| file.write(fills) end #This will throw Errno::ENOSPC #This will leave a 0kb file on the disk 

Eg. When not using File.open block argument and closing the IO with an ensure block

begin io = File.open('/full_drive/test.txt', 'wb') io.write("test") ensure io.close end #This will throw Errno::ENOSPC #This will leave a 0kb file on the disk 

Currently tested in RHEL5.

Notes:

• I've encountered this in ruby-1.9.2
• I've tested this with ruby-2.1.2
• I'm not sure if the issue is because of File.open usage of c-extension rb_ensure or io_close. reference: (http://ruby-doc.org/core-1.9.3/File.html#method-c-open)