From: Theodore Ts'o <tytso@mit.edu>
Date: Sun, 27 Feb 2011 21:43:24 +0000 (-0500)
Subject: ext4: don't leave PageWriteback set after memory failure
X-Git-Tag: v2.6.39-rc1~73^2~20
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a54aa76108619e5d8290b49081c2aaaeff5be9a2;p=pandora-kernel.git

ext4: don't leave PageWriteback set after memory failure

In ext4_bio_write_page(), if the memory allocation for the struct
ext4_io_page fails, it returns with the page's PageWriteback flag set.
This will end up causing the page not to skip writeback in
WB_SYNC_NONE mode, and in WB_SYNC_ALL mode (i.e., on a sync, fsync, or
umount) the writeback daemon will get stuck forever on the
wait_on_page_writeback() function in write_cache_pages_da().

Or, if journalling is enabled and the file gets deleted, it the
journal thread can get stuck in journal_finish_inode_data_buffers()
call to filemap_fdatawait().

Another place where things can get hung up is in
truncate_inode_pages(), called out of ext4_evict_inode().

Fix this by not setting PageWriteback until after we have successfully
allocated the struct ext4_io_page.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
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