[106/165] ext4: Fix possible lost inode write in no journal mode
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From: Greg KH on 30 Jul 2010 13:40 2.6.32-stable review patch. If anyone has any objections, please let us know. ------------------ commit 8b472d739b2ddd8ab7fb278874f696cd95b25a5e upstream (as of v2.6.34-rc6) In the no-journal case, ext4_write_inode() will fetch the bh and call sync_dirty_buffer() on it. However, if the bh has already been written and the bh reclaimed for some other purpose, AND if the inode is the only one in the inode table block in use, then ext4_get_inode_loc() will not read the inode table block from disk, but as an optimization, fill the block with zero's assuming that its caller will copy in the on-disk version of the inode. This is not done by ext4_write_inode(), so the contents of the inode can simply get lost. The fix is to use __ext4_get_inode_loc() with in_mem set to 0, instead of ext4_get_inode_loc(). Long term the API needs to be fixed so it's obvious why latter is not safe. Addresses-Google-Bug: #2526446 Signed-off-by: Curt Wohlgemuth <curtw(a)google.com> Signed-off-by: "Theodore Ts'o" <tytso(a)mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de> --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5260,7 +5260,7 @@ int ext4_write_inode(struct inode *inode } else { struct ext4_iloc iloc; - err = ext4_get_inode_loc(inode, &iloc); + err = __ext4_get_inode_loc(inode, &iloc, 0); if (err) return err; if (wait) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |