On Fri, Sep 05, 2014 at 10:29:16AM +0800, Li Xi wrote: > On Fri, Sep 5, 2014 at 9:59 AM, Theodore Ts'o <tytso@xxxxxxx> wrote: > > On Thu, Sep 04, 2014 at 04:49:58PM +0800, Li Xi wrote: > >> There are multiple places where ext4_mark_inode_dirty() is called holding > >> write lock of EXT4_I(inode)->i_data_sem. However, if > >> ext4_mark_inode_dirty() needs to expand inode size, this will cause > >> deadlock when ext4_xattr_block_set() tries to get read lock of > >> EXT4_I(inode)->i_data_sem. > > > > This was with inline data enabled, right? > I hit this problem when starting a kernel with project quota support for ext4. > The ext4 file system was not formated with project quota feature so it tried > to extend the space for project ID. And this problem happened every time > when the kernel was rebooted. Inline data was not enable on that file > system. I am not sure whether this problem will happen under other > circumstances. :) I'm not understanding why expanding the inode size would result in needing to call ext4_xattr_block_set. Was that becuse you were storing the project quota in the xattr? I'm just trying to understand the context. Please also note that a recent set of patches (sent to the ext4 list and in the ext4 git tree) has removed the need for taking i_data_sem in xattr.c: http://patchwork.ozlabs.org/patch/385347 http://patchwork.ozlabs.org/patch/385348 http://patchwork.ozlabs.org/patch/385346 (It's the 2/3 patch that removes taking i_data_sem read lock in xattr.c.) Regards, - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
