On Fri, Sep 5, 2014 at 11:30 AM, Theodore Ts'o <tytso@xxxxxxx> wrote: > 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. Yeah, you are right. The problem happened when the project ID was saved as xattr. And I can't reproduce the same problem with the new patches. > > 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.) > Great! Please ignore this patch since it won't be a problem any more. Regards, - Li Xi -- 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
