| Message ID | 874olytbpe.fsf@openvz.org |
|---|---|
| State | Rejected, archived |
| Headers | show |
On Wed, 03 Feb 2010 21:27:31 +0300, Dmitry Monakhov <dmonakhov@openvz.org> wrote: > > Some times we call ->write_begin() with opened journal > but write_begin() may internally call ext4_should_retry_alloc() > in case of ENOSPC, which result in deadlock. > This patch introduce new AOP_FLAG which should be tested on retry > alloc path. > Can you explain this further. We do a journal_stop before ext4_should_retry_alloc. So not sure about the deadlock. -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
"Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com> writes: > On Wed, 03 Feb 2010 21:27:31 +0300, Dmitry Monakhov <dmonakhov@openvz.org> wrote: >> >> Some times we call ->write_begin() with opened journal >> but write_begin() may internally call ext4_should_retry_alloc() >> in case of ENOSPC, which result in deadlock. >> This patch introduce new AOP_FLAG which should be tested on retry >> alloc path. >> > > Can you explain this further. We do a journal_stop before > ext4_should_retry_alloc. So not sure about the deadlock. move_extent_per_page ext4_journal_start -> current->journal_info != NULL ->write_begin ext4_journal_start ext4_journal_stop ext4_should_retry_alloc : here current->journal_info != NULL Sorry i've missed the fact that ext4_should_retry_alloc() check for current->journal_info and skip running transaction in that case. Seems what this check was added long time ago, but i miss it. So this patch is useless. > > -aneesh -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index af7b626..0efb224 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -792,6 +792,11 @@ struct ext4_inode_info { #define EXT4_DFL_CHECKINTERVAL 0 /* Don't use interval check */ /* + * Address space flags. + */ +#define EXT4_AOP_FLAG_NORETRY AOP_FLAG_LAST /* Do not allow to fail in to + retry alloc loop */ +/* * Behaviour when detecting errors */ #define EXT4_ERRORS_CONTINUE 1 /* Continue execution */ diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c818972..2d3fe4d 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -1593,7 +1593,8 @@ retry: } } - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + if (!(flags & EXT4_AOP_FLAG_NORETRY) && ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; @@ -3089,7 +3090,8 @@ retry: ext4_truncate_failed_write(inode); } - if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) + if (!(flags & EXT4_AOP_FLAG_NORETRY) && + ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 82c415b..f894382 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -796,7 +796,7 @@ move_extent_per_page(struct file *o_filp, struct inode *donor_inode, ext4_lblk_t orig_blk_offset; long long offs = orig_page_offset << PAGE_CACHE_SHIFT; unsigned long blocksize = orig_inode->i_sb->s_blocksize; - unsigned int w_flags = 0; + unsigned int w_flags = EXT4_AOP_FLAG_NORETRY; unsigned int tmp_data_size, data_size, replaced_size; void *fsdata; int i, jblocks; diff --git a/include/linux/fs.h b/include/linux/fs.h index b1bcb27..6f68707 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -504,6 +504,7 @@ enum positive_aop_returns { #define AOP_FLAG_NOFS 0x0004 /* used by filesystem to direct * helper code (eg buffer layer) * to clear GFP_FS from alloc */ +#define AOP_FLAG_LAST 0x0008 /* First unused private flag */ /* * oh the beauties of C type declarations.
Some times we call ->write_begin() with opened journal but write_begin() may internally call ext4_should_retry_alloc() in case of ENOSPC, which result in deadlock. This patch introduce new AOP_FLAG which should be tested on retry alloc path. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> --- fs/ext4/ext4.h | 5 +++++ fs/ext4/inode.c | 6 ++++-- fs/ext4/move_extent.c | 2 +- include/linux/fs.h | 1 + 4 files changed, 11 insertions(+), 3 deletions(-)