| Message ID | 1386670440-3158-2-git-send-email-jack@suse.cz |
|---|---|
| State | Accepted, archived |
| Headers | show |
Hi Jan, On Tue, Dec 10, 2013 at 11:13:58AM +0100, Jan Kara wrote: > Similarly as other ->write_begin functions in ext4, also > ext4_da_write_inline_data_begin() should retry allocation if the > conversion failed because of ENOSPC. This avoids returning ENOSPC > prematurely because of uncommitted block deletions. I don't see why we need to try again here. If there is no enough space in inline data, ext4_da_convert_inline_data_to_extent() just read the inline data into a page and clear EXT4_STATE_MAY_INLINE_DATA flag. If we try again, we will encounter an ENOSPC error again. So why do we need to retry allocation? Thanks, - Zheng > > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/ext4/inline.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c > index bae987549dc3..ed6e71fe5e9d 100644 > --- a/fs/ext4/inline.c > +++ b/fs/ext4/inline.c > @@ -849,11 +849,13 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > handle_t *handle; > struct page *page; > struct ext4_iloc iloc; > + int retries; > > ret = ext4_get_inode_loc(inode, &iloc); > if (ret) > return ret; > > +retry_journal: > handle = ext4_journal_start(inode, EXT4_HT_INODE, 1); > if (IS_ERR(handle)) { > ret = PTR_ERR(handle); > @@ -875,6 +877,11 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > inode, > flags, > fsdata); > + ext4_journal_stop(handle); > + handle = NULL; > + if (ret == -ENOSPC && > + ext4_should_retry_alloc(inode->i_sb, &retries)) > + goto retry_journal; > goto out; > } > > -- > 1.8.1.4 > > -- > 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 -- 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
On Thu 12-12-13 14:44:22, Zheng Liu wrote: > Hi Jan, > > On Tue, Dec 10, 2013 at 11:13:58AM +0100, Jan Kara wrote: > > Similarly as other ->write_begin functions in ext4, also > > ext4_da_write_inline_data_begin() should retry allocation if the > > conversion failed because of ENOSPC. This avoids returning ENOSPC > > prematurely because of uncommitted block deletions. > > I don't see why we need to try again here. If there is no enough space > in inline data, ext4_da_convert_inline_data_to_extent() just read the > inline data into a page and clear EXT4_STATE_MAY_INLINE_DATA flag. If > we try again, we will encounter an ENOSPC error again. So why do we > need to retry allocation? Umm, I don't think so. ext4_da_convert_inline_data_to_extent() calls ext4_da_get_block_prep() and that can falsely fail with ENOSPC if there are blocks freed in currently running transaction. So we call ext4_should_retry_alloc() which forces commit of the current transaction and then we retry the allocation. Honza > > > > Signed-off-by: Jan Kara <jack@suse.cz> > > --- > > fs/ext4/inline.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c > > index bae987549dc3..ed6e71fe5e9d 100644 > > --- a/fs/ext4/inline.c > > +++ b/fs/ext4/inline.c > > @@ -849,11 +849,13 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > > handle_t *handle; > > struct page *page; > > struct ext4_iloc iloc; > > + int retries; > > > > ret = ext4_get_inode_loc(inode, &iloc); > > if (ret) > > return ret; > > > > +retry_journal: > > handle = ext4_journal_start(inode, EXT4_HT_INODE, 1); > > if (IS_ERR(handle)) { > > ret = PTR_ERR(handle); > > @@ -875,6 +877,11 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > > inode, > > flags, > > fsdata); > > + ext4_journal_stop(handle); > > + handle = NULL; > > + if (ret == -ENOSPC && > > + ext4_should_retry_alloc(inode->i_sb, &retries)) > > + goto retry_journal; > > goto out; > > } > > > > -- > > 1.8.1.4 > > > > -- > > 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
On Thu, Dec 12, 2013 at 10:39:36AM +0100, Jan Kara wrote: > On Thu 12-12-13 14:44:22, Zheng Liu wrote: > > Hi Jan, > > > > On Tue, Dec 10, 2013 at 11:13:58AM +0100, Jan Kara wrote: > > > Similarly as other ->write_begin functions in ext4, also > > > ext4_da_write_inline_data_begin() should retry allocation if the > > > conversion failed because of ENOSPC. This avoids returning ENOSPC > > > prematurely because of uncommitted block deletions. > > > > I don't see why we need to try again here. If there is no enough space > > in inline data, ext4_da_convert_inline_data_to_extent() just read the > > inline data into a page and clear EXT4_STATE_MAY_INLINE_DATA flag. If > > we try again, we will encounter an ENOSPC error again. So why do we > > need to retry allocation? > Umm, I don't think so. ext4_da_convert_inline_data_to_extent() calls > ext4_da_get_block_prep() and that can falsely fail with ENOSPC if there are > blocks freed in currently running transaction. So we call > ext4_should_retry_alloc() which forces commit of the current transaction > and then we retry the allocation. Ah, I see. Thanks for your explanation. - Zheng > > Honza > > > > > > > Signed-off-by: Jan Kara <jack@suse.cz> > > > --- > > > fs/ext4/inline.c | 7 +++++++ > > > 1 file changed, 7 insertions(+) > > > > > > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c > > > index bae987549dc3..ed6e71fe5e9d 100644 > > > --- a/fs/ext4/inline.c > > > +++ b/fs/ext4/inline.c > > > @@ -849,11 +849,13 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > > > handle_t *handle; > > > struct page *page; > > > struct ext4_iloc iloc; > > > + int retries; > > > > > > ret = ext4_get_inode_loc(inode, &iloc); > > > if (ret) > > > return ret; > > > > > > +retry_journal: > > > handle = ext4_journal_start(inode, EXT4_HT_INODE, 1); > > > if (IS_ERR(handle)) { > > > ret = PTR_ERR(handle); > > > @@ -875,6 +877,11 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, > > > inode, > > > flags, > > > fsdata); > > > + ext4_journal_stop(handle); > > > + handle = NULL; > > > + if (ret == -ENOSPC && > > > + ext4_should_retry_alloc(inode->i_sb, &retries)) > > > + goto retry_journal; > > > goto out; > > > } > > > > > > -- > > > 1.8.1.4 > > > > > > -- > > > 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 > -- > Jan Kara <jack@suse.cz> > SUSE Labs, CR -- 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
On Tue, Dec 10, 2013 at 11:13:58AM +0100, Jan Kara wrote: > Similarly as other ->write_begin functions in ext4, also > ext4_da_write_inline_data_begin() should retry allocation if the > conversion failed because of ENOSPC. This avoids returning ENOSPC > prematurely because of uncommitted block deletions. > > Signed-off-by: Jan Kara <jack@suse.cz> Thanks, applied. - Ted -- 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/inline.c b/fs/ext4/inline.c index bae987549dc3..ed6e71fe5e9d 100644 --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -849,11 +849,13 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, handle_t *handle; struct page *page; struct ext4_iloc iloc; + int retries; ret = ext4_get_inode_loc(inode, &iloc); if (ret) return ret; +retry_journal: handle = ext4_journal_start(inode, EXT4_HT_INODE, 1); if (IS_ERR(handle)) { ret = PTR_ERR(handle); @@ -875,6 +877,11 @@ int ext4_da_write_inline_data_begin(struct address_space *mapping, inode, flags, fsdata); + ext4_journal_stop(handle); + handle = NULL; + if (ret == -ENOSPC && + ext4_should_retry_alloc(inode->i_sb, &retries)) + goto retry_journal; goto out; }
Similarly as other ->write_begin functions in ext4, also ext4_da_write_inline_data_begin() should retry allocation if the conversion failed because of ENOSPC. This avoids returning ENOSPC prematurely because of uncommitted block deletions. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/ext4/inline.c | 7 +++++++ 1 file changed, 7 insertions(+)