From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joel Becker Date: Thu Sep 20 11:22:56 2007 Subject: [Ocfs2-devel] [PATCH 01/15] ocfs2: move nonsparse hole-filling into ocfs2_write_begin() In-Reply-To: <200709192012.l8JKCFfG012138@agmgw2.us.oracle.com> References: <200709192012.l8JKCFfG012138@agmgw2.us.oracle.com> Message-ID: <20070920182219.GD30391@tasint.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com On Tue, Aug 28, 2007 at 05:13:23PM -0700, Mark Fasheh wrote: > By doing this, we can remove any higher level logic which has to have > knowledge of btree functionality - any callers of ocfs2_write_begin() can > now expect it to do anything necessary to prepare the inode for new data. I like the way extend_file gains smarts - it knows what it's doing. I also like the clean comments about how we prevent cluster and local concurrent access. Signed-off-by: Joel Becker > > Signed-off-by: Mark Fasheh > --- > fs/ocfs2/aops.c | 40 +++++++++- > fs/ocfs2/file.c | 217 ++++++++++++++++++++----------------------------------- > fs/ocfs2/file.h | 2 + > 3 files changed, 115 insertions(+), 144 deletions(-) > > diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c > index 460d440..97394c5 100644 > --- a/fs/ocfs2/aops.c > +++ b/fs/ocfs2/aops.c > @@ -301,12 +301,8 @@ int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page, > { > int ret; > > - down_read(&OCFS2_I(inode)->ip_alloc_sem); > - > ret = block_prepare_write(page, from, to, ocfs2_get_block); > > - up_read(&OCFS2_I(inode)->ip_alloc_sem); > - > return ret; > } > > @@ -1353,6 +1349,36 @@ out: > return ret; > } > > +/* > + * This function only does anything for file systems which can't > + * handle sparse files. > + * > + * What we want to do here is fill in any hole between the current end > + * of allocation and the end of our write. That way the rest of the > + * write path can treat it as an non-allocating write, which has no > + * special case code for sparse/nonsparse files. > + */ > +static int ocfs2_expand_nonsparse_inode(struct inode *inode, loff_t pos, > + unsigned len, > + struct ocfs2_write_ctxt *wc) > +{ > + int ret; > + struct ocfs2_super *osb = OCFS2_SB(inode->i_sb); > + loff_t newsize = pos + len; > + > + if (ocfs2_sparse_alloc(osb)) > + return 0; > + > + if (newsize <= i_size_read(inode)) > + return 0; > + > + ret = ocfs2_extend_no_holes(inode, newsize, newsize - len); > + if (ret) > + mlog_errno(ret); > + > + return ret; > +} > + > int ocfs2_write_begin_nolock(struct address_space *mapping, > loff_t pos, unsigned len, unsigned flags, > struct page **pagep, void **fsdata, > @@ -1374,6 +1400,12 @@ int ocfs2_write_begin_nolock(struct address_space *mapping, > return ret; > } > > + ret = ocfs2_expand_nonsparse_inode(inode, pos, len, wc); > + if (ret) { > + mlog_errno(ret); > + goto out; > + } > + > ret = ocfs2_populate_write_desc(inode, wc, &clusters_to_alloc, > &extents_to_split); > if (ret) { > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > index 4ffa715..429ebcb 100644 > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -780,25 +780,6 @@ leave: > return status; > } > > -static int ocfs2_extend_allocation(struct inode *inode, u32 logical_start, > - u32 clusters_to_add, int mark_unwritten) > -{ > - int ret; > - > - /* > - * The alloc sem blocks peope in read/write from reading our > - * allocation until we're done changing it. We depend on > - * i_mutex to block other extend/truncate calls while we're > - * here. > - */ > - down_write(&OCFS2_I(inode)->ip_alloc_sem); > - ret = __ocfs2_extend_allocation(inode, logical_start, clusters_to_add, > - mark_unwritten); > - up_write(&OCFS2_I(inode)->ip_alloc_sem); > - > - return ret; > -} > - > /* Some parts of this taken from generic_cont_expand, which turned out > * to be too fragile to do exactly what we need without us having to > * worry about recursive locking in ->prepare_write() and > @@ -890,25 +871,47 @@ out: > return ret; > } > > -/* > - * A tail_to_skip value > 0 indicates that we're being called from > - * ocfs2_file_aio_write(). This has the following implications: > - * > - * - we don't want to update i_size > - * - di_bh will be NULL, which is fine because it's only used in the > - * case where we want to update i_size. > - * - ocfs2_zero_extend() will then only be filling the hole created > - * between i_size and the start of the write. > - */ > +int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size, u64 zero_to) > +{ > + int ret; > + u32 clusters_to_add; > + struct ocfs2_inode_info *oi = OCFS2_I(inode); > + > + clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size); > + if (clusters_to_add < oi->ip_clusters) > + clusters_to_add = 0; > + else > + clusters_to_add -= oi->ip_clusters; > + > + if (clusters_to_add) { > + ret = __ocfs2_extend_allocation(inode, oi->ip_clusters, > + clusters_to_add, 0); > + if (ret) { > + mlog_errno(ret); > + goto out; > + } > + } > + > + /* > + * Call this even if we don't add any clusters to the tree. We > + * still need to zero the area between the old i_size and the > + * new i_size. > + */ > + ret = ocfs2_zero_extend(inode, zero_to); > + if (ret < 0) > + mlog_errno(ret); > + > +out: > + return ret; > +} > + > static int ocfs2_extend_file(struct inode *inode, > struct buffer_head *di_bh, > - u64 new_i_size, > - size_t tail_to_skip) > + u64 new_i_size) > { > int ret = 0; > - u32 clusters_to_add = 0; > > - BUG_ON(!tail_to_skip && !di_bh); > + BUG_ON(!di_bh); > > /* setattr sometimes calls us like this. */ > if (new_i_size == 0) > @@ -918,13 +921,8 @@ static int ocfs2_extend_file(struct inode *inode, > goto out; > BUG_ON(new_i_size < i_size_read(inode)); > > - if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) { > - BUG_ON(tail_to_skip != 0); > + if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) > goto out_update_size; > - } > - > - clusters_to_add = ocfs2_clusters_for_bytes(inode->i_sb, new_i_size) - > - OCFS2_I(inode)->ip_clusters; > > /* > * protect the pages that ocfs2_zero_extend is going to be > @@ -939,35 +937,25 @@ static int ocfs2_extend_file(struct inode *inode, > goto out; > } > > - if (clusters_to_add) { > - ret = ocfs2_extend_allocation(inode, > - OCFS2_I(inode)->ip_clusters, > - clusters_to_add, 0); > - if (ret < 0) { > - mlog_errno(ret); > - goto out_unlock; > - } > - } > - > /* > - * Call this even if we don't add any clusters to the tree. We > - * still need to zero the area between the old i_size and the > - * new i_size. > + * The alloc sem blocks people in read/write from reading our > + * allocation until we're done changing it. We depend on > + * i_mutex to block other extend/truncate calls while we're > + * here. > */ > - ret = ocfs2_zero_extend(inode, (u64)new_i_size - tail_to_skip); > + down_write(&OCFS2_I(inode)->ip_alloc_sem); > + ret = ocfs2_extend_no_holes(inode, new_i_size, new_i_size); > + up_write(&OCFS2_I(inode)->ip_alloc_sem); > + > if (ret < 0) { > mlog_errno(ret); > goto out_unlock; > } > > out_update_size: > - if (!tail_to_skip) { > - /* We're being called from ocfs2_setattr() which wants > - * us to update i_size */ > - ret = ocfs2_simple_size_update(inode, di_bh, new_i_size); > - if (ret < 0) > - mlog_errno(ret); > - } > + ret = ocfs2_simple_size_update(inode, di_bh, new_i_size); > + if (ret < 0) > + mlog_errno(ret); > > out_unlock: > if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) > @@ -1036,7 +1024,7 @@ int ocfs2_setattr(struct dentry *dentry, struct iattr *attr) > if (i_size_read(inode) > attr->ia_size) > status = ocfs2_truncate_file(inode, bh, attr->ia_size); > else > - status = ocfs2_extend_file(inode, bh, attr->ia_size, 0); > + status = ocfs2_extend_file(inode, bh, attr->ia_size); > if (status < 0) { > if (status != -ENOSPC) > mlog_errno(status); > @@ -1714,15 +1702,13 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry, > int appending, > int *direct_io) > { > - int ret = 0, meta_level = appending; > + int ret = 0, meta_level = 0; > struct inode *inode = dentry->d_inode; > - u32 clusters; > - loff_t newsize, saved_pos; > + loff_t saved_pos, end; > > /* > - * We sample i_size under a read level meta lock to see if our write > - * is extending the file, if it is we back off and get a write level > - * meta lock. > + * We start with a read level meta lock and only jump to an ex > + * if we need to make modifications here. > */ > for(;;) { > ret = ocfs2_meta_lock(inode, NULL, meta_level); > @@ -1764,87 +1750,38 @@ static int ocfs2_prepare_inode_for_write(struct dentry *dentry, > saved_pos = *ppos; > } > > - if (ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) { > - loff_t end = saved_pos + count; > - > - /* > - * Skip the O_DIRECT checks if we don't need > - * them. > - */ > - if (!direct_io || !(*direct_io)) > - break; > - > - /* > - * Allowing concurrent direct writes means > - * i_size changes wouldn't be synchronized, so > - * one node could wind up truncating another > - * nodes writes. > - */ > - if (end > i_size_read(inode)) { > - *direct_io = 0; > - break; > - } > + end = saved_pos + count; > > - /* > - * We don't fill holes during direct io, so > - * check for them here. If any are found, the > - * caller will have to retake some cluster > - * locks and initiate the io as buffered. > - */ > - ret = ocfs2_check_range_for_holes(inode, saved_pos, > - count); > - if (ret == 1) { > - *direct_io = 0; > - ret = 0; > - } else if (ret < 0) > - mlog_errno(ret); > + /* > + * Skip the O_DIRECT checks if we don't need > + * them. > + */ > + if (!direct_io || !(*direct_io)) > break; > - } > > /* > - * The rest of this loop is concerned with legacy file > - * systems which don't support sparse files. > + * Allowing concurrent direct writes means > + * i_size changes wouldn't be synchronized, so > + * one node could wind up truncating another > + * nodes writes. > */ > - > - newsize = count + saved_pos; > - > - mlog(0, "pos=%lld newsize=%lld cursize=%lld\n", > - (long long) saved_pos, (long long) newsize, > - (long long) i_size_read(inode)); > - > - /* No need for a higher level metadata lock if we're > - * never going past i_size. */ > - if (newsize <= i_size_read(inode)) > + if (end > i_size_read(inode)) { > + *direct_io = 0; > break; > - > - if (meta_level == 0) { > - ocfs2_meta_unlock(inode, meta_level); > - meta_level = 1; > - continue; > } > > - spin_lock(&OCFS2_I(inode)->ip_lock); > - clusters = ocfs2_clusters_for_bytes(inode->i_sb, newsize) - > - OCFS2_I(inode)->ip_clusters; > - spin_unlock(&OCFS2_I(inode)->ip_lock); > - > - mlog(0, "Writing at EOF, may need more allocation: " > - "i_size = %lld, newsize = %lld, need %u clusters\n", > - (long long) i_size_read(inode), (long long) newsize, > - clusters); > - > - /* We only want to continue the rest of this loop if > - * our extend will actually require more > - * allocation. */ > - if (!clusters) > - break; > - > - ret = ocfs2_extend_file(inode, NULL, newsize, count); > - if (ret < 0) { > - if (ret != -ENOSPC) > - mlog_errno(ret); > - goto out_unlock; > - } > + /* > + * We don't fill holes during direct io, so > + * check for them here. If any are found, the > + * caller will have to retake some cluster > + * locks and initiate the io as buffered. > + */ > + ret = ocfs2_check_range_for_holes(inode, saved_pos, count); > + if (ret == 1) { > + *direct_io = 0; > + ret = 0; > + } else if (ret < 0) > + mlog_errno(ret); > break; > } > > diff --git a/fs/ocfs2/file.h b/fs/ocfs2/file.h > index 36fe27f..066f14a 100644 > --- a/fs/ocfs2/file.h > +++ b/fs/ocfs2/file.h > @@ -47,6 +47,8 @@ int ocfs2_do_extend_allocation(struct ocfs2_super *osb, > struct ocfs2_alloc_context *data_ac, > struct ocfs2_alloc_context *meta_ac, > enum ocfs2_alloc_restarted *reason_ret); > +int ocfs2_extend_no_holes(struct inode *inode, u64 new_i_size, > + u64 zero_to); > int ocfs2_lock_allocators(struct inode *inode, struct ocfs2_dinode *di, > u32 clusters_to_add, u32 extents_to_split, > struct ocfs2_alloc_context **data_ac, > -- > 1.5.0.6 > > > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel@oss.oracle.com > http://oss.oracle.com/mailman/listinfo/ocfs2-devel -- "People with narrow minds usually have broad tongues." Joel Becker Principal Software Developer Oracle E-mail: joel.becker@oracle.com Phone: (650) 506-8127