From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Whitehouse Date: Fri, 13 Apr 2012 11:10:33 +0100 Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Extend the life of the reservations structure In-Reply-To: References: Message-ID: <1334311833.2746.5.camel@menhir> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, On Thu, 2012-04-12 at 11:43 -0400, Bob Peterson wrote: > Hi, > > This patch lengthens the life of the reservations structure. > See notes below. > > Regards, > > Bob Peterson > Red Hat GFS > > Signed-off-by: Bob Peterson > -- > Author: Bob Peterson > Date: Thu Apr 12 11:37:24 2012 -0500 > > GFS2: Extend the life of the reservations structure > > This patch lengthens the lifespan of the reservations structure for > inodes. Before, they were allocated and deallocated for every write > operation. With this patch, they are allocated when the first write > occurs, and deallocated when the last process closes the file. > It's more efficient to do it this way because it saves GFS2 a lot of > unnecessary allocates and frees. It also gives us more flexibility > for the future: (1) we can now fold the qadata structure back into > the structure and save those alloc/frees, (2) we can use this for > multi-block reservations. > > diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c > index 56dc1f0..a793957 100644 > --- a/fs/gfs2/aops.c > +++ b/fs/gfs2/aops.c > @@ -879,7 +879,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping, > brelse(dibh); > failed: > gfs2_trans_end(sdp); > - if (ip->i_res) > + if (gfs2_mb_reserved(ip)) > gfs2_inplace_release(ip); > if (qa) { > gfs2_quota_unlock(ip); > diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c > index 31b199f..3a1a60a 100644 > --- a/fs/gfs2/file.c > +++ b/fs/gfs2/file.c > @@ -384,6 +384,10 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) > set_bit(GLF_DIRTY, &ip->i_gl->gl_flags); > set_bit(GIF_SW_PAGED, &ip->i_flags); > > + ret = gfs2_rs_alloc(ip); > + if (ret) > + goto out_unlock; > + I don't think the locking is quite right here... at least I can't see any locking at all in this case. > if (!gfs2_write_alloc_required(ip, pos, PAGE_CACHE_SIZE)) { > lock_page(page); > if (!PageUptodate(page) || page->mapping != inode->i_mapping) { > @@ -569,10 +573,17 @@ static int gfs2_release(struct inode *inode, struct file *file) > { > struct gfs2_sbd *sdp = inode->i_sb->s_fs_info; > struct gfs2_file *fp; > + struct gfs2_inode *ip = GFS2_I(inode); > > fp = file->private_data; > file->private_data = NULL; > > + if (file->f_mode & FMODE_WRITE) { > + mutex_lock(&inode->i_mutex); > + if (ip->i_res && (atomic_read(&inode->i_writecount) == 1)) > + gfs2_rs_delete(ip); > + mutex_unlock(&inode->i_mutex); > + } > if (gfs2_assert_warn(sdp, fp)) > return -EIO; > > @@ -653,12 +664,16 @@ static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov, > unsigned long nr_segs, loff_t pos) > { > struct file *file = iocb->ki_filp; > + struct dentry *dentry = file->f_dentry; > + struct gfs2_inode *ip = GFS2_I(dentry->d_inode); > + int ret; > + > + ret = gfs2_rs_alloc(ip); > + if (ret) > + return ret; Again, there is no locking here. > > if (file->f_flags & O_APPEND) { > - struct dentry *dentry = file->f_dentry; > - struct gfs2_inode *ip = GFS2_I(dentry->d_inode); > struct gfs2_holder gh; > - int ret; > > ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh); > if (ret) > diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c > index a9ba244..127b1a4 100644 > --- a/fs/gfs2/inode.c > +++ b/fs/gfs2/inode.c > @@ -681,6 +681,10 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, > if (error) > goto fail_gunlock; > > + error = gfs2_rs_alloc(dip); > + if (error) > + goto fail_gunlock; > + > error = alloc_dinode(dip, &inum.no_addr, &generation); > if (error) > goto fail_gunlock; > @@ -704,6 +708,11 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, > if (error) > goto fail_gunlock2; > > + /* the new inode needs a reservation so it can allocate xattrs. */ > + error = gfs2_rs_alloc(GFS2_I(inode)); > + if (error) > + goto fail_gunlock2; > + > error = gfs2_acl_create(dip, inode); > if (error) > goto fail_gunlock2; > @@ -722,7 +731,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, > gfs2_trans_end(sdp); > /* Check if we reserved space in the rgrp. Function link_dinode may > not, depending on whether alloc is required. */ > - if (dip->i_res) > + if (gfs2_mb_reserved(dip)) > gfs2_inplace_release(dip); > gfs2_quota_unlock(dip); > gfs2_qadata_put(dip); > @@ -734,6 +743,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry, > fail_gunlock2: > gfs2_glock_dq_uninit(ghs + 1); > fail_gunlock: > + gfs2_rs_delete(dip); > gfs2_glock_dq_uninit(ghs); > if (inode && !IS_ERR(inode)) { > set_bit(GIF_ALLOC_FAILED, &GFS2_I(inode)->i_flags); > diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c > index 146c3d2..af590de 100644 > --- a/fs/gfs2/rgrp.c > +++ b/fs/gfs2/rgrp.c > @@ -418,6 +418,34 @@ void gfs2_free_clones(struct gfs2_rgrpd *rgd) > } > } > > +/** > + * gfs2_rs_alloc - make sure we have a reservation assigned to the inode > + * @ip: the inode for this reservation > + */ > +int gfs2_rs_alloc(struct gfs2_inode *ip) > +{ > + if (ip->i_res) > + return 0; > + ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS); > + if (!ip->i_res) > + return -ENOMEM; > + return 0; > +} > + I wonder whether it would be better to do this at open/create time, assuming that the file is being opened or created for writing. That means fewer cases to catch. The only issue I can see with that is catching files that are created and then never opened for writing - not sure if that is possible, but worth checking I think. So I think the locking needs sorting out here, but otherwise it looks good, Steve. > +/** > + * gfs2_rs_delete - delete a reservation > + * @ip: The inode for this reservation > + * > + */ > +void gfs2_rs_delete(struct gfs2_inode *ip) > +{ > + if (ip->i_res == NULL) > + return; > + > + kmem_cache_free(gfs2_rsrv_cachep, ip->i_res); > + ip->i_res = NULL; > +} > + > void gfs2_clear_rgrpd(struct gfs2_sbd *sdp) > { > struct rb_node *n; > @@ -1001,22 +1029,6 @@ struct gfs2_qadata *gfs2_qadata_get(struct gfs2_inode *ip) > } > > /** > - * gfs2_blkrsv_get - get the struct gfs2_blkreserv structure for an inode > - * @ip: the incore GFS2 inode structure > - * > - * Returns: the struct gfs2_qadata > - */ > - > -static int gfs2_blkrsv_get(struct gfs2_inode *ip) > -{ > - BUG_ON(ip->i_res != NULL); > - ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS); > - if (!ip->i_res) > - return -ENOMEM; > - return 0; > -} > - > -/** > * try_rgrp_fit - See if a given reservation will fit in a given RG > * @rgd: the RG data > * @ip: the inode > @@ -1170,13 +1182,6 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked) > return -ENOSPC; > } > > -static void gfs2_blkrsv_put(struct gfs2_inode *ip) > -{ > - BUG_ON(ip->i_res == NULL); > - kmem_cache_free(gfs2_rsrv_cachep, ip->i_res); > - ip->i_res = NULL; > -} > - > /** > * gfs2_inplace_reserve - Reserve space in the filesystem > * @ip: the inode to reserve space for > @@ -1189,14 +1194,10 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested) > { > struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode); > struct gfs2_blkreserv *rs; > - int error; > + int error = 0; > u64 last_unlinked = NO_BLOCK; > int tries = 0; > > - error = gfs2_blkrsv_get(ip); > - if (error) > - return error; > - > rs = ip->i_res; > rs->rs_requested = requested; > if (gfs2_assert_warn(sdp, requested)) { > @@ -1221,7 +1222,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested) > > out: > if (error) > - gfs2_blkrsv_put(ip); > + rs->rs_requested = 0; > return error; > } > > @@ -1238,7 +1239,7 @@ void gfs2_inplace_release(struct gfs2_inode *ip) > > if (rs->rs_rgd_gh.gh_gl) > gfs2_glock_dq_uninit(&rs->rs_rgd_gh); > - gfs2_blkrsv_put(ip); > + rs->rs_requested = 0; > } > > /** > @@ -1506,7 +1507,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks, > /* Only happens if there is a bug in gfs2, return something distinctive > * to ensure that it is noticed. > */ > - if (ip->i_res == NULL) > + if (ip->i_res->rs_requested == 0) > return -ECANCELED; > > rgd = ip->i_rgd; > diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h > index b4b10f4..d9eda5f 100644 > --- a/fs/gfs2/rgrp.h > +++ b/fs/gfs2/rgrp.h > @@ -43,6 +43,8 @@ extern void gfs2_inplace_release(struct gfs2_inode *ip); > extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n, > bool dinode, u64 *generation); > > +extern int gfs2_rs_alloc(struct gfs2_inode *ip); > +extern void gfs2_rs_delete(struct gfs2_inode *ip); > extern void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta); > extern void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen); > extern void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip); > @@ -68,4 +70,12 @@ extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset, > const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed); > extern int gfs2_fitrim(struct file *filp, void __user *argp); > > +/* This is how to tell if a reservation is "inplace" reserved: */ > +static inline int gfs2_mb_reserved(struct gfs2_inode *ip) > +{ > + if (ip->i_res && ip->i_res->rs_requested) > + return 1; > + return 0; > +} > + > #endif /* __RGRP_DOT_H__ */ > diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c > index 6172fa7..a42df66 100644 > --- a/fs/gfs2/super.c > +++ b/fs/gfs2/super.c > @@ -1554,6 +1554,7 @@ out_unlock: > out: > /* Case 3 starts here */ > truncate_inode_pages(&inode->i_data, 0); > + gfs2_rs_delete(ip); > end_writeback(inode); > gfs2_dir_hash_inval(ip); > ip->i_gl->gl_object = NULL; > @@ -1576,6 +1577,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb) > ip->i_flags = 0; > ip->i_gl = NULL; > ip->i_rgd = NULL; > + ip->i_res = NULL; > } > return &ip->i_inode; > } > diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h > index 125d457..41f42cd 100644 > --- a/fs/gfs2/trans.h > +++ b/fs/gfs2/trans.h > @@ -31,7 +31,7 @@ struct gfs2_glock; > static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip) > { > const struct gfs2_blkreserv *rs = ip->i_res; > - if (rs->rs_requested < ip->i_rgd->rd_length) > + if (rs && rs->rs_requested < ip->i_rgd->rd_length) > return rs->rs_requested + 1; > return ip->i_rgd->rd_length; > } >