Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753513AbZLAESJ (ORCPT ); Mon, 30 Nov 2009 23:18:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753365AbZLAESI (ORCPT ); Mon, 30 Nov 2009 23:18:08 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:33006 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753445AbZLAESG (ORCPT ); Mon, 30 Nov 2009 23:18:06 -0500 Date: Mon, 30 Nov 2009 23:17:43 -0500 Message-Id: <200912010417.nB14Hhbm030497@agora.fsl.cs.sunysb.edu> From: Erez Zadok To: Valerie Aurora Cc: Jan Blunck , Alexander Viro , Christoph Hellwig , Andy Whitcroft , Scott James Remnant , Sandu Popa Marius , Jan Rekorajski , "J. R. Okajima" , Arnd Bergmann , Vladimir Dronnikov , Felix Fietkau , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 34/41] fallthru: tmpfs fallthru support In-reply-to: Your message of "Wed, 21 Oct 2009 12:19:32 PDT." <1256152779-10054-35-git-send-email-vaurora@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7172 Lines: 206 In message <1256152779-10054-35-git-send-email-vaurora@redhat.com>, Valerie Aurora writes: > Add support for fallthru directory entries to tmpfs Need to CC tmpfs maintainers here. > XXX - Makes up inode number for dirent > > Signed-off-by: Valerie Aurora > --- > fs/dcache.c | 3 +- > fs/libfs.c | 21 +++++++++++++++++-- > mm/shmem.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++------ > 3 files changed, 73 insertions(+), 11 deletions(-) > > diff --git a/fs/dcache.c b/fs/dcache.c > index ca8a661..8ef2d89 100644 > --- a/fs/dcache.c > +++ b/fs/dcache.c > @@ -2292,7 +2292,8 @@ resume: > struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child); > next = tmp->next; > if (d_unhashed(dentry)||(!dentry->d_inode && > - !d_is_whiteout(dentry))) > + !d_is_whiteout(dentry) && > + !d_is_fallthru(dentry))) > continue; > if (!list_empty(&dentry->d_subdirs)) { > this_parent = dentry; > diff --git a/fs/libfs.c b/fs/libfs.c > index dcec3d3..01f3e73 100644 > --- a/fs/libfs.c > +++ b/fs/libfs.c > @@ -133,6 +133,7 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) > struct dentry *cursor = filp->private_data; > struct list_head *p, *q = &cursor->d_u.d_child; > ino_t ino; > + int d_type; > int i = filp->f_pos; > > switch (i) { > @@ -158,14 +159,28 @@ int dcache_readdir(struct file * filp, void * dirent, filldir_t filldir) > for (p=q->next; p != &dentry->d_subdirs; p=p->next) { > struct dentry *next; > next = list_entry(p, struct dentry, d_u.d_child); > - if (d_unhashed(next) || !next->d_inode) > + if (d_unhashed(next) || (!next->d_inode && !d_is_fallthru(next))) > continue; > > + if (d_is_fallthru(next)) { > + /* XXX We don't know the inode > + * number of the directory > + * entry in the underlying > + * file system. Should look > + * it up, either on fallthru > + * creation at first readdir > + * or now at filldir time. */ > + ino = 123; /* Made up ino */ Ok, so here it's 123, as in ext2, but not jffs2, who had it set to 100... > + d_type = DT_UNKNOWN; > + } else { > + ino = next->d_inode->i_ino; > + d_type = dt_type(next->d_inode); > + } > + > spin_unlock(&dcache_lock); > if (filldir(dirent, next->d_name.name, > next->d_name.len, filp->f_pos, > - next->d_inode->i_ino, > - dt_type(next->d_inode)) < 0) > + ino, d_type) < 0) > return 0; > spin_lock(&dcache_lock); > /* next is still alive */ > diff --git a/mm/shmem.c b/mm/shmem.c > index 2faa14b..4f4b4b6 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -1798,8 +1798,7 @@ static int shmem_rmdir(struct inode *dir, struct dentry *dentry); > static int shmem_unlink(struct inode *dir, struct dentry *dentry); > > /* > - * This is the whiteout support for tmpfs. It uses one singleton whiteout > - * inode per superblock thus it is very similar to shmem_link(). > + * Create a dentry to signify a whiteout. > */ > static int shmem_whiteout(struct inode *dir, struct dentry *old_dentry, > struct dentry *new_dentry) > @@ -1830,8 +1829,10 @@ static int shmem_whiteout(struct inode *dir, struct dentry *old_dentry, > spin_unlock(&sbinfo->stat_lock); > } > > - if (old_dentry->d_inode) { > - if (S_ISDIR(old_dentry->d_inode->i_mode)) > + if (old_dentry->d_inode || d_is_fallthru(old_dentry)) { > + /* A fallthru for a dir is treated like a regular link */ > + if (old_dentry->d_inode && > + S_ISDIR(old_dentry->d_inode->i_mode)) > shmem_rmdir(dir, old_dentry); > else > shmem_unlink(dir, old_dentry); > @@ -1848,6 +1849,48 @@ static int shmem_whiteout(struct inode *dir, struct dentry *old_dentry, > } > > static void shmem_d_instantiate(struct inode *dir, struct dentry *dentry, > + struct inode *inode); > + > +/* > + * Create a dentry to signify a fallthru. A fallthru in tmpfs is the > + * logical equivalent of an in-kernel readdir() cache. It can't be > + * deleted until the file system is unmounted. > + */ > +static int shmem_fallthru(struct inode *dir, struct dentry *dentry) > +{ > + struct shmem_sb_info *sbinfo = SHMEM_SB(dir->i_sb); > + > + /* FIXME: this is stupid */ > + if (!(dir->i_sb->s_flags & MS_WHITEOUT)) > + return -EPERM; > + > + if (dentry->d_inode || d_is_fallthru(dentry) || d_is_whiteout(dentry)) > + return -EEXIST; > + > + /* > + * Each new link needs a new dentry, pinning lowmem, and tmpfs > + * dentries cannot be pruned until they are unlinked. > + */ > + if (sbinfo->max_inodes) { > + spin_lock(&sbinfo->stat_lock); > + if (!sbinfo->free_inodes) { > + spin_unlock(&sbinfo->stat_lock); > + return -ENOSPC; > + } > + sbinfo->free_inodes--; > + spin_unlock(&sbinfo->stat_lock); > + } > + > + shmem_d_instantiate(dir, dentry, NULL); > + dir->i_ctime = dir->i_mtime = CURRENT_TIME; > + > + spin_lock(&dentry->d_lock); > + dentry->d_flags |= DCACHE_FALLTHRU; > + spin_unlock(&dentry->d_lock); > + return 0; > +} > + > +static void shmem_d_instantiate(struct inode *dir, struct dentry *dentry, > struct inode *inode) > { > if (d_is_whiteout(dentry)) { > @@ -1855,14 +1898,15 @@ static void shmem_d_instantiate(struct inode *dir, struct dentry *dentry, > shmem_free_inode(dir->i_sb); > if (S_ISDIR(inode->i_mode)) > inode->i_mode |= S_OPAQUE; > + } else if (d_is_fallthru(dentry)) { > + shmem_free_inode(dir->i_sb); > } else { > /* New dentry */ > dir->i_size += BOGO_DIRENT_SIZE; > dget(dentry); /* Extra count - pin the dentry in core */ > } > - /* Will clear DCACHE_WHITEOUT flag */ > + /* Will clear DCACHE_WHITEOUT and DCACHE_FALLTHRU flags */ > d_instantiate(dentry, inode); > - > } > /* > * File creation. Allocate an inode, and we're done.. > @@ -1947,7 +1991,8 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) > { > struct inode *inode = dentry->d_inode; > > - if (d_is_whiteout(dentry) || (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))) > + if (d_is_whiteout(dentry) || d_is_fallthru(dentry) || > + (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))) > shmem_free_inode(dir->i_sb); I'd reorder this || condition above so the more common sub-conditions to be true, show up first (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode). d_is_whatever should go last. > > if (inode) { > @@ -2583,6 +2628,7 @@ static const struct inode_operations shmem_dir_inode_operations = { > .mknod = shmem_mknod, > .rename = shmem_rename, > .whiteout = shmem_whiteout, > + .fallthru = shmem_fallthru, > #endif > #ifdef CONFIG_TMPFS_POSIX_ACL > .setattr = shmem_notify_change, > -- > 1.6.3.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Erez. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/