From: Ian Kent Subject: Re: [PATCH 14/38] fallthru: ext2 fallthru support Date: Tue, 13 Jul 2010 12:30:43 +0800 Message-ID: <20100713043041.GD3949@zeus.themaw.net> References: <1276627208-17242-1-git-send-email-vaurora@redhat.com> <1276627208-17242-15-git-send-email-vaurora@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexander Viro , Miklos Szeredi , Jan Blunck , Christoph Hellwig , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Theodore Tso , linux-ext4@vger.kernel.org To: Valerie Aurora Return-path: Received: from out1.smtp.messagingengine.com ([66.111.4.25]:47305 "EHLO out1.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747Ab0GMEay (ORCPT ); Tue, 13 Jul 2010 00:30:54 -0400 Content-Disposition: inline In-Reply-To: <1276627208-17242-15-git-send-email-vaurora@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Jun 15, 2010 at 11:39:44AM -0700, Valerie Aurora wrote: > Add support for fallthru directory entries to ext2. > > XXX What to do for d_ino for fallthrus? If we return the inode from > the the underlying file system, it comes from a different inode > "namespace" and that will produce spurious matches. This argues for > implementation of fallthrus as symlinks because they have to allocate > an inode (and inode number) anyway, and we can later reuse it if we > copy the file up. > > Cc: Theodore Tso > Cc: linux-ext4@vger.kernel.org > Signed-off-by: Valerie Aurora > Signed-off-by: Jan Blunck > --- > fs/ext2/dir.c | 92 ++++++++++++++++++++++++++++++++++++++++++++-- > fs/ext2/ext2.h | 1 + > fs/ext2/namei.c | 22 +++++++++++ > include/linux/ext2_fs.h | 1 + > 4 files changed, 112 insertions(+), 4 deletions(-) > > diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c > index 030bd46..f3b4aff 100644 > --- a/fs/ext2/dir.c > +++ b/fs/ext2/dir.c > @@ -219,7 +219,8 @@ static inline int ext2_match (int len, const char * const name, > { > if (len != de->name_len) > return 0; > - if (!de->inode && (de->file_type != EXT2_FT_WHT)) > + if (!de->inode && ((de->file_type != EXT2_FT_WHT) && > + (de->file_type != EXT2_FT_FALLTHRU))) > return 0; > return !memcmp(name, de->name, len); > } > @@ -256,6 +257,7 @@ static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { > [EXT2_FT_SOCK] = DT_SOCK, > [EXT2_FT_SYMLINK] = DT_LNK, > [EXT2_FT_WHT] = DT_WHT, > + [EXT2_FT_FALLTHRU] = DT_UNKNOWN, > }; > > #define S_SHIFT 12 > @@ -342,6 +344,24 @@ ext2_readdir (struct file * filp, void * dirent, filldir_t filldir) > ext2_put_page(page); > return 0; > } > + } else if (de->file_type == EXT2_FT_FALLTHRU) { > + int over; > + unsigned char d_type = DT_UNKNOWN; > + > + offset = (char *)de - kaddr; > + /* 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. */ > + over = filldir(dirent, de->name, de->name_len, > + (n< + 123 /* Made up ino */, d_type); > + if (over) { > + ext2_put_page(page); > + return 0; > + } > } > filp->f_pos += ext2_rec_len_from_disk(de->rec_len); > } > @@ -463,6 +483,10 @@ ino_t ext2_inode_by_dentry(struct inode *dir, struct dentry *dentry) > spin_lock(&dentry->d_lock); > dentry->d_flags |= DCACHE_WHITEOUT; > spin_unlock(&dentry->d_lock); > + } else if(!res && de->file_type == EXT2_FT_FALLTHRU) { > + spin_lock(&dentry->d_lock); > + dentry->d_flags |= DCACHE_FALLTHRU; > + spin_unlock(&dentry->d_lock); > } > ext2_put_page(page); > } > @@ -532,6 +556,7 @@ static ext2_dirent * ext2_append_entry(struct dentry * dentry, > de->name_len = 0; > de->rec_len = ext2_rec_len_to_disk(chunk_size); > de->inode = 0; > + de->file_type = 0; > goto got_it; > } > if (de->rec_len == 0) { > @@ -545,6 +570,7 @@ static ext2_dirent * ext2_append_entry(struct dentry * dentry, > name_len = EXT2_DIR_REC_LEN(de->name_len); > rec_len = ext2_rec_len_from_disk(de->rec_len); > if (!de->inode && (de->file_type != EXT2_FT_WHT) && > + (de->file_type != EXT2_FT_FALLTHRU) && > (rec_len >= reclen)) > goto got_it; > if (rec_len >= name_len + reclen) > @@ -587,7 +613,8 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode) > > err = -EEXIST; > if (ext2_match (namelen, name, de)) { > - if (de->file_type == EXT2_FT_WHT) > + if ((de->file_type == EXT2_FT_WHT) || > + (de->file_type == EXT2_FT_FALLTHRU)) > goto got_it; > goto out_unlock; > } > @@ -602,7 +629,8 @@ got_it: > &page, NULL); > if (err) > goto out_unlock; > - if (de->inode || ((de->file_type == EXT2_FT_WHT) && > + if (de->inode || (((de->file_type == EXT2_FT_WHT) || > + (de->file_type == EXT2_FT_FALLTHRU)) && > !ext2_match (namelen, name, de))) { > ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); > de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); > @@ -627,6 +655,60 @@ out_unlock: > } > > /* > + * Create a fallthru entry. > + */ > +int ext2_fallthru_entry (struct inode *dir, struct dentry *dentry) > +{ > + const char *name = dentry->d_name.name; > + int namelen = dentry->d_name.len; > + unsigned short rec_len, name_len; > + ext2_dirent * de; > + struct page *page; > + loff_t pos; > + int err; > + > + de = ext2_append_entry(dentry, &page); > + if (IS_ERR(de)) > + return PTR_ERR(de); > + > + err = -EEXIST; > + if (ext2_match (namelen, name, de)) > + goto out_unlock; > + > + name_len = EXT2_DIR_REC_LEN(de->name_len); > + rec_len = ext2_rec_len_from_disk(de->rec_len); > + > + pos = page_offset(page) + > + (char*)de - (char*)page_address(page); > + err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0, > + &page, NULL); > + if (err) > + goto out_unlock; > + if (de->inode || (de->file_type == EXT2_FT_WHT) || > + (de->file_type == EXT2_FT_FALLTHRU)) { > + ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); > + de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); > + de->rec_len = ext2_rec_len_to_disk(name_len); > + de = de1; > + } And again, what's foing on here? > + de->name_len = namelen; > + memcpy(de->name, name, namelen); > + de->inode = 0; > + de->file_type = EXT2_FT_FALLTHRU; > + err = ext2_commit_chunk(page, pos, rec_len); > + dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; > + EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; > + mark_inode_dirty(dir); > + /* OFFSET_CACHE */ > +out_put: > + ext2_put_page(page); > + return err; > +out_unlock: > + unlock_page(page); > + goto out_put; > +} > + > +/* > * ext2_delete_entry deletes a directory entry by merging it with the > * previous entry. Page is up-to-date. Releases the page. > */ > @@ -711,7 +793,9 @@ int ext2_whiteout_entry (struct inode * dir, struct dentry * dentry, > */ > if (ext2_match (namelen, name, de)) > de->inode = 0; > - if (de->inode || (de->file_type == EXT2_FT_WHT)) { > + if (de->inode || (((de->file_type == EXT2_FT_WHT) || > + (de->file_type == EXT2_FT_FALLTHRU)) && > + !ext2_match (namelen, name, de))) { > ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); > de1->rec_len = ext2_rec_len_to_disk(rec_len - name_len); > de->rec_len = ext2_rec_len_to_disk(name_len); > diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h > index 44d190c..2fa32b3 100644 > --- a/fs/ext2/ext2.h > +++ b/fs/ext2/ext2.h > @@ -108,6 +108,7 @@ extern struct ext2_dir_entry_2 * ext2_find_entry (struct inode *,struct qstr *, > extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *); > extern int ext2_whiteout_entry (struct inode *, struct dentry *, > struct ext2_dir_entry_2 *, struct page *); > +extern int ext2_fallthru_entry (struct inode *, struct dentry *); > extern int ext2_empty_dir (struct inode *); > extern struct ext2_dir_entry_2 * ext2_dotdot (struct inode *, struct page **); > extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, struct inode *, int); > diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c > index 12195a5..f28154c 100644 > --- a/fs/ext2/namei.c > +++ b/fs/ext2/namei.c > @@ -349,6 +349,7 @@ static int ext2_whiteout(struct inode *dir, struct dentry *dentry, > goto out; > > spin_lock(&new_dentry->d_lock); > + new_dentry->d_flags &= ~DCACHE_FALLTHRU; > new_dentry->d_flags |= DCACHE_WHITEOUT; > spin_unlock(&new_dentry->d_lock); > d_add(new_dentry, NULL); > @@ -367,6 +368,26 @@ out: > return err; > } > > +/* > + * Create a fallthru entry. > + */ > +static int ext2_fallthru (struct inode *dir, struct dentry *dentry) > +{ > + int err; > + > + dquot_initialize(dir); > + > + err = ext2_fallthru_entry(dir, dentry); > + if (err) > + return err; > + > + d_instantiate(dentry, NULL); > + spin_lock(&dentry->d_lock); > + dentry->d_flags |= DCACHE_FALLTHRU; > + spin_unlock(&dentry->d_lock); > + return 0; > +} > + > static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, > struct inode * new_dir, struct dentry * new_dentry ) > { > @@ -470,6 +491,7 @@ const struct inode_operations ext2_dir_inode_operations = { > .rmdir = ext2_rmdir, > .mknod = ext2_mknod, > .whiteout = ext2_whiteout, > + .fallthru = ext2_fallthru, > .rename = ext2_rename, > #ifdef CONFIG_EXT2_FS_XATTR > .setxattr = generic_setxattr, > diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h > index 20468bd..cb3d400 100644 > --- a/include/linux/ext2_fs.h > +++ b/include/linux/ext2_fs.h > @@ -577,6 +577,7 @@ enum { > EXT2_FT_SOCK = 6, > EXT2_FT_SYMLINK = 7, > EXT2_FT_WHT = 8, > + EXT2_FT_FALLTHRU = 9, > EXT2_FT_MAX > }; > > -- > 1.6.3.3 > > -- > 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/