Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753458AbZLAERh (ORCPT ); Mon, 30 Nov 2009 23:17:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753365AbZLAERg (ORCPT ); Mon, 30 Nov 2009 23:17:36 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:51168 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753323AbZLAERe (ORCPT ); Mon, 30 Nov 2009 23:17:34 -0500 Date: Mon, 30 Nov 2009 23:17:11 -0500 Message-Id: <200912010417.nB14HBsi030481@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, Theodore Tso , linux-ext4@vger.kernel.org Subject: Re: [PATCH 32/41] fallthru: ext2 fallthru support In-reply-to: Your message of "Wed, 21 Oct 2009 12:19:30 PDT." <1256152779-10054-33-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: 9624 Lines: 279 In message <1256152779-10054-33-git-send-email-vaurora@redhat.com>, Valerie Aurora writes: > Add support for fallthru directory entries to ext2. > > XXX - Makes up inode number for fallthru entry > XXX - Might be better implemented as special symlinks > > 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 | 20 ++++++++++ > include/linux/ext2_fs.h | 1 + > 4 files changed, 110 insertions(+), 4 deletions(-) > > diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c > index d4628c0..2665bc6 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))) Extra set of () unnecessary here and in several places below. > 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); So, why 123 and not at least some other unused number below 10: at least that way it's in the ext2 "reserved" range should something go horribly wrong (like a power failure right shortly thereafter). BTW, this yet-unimplemented functionality should be mentioned under "limitations" or something in the current design doc. I also think the design doc should list all short-term and long-term things that need to be implemented, and in what order. > + 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; > + } > + 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 a7f057f..328fc1c 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 9c4eef2..2ac44f1 100644 > --- a/fs/ext2/namei.c > +++ b/fs/ext2/namei.c > @@ -333,6 +333,7 @@ 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); > @@ -351,6 +352,24 @@ out: > return err; > } > > +/* > + * Create a fallthru entry. > + */ > +static int ext2_fallthru (struct inode *dir, struct dentry *dentry) > +{ > + int err; > + > + 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 ) > { > @@ -451,6 +470,7 @@ 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 bd10826..f6b68ec 100644 > --- a/include/linux/ext2_fs.h > +++ b/include/linux/ext2_fs.h > @@ -577,6 +577,7 @@ enum { > EXT2_FT_SOCK, > EXT2_FT_SYMLINK, > EXT2_FT_WHT, > + EXT2_FT_FALLTHRU, > EXT2_FT_MAX > }; > > -- > 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/