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    Subject[Aufs 06/25] aufs xino
    Date
    initial commit
    external inode number translation table and bitmap

    Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
    ---
    fs/aufs/xino.c | 1181 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 1181 insertions(+), 0 deletions(-)
    create mode 100644 fs/aufs/xino.c

    diff --git a/fs/aufs/xino.c b/fs/aufs/xino.c
    new file mode 100644
    index 0000000..bc19b86
    --- /dev/null
    +++ b/fs/aufs/xino.c
    @@ -0,0 +1,1181 @@
    +/*
    + * Copyright (C) 2005-2009 Junjiro R. Okajima
    + *
    + * This program, aufs is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License as published by
    + * the Free Software Foundation; either version 2 of the License, or
    + * (at your option) any later version.
    + */
    +
    +/*
    + * external inode number translation table and bitmap
    + */
    +
    +#include <linux/seq_file.h>
    +#include <linux/uaccess.h>
    +#include "aufs.h"
    +
    +ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
    + loff_t *pos)
    +{
    + ssize_t err;
    + mm_segment_t oldfs;
    +
    + oldfs = get_fs();
    + set_fs(KERNEL_DS);
    + do {
    + /* todo: signal_pending? */
    + err = func(file, (char __user *)buf, size, pos);
    + } while (err == -EAGAIN || err == -EINTR);
    + set_fs(oldfs);
    +
    +#if 0 /* reserved for future use */
    + if (err > 0)
    + fsnotify_access(file->f_dentry);
    +#endif
    +
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +static ssize_t do_xino_fwrite(au_writef_t func, struct file *file, void *buf,
    + size_t size, loff_t *pos)
    +{
    + ssize_t err;
    + mm_segment_t oldfs;
    +
    + oldfs = get_fs();
    + set_fs(KERNEL_DS);
    + lockdep_off();
    + do {
    + /* todo: signal_pending? */
    + err = func(file, (const char __user *)buf, size, pos);
    + } while (err == -EAGAIN || err == -EINTR);
    + lockdep_on();
    + set_fs(oldfs);
    +
    +#if 0 /* reserved for future use */
    + if (err > 0)
    + fsnotify_modify(file->f_dentry);
    +#endif
    +
    + return err;
    +}
    +
    +struct do_xino_fwrite_args {
    + ssize_t *errp;
    + au_writef_t func;
    + struct file *file;
    + void *buf;
    + size_t size;
    + loff_t *pos;
    +};
    +
    +static void call_do_xino_fwrite(void *args)
    +{
    + struct do_xino_fwrite_args *a = args;
    + *a->errp = do_xino_fwrite(a->func, a->file, a->buf, a->size, a->pos);
    +}
    +
    +ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
    + loff_t *pos)
    +{
    + ssize_t err;
    +
    + /* todo: signal block and no wkq? */
    + /* todo: new credential scheme */
    + /*
    + * it breaks RLIMIT_FSIZE and normal user's limit,
    + * users should care about quota and real 'filesystem full.'
    + */
    + if (!au_test_wkq(current)) {
    + int wkq_err;
    + struct do_xino_fwrite_args args = {
    + .errp = &err,
    + .func = func,
    + .file = file,
    + .buf = buf,
    + .size = size,
    + .pos = pos
    + };
    +
    + wkq_err = au_wkq_wait(call_do_xino_fwrite, &args);
    + if (unlikely(wkq_err))
    + err = wkq_err;
    + } else
    + err = do_xino_fwrite(func, file, buf, size, pos);
    +
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/*
    + * create a new xinofile at the same place/path as @base_file.
    + */
    +static struct file *au_xino_create2(struct file *base_file,
    + struct file *copy_src)
    +{
    + struct file *file;
    + struct dentry *base, *dentry, *parent;
    + struct inode *dir;
    + struct qstr *name;
    + int err;
    +
    + base = base_file->f_dentry;
    + parent = base->d_parent; /* dir inode is locked */
    + dir = parent->d_inode;
    + IMustLock(dir);
    +
    + file = ERR_PTR(-EINVAL);
    + name = &base->d_name;
    + dentry = vfsub_lookup_one_len(name->name, parent, name->len);
    + if (IS_ERR(dentry)) {
    + file = (void *)dentry;
    + AuErr("%.*s lookup err %ld\n", AuLNPair(name), PTR_ERR(dentry));
    + goto out;
    + }
    +
    + /* no need to mnt_want_write() since we call dentry_open() later */
    + err = vfs_create(dir, dentry, S_IRUGO | S_IWUGO, NULL);
    + if (unlikely(err)) {
    + file = ERR_PTR(err);
    + AuErr("%.*s create err %d\n", AuLNPair(name), err);
    + goto out_dput;
    + }
    +
    + file = dentry_open(dget(dentry), mntget(base_file->f_vfsmnt),
    + O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
    + current_cred());
    + if (IS_ERR(file)) {
    + AuErr("%.*s open err %ld\n", AuLNPair(name), PTR_ERR(file));
    + goto out_dput;
    + }
    +
    + err = vfsub_unlink(dir, &file->f_path, /*force*/0);
    + if (unlikely(err)) {
    + AuErr("%.*s unlink err %d\n", AuLNPair(name), err);
    + goto out_fput;
    + }
    +
    + if (copy_src) {
    + /* no one can touch copy_src xino */
    + err = au_copy_file(file, copy_src,
    + i_size_read(copy_src->f_dentry->d_inode));
    + if (unlikely(err)) {
    + AuErr("%.*s copy err %d\n", AuLNPair(name), err);
    + goto out_fput;
    + }
    + }
    + goto out_dput; /* success */
    +
    + out_fput:
    + fput(file);
    + file = ERR_PTR(err);
    + out_dput:
    + dput(dentry);
    + out:
    + return file;
    +}
    +
    +struct au_xino_lock_dir {
    + struct au_hinode *hdir;
    + struct dentry *parent;
    + struct mutex *mtx;
    +};
    +
    +static void au_xino_lock_dir(struct super_block *sb, struct file *xino,
    + struct au_xino_lock_dir *ldir)
    +{
    + aufs_bindex_t brid, bindex;
    +
    + ldir->hdir = NULL;
    + bindex = -1;
    + brid = au_xino_brid(sb);
    + if (brid >= 0)
    + bindex = au_br_index(sb, brid);
    + if (bindex >= 0) {
    + ldir->hdir = au_hi(sb->s_root->d_inode, bindex);
    + au_hin_imtx_lock_nested(ldir->hdir, AuLsc_I_PARENT);
    + } else {
    + ldir->parent = dget_parent(xino->f_dentry);
    + ldir->mtx = &ldir->parent->d_inode->i_mutex;
    + mutex_lock_nested(ldir->mtx, AuLsc_I_PARENT);
    + }
    +}
    +
    +static void au_xino_unlock_dir(struct au_xino_lock_dir *ldir)
    +{
    + if (ldir->hdir)
    + au_hin_imtx_unlock(ldir->hdir);
    + else {
    + mutex_unlock(ldir->mtx);
    + dput(ldir->parent);
    + }
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/* trucate xino files asynchronously */
    +
    +int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex)
    +{
    + int err;
    + aufs_bindex_t bi, bend;
    + struct au_branch *br;
    + struct file *new_xino, *file;
    + struct super_block *h_sb;
    + struct au_xino_lock_dir ldir;
    +
    + err = -EINVAL;
    + bend = au_sbend(sb);
    + if (unlikely(bindex < 0 || bend < bindex))
    + goto out;
    + br = au_sbr(sb, bindex);
    + file = br->br_xino.xi_file;
    + if (!file)
    + goto out;
    +
    + au_xino_lock_dir(sb, file, &ldir);
    + /* mnt_want_write() is unnecessary here */
    + new_xino = au_xino_create2(file, file);
    + au_xino_unlock_dir(&ldir);
    + err = PTR_ERR(new_xino);
    + if (IS_ERR(new_xino))
    + goto out;
    + err = 0;
    + fput(file);
    + br->br_xino.xi_file = new_xino;
    +
    + h_sb = br->br_mnt->mnt_sb;
    + for (bi = 0; bi <= bend; bi++) {
    + if (unlikely(bi == bindex))
    + continue;
    + br = au_sbr(sb, bi);
    + if (br->br_mnt->mnt_sb != h_sb)
    + continue;
    +
    + fput(br->br_xino.xi_file);
    + br->br_xino.xi_file = new_xino;
    + get_file(new_xino);
    + }
    +
    + out:
    + return err;
    +}
    +
    +struct xino_do_trunc_args {
    + struct super_block *sb;
    + struct au_branch *br;
    +};
    +
    +static void xino_do_trunc(void *_args)
    +{
    + struct xino_do_trunc_args *args = _args;
    + struct super_block *sb;
    + struct au_branch *br;
    + struct inode *dir;
    + int err;
    + aufs_bindex_t bindex;
    +
    + err = 0;
    + sb = args->sb;
    + dir = sb->s_root->d_inode;
    + br = args->br;
    +
    + si_noflush_write_lock(sb);
    + ii_read_lock_parent(dir);
    + bindex = au_br_index(sb, br->br_id);
    + err = au_xino_trunc(sb, bindex);
    + if (unlikely(err))
    + goto out;
    +
    + if (br->br_xino.xi_file->f_dentry->d_inode->i_blocks
    + >= br->br_xino_upper)
    + br->br_xino_upper += AUFS_XINO_TRUNC_STEP;
    +
    + out:
    + ii_read_unlock(dir);
    + if (unlikely(err))
    + AuWarn("err b%d, (%d)\n", bindex, err);
    + atomic_dec(&br->br_xino_running);
    + atomic_dec(&br->br_count);
    + au_nwt_done(&au_sbi(sb)->si_nowait);
    + si_write_unlock(sb);
    + kfree(args);
    +}
    +
    +static void xino_try_trunc(struct super_block *sb, struct au_branch *br)
    +{
    + struct xino_do_trunc_args *args;
    + int wkq_err;
    +
    + if (br->br_xino.xi_file->f_dentry->d_inode->i_blocks
    + < br->br_xino_upper)
    + return;
    +
    + if (atomic_inc_return(&br->br_xino_running) > 1)
    + goto out;
    +
    + /* lock and kfree() will be called in trunc_xino() */
    + args = kmalloc(sizeof(*args), GFP_NOFS);
    + if (unlikely(!args)) {
    + AuErr1("no memory\n");
    + goto out_args;
    + }
    +
    + atomic_inc(&br->br_count);
    + args->sb = sb;
    + args->br = br;
    + wkq_err = au_wkq_nowait(xino_do_trunc, args, sb);
    + if (!wkq_err)
    + return; /* success */
    +
    + AuErr("wkq %d\n", wkq_err);
    + atomic_dec(&br->br_count);
    +
    + out_args:
    + kfree(args);
    + out:
    + atomic_dec(&br->br_xino_running);
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +static const loff_t au_loff_max = LLONG_MAX;
    +
    +static int au_xino_do_write(au_writef_t write, struct file *file,
    + ino_t h_ino, ino_t ino)
    +{
    + loff_t pos;
    + ssize_t sz;
    +
    + pos = h_ino;
    + if (unlikely(au_loff_max / sizeof(ino) - 1 < pos)) {
    + AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
    + return -EFBIG;
    + }
    + pos *= sizeof(ino);
    + sz = xino_fwrite(write, file, &ino, sizeof(ino), &pos);
    + if (sz == sizeof(ino))
    + return 0; /* success */
    +
    + AuIOErr("write failed (%zd)\n", sz);
    + return -EIO;
    +}
    +
    +/*
    + * write @ino to the xinofile for the specified branch{@sb, @bindex}
    + * at the position of @h_ino.
    + * even if @ino is zero, it is written to the xinofile and means no entry.
    + * if the size of the xino file on a specific filesystem exceeds the watermark,
    + * try truncating it.
    + */
    +int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
    + ino_t ino)
    +{
    + int err;
    + unsigned int mnt_flags;
    + struct au_branch *br;
    +
    + BUILD_BUG_ON(sizeof(long long) != sizeof(au_loff_max)
    + || ((loff_t)-1) > 0);
    +
    + mnt_flags = au_mntflags(sb);
    + if (!au_opt_test(mnt_flags, XINO))
    + return 0;
    +
    + br = au_sbr(sb, bindex);
    + err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
    + h_ino, ino);
    + if (!err) {
    + if (au_opt_test(mnt_flags, TRUNC_XINO)
    + && au_test_fs_trunc_xino(br->br_mnt->mnt_sb))
    + xino_try_trunc(sb, br);
    + return 0; /* success */
    + }
    +
    + AuIOErr("write failed (%d)\n", err);
    + return -EIO;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/* aufs inode number bitmap */
    +
    +static const int page_bits = (int)PAGE_SIZE * BITS_PER_BYTE;
    +static ino_t xib_calc_ino(unsigned long pindex, int bit)
    +{
    + ino_t ino;
    +
    + AuDebugOn(bit < 0 || page_bits <= bit);
    + ino = AUFS_FIRST_INO + pindex * page_bits + bit;
    + return ino;
    +}
    +
    +static void xib_calc_bit(ino_t ino, unsigned long *pindex, int *bit)
    +{
    + AuDebugOn(ino < AUFS_FIRST_INO);
    + ino -= AUFS_FIRST_INO;
    + *pindex = ino / page_bits;
    + *bit = ino % page_bits;
    +}
    +
    +static int xib_pindex(struct super_block *sb, unsigned long pindex)
    +{
    + int err;
    + loff_t pos;
    + ssize_t sz;
    + struct au_sbinfo *sbinfo;
    + struct file *xib;
    + unsigned long *p;
    +
    + sbinfo = au_sbi(sb);
    + MtxMustLock(&sbinfo->si_xib_mtx);
    + AuDebugOn(pindex > ULONG_MAX / PAGE_SIZE
    + || !au_opt_test(sbinfo->si_mntflags, XINO));
    +
    + if (pindex == sbinfo->si_xib_last_pindex)
    + return 0;
    +
    + xib = sbinfo->si_xib;
    + p = sbinfo->si_xib_buf;
    + pos = sbinfo->si_xib_last_pindex;
    + pos *= PAGE_SIZE;
    + sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
    + if (unlikely(sz != PAGE_SIZE))
    + goto out;
    +
    + pos = pindex;
    + pos *= PAGE_SIZE;
    + if (i_size_read(xib->f_dentry->d_inode) >= pos + PAGE_SIZE)
    + sz = xino_fread(sbinfo->si_xread, xib, p, PAGE_SIZE, &pos);
    + else {
    + memset(p, 0, PAGE_SIZE);
    + sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
    + }
    + if (sz == PAGE_SIZE) {
    + sbinfo->si_xib_last_pindex = pindex;
    + return 0; /* success */
    + }
    +
    + out:
    + AuIOErr1("write failed (%zd)\n", sz);
    + err = sz;
    + if (sz >= 0)
    + err = -EIO;
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
    + ino_t ino)
    +{
    + int err, bit;
    + unsigned long pindex;
    + struct au_sbinfo *sbinfo;
    +
    + if (!au_opt_test(au_mntflags(sb), XINO))
    + return 0;
    +
    + err = 0;
    + if (ino) {
    + sbinfo = au_sbi(sb);
    + xib_calc_bit(ino, &pindex, &bit);
    + AuDebugOn(page_bits <= bit);
    + mutex_lock(&sbinfo->si_xib_mtx);
    + err = xib_pindex(sb, pindex);
    + if (!err) {
    + clear_bit(bit, sbinfo->si_xib_buf);
    + sbinfo->si_xib_next_bit = bit;
    + }
    + mutex_unlock(&sbinfo->si_xib_mtx);
    + }
    +
    + if (!err)
    + err = au_xino_write(sb, bindex, h_ino, 0);
    + return err;
    +}
    +
    +/* get an unused inode number from bitmap */
    +ino_t au_xino_new_ino(struct super_block *sb)
    +{
    + ino_t ino;
    + unsigned long *p, pindex, ul, pend;
    + struct au_sbinfo *sbinfo;
    + struct file *file;
    + int free_bit, err;
    +
    + if (!au_opt_test(au_mntflags(sb), XINO))
    + return iunique(sb, AUFS_FIRST_INO);
    +
    + sbinfo = au_sbi(sb);
    + mutex_lock(&sbinfo->si_xib_mtx);
    + p = sbinfo->si_xib_buf;
    + free_bit = sbinfo->si_xib_next_bit;
    + if (free_bit < page_bits && !test_bit(free_bit, p))
    + goto out; /* success */
    + free_bit = find_first_zero_bit(p, page_bits);
    + if (free_bit < page_bits)
    + goto out; /* success */
    +
    + pindex = sbinfo->si_xib_last_pindex;
    + for (ul = pindex - 1; ul < ULONG_MAX; ul--) {
    + err = xib_pindex(sb, ul);
    + if (unlikely(err))
    + goto out_err;
    + free_bit = find_first_zero_bit(p, page_bits);
    + if (free_bit < page_bits)
    + goto out; /* success */
    + }
    +
    + file = sbinfo->si_xib;
    + pend = i_size_read(file->f_dentry->d_inode) / PAGE_SIZE;
    + for (ul = pindex + 1; ul <= pend; ul++) {
    + err = xib_pindex(sb, ul);
    + if (unlikely(err))
    + goto out_err;
    + free_bit = find_first_zero_bit(p, page_bits);
    + if (free_bit < page_bits)
    + goto out; /* success */
    + }
    + BUG();
    +
    + out:
    + set_bit(free_bit, p);
    + sbinfo->si_xib_next_bit++;
    + pindex = sbinfo->si_xib_last_pindex;
    + mutex_unlock(&sbinfo->si_xib_mtx);
    + ino = xib_calc_ino(pindex, free_bit);
    + AuDbg("i%lu\n", (unsigned long)ino);
    + return ino;
    + out_err:
    + mutex_unlock(&sbinfo->si_xib_mtx);
    + AuDbg("i0\n");
    + return 0;
    +}
    +
    +/*
    + * read @ino from xinofile for the specified branch{@sb, @bindex}
    + * at the position of @h_ino.
    + * if @ino does not exist and @do_new is true, get new one.
    + */
    +int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
    + ino_t *ino)
    +{
    + int err;
    + ssize_t sz;
    + loff_t pos;
    + struct file *file;
    + struct au_sbinfo *sbinfo;
    +
    + *ino = 0;
    + if (!au_opt_test(au_mntflags(sb), XINO))
    + return 0; /* no xino */
    +
    + err = 0;
    + sbinfo = au_sbi(sb);
    + pos = h_ino;
    + if (unlikely(au_loff_max / sizeof(*ino) - 1 < pos)) {
    + AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
    + return -EFBIG;
    + }
    + pos *= sizeof(*ino);
    +
    + file = au_sbr(sb, bindex)->br_xino.xi_file;
    + if (i_size_read(file->f_dentry->d_inode) < pos + sizeof(*ino))
    + return 0; /* no ino */
    +
    + sz = xino_fread(sbinfo->si_xread, file, ino, sizeof(*ino), &pos);
    + if (sz == sizeof(*ino))
    + return 0; /* success */
    +
    + err = sz;
    + if (unlikely(sz >= 0)) {
    + err = -EIO;
    + AuIOErr("xino read error (%zd)\n", sz);
    + }
    +
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/* create and set a new xino file */
    +
    +struct file *au_xino_create(struct super_block *sb, char *fname, int silent)
    +{
    + struct file *file;
    + struct dentry *h_parent, *d;
    + struct inode *h_dir;
    + int err;
    +
    + /*
    + * at mount-time, and the xino file is the default path,
    + * hinotify is disabled so we have no inotify events to ignore.
    + * when a user specified the xino, we cannot get au_hdir to be ignored.
    + */
    + file = vfsub_filp_open(fname, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
    + S_IRUGO | S_IWUGO);
    + if (IS_ERR(file)) {
    + if (!silent)
    + AuErr("open %s(%ld)\n", fname, PTR_ERR(file));
    + return file;
    + }
    +
    + /* keep file count */
    + h_parent = dget_parent(file->f_dentry);
    + h_dir = h_parent->d_inode;
    + mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
    + /* mnt_want_write() is unnecessary here */
    + err = vfsub_unlink(h_dir, &file->f_path, /*force*/0);
    + mutex_unlock(&h_dir->i_mutex);
    + dput(h_parent);
    + if (unlikely(err)) {
    + if (!silent)
    + AuErr("unlink %s(%d)\n", fname, err);
    + goto out;
    + }
    +
    + err = -EINVAL;
    + d = file->f_dentry;
    + if (unlikely(sb == d->d_sb)) {
    + if (!silent)
    + AuErr("%s must be outside\n", fname);
    + goto out;
    + }
    + if (unlikely(au_test_fs_bad_xino(d->d_sb))) {
    + if (!silent)
    + AuErr("xino doesn't support %s(%s)\n",
    + fname, au_sbtype(d->d_sb));
    + goto out;
    + }
    + return file; /* success */
    +
    + out:
    + fput(file);
    + file = ERR_PTR(err);
    + return file;
    +}
    +
    +/*
    + * find another branch who is on the same filesystem of the specified
    + * branch{@btgt}. search until @bend.
    + */
    +static int is_sb_shared(struct super_block *sb, aufs_bindex_t btgt,
    + aufs_bindex_t bend)
    +{
    + aufs_bindex_t bindex;
    + struct super_block *tgt_sb = au_sbr_sb(sb, btgt);
    +
    + for (bindex = 0; bindex < btgt; bindex++)
    + if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
    + return bindex;
    + for (bindex++; bindex <= bend; bindex++)
    + if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
    + return bindex;
    + return -1;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/*
    + * initialize the xinofile for the specified branch @br
    + * at the place/path where @base_file indicates.
    + * test whether another branch is on the same filesystem or not,
    + * if @do_test is true.
    + */
    +int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t h_ino,
    + struct file *base_file, int do_test)
    +{
    + int err;
    + ino_t ino;
    + aufs_bindex_t bend, bindex;
    + struct au_branch *shared_br, *b;
    + struct file *file;
    + struct super_block *tgt_sb;
    +
    + shared_br = NULL;
    + bend = au_sbend(sb);
    + if (do_test) {
    + tgt_sb = br->br_mnt->mnt_sb;
    + for (bindex = 0; bindex <= bend; bindex++) {
    + b = au_sbr(sb, bindex);
    + if (tgt_sb == b->br_mnt->mnt_sb) {
    + shared_br = b;
    + break;
    + }
    + }
    + }
    +
    + if (!shared_br || !shared_br->br_xino.xi_file) {
    + struct au_xino_lock_dir ldir;
    +
    + au_xino_lock_dir(sb, base_file, &ldir);
    + /* mnt_want_write() is unnecessary here */
    + file = au_xino_create2(base_file, NULL);
    + au_xino_unlock_dir(&ldir);
    + err = PTR_ERR(file);
    + if (IS_ERR(file))
    + goto out;
    + br->br_xino.xi_file = file;
    + } else {
    + br->br_xino.xi_file = shared_br->br_xino.xi_file;
    + get_file(br->br_xino.xi_file);
    + }
    +
    + ino = AUFS_ROOT_INO;
    + err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
    + h_ino, ino);
    + if (!err)
    + return 0; /* success */
    +
    +
    + out:
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/* trucate a xino bitmap file */
    +
    +/* todo: slow */
    +static int do_xib_restore(struct super_block *sb, struct file *file, void *page)
    +{
    + int err, bit;
    + ssize_t sz;
    + unsigned long pindex;
    + loff_t pos, pend;
    + struct au_sbinfo *sbinfo;
    + au_readf_t func;
    + ino_t *ino;
    + unsigned long *p;
    +
    + err = 0;
    + sbinfo = au_sbi(sb);
    + p = sbinfo->si_xib_buf;
    + func = sbinfo->si_xread;
    + pend = i_size_read(file->f_dentry->d_inode);
    + pos = 0;
    + while (pos < pend) {
    + sz = xino_fread(func, file, page, PAGE_SIZE, &pos);
    + err = sz;
    + if (unlikely(sz <= 0))
    + goto out;
    +
    + err = 0;
    + for (ino = page; sz > 0; ino++, sz -= sizeof(ino)) {
    + if (unlikely(*ino < AUFS_FIRST_INO))
    + continue;
    +
    + xib_calc_bit(*ino, &pindex, &bit);
    + AuDebugOn(page_bits <= bit);
    + err = xib_pindex(sb, pindex);
    + if (!err)
    + set_bit(bit, p);
    + else
    + goto out;
    + }
    + }
    +
    + out:
    + return err;
    +}
    +
    +static int xib_restore(struct super_block *sb)
    +{
    + int err;
    + aufs_bindex_t bindex, bend;
    + void *page;
    +
    + err = -ENOMEM;
    + page = (void *)__get_free_page(GFP_NOFS);
    + if (unlikely(!page))
    + goto out;
    +
    + err = 0;
    + bend = au_sbend(sb);
    + for (bindex = 0; !err && bindex <= bend; bindex++)
    + if (!bindex || is_sb_shared(sb, bindex, bindex - 1) < 0)
    + err = do_xib_restore
    + (sb, au_sbr(sb, bindex)->br_xino.xi_file, page);
    + else
    + AuDbg("b%d\n", bindex);
    + free_page((unsigned long)page);
    +
    + out:
    + return err;
    +}
    +
    +int au_xib_trunc(struct super_block *sb)
    +{
    + int err;
    + ssize_t sz;
    + loff_t pos;
    + struct au_xino_lock_dir ldir;
    + struct au_sbinfo *sbinfo;
    + unsigned long *p;
    + struct file *file;
    +
    + err = 0;
    + sbinfo = au_sbi(sb);
    + if (!au_opt_test(sbinfo->si_mntflags, XINO))
    + goto out;
    +
    + file = sbinfo->si_xib;
    + if (i_size_read(file->f_dentry->d_inode) <= PAGE_SIZE)
    + goto out;
    +
    + au_xino_lock_dir(sb, file, &ldir);
    + /* mnt_want_write() is unnecessary here */
    + file = au_xino_create2(sbinfo->si_xib, NULL);
    + au_xino_unlock_dir(&ldir);
    + err = PTR_ERR(file);
    + if (IS_ERR(file))
    + goto out;
    + fput(sbinfo->si_xib);
    + sbinfo->si_xib = file;
    +
    + p = sbinfo->si_xib_buf;
    + memset(p, 0, PAGE_SIZE);
    + pos = 0;
    + sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xib, p, PAGE_SIZE, &pos);
    + if (unlikely(sz != PAGE_SIZE)) {
    + err = sz;
    + AuIOErr("err %d\n", err);
    + if (sz >= 0)
    + err = -EIO;
    + goto out;
    + }
    +
    + mutex_lock(&sbinfo->si_xib_mtx);
    + /* mnt_want_write() is unnecessary here */
    + err = xib_restore(sb);
    + mutex_unlock(&sbinfo->si_xib_mtx);
    +
    +out:
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/*
    + * xino mount option handlers
    + */
    +static au_readf_t find_readf(struct file *h_file)
    +{
    + const struct file_operations *fop = h_file->f_op;
    +
    + if (fop) {
    + if (fop->read)
    + return fop->read;
    + if (fop->aio_read)
    + return do_sync_read;
    + }
    + return ERR_PTR(-ENOSYS);
    +}
    +
    +static au_writef_t find_writef(struct file *h_file)
    +{
    + const struct file_operations *fop = h_file->f_op;
    +
    + if (fop) {
    + if (fop->write)
    + return fop->write;
    + if (fop->aio_write)
    + return do_sync_write;
    + }
    + return ERR_PTR(-ENOSYS);
    +}
    +
    +/* xino bitmap */
    +static void xino_clear_xib(struct super_block *sb)
    +{
    + struct au_sbinfo *sbinfo;
    +
    + sbinfo = au_sbi(sb);
    + sbinfo->si_xread = NULL;
    + sbinfo->si_xwrite = NULL;
    + if (sbinfo->si_xib)
    + fput(sbinfo->si_xib);
    + sbinfo->si_xib = NULL;
    + free_page((unsigned long)sbinfo->si_xib_buf);
    + sbinfo->si_xib_buf = NULL;
    +}
    +
    +static int au_xino_set_xib(struct super_block *sb, struct file *base)
    +{
    + int err;
    + loff_t pos;
    + struct au_sbinfo *sbinfo;
    + struct file *file;
    +
    + sbinfo = au_sbi(sb);
    + file = au_xino_create2(base, sbinfo->si_xib);
    + err = PTR_ERR(file);
    + if (IS_ERR(file))
    + goto out;
    + if (sbinfo->si_xib)
    + fput(sbinfo->si_xib);
    + sbinfo->si_xib = file;
    + sbinfo->si_xread = find_readf(file);
    + sbinfo->si_xwrite = find_writef(file);
    +
    + err = -ENOMEM;
    + if (!sbinfo->si_xib_buf)
    + sbinfo->si_xib_buf = (void *)get_zeroed_page(GFP_NOFS);
    + if (unlikely(!sbinfo->si_xib_buf))
    + goto out_unset;
    +
    + sbinfo->si_xib_last_pindex = 0;
    + sbinfo->si_xib_next_bit = 0;
    + if (i_size_read(file->f_dentry->d_inode) < PAGE_SIZE) {
    + pos = 0;
    + err = xino_fwrite(sbinfo->si_xwrite, file, sbinfo->si_xib_buf,
    + PAGE_SIZE, &pos);
    + if (unlikely(err != PAGE_SIZE))
    + goto out_free;
    + }
    + err = 0;
    + goto out; /* success */
    +
    + out_free:
    + free_page((unsigned long)sbinfo->si_xib_buf);
    + sbinfo->si_xib_buf = NULL;
    + if (err >= 0)
    + err = -EIO;
    + out_unset:
    + fput(sbinfo->si_xib);
    + sbinfo->si_xib = NULL;
    + sbinfo->si_xread = NULL;
    + sbinfo->si_xwrite = NULL;
    + out:
    + return err;
    +}
    +
    +/* xino for each branch */
    +static void xino_clear_br(struct super_block *sb)
    +{
    + aufs_bindex_t bindex, bend;
    + struct au_branch *br;
    +
    + bend = au_sbend(sb);
    + for (bindex = 0; bindex <= bend; bindex++) {
    + br = au_sbr(sb, bindex);
    + if (!br || !br->br_xino.xi_file)
    + continue;
    +
    + fput(br->br_xino.xi_file);
    + br->br_xino.xi_file = NULL;
    + }
    +}
    +
    +static int au_xino_set_br(struct super_block *sb, struct file *base)
    +{
    + int err;
    + ino_t ino;
    + aufs_bindex_t bindex, bend, bshared;
    + struct {
    + struct file *old, *new;
    + } *fpair, *p;
    + struct au_branch *br;
    + struct inode *inode;
    + au_writef_t writef;
    +
    + err = -ENOMEM;
    + bend = au_sbend(sb);
    + fpair = kcalloc(bend + 1, sizeof(*fpair), GFP_NOFS);
    + if (unlikely(!fpair))
    + goto out;
    +
    + inode = sb->s_root->d_inode;
    + ino = AUFS_ROOT_INO;
    + writef = au_sbi(sb)->si_xwrite;
    + for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
    + br = au_sbr(sb, bindex);
    + bshared = is_sb_shared(sb, bindex, bindex - 1);
    + if (bshared >= 0) {
    + /* shared xino */
    + *p = fpair[bshared];
    + get_file(p->new);
    + }
    +
    + if (!p->new) {
    + /* new xino */
    + p->old = br->br_xino.xi_file;
    + p->new = au_xino_create2(base, br->br_xino.xi_file);
    + err = PTR_ERR(p->new);
    + if (IS_ERR(p->new)) {
    + p->new = NULL;
    + goto out_pair;
    + }
    + }
    +
    + err = au_xino_do_write(writef, p->new,
    + au_h_iptr(inode, bindex)->i_ino, ino);
    + if (unlikely(err))
    + goto out_pair;
    + }
    +
    + for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
    + br = au_sbr(sb, bindex);
    + if (br->br_xino.xi_file)
    + fput(br->br_xino.xi_file);
    + get_file(p->new);
    + br->br_xino.xi_file = p->new;
    + }
    +
    + out_pair:
    + for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++)
    + if (p->new)
    + fput(p->new);
    + else
    + break;
    + kfree(fpair);
    + out:
    + return err;
    +}
    +
    +void au_xino_clr(struct super_block *sb)
    +{
    + struct au_sbinfo *sbinfo;
    +
    + xino_clear_xib(sb);
    + xino_clear_br(sb);
    + sbinfo = au_sbi(sb);
    + /* lvalue, do not call au_mntflags() */
    + au_opt_clr(sbinfo->si_mntflags, XINO);
    +}
    +
    +int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount)
    +{
    + int err, skip;
    + struct dentry *parent, *cur_parent;
    + struct qstr *dname, *cur_name;
    + struct file *cur_xino;
    + struct inode *dir;
    + struct au_sbinfo *sbinfo;
    +
    + err = 0;
    + sbinfo = au_sbi(sb);
    + parent = dget_parent(xino->file->f_dentry);
    + if (remount) {
    + skip = 0;
    + dname = &xino->file->f_dentry->d_name;
    + cur_xino = sbinfo->si_xib;
    + if (cur_xino) {
    + cur_parent = dget_parent(cur_xino->f_dentry);
    + cur_name = &cur_xino->f_dentry->d_name;
    + skip = (cur_parent == parent
    + && dname->len == cur_name->len
    + && !memcmp(dname->name, cur_name->name,
    + dname->len));
    + dput(cur_parent);
    + }
    + if (skip)
    + goto out;
    + }
    +
    + au_opt_set(sbinfo->si_mntflags, XINO);
    + dir = parent->d_inode;
    + mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
    + /* mnt_want_write() is unnecessary here */
    + err = au_xino_set_xib(sb, xino->file);
    + if (!err)
    + err = au_xino_set_br(sb, xino->file);
    + mutex_unlock(&dir->i_mutex);
    + if (!err)
    + goto out; /* success */
    +
    + /* reset all */
    + AuIOErr("failed creating xino(%d).\n", err);
    +
    + out:
    + dput(parent);
    + return err;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +/*
    + * create a xinofile at the default place/path.
    + */
    +struct file *au_xino_def(struct super_block *sb)
    +{
    + struct file *file;
    + char *page, *p;
    + struct au_branch *br;
    + struct super_block *h_sb;
    + struct path path;
    + aufs_bindex_t bend, bindex, bwr;
    +
    + br = NULL;
    + bend = au_sbend(sb);
    + bwr = -1;
    + for (bindex = 0; bindex <= bend; bindex++) {
    + br = au_sbr(sb, bindex);
    + if (au_br_writable(br->br_perm)
    + && !au_test_fs_bad_xino(br->br_mnt->mnt_sb)) {
    + bwr = bindex;
    + break;
    + }
    + }
    +
    + if (bwr >= 0) {
    + file = ERR_PTR(-ENOMEM);
    + page = __getname();
    + if (unlikely(!page))
    + goto out;
    + path.mnt = br->br_mnt;
    + path.dentry = au_h_dptr(sb->s_root, bwr);
    + p = d_path(&path, page, PATH_MAX - sizeof(AUFS_XINO_FNAME));
    + file = (void *)p;
    + if (!IS_ERR(p)) {
    + strcat(p, "/" AUFS_XINO_FNAME);
    + AuDbg("%s\n", p);
    + file = au_xino_create(sb, p, /*silent*/0);
    + if (!IS_ERR(file))
    + au_xino_brid_set(sb, br->br_id);
    + }
    + __putname(page);
    + } else {
    + file = au_xino_create(sb, AUFS_XINO_DEFPATH, /*silent*/0);
    + if (IS_ERR(file))
    + goto out;
    + h_sb = file->f_dentry->d_sb;
    + if (unlikely(au_test_fs_bad_xino(h_sb))) {
    + AuErr("xino doesn't support %s(%s)\n",
    + AUFS_XINO_DEFPATH, au_sbtype(h_sb));
    + fput(file);
    + file = ERR_PTR(-EINVAL);
    + }
    + if (!IS_ERR(file))
    + au_xino_brid_set(sb, -1);
    + }
    +
    + out:
    + return file;
    +}
    +
    +/* ---------------------------------------------------------------------- */
    +
    +int au_xino_path(struct seq_file *seq, struct file *file)
    +{
    + int err;
    +
    + err = au_seq_path(seq, &file->f_path);
    + if (unlikely(err < 0))
    + goto out;
    +
    + err = 0;
    +#define Deleted "\\040(deleted)"
    + seq->count -= sizeof(Deleted) - 1;
    + AuDebugOn(memcmp(seq->buf + seq->count, Deleted,
    + sizeof(Deleted) - 1));
    +#undef Deleted
    +
    + out:
    + return err;
    +}
    --
    1.6.1.284.g5dc13


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