[Aufs 05/25] aufs branch directory/filesystem

J. R. Okajima
2009-03-09T03:34:37Z

branch management

Signed-off-by: J. R. Okajima <hooanon05@yahoo.co.jp>
---
fs/aufs/branch.c | 944 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/aufs/branch.h | 200 ++++++++++++
2 files changed, 1144 insertions(+), 0 deletions(-)
create mode 100644 fs/aufs/branch.c
create mode 100644 fs/aufs/branch.h

diff --git a/fs/aufs/branch.c b/fs/aufs/branch.c
new file mode 100644
index 0000000..232f5b3
--- /dev/null
+++ b/fs/aufs/branch.c
@@ -0,0 +1,944 @@
+/*
+ * 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.
+ */
+
+/*
+ * branch management
+ */
+
+#include "aufs.h"
+
+/*
+ * free a single branch
+ */
+static void au_br_do_free(struct au_branch *br)
+{
+ int i;
+ struct au_wbr *wbr;
+
+ if (br->br_xino.xi_file)
+ fput(br->br_xino.xi_file);
+ mutex_destroy(&br->br_xino.xi_nondir_mtx);
+
+ AuDebugOn(atomic_read(&br->br_count));
+
+ wbr = br->br_wbr;
+ if (wbr) {
+ for (i = 0; i < AuBrWh_Last; i++)
+ dput(wbr->wbr_wh[i]);
+ AuDebugOn(atomic_read(&wbr->wbr_wh_running));
+ au_rwsem_destroy(&wbr->wbr_wh_rwsem);
+ }
+
+ /* some filesystems acquire extra lock */
+ lockdep_off();
+ mntput(br->br_mnt);
+ lockdep_on();
+
+ kfree(wbr);
+ kfree(br);
+}
+
+/*
+ * frees all branches
+ */
+void au_br_free(struct au_sbinfo *sbinfo)
+{
+ aufs_bindex_t bmax;
+ struct au_branch **br;
+
+ bmax = sbinfo->si_bend + 1;
+ br = sbinfo->si_branch;
+ while (bmax--)
+ au_br_do_free(*br++);
+}
+
+/*
+ * find the index of a branch which is specified by @br_id.
+ */
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id)
+{
+ aufs_bindex_t bindex, bend;
+
+ bend = au_sbend(sb);
+ for (bindex = 0; bindex <= bend; bindex++)
+ if (au_sbr_id(sb, bindex) == br_id)
+ return bindex;
+ return -1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * add a branch
+ */
+
+static int test_overlap(struct super_block *sb, struct dentry *h_d1,
+ struct dentry *h_d2)
+{
+ if (unlikely(h_d1 == h_d2))
+ return 1;
+ return !!au_test_subdir(h_d1, h_d2)
+ || !!au_test_subdir(h_d2, h_d1)
+ || au_test_loopback_overlap(sb, h_d1, h_d2)
+ || au_test_loopback_overlap(sb, h_d2, h_d1);
+}
+
+/*
+ * returns a newly allocated branch. @new_nbranch is a number of branches
+ * after adding a branch.
+ */
+static struct au_branch *au_br_alloc(struct super_block *sb, int new_nbranch,
+ int perm)
+{
+ struct au_branch *add_branch;
+ struct dentry *root;
+
+ root = sb->s_root;
+ add_branch = kmalloc(sizeof(*add_branch), GFP_NOFS);
+ if (unlikely(!add_branch))
+ goto out;
+
+ add_branch->br_wbr = NULL;
+ if (au_br_writable(perm)) {
+ /* may be freed separately at changing the branch permission */
+ add_branch->br_wbr = kmalloc(sizeof(*add_branch->br_wbr),
+ GFP_NOFS);
+ if (unlikely(!add_branch->br_wbr))
+ goto out_br;
+ }
+
+ if (unlikely(au_sbr_realloc(au_sbi(sb), new_nbranch)
+ || au_di_realloc(au_di(root), new_nbranch)
+ || au_ii_realloc(au_ii(root->d_inode), new_nbranch)))
+ goto out_wbr;
+ return add_branch; /* success */
+
+ out_wbr:
+ kfree(add_branch->br_wbr);
+ out_br:
+ kfree(add_branch);
+ out:
+ return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * test if the branch permission is legal or not.
+ */
+static int test_br(struct inode *inode, int brperm, char *path)
+{
+ int err;
+
+ err = 0;
+ if (unlikely(au_br_writable(brperm) && IS_RDONLY(inode))) {
+ AuErr("write permission for readonly mount or inode, %s\n",
+ path);
+ err = -EINVAL;
+ }
+
+ return err;
+}
+
+/*
+ * returns:
+ * 0: success, the caller will add it
+ * plus: success, it is already unified, the caller should ignore it
+ * minus: error
+ */
+static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+ int err;
+ aufs_bindex_t bend, bindex;
+ struct dentry *root;
+ struct inode *inode, *h_inode;
+
+ root = sb->s_root;
+ bend = au_sbend(sb);
+ if (unlikely(bend >= 0
+ && au_find_dbindex(root, add->path.dentry) >= 0)) {
+ err = 1;
+ if (!remount) {
+ err = -EINVAL;
+ AuErr("%s duplicated\n", add->pathname);
+ }
+ goto out;
+ }
+
+ err = -ENOSPC; /* -E2BIG; */
+ if (unlikely(AUFS_BRANCH_MAX <= add->bindex
+ || AUFS_BRANCH_MAX - 1 <= bend)) {
+ AuErr("number of branches exceeded %s\n", add->pathname);
+ goto out;
+ }
+
+ err = -EDOM;
+ if (unlikely(add->bindex < 0 || bend + 1 < add->bindex)) {
+ AuErr("bad index %d\n", add->bindex);
+ goto out;
+ }
+
+ inode = add->path.dentry->d_inode;
+ err = -ENOENT;
+ if (unlikely(!inode->i_nlink)) {
+ AuErr("no existence %s\n", add->pathname);
+ goto out;
+ }
+
+ err = -EINVAL;
+ if (unlikely(inode->i_sb == sb)) {
+ AuErr("%s must be outside\n", add->pathname);
+ goto out;
+ }
+
+ if (unlikely(au_test_fs_unsuppoted(inode->i_sb))) {
+ AuErr("unsupported filesystem, %s (%s)\n",
+ add->pathname, au_sbtype(inode->i_sb));
+ goto out;
+ }
+
+ err = test_br(add->path.dentry->d_inode, add->perm, add->pathname);
+ if (unlikely(err))
+ goto out;
+
+ if (bend < 0)
+ return 0; /* success */
+
+ err = -EINVAL;
+ for (bindex = 0; bindex <= bend; bindex++)
+ if (unlikely(test_overlap(sb, add->path.dentry,
+ au_h_dptr(root, bindex)))) {
+ AuErr("%s is overlapped\n", add->pathname);
+ goto out;
+ }
+
+ err = 0;
+ if (au_opt_test(au_mntflags(sb), WARN_PERM)) {
+ h_inode = au_h_dptr(root, 0)->d_inode;
+ if ((h_inode->i_mode & S_IALLUGO) != (inode->i_mode & S_IALLUGO)
+ || h_inode->i_uid != inode->i_uid
+ || h_inode->i_gid != inode->i_gid)
+ AuWarn("uid/gid/perm %s %u/%u/0%o, %u/%u/0%o\n",
+ add->pathname,
+ inode->i_uid, inode->i_gid,
+ (inode->i_mode & S_IALLUGO),
+ h_inode->i_uid, h_inode->i_gid,
+ (h_inode->i_mode & S_IALLUGO));
+ }
+
+ out:
+ return err;
+}
+
+/*
+ * initialize or clean the whiteouts for an adding branch
+ */
+static int au_br_init_wh(struct super_block *sb, struct au_branch *br,
+ int new_perm, struct dentry *h_root)
+{
+ int err, old_perm;
+ aufs_bindex_t bindex;
+ struct mutex *h_mtx;
+ struct au_wbr *wbr;
+ struct au_hinode *hdir;
+
+ wbr = br->br_wbr;
+ old_perm = br->br_perm;
+ br->br_perm = new_perm;
+ hdir = NULL;
+ h_mtx = NULL;
+ bindex = au_br_index(sb, br->br_id);
+ if (0 <= bindex) {
+ hdir = au_hi(sb->s_root->d_inode, bindex);
+ au_hin_imtx_lock_nested(hdir, AuLsc_I_PARENT);
+ } else {
+ h_mtx = &h_root->d_inode->i_mutex;
+ mutex_lock_nested(h_mtx, AuLsc_I_PARENT);
+ }
+ if (!wbr)
+ err = au_wh_init(h_root, br, sb);
+ else {
+ wbr_wh_write_lock(wbr);
+ err = au_wh_init(h_root, br, sb);
+ wbr_wh_write_unlock(wbr);
+ }
+ if (hdir)
+ au_hin_imtx_unlock(hdir);
+ else
+ mutex_unlock(h_mtx);
+ br->br_perm = old_perm;
+
+ if (!err && wbr && !au_br_writable(new_perm)) {
+ kfree(wbr);
+ br->br_wbr = NULL;
+ }
+
+ return err;
+}
+
+static int au_wbr_init(struct au_branch *br, struct super_block *sb,
+ int perm, struct path *path)
+{
+ int err;
+ struct au_wbr *wbr;
+
+ wbr = br->br_wbr;
+ init_rwsem(&wbr->wbr_wh_rwsem);
+ memset(wbr->wbr_wh, 0, sizeof(wbr->wbr_wh));
+ atomic_set(&wbr->wbr_wh_running, 0);
+ wbr->wbr_bytes = 0;
+
+ err = au_br_init_wh(sb, br, perm, path->dentry);
+
+ return err;
+}
+
+/* intialize a new branch */
+static int au_br_init(struct au_branch *br, struct super_block *sb,
+ struct au_opt_add *add)
+{
+ int err;
+
+ err = 0;
+ br->br_xino.xi_file = NULL;
+ mutex_init(&br->br_xino.xi_nondir_mtx);
+ br->br_perm = add->perm;
+ br->br_mnt = add->path.mnt; /* set first, mntget() later */
+ atomic_set(&br->br_count, 0);
+ br->br_xino_upper = AUFS_XINO_TRUNC_INIT;
+ atomic_set(&br->br_xino_running, 0);
+ br->br_id = au_new_br_id(sb);
+
+ if (au_br_writable(add->perm)) {
+ err = au_wbr_init(br, sb, add->perm, &add->path);
+ if (unlikely(err))
+ goto out;
+ }
+
+ if (au_opt_test(au_mntflags(sb), XINO)) {
+ err = au_xino_br(sb, br, add->path.dentry->d_inode->i_ino,
+ au_sbr(sb, 0)->br_xino.xi_file, /*do_test*/1);
+ if (unlikely(err)) {
+ AuDebugOn(br->br_xino.xi_file);
+ goto out;
+ }
+ }
+
+ sysaufs_br_init(br);
+ mntget(add->path.mnt);
+
+ out:
+ return err;
+}
+
+static void au_br_do_add_brp(struct au_sbinfo *sbinfo, aufs_bindex_t bindex,
+ struct au_branch *br, aufs_bindex_t bend,
+ aufs_bindex_t amount)
+{
+ struct au_branch **brp;
+
+ brp = sbinfo->si_branch + bindex;
+ memmove(brp + 1, brp, sizeof(*brp) * amount);
+ *brp = br;
+ sbinfo->si_bend++;
+ if (unlikely(bend < 0))
+ sbinfo->si_bend = 0;
+}
+
+static void au_br_do_add_hdp(struct au_dinfo *dinfo, aufs_bindex_t bindex,
+ aufs_bindex_t bend, aufs_bindex_t amount)
+{
+ struct au_hdentry *hdp;
+
+ hdp = dinfo->di_hdentry + bindex;
+ memmove(hdp + 1, hdp, sizeof(*hdp) * amount);
+ au_h_dentry_init(hdp);
+ dinfo->di_bend++;
+ if (unlikely(bend < 0))
+ dinfo->di_bstart = 0;
+}
+
+static void au_br_do_add_hip(struct au_iinfo *iinfo, aufs_bindex_t bindex,
+ aufs_bindex_t bend, aufs_bindex_t amount)
+{
+ struct au_hinode *hip;
+
+ hip = iinfo->ii_hinode + bindex;
+ memmove(hip + 1, hip, sizeof(*hip) * amount);
+ hip->hi_inode = NULL;
+ au_hin_init(hip, NULL);
+ iinfo->ii_bend++;
+ if (unlikely(bend < 0))
+ iinfo->ii_bstart = 0;
+}
+
+static void au_br_do_add(struct super_block *sb, struct dentry *h_dentry,
+ struct au_branch *br, aufs_bindex_t bindex)
+{
+ struct dentry *root;
+ struct inode *root_inode;
+ aufs_bindex_t bend, amount;
+
+ root = sb->s_root;
+ root_inode = root->d_inode;
+ au_plink_block_maintain(sb);
+ bend = au_sbend(sb);
+ amount = bend + 1 - bindex;
+ au_br_do_add_brp(au_sbi(sb), bindex, br, bend, amount);
+ au_br_do_add_hdp(au_di(root), bindex, bend, amount);
+ au_br_do_add_hip(au_ii(root_inode), bindex, bend, amount);
+ au_set_h_dptr(root, bindex, dget(h_dentry));
+ au_set_h_iptr(root_inode, bindex, au_igrab(h_dentry->d_inode),
+ /*flags*/0);
+}
+
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+ int err;
+ unsigned long long maxb;
+ aufs_bindex_t bend, add_bindex;
+ struct dentry *root, *h_dentry;
+ struct inode *root_inode;
+ struct au_branch *add_branch;
+
+ root = sb->s_root;
+ root_inode = root->d_inode;
+ IMustLock(root_inode);
+ err = test_add(sb, add, remount);
+ if (unlikely(err < 0))
+ goto out;
+ if (err) {
+ err = 0;
+ goto out; /* success */
+ }
+
+ bend = au_sbend(sb);
+ add_branch = au_br_alloc(sb, bend + 2, add->perm);
+ err = PTR_ERR(add_branch);
+ if (IS_ERR(add_branch))
+ goto out;
+
+ err = au_br_init(add_branch, sb, add);
+ if (unlikely(err)) {
+ au_br_do_free(add_branch);
+ goto out;
+ }
+
+ add_bindex = add->bindex;
+ h_dentry = add->path.dentry;
+ if (!remount)
+ au_br_do_add(sb, h_dentry, add_branch, add_bindex);
+ else {
+ sysaufs_brs_del(sb, add_bindex);
+ au_br_do_add(sb, h_dentry, add_branch, add_bindex);
+ sysaufs_brs_add(sb, add_bindex);
+ }
+
+ if (!add_bindex)
+ au_cpup_attr_all(root_inode, /*force*/1);
+ else
+ au_add_nlink(root_inode, h_dentry->d_inode);
+ maxb = h_dentry->d_sb->s_maxbytes;
+ if (sb->s_maxbytes < maxb)
+ sb->s_maxbytes = maxb;
+
+ /*
+ * this test/set prevents aufs from handling unnecesary inotify events
+ * of xino files, in a case of re-adding a writable branch which was
+ * once detached from aufs.
+ */
+ if (au_xino_brid(sb) < 0
+ && au_br_writable(add_branch->br_perm)
+ && !au_test_fs_bad_xino(h_dentry->d_sb)
+ && add_branch->br_xino.xi_file
+ && add_branch->br_xino.xi_file->f_dentry->d_parent == h_dentry)
+ au_xino_brid_set(sb, add_branch->br_id);
+
+ out:
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * delete a branch
+ */
+
+/* to show the line number, do not make it inlined function */
+#define AuVerbose(do_info, fmt, args...) do { \
+ if (do_info) \
+ AuInfo(fmt, ##args); \
+} while (0)
+
+/*
+ * test if the branch is deletable or not.
+ */
+static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
+ unsigned int sigen)
+{
+ int err, i, j, ndentry;
+ aufs_bindex_t bstart, bend;
+ unsigned char verbose;
+ struct au_dcsub_pages dpages;
+ struct au_dpage *dpage;
+ struct dentry *d;
+ struct inode *inode;
+
+ err = au_dpages_init(&dpages, GFP_NOFS);
+ if (unlikely(err))
+ goto out;
+ err = au_dcsub_pages(&dpages, root, NULL, NULL);
+ if (unlikely(err))
+ goto out_dpages;
+
+ verbose = !!au_opt_test(au_mntflags(root->d_sb), VERBOSE);
+ for (i = 0; !err && i < dpages.ndpage; i++) {
+ dpage = dpages.dpages + i;
+ ndentry = dpage->ndentry;
+ for (j = 0; !err && j < ndentry; j++) {
+ d = dpage->dentries[j];
+ AuDebugOn(!atomic_read(&d->d_count));
+ inode = d->d_inode;
+ if (au_digen(d) == sigen && au_iigen(inode) == sigen)
+ di_read_lock_child(d, AuLock_IR);
+ else {
+ di_write_lock_child(d);
+ err = au_reval_dpath(d, sigen);
+ if (!err)
+ di_downgrade_lock(d, AuLock_IR);
+ else {
+ di_write_unlock(d);
+ break;
+ }
+ }
+
+ bstart = au_dbstart(d);
+ bend = au_dbend(d);
+ if (bstart <= bindex
+ && bindex <= bend
+ && au_h_dptr(d, bindex)
+ && (!S_ISDIR(inode->i_mode) || bstart == bend)) {
+ err = -EBUSY;
+ AuVerbose(verbose, "busy %.*s\n", AuDLNPair(d));
+ }
+ di_read_unlock(d, AuLock_IR);
+ }
+ }
+
+ out_dpages:
+ au_dpages_free(&dpages);
+ out:
+ return err;
+}
+
+static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
+ unsigned int sigen)
+{
+ int err;
+ struct inode *i;
+ aufs_bindex_t bstart, bend;
+ unsigned char verbose;
+
+ err = 0;
+ verbose = !!au_opt_test(au_mntflags(sb), VERBOSE);
+ list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
+ AuDebugOn(!atomic_read(&i->i_count));
+ if (!list_empty(&i->i_dentry))
+ continue;
+
+ if (au_iigen(i) == sigen)
+ ii_read_lock_child(i);
+ else {
+ ii_write_lock_child(i);
+ err = au_refresh_hinode_self(i, /*do_attr*/1);
+ if (!err)
+ ii_downgrade_lock(i);
+ else {
+ ii_write_unlock(i);
+ break;
+ }
+ }
+
+ bstart = au_ibstart(i);
+ bend = au_ibend(i);
+ if (bstart <= bindex
+ && bindex <= bend
+ && au_h_iptr(i, bindex)
+ && (!S_ISDIR(i->i_mode) || bstart == bend)) {
+ err = -EBUSY;
+ AuVerbose(verbose, "busy i%lu\n", i->i_ino);
+ ii_read_unlock(i);
+ break;
+ }
+ ii_read_unlock(i);
+ }
+
+ return err;
+}
+
+static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
+{
+ int err;
+ unsigned int sigen;
+
+ sigen = au_sigen(root->d_sb);
+ DiMustNoWaiters(root);
+ IiMustNoWaiters(root->d_inode);
+ di_write_unlock(root);
+ err = test_dentry_busy(root, bindex, sigen);
+ if (!err)
+ err = test_inode_busy(root->d_sb, bindex, sigen);
+ di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
+
+ return err;
+}
+
+static void au_br_do_del_brp(struct au_sbinfo *sbinfo,
+ const aufs_bindex_t bindex,
+ const aufs_bindex_t bend)
+{
+ struct au_branch **brp, **p;
+
+ brp = sbinfo->si_branch + bindex;
+ if (bindex < bend)
+ memmove(brp, brp + 1, sizeof(*brp) * (bend - bindex));
+ sbinfo->si_branch[0 + bend] = NULL;
+ sbinfo->si_bend--;
+
+ p = krealloc(sbinfo->si_branch, sizeof(*p) * bend, GFP_NOFS);
+ if (p)
+ sbinfo->si_branch = p;
+}
+
+static void au_br_do_del_hdp(struct au_dinfo *dinfo, const aufs_bindex_t bindex,
+ const aufs_bindex_t bend)
+{
+ struct au_hdentry *hdp, *p;
+
+ hdp = dinfo->di_hdentry + bindex;
+ if (bindex < bend)
+ memmove(hdp, hdp + 1, sizeof(*hdp) * (bend - bindex));
+ dinfo->di_hdentry[0 + bend].hd_dentry = NULL;
+ dinfo->di_bend--;
+
+ p = krealloc(dinfo->di_hdentry, sizeof(*p) * bend, GFP_NOFS);
+ if (p)
+ dinfo->di_hdentry = p;
+}
+
+static void au_br_do_del_hip(struct au_iinfo *iinfo, const aufs_bindex_t bindex,
+ const aufs_bindex_t bend)
+{
+ struct au_hinode *hip, *p;
+
+ hip = iinfo->ii_hinode + bindex;
+ if (bindex < bend)
+ memmove(hip, hip + 1, sizeof(*hip) * (bend - bindex));
+ iinfo->ii_hinode[0 + bend].hi_inode = NULL;
+ au_hin_init(iinfo->ii_hinode + bend, NULL);
+ iinfo->ii_bend--;
+
+ p = krealloc(iinfo->ii_hinode, sizeof(*p) * bend, GFP_NOFS);
+ if (p)
+ iinfo->ii_hinode = p;
+}
+
+static void au_br_do_del(struct super_block *sb, aufs_bindex_t bindex,
+ struct au_branch *br)
+{
+ aufs_bindex_t bend;
+ struct au_sbinfo *sbinfo;
+ struct dentry *root;
+ struct inode *inode;
+
+ root = sb->s_root;
+ inode = root->d_inode;
+ au_plink_block_maintain(sb);
+ sbinfo = au_sbi(sb);
+ bend = sbinfo->si_bend;
+
+ dput(au_h_dptr(root, bindex));
+ au_hiput(au_hi(inode, bindex));
+ au_br_do_free(br);
+
+ au_br_do_del_brp(sbinfo, bindex, bend);
+ au_br_do_del_hdp(au_di(root), bindex, bend);
+ au_br_do_del_hip(au_ii(inode), bindex, bend);
+}
+
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
+{
+ int err, rerr, i;
+ unsigned int mnt_flags;
+ aufs_bindex_t bindex, bend, br_id;
+ unsigned char do_wh, verbose;
+ struct au_branch *br;
+ struct au_wbr *wbr;
+
+ err = 0;
+ bindex = au_find_dbindex(sb->s_root, del->h_path.dentry);
+ if (bindex < 0) {
+ if (remount)
+ goto out; /* success */
+ err = -ENOENT;
+ AuErr("%s no such branch\n", del->pathname);
+ goto out;
+ }
+ AuDbg("bindex b%d\n", bindex);
+
+ err = -EBUSY;
+ mnt_flags = au_mntflags(sb);
+ verbose = !!au_opt_test(mnt_flags, VERBOSE);
+ bend = au_sbend(sb);
+ if (unlikely(!bend)) {
+ AuVerbose(verbose, "no more branches left\n");
+ goto out;
+ }
+ br = au_sbr(sb, bindex);
+ i = atomic_read(&br->br_count);
+ if (unlikely(i)) {
+ AuVerbose(verbose, "%d file(s) opened\n", i);
+ goto out;
+ }
+
+ wbr = br->br_wbr;
+ do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_orph);
+ if (do_wh) {
+ for (i = 0; i < AuBrWh_Last; i++) {
+ dput(wbr->wbr_wh[i]);
+ wbr->wbr_wh[i] = NULL;
+ }
+ }
+
+ err = test_children_busy(sb->s_root, bindex);
+ if (unlikely(err)) {
+ if (do_wh)
+ goto out_wh;
+ goto out;
+ }
+
+ err = 0;
+ br_id = br->br_id;
+ if (!remount)
+ au_br_do_del(sb, bindex, br);
+ else {
+ sysaufs_brs_del(sb, bindex);
+ au_br_do_del(sb, bindex, br);
+ sysaufs_brs_add(sb, bindex);
+ }
+
+ if (!bindex)
+ au_cpup_attr_all(sb->s_root->d_inode, /*force*/1);
+ else
+ au_sub_nlink(sb->s_root->d_inode, del->h_path.dentry->d_inode);
+ if (au_opt_test(mnt_flags, PLINK))
+ au_plink_half_refresh(sb, br_id);
+
+ if (sb->s_maxbytes == del->h_path.dentry->d_sb->s_maxbytes) {
+ bend--;
+ sb->s_maxbytes = 0;
+ for (bindex = 0; bindex <= bend; bindex++) {
+ unsigned long long maxb;
+
+ maxb = au_sbr_sb(sb, bindex)->s_maxbytes;
+ if (sb->s_maxbytes < maxb)
+ sb->s_maxbytes = maxb;
+ }
+ }
+
+ if (au_xino_brid(sb) == br->br_id)
+ au_xino_brid_set(sb, -1);
+ goto out; /* success */
+
+ out_wh:
+ /* revert */
+ rerr = au_br_init_wh(sb, br, br->br_perm, del->h_path.dentry);
+ if (rerr)
+ AuWarn("failed re-creating base whiteout, %s. (%d)\n",
+ del->pathname, rerr);
+ out:
+ return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * change a branch permission
+ */
+
+static int do_need_sigen_inc(int a, int b)
+{
+ return au_br_whable(a) && !au_br_whable(b);
+}
+
+static int need_sigen_inc(int old, int new)
+{
+ return do_need_sigen_inc(old, new)
+ || do_need_sigen_inc(new, old);
+}
+
+static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
+{
+ int err;
+ unsigned long n, ul, bytes, files;
+ aufs_bindex_t bstart;
+ struct file *file, *hf, **a;
+ const int step_bytes = 1024, /* memory allocation unit */
+ step_files = step_bytes / sizeof(*a);
+
+ err = -ENOMEM;
+ n = 0;
+ bytes = step_bytes;
+ files = step_files;
+ a = kmalloc(bytes, GFP_NOFS);
+ if (unlikely(!a))
+ goto out;
+
+ /* no need file_list_lock() since sbinfo is locked? defered? */
+ list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
+ if (special_file(file->f_dentry->d_inode->i_mode))
+ continue;
+
+ AuDbg("%.*s\n", AuDLNPair(file->f_dentry));
+ fi_read_lock(file);
+ if (unlikely(au_test_mmapped(file))) {
+ err = -EBUSY;
+ FiMustNoWaiters(file);
+ fi_read_unlock(file);
+ goto out_free;
+ }
+
+ bstart = au_fbstart(file);
+ if (!S_ISREG(file->f_dentry->d_inode->i_mode)
+ || !(file->f_mode & FMODE_WRITE)
+ || bstart != bindex) {
+ FiMustNoWaiters(file);
+ fi_read_unlock(file);
+ continue;
+ }
+
+ hf = au_h_fptr(file, bstart);
+ FiMustNoWaiters(file);
+ fi_read_unlock(file);
+
+ if (n < files)
+ a[n++] = hf;
+ else {
+ void *p;
+
+ err = -ENOMEM;
+ bytes += step_bytes;
+ files += step_files;
+ p = krealloc(a, bytes, GFP_NOFS);
+ if (p) {
+ a = p;
+ a[n++] = hf;
+ } else
+ goto out_free;
+ }
+ }
+
+ err = 0;
+ for (ul = 0; ul < n; ul++) {
+ /* todo: already flushed? */
+ hf = a[ul];
+ hf->f_flags = au_file_roflags(hf->f_flags);
+ hf->f_mode &= ~FMODE_WRITE;
+ file_release_write(hf);
+ mnt_drop_write(hf->f_vfsmnt);
+ }
+
+ out_free:
+ kfree(a);
+ out:
+ return err;
+}
+
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+ int *do_update)
+{
+ int err, rerr;
+ aufs_bindex_t bindex;
+ struct dentry *root;
+ struct au_branch *br;
+
+ root = sb->s_root;
+ au_plink_block_maintain(sb);
+ bindex = au_find_dbindex(root, mod->h_root);
+ if (bindex < 0) {
+ if (remount)
+ return 0; /* success */
+ err = -ENOENT;
+ AuErr("%s no such branch\n", mod->path);
+ goto out;
+ }
+ AuDbg("bindex b%d\n", bindex);
+
+ err = test_br(mod->h_root->d_inode, mod->perm, mod->path);
+ if (unlikely(err))
+ goto out;
+
+ br = au_sbr(sb, bindex);
+ if (br->br_perm == mod->perm)
+ return 0; /* success */
+
+ if (au_br_writable(br->br_perm)) {
+ /* remove whiteout base */
+ err = au_br_init_wh(sb, br, mod->perm, mod->h_root);
+ if (unlikely(err))
+ goto out;
+
+ if (!au_br_writable(mod->perm)) {
+ /* rw --> ro, file might be mmapped */
+ DiMustNoWaiters(root);
+ IiMustNoWaiters(root->d_inode);
+ di_write_unlock(root);
+ err = au_br_mod_files_ro(sb, bindex);
+ /* aufs_write_lock() calls ..._child() */
+ di_write_lock_child(root);
+
+ if (unlikely(err)) {
+ rerr = -ENOMEM;
+ br->br_wbr = kmalloc(sizeof(*br->br_wbr),
+ GFP_NOFS);
+ if (br->br_wbr)
+ rerr = au_br_init_wh
+ (sb, br, br->br_perm,
+ mod->h_root);
+ if (unlikely(rerr)) {
+ AuIOErr("nested error %d (%d)\n",
+ rerr, err);
+ br->br_perm = mod->perm;
+ }
+ }
+ }
+ } else if (au_br_writable(mod->perm)) {
+ /* ro --> rw */
+ err = -ENOMEM;
+ br->br_wbr = kmalloc(sizeof(*br->br_wbr), GFP_NOFS);
+ if (br->br_wbr) {
+ struct path path = {
+ .mnt = br->br_mnt,
+ .dentry = mod->h_root
+ };
+
+ err = au_wbr_init(br, sb, mod->perm, &path);
+ if (unlikely(err)) {
+ kfree(br->br_wbr);
+ br->br_wbr = NULL;
+ }
+ }
+ }
+
+ if (!err) {
+ *do_update |= need_sigen_inc(br->br_perm, mod->perm);
+ br->br_perm = mod->perm;
+ }
+
+ out:
+ return err;
+}
diff --git a/fs/aufs/branch.h b/fs/aufs/branch.h
new file mode 100644
index 0000000..5a7fed4
--- /dev/null
+++ b/fs/aufs/branch.h
@@ -0,0 +1,200 @@
+/*
+ * 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.
+ */
+
+/*
+ * branch filesystems and xino for them
+ */
+
+#ifndef __AUFS_BRANCH_H__
+#define __AUFS_BRANCH_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/sysfs.h>
+#include <linux/aufs_type.h>
+#include "rwsem.h"
+#include "super.h"
+
+/* ---------------------------------------------------------------------- */
+
+/* a xino file */
+struct au_xino_file {
+ struct file *xi_file;
+ struct mutex xi_nondir_mtx;
+
+ /* todo: make xino files an array to support huge inode number */
+};
+
+/* members for writable branch only */
+enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_ORPH, AuBrWh_Last};
+struct au_wbr {
+ struct rw_semaphore wbr_wh_rwsem;
+ struct dentry *wbr_wh[AuBrWh_Last];
+ atomic_t wbr_wh_running;
+#define wbr_whbase wbr_wh[AuBrWh_BASE] /* whiteout base */
+#define wbr_plink wbr_wh[AuBrWh_PLINK] /* pseudo-link dir */
+#define wbr_orph wbr_wh[AuBrWh_ORPH] /* dir for orphans */
+
+ /* mfs mode */
+ unsigned long long wbr_bytes;
+};
+
+/* protected by superblock rwsem */
+struct au_branch {
+ struct au_xino_file br_xino;
+
+ aufs_bindex_t br_id;
+
+ int br_perm;
+ struct vfsmount *br_mnt;
+ atomic_t br_count;
+
+ struct au_wbr *br_wbr;
+
+ /* xino truncation */
+ blkcnt_t br_xino_upper; /* watermark in blocks */
+ atomic_t br_xino_running;
+
+#ifdef CONFIG_SYSFS
+ /* an entry under sysfs per mount-point */
+ char br_name[8];
+ struct attribute br_attr;
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* branch permission and attribute */
+enum {
+ AuBrPerm_RW, /* writable, linkable wh */
+ AuBrPerm_RO, /* readonly, no wh */
+ AuBrPerm_RR, /* natively readonly, no wh */
+
+ AuBrPerm_RWNoLinkWH, /* un-linkable whiteouts */
+
+ AuBrPerm_ROWH, /* whiteout-able */
+ AuBrPerm_RRWH, /* whiteout-able */
+
+ AuBrPerm_Last
+};
+
+static inline int au_br_writable(int brperm)
+{
+ return brperm == AuBrPerm_RW || brperm == AuBrPerm_RWNoLinkWH;
+}
+
+static inline int au_br_whable(int brperm)
+{
+ return brperm == AuBrPerm_RW
+ || brperm == AuBrPerm_ROWH
+ || brperm == AuBrPerm_RRWH;
+}
+
+static inline int au_br_rdonly(struct au_branch *br)
+{
+ return ((br->br_mnt->mnt_sb->s_flags & MS_RDONLY)
+ || !au_br_writable(br->br_perm))
+ ? -EROFS : 0;
+}
+
+static inline int au_br_hinotifyable(int brperm __maybe_unused)
+{
+#ifdef CONFIG_AUFS_HINOTIFY
+ return brperm != AuBrPerm_RR && brperm != AuBrPerm_RRWH;
+#else
+ return 0;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* branch.c */
+struct au_sbinfo;
+void au_br_free(struct au_sbinfo *sinfo);
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
+struct au_opt_add;
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
+struct au_opt_del;
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
+struct au_opt_mod;
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+ int *do_update);
+
+/* xino.c */
+int au_xib_trunc(struct super_block *sb);
+ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
+ loff_t *pos);
+ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
+ loff_t *pos);
+struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
+ino_t au_xino_new_ino(struct super_block *sb);
+int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+ ino_t ino);
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+ ino_t ino);
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+ ino_t *ino);
+int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
+ struct file *base_file, int do_test);
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
+
+struct au_opt_xino;
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
+void au_xino_clr(struct super_block *sb);
+struct file *au_xino_def(struct super_block *sb);
+int au_xino_path(struct seq_file *seq, struct file *file);
+
+/* ---------------------------------------------------------------------- */
+
+/* Superblock to branch */
+static inline
+aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
+{
+ return au_sbr(sb, bindex)->br_id;
+}
+
+static inline
+struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+ return au_sbr(sb, bindex)->br_mnt;
+}
+
+static inline
+struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
+{
+ return au_sbr_mnt(sb, bindex)->mnt_sb;
+}
+
+static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
+{
+ atomic_dec(&au_sbr(sb, bindex)->br_count);
+}
+
+static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
+{
+ return au_sbr(sb, bindex)->br_perm;
+}
+
+static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
+{
+ return au_br_whable(au_sbr_perm(sb, bindex));
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * wbr_wh_read_lock, wbr_wh_write_lock
+ * wbr_wh_read_unlock, wbr_wh_write_unlock, wbr_wh_downgrade_lock
+ */
+AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, &wbr->wbr_wh_rwsem);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_BRANCH_H__ */
--
1.6.1.284.g5dc13