static int au_wbr_bu(struct super_block *sb, aufs_bindex_t bindex)
{
for (; bindex >= 0; bindex--)
if (!au_br_rdonly(au_sbr(sb, bindex)))
return bindex;
return -EROFS;
}
/* an exception for the policy other than tdp */
static int au_wbr_create_exp(struct dentry *dentry)
{
int err;
aufs_bindex_t bwh, bdiropq;
struct dentry *parent;
err = -1;
bwh = au_dbwh(dentry);
parent = dget_parent(dentry);
bdiropq = au_dbdiropq(parent);
if (bwh >= 0) {
if (bdiropq >= 0)
err = min(bdiropq, bwh);
else
err = bwh;
AuDbg("%d\n", err);
} else if (bdiropq >= 0) {
err = bdiropq;
AuDbg("%d\n", err);
}
dput(parent);
if (err >= 0)
err = au_wbr_nonopq(dentry, err);
if (err >= 0 && au_br_rdonly(au_sbr(dentry->d_sb, err)))
err = -1;
AuDbg("%d\n", err);
return err;
}
static int au_wbr_create_mfs(struct dentry *dentry, unsigned int flags)
{
int err;
struct dentry *parent;
struct super_block *sb;
struct au_wbr_mfs *mfs;
err = au_wbr_create_exp(dentry);
if (err >= 0)
goto out;
sb = dentry->d_sb;
parent = NULL;
if (au_ftest_wbr(flags, PARENT))
parent = dget_parent(dentry);
mfs = &au_sbi(sb)->si_wbr_mfs;
mutex_lock(&mfs->mfs_lock);
if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
|| mfs->mfs_bindex < 0
|| au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
au_mfs(dentry, parent);
mutex_unlock(&mfs->mfs_lock);
err = mfs->mfs_bindex;
dput(parent);
if (err >= 0)
err = au_wbr_nonopq(dentry, err);
out:
AuDbg("b%d\n", err);
return err;
}
static int au_wbr_create_mfs(struct dentry *dentry, int isdir __maybe_unused)
{
int err;
struct super_block *sb;
struct au_wbr_mfs *mfs;
err = au_wbr_create_exp(dentry);
if (err >= 0)
goto out;
sb = dentry->d_sb;
mfs = &au_sbi(sb)->si_wbr_mfs;
mutex_lock(&mfs->mfs_lock);
if (time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
|| mfs->mfs_bindex < 0
|| au_br_rdonly(au_sbr(sb, mfs->mfs_bindex)))
au_mfs(dentry);
mutex_unlock(&mfs->mfs_lock);
err = mfs->mfs_bindex;
if (err >= 0)
err = au_wbr_nonopq(dentry, err);
out:
AuDbg("b%d\n", err);
return err;
}
/* most free space */
static void au_mfs(struct dentry *dentry)
{
struct super_block *sb;
struct au_branch *br;
struct au_wbr_mfs *mfs;
aufs_bindex_t bindex, bend;
int err;
unsigned long long b, bavail;
struct path h_path;
/* reduce the stack usage */
struct kstatfs *st;
st = kmalloc(sizeof(*st), GFP_NOFS);
if (unlikely(!st)) {
AuWarn1("failed updating mfs(%d), ignored\n", -ENOMEM);
return;
}
bavail = 0;
sb = dentry->d_sb;
mfs = &au_sbi(sb)->si_wbr_mfs;
MtxMustLock(&mfs->mfs_lock);
mfs->mfs_bindex = -EROFS;
mfs->mfsrr_bytes = 0;
bend = au_sbend(sb);
for (bindex = 0; bindex <= bend; bindex++) {
br = au_sbr(sb, bindex);
if (au_br_rdonly(br))
continue;
/* sb->s_root for NFS is unreliable */
h_path.mnt = br->br_mnt;
h_path.dentry = h_path.mnt->mnt_root;
err = vfs_statfs(&h_path, st);
if (unlikely(err)) {
AuWarn1("failed statfs, b%d, %d\n", bindex, err);
continue;
}
/* when the available size is equal, select the lower one */
BUILD_BUG_ON(sizeof(b) < sizeof(st->f_bavail)
|| sizeof(b) < sizeof(st->f_bsize));
b = st->f_bavail * st->f_bsize;
br->br_wbr->wbr_bytes = b;
if (b >= bavail) {
bavail = b;
mfs->mfs_bindex = bindex;
mfs->mfs_jiffy = jiffies;
}
}
mfs->mfsrr_bytes = bavail;
AuDbg("b%d\n", mfs->mfs_bindex);
kfree(st);
}
/* top down parent */
static int au_wbr_create_tdp(struct dentry *dentry,
unsigned int flags __maybe_unused)
{
int err;
aufs_bindex_t bstart, bindex;
struct super_block *sb;
struct dentry *parent, *h_parent;
sb = dentry->d_sb;
bstart = au_dbstart(dentry);
err = bstart;
if (!au_br_rdonly(au_sbr(sb, bstart)))
goto out;
err = -EROFS;
parent = dget_parent(dentry);
for (bindex = au_dbstart(parent); bindex < bstart; bindex++) {
h_parent = au_h_dptr(parent, bindex);
if (!h_parent || !h_parent->d_inode)
continue;
if (!au_br_rdonly(au_sbr(sb, bindex))) {
err = bindex;
break;
}
}
dput(parent);
/* bottom up here */
if (unlikely(err < 0)) {
err = au_wbr_bu(sb, bstart - 1);
if (err >= 0)
err = au_wbr_nonopq(dentry, err);
}
out:
AuDbg("b%d\n", err);
return err;
}
/* mainly for link(2) and rename(2) */
int au_wbr(struct dentry *dentry, aufs_bindex_t btgt)
{
aufs_bindex_t bdiropq, bwh;
struct dentry *parent;
struct au_branch *br;
parent = dentry->d_parent;
IMustLock(parent->d_inode); /* dir is locked */
bdiropq = au_dbdiropq(parent);
bwh = au_dbwh(dentry);
br = au_sbr(dentry->d_sb, btgt);
if (au_br_rdonly(br)
|| (0 <= bdiropq && bdiropq < btgt)
|| (0 <= bwh && bwh < btgt))
btgt = -1;
AuDbg("btgt %d\n", btgt);
return btgt;
}
static int au_wbr_create_rr(struct dentry *dentry, int isdir)
{
int err, nbr;
unsigned int u;
aufs_bindex_t bindex, bend;
struct super_block *sb;
atomic_t *next;
err = au_wbr_create_exp(dentry);
if (err >= 0)
goto out;
sb = dentry->d_sb;
next = &au_sbi(sb)->si_wbr_rr_next;
bend = au_sbend(sb);
nbr = bend + 1;
for (bindex = 0; bindex <= bend; bindex++) {
if (!isdir) {
err = atomic_dec_return(next) + 1;
/* modulo for 0 is meaningless */
if (unlikely(!err))
err = atomic_dec_return(next) + 1;
} else
err = atomic_read(next);
AuDbg("%d\n", err);
u = err;
err = u % nbr;
AuDbg("%d\n", err);
if (!au_br_rdonly(au_sbr(sb, err)))
break;
err = -EROFS;
}
if (err >= 0)
err = au_wbr_nonopq(dentry, err);
out:
AuDbg("%d\n", err);
return err;
}
static int au_fhsm_stfs(struct super_block *sb, aufs_bindex_t bindex,
struct aufs_stfs *rstfs, int do_lock, int do_notify)
{
int err;
struct au_branch *br;
struct au_br_fhsm *bf;
br = au_sbr(sb, bindex);
AuDebugOn(au_br_rdonly(br));
bf = br->br_fhsm;
AuDebugOn(!bf);
if (do_lock)
mutex_lock(&bf->bf_lock);
else
MtxMustLock(&bf->bf_lock);
/* sb->s_root for NFS is unreliable */
err = au_br_stfs(br, &bf->bf_stfs);
if (unlikely(err)) {
AuErr1("FHSM failed (%d), b%d, ignored.\n", bindex, err);
goto out;
}
bf->bf_jiffy = jiffies;
bf->bf_readable = 1;
if (do_notify)
au_fhsm_notify(sb, /*val*/1);
if (rstfs)
*rstfs = bf->bf_stfs;
out:
if (do_lock)
mutex_unlock(&bf->bf_lock);
au_fhsm_notify(sb, /*val*/1);
return err;
}
int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
struct inode *inode)
{
int err;
err = au_br_rdonly(au_sbr(sb, bindex));
/* pseudo-link after flushed may happen out of bounds */
if (!err
&& inode
&& au_ibstart(inode) <= bindex
&& bindex <= au_ibend(inode)) {
/*
* permission check is unnecessary since vfsub routine
* will be called later
*/
struct inode *hi = au_h_iptr(inode, bindex);
if (hi)
err = IS_IMMUTABLE(hi) ? -EROFS : 0;
}
return err;
}
static int aufs_permission(struct inode *inode, int mask)
{
int err;
aufs_bindex_t bindex, bend;
const unsigned char isdir = !!S_ISDIR(inode->i_mode),
write_mask = !!(mask & (MAY_WRITE | MAY_APPEND));
struct inode *h_inode;
struct super_block *sb;
struct au_branch *br;
/* todo: support rcu-walk? */
if (mask & MAY_NOT_BLOCK)
return -ECHILD;
sb = inode->i_sb;
si_read_lock(sb, AuLock_FLUSH);
ii_read_lock_child(inode);
#if 0
err = au_iigen_test(inode, au_sigen(sb));
if (unlikely(err))
goto out;
#endif
if (!isdir || write_mask) {
err = au_busy_or_stale();
h_inode = au_h_iptr(inode, au_ibstart(inode));
if (unlikely(!h_inode
|| (h_inode->i_mode & S_IFMT)
!= (inode->i_mode & S_IFMT)))
goto out;
err = 0;
bindex = au_ibstart(inode);
br = au_sbr(sb, bindex);
err = h_permission(h_inode, mask, br->br_mnt, br->br_perm);
if (write_mask
&& !err
&& !special_file(h_inode->i_mode)) {
/* test whether the upper writable branch exists */
err = -EROFS;
for (; bindex >= 0; bindex--)
if (!au_br_rdonly(au_sbr(sb, bindex))) {
err = 0;
break;
}
}
goto out;
}
/* non-write to dir */
err = 0;
bend = au_ibend(inode);
for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
h_inode = au_h_iptr(inode, bindex);
if (h_inode) {
err = au_busy_or_stale();
if (unlikely(!S_ISDIR(h_inode->i_mode)))
break;
br = au_sbr(sb, bindex);
err = h_permission(h_inode, mask, br->br_mnt,
br->br_perm);
}
}
out:
ii_read_unlock(inode);
si_read_unlock(sb);
return err;
}
static int au_mvd_args(const unsigned char dmsg, struct au_mvd_args *a)
{
int err;
struct au_branch *br;
err = -EISDIR;
if (unlikely(S_ISDIR(a->inode->i_mode)))
goto out;
err = -EINVAL;
if (!(a->mvdown.flags & AUFS_MVDOWN_BRID_UPPER))
a->mvd_bsrc = au_ibstart(a->inode);
else {
a->mvd_bsrc = au_br_index(a->sb, a->mvd_src_brid);
if (unlikely(a->mvd_bsrc < 0
|| (a->mvd_bsrc < au_dbstart(a->dentry)
|| au_dbend(a->dentry) < a->mvd_bsrc
|| !au_h_dptr(a->dentry, a->mvd_bsrc))
|| (a->mvd_bsrc < au_ibstart(a->inode)
|| au_ibend(a->inode) < a->mvd_bsrc
|| !au_h_iptr(a->inode, a->mvd_bsrc)))) {
a->mvd_errno = EAU_MVDOWN_NOUPPER;
AU_MVD_PR(dmsg, "no upper\n");
goto out;
}
}
if (unlikely(a->mvd_bsrc == au_sbend(a->sb))) {
a->mvd_errno = EAU_MVDOWN_BOTTOM;
AU_MVD_PR(dmsg, "on the bottom\n");
goto out;
}
a->mvd_h_src_inode = au_h_iptr(a->inode, a->mvd_bsrc);
br = au_sbr(a->sb, a->mvd_bsrc);
err = au_br_rdonly(br);
if (!(a->mvdown.flags & AUFS_MVDOWN_ROUPPER)) {
if (unlikely(err))
goto out;
} else if (!(vfsub_native_ro(a->mvd_h_src_inode)
|| IS_APPEND(a->mvd_h_src_inode))) {
if (err)
a->mvdown.flags |= AUFS_MVDOWN_ROUPPER_R;
/* go on */
} else
goto out;
err = -EINVAL;
if (!(a->mvdown.flags & AUFS_MVDOWN_BRID_LOWER)) {
a->mvd_bdst = find_lower_writable(a);
if (unlikely(a->mvd_bdst < 0)) {
a->mvd_errno = EAU_MVDOWN_BOTTOM;
AU_MVD_PR(dmsg, "no writable lower branch\n");
goto out;
}
} else {
a->mvd_bdst = au_br_index(a->sb, a->mvd_dst_brid);
if (unlikely(a->mvd_bdst < 0
|| au_sbend(a->sb) < a->mvd_bdst)) {
a->mvd_errno = EAU_MVDOWN_NOLOWERBR;
AU_MVD_PR(dmsg, "no lower brid\n");
goto out;
}
}
err = au_mvd_args_busy(dmsg, a);
if (!err)
err = au_mvd_args_parent(dmsg, a);
if (!err)
err = au_mvd_args_intermediate(dmsg, a);
if (!err)
err = au_mvd_args_exist(dmsg, a);
if (!err)
AuDbg("b%d, b%d\n", a->mvd_bsrc, a->mvd_bdst);
out:
AuTraceErr(err);
return err;
}