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dir.c
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dir.c
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// SPDX-License-Identifier: GPL-2.0-or-later
/* dir.c: AFS filesystem directory handling
*
* Copyright (C) 2002, 2018 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include <linux/task_io_accounting_ops.h>
#include "internal.h"
#include "afs_fs.h"
#include "xdr_fs.h"
static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);
static int afs_dir_open(struct inode *inode, struct file *file);
static int afs_readdir(struct file *file, struct dir_context *ctx);
static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
static int afs_d_delete(const struct dentry *dentry);
static void afs_d_iput(struct dentry *dentry, struct inode *inode);
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
loff_t fpos, u64 ino, unsigned dtype);
static int afs_create(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, umode_t mode, bool excl);
static int afs_mkdir(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, umode_t mode);
static int afs_rmdir(struct inode *dir, struct dentry *dentry);
static int afs_unlink(struct inode *dir, struct dentry *dentry);
static int afs_link(struct dentry *from, struct inode *dir,
struct dentry *dentry);
static int afs_symlink(struct user_namespace *mnt_userns, struct inode *dir,
struct dentry *dentry, const char *content);
static int afs_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
struct dentry *old_dentry, struct inode *new_dir,
struct dentry *new_dentry, unsigned int flags);
static int afs_dir_releasepage(struct page *page, gfp_t gfp_flags);
static void afs_dir_invalidatepage(struct page *page, unsigned int offset,
unsigned int length);
static int afs_dir_set_page_dirty(struct page *page)
{
BUG(); /* This should never happen. */
}
const struct file_operations afs_dir_file_operations = {
.open = afs_dir_open,
.release = afs_release,
.iterate_shared = afs_readdir,
.lock = afs_lock,
.llseek = generic_file_llseek,
};
const struct inode_operations afs_dir_inode_operations = {
.create = afs_create,
.lookup = afs_lookup,
.link = afs_link,
.unlink = afs_unlink,
.symlink = afs_symlink,
.mkdir = afs_mkdir,
.rmdir = afs_rmdir,
.rename = afs_rename,
.permission = afs_permission,
.getattr = afs_getattr,
.setattr = afs_setattr,
};
const struct address_space_operations afs_dir_aops = {
.set_page_dirty = afs_dir_set_page_dirty,
.releasepage = afs_dir_releasepage,
.invalidatepage = afs_dir_invalidatepage,
};
const struct dentry_operations afs_fs_dentry_operations = {
.d_revalidate = afs_d_revalidate,
.d_delete = afs_d_delete,
.d_release = afs_d_release,
.d_automount = afs_d_automount,
.d_iput = afs_d_iput,
};
struct afs_lookup_one_cookie {
struct dir_context ctx;
struct qstr name;
bool found;
struct afs_fid fid;
};
struct afs_lookup_cookie {
struct dir_context ctx;
struct qstr name;
bool found;
bool one_only;
unsigned short nr_fids;
struct afs_fid fids[50];
};
/*
* Drop the refs that we're holding on the pages we were reading into. We've
* got refs on the first nr_pages pages.
*/
static void afs_dir_read_cleanup(struct afs_read *req)
{
struct address_space *mapping = req->vnode->vfs_inode.i_mapping;
struct page *page;
pgoff_t last = req->nr_pages - 1;
XA_STATE(xas, &mapping->i_pages, 0);
if (unlikely(!req->nr_pages))
return;
rcu_read_lock();
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
BUG_ON(xa_is_value(page));
BUG_ON(PageCompound(page));
ASSERTCMP(page->mapping, ==, mapping);
put_page(page);
}
rcu_read_unlock();
}
/*
* check that a directory page is valid
*/
static bool afs_dir_check_page(struct afs_vnode *dvnode, struct page *page,
loff_t i_size)
{
struct afs_xdr_dir_page *dbuf;
loff_t latter, off;
int tmp, qty;
/* Determine how many magic numbers there should be in this page, but
* we must take care because the directory may change size under us.
*/
off = page_offset(page);
if (i_size <= off)
goto checked;
latter = i_size - off;
if (latter >= PAGE_SIZE)
qty = PAGE_SIZE;
else
qty = latter;
qty /= sizeof(union afs_xdr_dir_block);
/* check them */
dbuf = kmap_atomic(page);
for (tmp = 0; tmp < qty; tmp++) {
if (dbuf->blocks[tmp].hdr.magic != AFS_DIR_MAGIC) {
printk("kAFS: %s(%lx): bad magic %d/%d is %04hx\n",
__func__, dvnode->vfs_inode.i_ino, tmp, qty,
ntohs(dbuf->blocks[tmp].hdr.magic));
trace_afs_dir_check_failed(dvnode, off, i_size);
kunmap(page);
trace_afs_file_error(dvnode, -EIO, afs_file_error_dir_bad_magic);
goto error;
}
/* Make sure each block is NUL terminated so we can reasonably
* use string functions on it. The filenames in the page
* *should* be NUL-terminated anyway.
*/
((u8 *)&dbuf->blocks[tmp])[AFS_DIR_BLOCK_SIZE - 1] = 0;
}
kunmap_atomic(dbuf);
checked:
afs_stat_v(dvnode, n_read_dir);
return true;
error:
return false;
}
/*
* Dump the contents of a directory.
*/
static void afs_dir_dump(struct afs_vnode *dvnode, struct afs_read *req)
{
struct afs_xdr_dir_page *dbuf;
struct address_space *mapping = dvnode->vfs_inode.i_mapping;
struct page *page;
unsigned int i, qty = PAGE_SIZE / sizeof(union afs_xdr_dir_block);
pgoff_t last = req->nr_pages - 1;
XA_STATE(xas, &mapping->i_pages, 0);
pr_warn("DIR %llx:%llx f=%llx l=%llx al=%llx\n",
dvnode->fid.vid, dvnode->fid.vnode,
req->file_size, req->len, req->actual_len);
pr_warn("DIR %llx %x %zx %zx\n",
req->pos, req->nr_pages,
req->iter->iov_offset, iov_iter_count(req->iter));
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
BUG_ON(PageCompound(page));
BUG_ON(page->mapping != mapping);
dbuf = kmap_atomic(page);
for (i = 0; i < qty; i++) {
union afs_xdr_dir_block *block = &dbuf->blocks[i];
pr_warn("[%02lx] %32phN\n", page->index * qty + i, block);
}
kunmap_atomic(dbuf);
}
}
/*
* Check all the pages in a directory. All the pages are held pinned.
*/
static int afs_dir_check(struct afs_vnode *dvnode, struct afs_read *req)
{
struct address_space *mapping = dvnode->vfs_inode.i_mapping;
struct page *page;
pgoff_t last = req->nr_pages - 1;
int ret = 0;
XA_STATE(xas, &mapping->i_pages, 0);
if (unlikely(!req->nr_pages))
return 0;
rcu_read_lock();
xas_for_each(&xas, page, last) {
if (xas_retry(&xas, page))
continue;
BUG_ON(PageCompound(page));
BUG_ON(page->mapping != mapping);
if (!afs_dir_check_page(dvnode, page, req->file_size)) {
afs_dir_dump(dvnode, req);
ret = -EIO;
break;
}
}
rcu_read_unlock();
return ret;
}
/*
* open an AFS directory file
*/
static int afs_dir_open(struct inode *inode, struct file *file)
{
_enter("{%lu}", inode->i_ino);
BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(inode)->flags))
return -ENOENT;
return afs_open(inode, file);
}
/*
* Read the directory into the pagecache in one go, scrubbing the previous
* contents. The list of pages is returned, pinning them so that they don't
* get reclaimed during the iteration.
*/
static struct afs_read *afs_read_dir(struct afs_vnode *dvnode, struct key *key)
__acquires(&dvnode->validate_lock)
{
struct afs_read *req;
loff_t i_size;
int nr_pages, i, n;
int ret;
_enter("");
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (!req)
return ERR_PTR(-ENOMEM);
refcount_set(&req->usage, 1);
req->vnode = dvnode;
req->key = key_get(key);
req->cleanup = afs_dir_read_cleanup;
expand:
i_size = i_size_read(&dvnode->vfs_inode);
if (i_size < 2048) {
ret = afs_bad(dvnode, afs_file_error_dir_small);
goto error;
}
if (i_size > 2048 * 1024) {
trace_afs_file_error(dvnode, -EFBIG, afs_file_error_dir_big);
ret = -EFBIG;
goto error;
}
_enter("%llu", i_size);
nr_pages = (i_size + PAGE_SIZE - 1) / PAGE_SIZE;
req->actual_len = i_size; /* May change */
req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
req->data_version = dvnode->status.data_version; /* May change */
iov_iter_xarray(&req->def_iter, READ, &dvnode->vfs_inode.i_mapping->i_pages,
0, i_size);
req->iter = &req->def_iter;
/* Fill in any gaps that we might find where the memory reclaimer has
* been at work and pin all the pages. If there are any gaps, we will
* need to reread the entire directory contents.
*/
i = req->nr_pages;
while (i < nr_pages) {
struct page *pages[8], *page;
n = find_get_pages_contig(dvnode->vfs_inode.i_mapping, i,
min_t(unsigned int, nr_pages - i,
ARRAY_SIZE(pages)),
pages);
_debug("find %u at %u/%u", n, i, nr_pages);
if (n == 0) {
gfp_t gfp = dvnode->vfs_inode.i_mapping->gfp_mask;
if (test_and_clear_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
afs_stat_v(dvnode, n_inval);
ret = -ENOMEM;
page = __page_cache_alloc(gfp);
if (!page)
goto error;
ret = add_to_page_cache_lru(page,
dvnode->vfs_inode.i_mapping,
i, gfp);
if (ret < 0)
goto error;
attach_page_private(page, (void *)1);
unlock_page(page);
req->nr_pages++;
i++;
} else {
req->nr_pages += n;
i += n;
}
}
/* If we're going to reload, we need to lock all the pages to prevent
* races.
*/
ret = -ERESTARTSYS;
if (down_read_killable(&dvnode->validate_lock) < 0)
goto error;
if (test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags))
goto success;
up_read(&dvnode->validate_lock);
if (down_write_killable(&dvnode->validate_lock) < 0)
goto error;
if (!test_bit(AFS_VNODE_DIR_VALID, &dvnode->flags)) {
trace_afs_reload_dir(dvnode);
ret = afs_fetch_data(dvnode, req);
if (ret < 0)
goto error_unlock;
task_io_account_read(PAGE_SIZE * req->nr_pages);
if (req->len < req->file_size) {
/* The content has grown, so we need to expand the
* buffer.
*/
up_write(&dvnode->validate_lock);
goto expand;
}
/* Validate the data we just read. */
ret = afs_dir_check(dvnode, req);
if (ret < 0)
goto error_unlock;
// TODO: Trim excess pages
set_bit(AFS_VNODE_DIR_VALID, &dvnode->flags);
}
downgrade_write(&dvnode->validate_lock);
success:
return req;
error_unlock:
up_write(&dvnode->validate_lock);
error:
afs_put_read(req);
_leave(" = %d", ret);
return ERR_PTR(ret);
}
/*
* deal with one block in an AFS directory
*/
static int afs_dir_iterate_block(struct afs_vnode *dvnode,
struct dir_context *ctx,
union afs_xdr_dir_block *block,
unsigned blkoff)
{
union afs_xdr_dirent *dire;
unsigned offset, next, curr, nr_slots;
size_t nlen;
int tmp;
_enter("%u,%x,%p,,",(unsigned)ctx->pos,blkoff,block);
curr = (ctx->pos - blkoff) / sizeof(union afs_xdr_dirent);
/* walk through the block, an entry at a time */
for (offset = (blkoff == 0 ? AFS_DIR_RESV_BLOCKS0 : AFS_DIR_RESV_BLOCKS);
offset < AFS_DIR_SLOTS_PER_BLOCK;
offset = next
) {
/* skip entries marked unused in the bitmap */
if (!(block->hdr.bitmap[offset / 8] &
(1 << (offset % 8)))) {
_debug("ENT[%zu.%u]: unused",
blkoff / sizeof(union afs_xdr_dir_block), offset);
next = offset + 1;
if (offset >= curr)
ctx->pos = blkoff +
next * sizeof(union afs_xdr_dirent);
continue;
}
/* got a valid entry */
dire = &block->dirents[offset];
nlen = strnlen(dire->u.name,
sizeof(*block) -
offset * sizeof(union afs_xdr_dirent));
if (nlen > AFSNAMEMAX - 1) {
_debug("ENT[%zu]: name too long (len %u/%zu)",
blkoff / sizeof(union afs_xdr_dir_block),
offset, nlen);
return afs_bad(dvnode, afs_file_error_dir_name_too_long);
}
_debug("ENT[%zu.%u]: %s %zu \"%s\"",
blkoff / sizeof(union afs_xdr_dir_block), offset,
(offset < curr ? "skip" : "fill"),
nlen, dire->u.name);
nr_slots = afs_dir_calc_slots(nlen);
next = offset + nr_slots;
if (next > AFS_DIR_SLOTS_PER_BLOCK) {
_debug("ENT[%zu.%u]:"
" %u extends beyond end dir block"
" (len %zu)",
blkoff / sizeof(union afs_xdr_dir_block),
offset, next, nlen);
return afs_bad(dvnode, afs_file_error_dir_over_end);
}
/* Check that the name-extension dirents are all allocated */
for (tmp = 1; tmp < nr_slots; tmp++) {
unsigned int ix = offset + tmp;
if (!(block->hdr.bitmap[ix / 8] & (1 << (ix % 8)))) {
_debug("ENT[%zu.u]:"
" %u unmarked extension (%u/%u)",
blkoff / sizeof(union afs_xdr_dir_block),
offset, tmp, nr_slots);
return afs_bad(dvnode, afs_file_error_dir_unmarked_ext);
}
}
/* skip if starts before the current position */
if (offset < curr)
continue;
/* found the next entry */
if (!dir_emit(ctx, dire->u.name, nlen,
ntohl(dire->u.vnode),
(ctx->actor == afs_lookup_filldir ||
ctx->actor == afs_lookup_one_filldir)?
ntohl(dire->u.unique) : DT_UNKNOWN)) {
_leave(" = 0 [full]");
return 0;
}
ctx->pos = blkoff + next * sizeof(union afs_xdr_dirent);
}
_leave(" = 1 [more]");
return 1;
}
/*
* iterate through the data blob that lists the contents of an AFS directory
*/
static int afs_dir_iterate(struct inode *dir, struct dir_context *ctx,
struct key *key, afs_dataversion_t *_dir_version)
{
struct afs_vnode *dvnode = AFS_FS_I(dir);
struct afs_xdr_dir_page *dbuf;
union afs_xdr_dir_block *dblock;
struct afs_read *req;
struct page *page;
unsigned blkoff, limit;
void __rcu **slot;
int ret;
_enter("{%lu},%u,,", dir->i_ino, (unsigned)ctx->pos);
if (test_bit(AFS_VNODE_DELETED, &AFS_FS_I(dir)->flags)) {
_leave(" = -ESTALE");
return -ESTALE;
}
req = afs_read_dir(dvnode, key);
if (IS_ERR(req))
return PTR_ERR(req);
*_dir_version = req->data_version;
/* round the file position up to the next entry boundary */
ctx->pos += sizeof(union afs_xdr_dirent) - 1;
ctx->pos &= ~(sizeof(union afs_xdr_dirent) - 1);
/* walk through the blocks in sequence */
ret = 0;
while (ctx->pos < req->actual_len) {
blkoff = ctx->pos & ~(sizeof(union afs_xdr_dir_block) - 1);
/* Fetch the appropriate page from the directory and re-add it
* to the LRU. We have all the pages pinned with an extra ref.
*/
rcu_read_lock();
page = NULL;
slot = radix_tree_lookup_slot(&dvnode->vfs_inode.i_mapping->i_pages,
blkoff / PAGE_SIZE);
if (slot)
page = radix_tree_deref_slot(slot);
rcu_read_unlock();
if (!page) {
ret = afs_bad(dvnode, afs_file_error_dir_missing_page);
break;
}
mark_page_accessed(page);
limit = blkoff & ~(PAGE_SIZE - 1);
dbuf = kmap(page);
/* deal with the individual blocks stashed on this page */
do {
dblock = &dbuf->blocks[(blkoff % PAGE_SIZE) /
sizeof(union afs_xdr_dir_block)];
ret = afs_dir_iterate_block(dvnode, ctx, dblock, blkoff);
if (ret != 1) {
kunmap(page);
goto out;
}
blkoff += sizeof(union afs_xdr_dir_block);
} while (ctx->pos < dir->i_size && blkoff < limit);
kunmap(page);
ret = 0;
}
out:
up_read(&dvnode->validate_lock);
afs_put_read(req);
_leave(" = %d", ret);
return ret;
}
/*
* read an AFS directory
*/
static int afs_readdir(struct file *file, struct dir_context *ctx)
{
afs_dataversion_t dir_version;
return afs_dir_iterate(file_inode(file), ctx, afs_file_key(file),
&dir_version);
}
/*
* Search the directory for a single name
* - if afs_dir_iterate_block() spots this function, it'll pass the FID
* uniquifier through dtype
*/
static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
struct afs_lookup_one_cookie *cookie =
container_of(ctx, struct afs_lookup_one_cookie, ctx);
_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
(unsigned long long) ino, dtype);
/* insanity checks first */
BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (cookie->name.len != nlen ||
memcmp(cookie->name.name, name, nlen) != 0) {
_leave(" = 0 [no]");
return 0;
}
cookie->fid.vnode = ino;
cookie->fid.unique = dtype;
cookie->found = 1;
_leave(" = -1 [found]");
return -1;
}
/*
* Do a lookup of a single name in a directory
* - just returns the FID the dentry name maps to if found
*/
static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
struct afs_fid *fid, struct key *key,
afs_dataversion_t *_dir_version)
{
struct afs_super_info *as = dir->i_sb->s_fs_info;
struct afs_lookup_one_cookie cookie = {
.ctx.actor = afs_lookup_one_filldir,
.name = dentry->d_name,
.fid.vid = as->volume->vid
};
int ret;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
/* search the directory */
ret = afs_dir_iterate(dir, &cookie.ctx, key, _dir_version);
if (ret < 0) {
_leave(" = %d [iter]", ret);
return ret;
}
ret = -ENOENT;
if (!cookie.found) {
_leave(" = -ENOENT [not found]");
return -ENOENT;
}
*fid = cookie.fid;
_leave(" = 0 { vn=%llu u=%u }", fid->vnode, fid->unique);
return 0;
}
/*
* search the directory for a name
* - if afs_dir_iterate_block() spots this function, it'll pass the FID
* uniquifier through dtype
*/
static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
int nlen, loff_t fpos, u64 ino, unsigned dtype)
{
struct afs_lookup_cookie *cookie =
container_of(ctx, struct afs_lookup_cookie, ctx);
int ret;
_enter("{%s,%u},%s,%u,,%llu,%u",
cookie->name.name, cookie->name.len, name, nlen,
(unsigned long long) ino, dtype);
/* insanity checks first */
BUILD_BUG_ON(sizeof(union afs_xdr_dir_block) != 2048);
BUILD_BUG_ON(sizeof(union afs_xdr_dirent) != 32);
if (cookie->found) {
if (cookie->nr_fids < 50) {
cookie->fids[cookie->nr_fids].vnode = ino;
cookie->fids[cookie->nr_fids].unique = dtype;
cookie->nr_fids++;
}
} else if (cookie->name.len == nlen &&
memcmp(cookie->name.name, name, nlen) == 0) {
cookie->fids[1].vnode = ino;
cookie->fids[1].unique = dtype;
cookie->found = 1;
if (cookie->one_only)
return -1;
}
ret = cookie->nr_fids >= 50 ? -1 : 0;
_leave(" = %d", ret);
return ret;
}
/*
* Deal with the result of a successful lookup operation. Turn all the files
* into inodes and save the first one - which is the one we actually want.
*/
static void afs_do_lookup_success(struct afs_operation *op)
{
struct afs_vnode_param *vp;
struct afs_vnode *vnode;
struct inode *inode;
u32 abort_code;
int i;
_enter("");
for (i = 0; i < op->nr_files; i++) {
switch (i) {
case 0:
vp = &op->file[0];
abort_code = vp->scb.status.abort_code;
if (abort_code != 0) {
op->ac.abort_code = abort_code;
op->error = afs_abort_to_error(abort_code);
}
break;
case 1:
vp = &op->file[1];
break;
default:
vp = &op->more_files[i - 2];
break;
}
if (!vp->scb.have_status && !vp->scb.have_error)
continue;
_debug("do [%u]", i);
if (vp->vnode) {
if (!test_bit(AFS_VNODE_UNSET, &vp->vnode->flags))
afs_vnode_commit_status(op, vp);
} else if (vp->scb.status.abort_code == 0) {
inode = afs_iget(op, vp);
if (!IS_ERR(inode)) {
vnode = AFS_FS_I(inode);
afs_cache_permit(vnode, op->key,
0 /* Assume vnode->cb_break is 0 */ +
op->cb_v_break,
&vp->scb);
vp->vnode = vnode;
vp->put_vnode = true;
}
} else {
_debug("- abort %d %llx:%llx.%x",
vp->scb.status.abort_code,
vp->fid.vid, vp->fid.vnode, vp->fid.unique);
}
}
_leave("");
}
static const struct afs_operation_ops afs_inline_bulk_status_operation = {
.issue_afs_rpc = afs_fs_inline_bulk_status,
.issue_yfs_rpc = yfs_fs_inline_bulk_status,
.success = afs_do_lookup_success,
};
static const struct afs_operation_ops afs_lookup_fetch_status_operation = {
.issue_afs_rpc = afs_fs_fetch_status,
.issue_yfs_rpc = yfs_fs_fetch_status,
.success = afs_do_lookup_success,
.aborted = afs_check_for_remote_deletion,
};
/*
* See if we know that the server we expect to use doesn't support
* FS.InlineBulkStatus.
*/
static bool afs_server_supports_ibulk(struct afs_vnode *dvnode)
{
struct afs_server_list *slist;
struct afs_volume *volume = dvnode->volume;
struct afs_server *server;
bool ret = true;
int i;
if (!test_bit(AFS_VOLUME_MAYBE_NO_IBULK, &volume->flags))
return true;
rcu_read_lock();
slist = rcu_dereference(volume->servers);
for (i = 0; i < slist->nr_servers; i++) {
server = slist->servers[i].server;
if (server == dvnode->cb_server) {
if (test_bit(AFS_SERVER_FL_NO_IBULK, &server->flags))
ret = false;
break;
}
}
rcu_read_unlock();
return ret;
}
/*
* Do a lookup in a directory. We make use of bulk lookup to query a slew of
* files in one go and create inodes for them. The inode of the file we were
* asked for is returned.
*/
static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
struct key *key)
{
struct afs_lookup_cookie *cookie;
struct afs_vnode_param *vp;
struct afs_operation *op;
struct afs_vnode *dvnode = AFS_FS_I(dir), *vnode;
struct inode *inode = NULL, *ti;
afs_dataversion_t data_version = READ_ONCE(dvnode->status.data_version);
long ret;
int i;
_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
cookie = kzalloc(sizeof(struct afs_lookup_cookie), GFP_KERNEL);
if (!cookie)
return ERR_PTR(-ENOMEM);
for (i = 0; i < ARRAY_SIZE(cookie->fids); i++)
cookie->fids[i].vid = dvnode->fid.vid;
cookie->ctx.actor = afs_lookup_filldir;
cookie->name = dentry->d_name;
cookie->nr_fids = 2; /* slot 0 is saved for the fid we actually want
* and slot 1 for the directory */
if (!afs_server_supports_ibulk(dvnode))
cookie->one_only = true;
/* search the directory */
ret = afs_dir_iterate(dir, &cookie->ctx, key, &data_version);
if (ret < 0)
goto out;
dentry->d_fsdata = (void *)(unsigned long)data_version;
ret = -ENOENT;
if (!cookie->found)
goto out;
/* Check to see if we already have an inode for the primary fid. */
inode = ilookup5(dir->i_sb, cookie->fids[1].vnode,
afs_ilookup5_test_by_fid, &cookie->fids[1]);
if (inode)
goto out; /* We do */
/* Okay, we didn't find it. We need to query the server - and whilst
* we're doing that, we're going to attempt to look up a bunch of other
* vnodes also.
*/
op = afs_alloc_operation(NULL, dvnode->volume);
if (IS_ERR(op)) {
ret = PTR_ERR(op);
goto out;
}
afs_op_set_vnode(op, 0, dvnode);
afs_op_set_fid(op, 1, &cookie->fids[1]);
op->nr_files = cookie->nr_fids;
_debug("nr_files %u", op->nr_files);
/* Need space for examining all the selected files */
op->error = -ENOMEM;
if (op->nr_files > 2) {
op->more_files = kvcalloc(op->nr_files - 2,
sizeof(struct afs_vnode_param),
GFP_KERNEL);
if (!op->more_files)
goto out_op;
for (i = 2; i < op->nr_files; i++) {
vp = &op->more_files[i - 2];
vp->fid = cookie->fids[i];
/* Find any inodes that already exist and get their
* callback counters.
*/
ti = ilookup5_nowait(dir->i_sb, vp->fid.vnode,
afs_ilookup5_test_by_fid, &vp->fid);
if (!IS_ERR_OR_NULL(ti)) {
vnode = AFS_FS_I(ti);
vp->dv_before = vnode->status.data_version;
vp->cb_break_before = afs_calc_vnode_cb_break(vnode);
vp->vnode = vnode;
vp->put_vnode = true;
vp->speculative = true; /* vnode not locked */
}
}
}
/* Try FS.InlineBulkStatus first. Abort codes for the individual
* lookups contained therein are stored in the reply without aborting
* the whole operation.
*/
op->error = -ENOTSUPP;
if (!cookie->one_only) {
op->ops = &afs_inline_bulk_status_operation;
afs_begin_vnode_operation(op);
afs_wait_for_operation(op);
}
if (op->error == -ENOTSUPP) {
/* We could try FS.BulkStatus next, but this aborts the entire
* op if any of the lookups fails - so, for the moment, revert
* to FS.FetchStatus for op->file[1].
*/
op->fetch_status.which = 1;
op->ops = &afs_lookup_fetch_status_operation;
afs_begin_vnode_operation(op);
afs_wait_for_operation(op);
}
inode = ERR_PTR(op->error);
out_op:
if (op->error == 0) {
inode = &op->file[1].vnode->vfs_inode;
op->file[1].vnode = NULL;
}
if (op->file[0].scb.have_status)
dentry->d_fsdata = (void *)(unsigned long)op->file[0].scb.status.data_version;
else
dentry->d_fsdata = (void *)(unsigned long)op->file[0].dv_before;
ret = afs_put_operation(op);
out:
kfree(cookie);
_leave("");
return inode ?: ERR_PTR(ret);
}
/*
* Look up an entry in a directory with @sys substitution.
*/
static struct dentry *afs_lookup_atsys(struct inode *dir, struct dentry *dentry,
struct key *key)
{
struct afs_sysnames *subs;
struct afs_net *net = afs_i2net(dir);
struct dentry *ret;
char *buf, *p, *name;
int len, i;
_enter("");
ret = ERR_PTR(-ENOMEM);
p = buf = kmalloc(AFSNAMEMAX, GFP_KERNEL);
if (!buf)
goto out_p;
if (dentry->d_name.len > 4) {
memcpy(p, dentry->d_name.name, dentry->d_name.len - 4);
p += dentry->d_name.len - 4;
}
/* There is an ordered list of substitutes that we have to try. */
read_lock(&net->sysnames_lock);
subs = net->sysnames;
refcount_inc(&subs->usage);
read_unlock(&net->sysnames_lock);
for (i = 0; i < subs->nr; i++) {
name = subs->subs[i];
len = dentry->d_name.len - 4 + strlen(name);
if (len >= AFSNAMEMAX) {
ret = ERR_PTR(-ENAMETOOLONG);
goto out_s;
}
strcpy(p, name);
ret = lookup_one_len(buf, dentry->d_parent, len);
if (IS_ERR(ret) || d_is_positive(ret))
goto out_s;
dput(ret);
}
/* We don't want to d_add() the @sys dentry here as we don't want to
* the cached dentry to hide changes to the sysnames list.
*/
ret = NULL;
out_s:
afs_put_sysnames(subs);