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Merge branch 'work.sysv' of git://git.kernel.org/pub/scm/linux/kernel…
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…/git/viro/vfs

Pull sysv updates from Al Viro:
 "Fabio's 'switch to kmap_local_page()' patchset (originally after the
  ext2 counterpart, with a lot of cleaning up done to it; as the matter
  of fact, ext2 side is in need of similar cleanups - calling
  conventions there are bloody awful).

  Plus the equivalents of minix stuff..."

* 'work.sysv' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  sysv: fix handling of delete_entry and set_link failures
  fs/sysv: Replace kmap() with kmap_local_page()
  fs/sysv: Use dir_put_page() in sysv_rename()
  fs/sysv: Change the signature of dir_get_page()
  fs/sysv: Use the offset_in_page() helper
  sysv: don't flush page immediately for DIRSYNC directories
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@torvalds
torvalds committed Feb 25, 2023
2 parents 397aa6b + abb7c74 commit d6b9cf4
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Showing 3 changed files with 111 additions and 88 deletions.
154 changes: 87 additions & 67 deletions fs/sysv/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -28,37 +28,50 @@ const struct file_operations sysv_dir_operations = {
.fsync = generic_file_fsync,
};

static inline void dir_put_page(struct page *page)
inline void dir_put_page(struct page *page, void *page_addr)
{
kunmap(page);
kunmap_local((void *)((unsigned long)page_addr & PAGE_MASK));
put_page(page);
}

static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
static void dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
{
struct address_space *mapping = page->mapping;
struct inode *dir = mapping->host;
int err = 0;

block_write_end(NULL, mapping, pos, len, len, page, NULL);
if (pos+len > dir->i_size) {
i_size_write(dir, pos+len);
mark_inode_dirty(dir);
}
if (IS_DIRSYNC(dir))
err = write_one_page(page);
else
unlock_page(page);
unlock_page(page);
}

static int sysv_handle_dirsync(struct inode *dir)
{
int err;

err = filemap_write_and_wait(dir->i_mapping);
if (!err)
err = sync_inode_metadata(dir, 1);
return err;
}

static struct page * dir_get_page(struct inode *dir, unsigned long n)
/*
* Calls to dir_get_page()/dir_put_page() must be nested according to the
* rules documented in mm/highmem.rst.
*
* NOTE: sysv_find_entry() and sysv_dotdot() act as calls to dir_get_page()
* and must be treated accordingly for nesting purposes.
*/
static void *dir_get_page(struct inode *dir, unsigned long n, struct page **p)
{
struct address_space *mapping = dir->i_mapping;
struct page *page = read_mapping_page(mapping, n, NULL);
if (!IS_ERR(page))
kmap(page);
return page;
if (IS_ERR(page))
return ERR_CAST(page);
*p = page;
return kmap_local_page(page);
}

static int sysv_readdir(struct file *file, struct dir_context *ctx)
Expand All @@ -80,11 +93,11 @@ static int sysv_readdir(struct file *file, struct dir_context *ctx)
for ( ; n < npages; n++, offset = 0) {
char *kaddr, *limit;
struct sysv_dir_entry *de;
struct page *page = dir_get_page(inode, n);
struct page *page;

if (IS_ERR(page))
kaddr = dir_get_page(inode, n, &page);
if (IS_ERR(kaddr))
continue;
kaddr = (char *)page_address(page);
de = (struct sysv_dir_entry *)(kaddr+offset);
limit = kaddr + PAGE_SIZE - SYSV_DIRSIZE;
for ( ;(char*)de <= limit; de++, ctx->pos += sizeof(*de)) {
Expand All @@ -96,11 +109,11 @@ static int sysv_readdir(struct file *file, struct dir_context *ctx)
if (!dir_emit(ctx, name, strnlen(name,SYSV_NAMELEN),
fs16_to_cpu(SYSV_SB(sb), de->inode),
DT_UNKNOWN)) {
dir_put_page(page);
dir_put_page(page, kaddr);
return 0;
}
}
dir_put_page(page);
dir_put_page(page, kaddr);
}
return 0;
}
Expand All @@ -123,6 +136,11 @@ static inline int namecompare(int len, int maxlen,
* returns the cache buffer in which the entry was found, and the entry
* itself (as a parameter - res_dir). It does NOT read the inode of the
* entry - you'll have to do that yourself if you want to.
*
* On Success dir_put_page() should be called on *res_page.
*
* sysv_find_entry() acts as a call to dir_get_page() and must be treated
* accordingly for nesting purposes.
*/
struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_page)
{
Expand All @@ -142,11 +160,10 @@ struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_
n = start;

do {
char *kaddr;
page = dir_get_page(dir, n);
if (!IS_ERR(page)) {
kaddr = (char*)page_address(page);
de = (struct sysv_dir_entry *) kaddr;
char *kaddr = dir_get_page(dir, n, &page);

if (!IS_ERR(kaddr)) {
de = (struct sysv_dir_entry *)kaddr;
kaddr += PAGE_SIZE - SYSV_DIRSIZE;
for ( ; (char *) de <= kaddr ; de++) {
if (!de->inode)
Expand All @@ -155,7 +172,7 @@ struct sysv_dir_entry *sysv_find_entry(struct dentry *dentry, struct page **res_
name, de->name))
goto found;
}
dir_put_page(page);
dir_put_page(page, kaddr);
}

if (++n >= npages)
Expand Down Expand Up @@ -185,11 +202,9 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)

/* We take care of directory expansion in the same loop */
for (n = 0; n <= npages; n++) {
page = dir_get_page(dir, n);
err = PTR_ERR(page);
if (IS_ERR(page))
goto out;
kaddr = (char*)page_address(page);
kaddr = dir_get_page(dir, n, &page);
if (IS_ERR(kaddr))
return PTR_ERR(kaddr);
de = (struct sysv_dir_entry *)kaddr;
kaddr += PAGE_SIZE - SYSV_DIRSIZE;
while ((char *)de <= kaddr) {
Expand All @@ -200,27 +215,26 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
goto out_page;
de++;
}
dir_put_page(page);
dir_put_page(page, kaddr);
}
BUG();
return -EINVAL;

got_it:
pos = page_offset(page) +
(char*)de - (char*)page_address(page);
pos = page_offset(page) + offset_in_page(de);
lock_page(page);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
if (err)
goto out_unlock;
memcpy (de->name, name, namelen);
memset (de->name + namelen, 0, SYSV_DIRSIZE - namelen - 2);
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
err = sysv_handle_dirsync(dir);
out_page:
dir_put_page(page);
out:
dir_put_page(page, kaddr);
return err;
out_unlock:
unlock_page(page);
Expand All @@ -230,19 +244,20 @@ int sysv_add_link(struct dentry *dentry, struct inode *inode)
int sysv_delete_entry(struct sysv_dir_entry *de, struct page *page)
{
struct inode *inode = page->mapping->host;
char *kaddr = (char*)page_address(page);
loff_t pos = page_offset(page) + (char *)de - kaddr;
loff_t pos = page_offset(page) + offset_in_page(de);
int err;

lock_page(page);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
BUG_ON(err);
if (err) {
unlock_page(page);
return err;
}
de->inode = 0;
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
dir_put_page(page);
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
inode->i_ctime = inode->i_mtime = current_time(inode);
mark_inode_dirty(inode);
return err;
return sysv_handle_dirsync(inode);
}

int sysv_make_empty(struct inode *inode, struct inode *dir)
Expand All @@ -259,9 +274,7 @@ int sysv_make_empty(struct inode *inode, struct inode *dir)
unlock_page(page);
goto fail;
}
kmap(page);

base = (char*)page_address(page);
base = kmap_local_page(page);
memset(base, 0, PAGE_SIZE);

de = (struct sysv_dir_entry *) base;
Expand All @@ -271,8 +284,9 @@ int sysv_make_empty(struct inode *inode, struct inode *dir)
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), dir->i_ino);
strcpy(de->name,"..");

kunmap(page);
err = dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE);
kunmap_local(base);
dir_commit_chunk(page, 0, 2 * SYSV_DIRSIZE);
err = sysv_handle_dirsync(inode);
fail:
put_page(page);
return err;
Expand All @@ -286,16 +300,15 @@ int sysv_empty_dir(struct inode * inode)
struct super_block *sb = inode->i_sb;
struct page *page = NULL;
unsigned long i, npages = dir_pages(inode);
char *kaddr;

for (i = 0; i < npages; i++) {
char *kaddr;
struct sysv_dir_entry * de;
page = dir_get_page(inode, i);
struct sysv_dir_entry *de;

if (IS_ERR(page))
kaddr = dir_get_page(inode, i, &page);
if (IS_ERR(kaddr))
continue;

kaddr = (char *)page_address(page);
de = (struct sysv_dir_entry *)kaddr;
kaddr += PAGE_SIZE-SYSV_DIRSIZE;

Expand All @@ -314,44 +327,51 @@ int sysv_empty_dir(struct inode * inode)
if (de->name[1] != '.' || de->name[2])
goto not_empty;
}
dir_put_page(page);
dir_put_page(page, kaddr);
}
return 1;

not_empty:
dir_put_page(page);
dir_put_page(page, kaddr);
return 0;
}

/* Releases the page */
void sysv_set_link(struct sysv_dir_entry *de, struct page *page,
int sysv_set_link(struct sysv_dir_entry *de, struct page *page,
struct inode *inode)
{
struct inode *dir = page->mapping->host;
loff_t pos = page_offset(page) +
(char *)de-(char*)page_address(page);
loff_t pos = page_offset(page) + offset_in_page(de);
int err;

lock_page(page);
err = sysv_prepare_chunk(page, pos, SYSV_DIRSIZE);
BUG_ON(err);
if (err) {
unlock_page(page);
return err;
}
de->inode = cpu_to_fs16(SYSV_SB(inode->i_sb), inode->i_ino);
err = dir_commit_chunk(page, pos, SYSV_DIRSIZE);
dir_put_page(page);
dir_commit_chunk(page, pos, SYSV_DIRSIZE);
dir->i_mtime = dir->i_ctime = current_time(dir);
mark_inode_dirty(dir);
return sysv_handle_dirsync(inode);
}

struct sysv_dir_entry * sysv_dotdot (struct inode *dir, struct page **p)
/*
* Calls to dir_get_page()/dir_put_page() must be nested according to the
* rules documented in mm/highmem.rst.
*
* sysv_dotdot() acts as a call to dir_get_page() and must be treated
* accordingly for nesting purposes.
*/
struct sysv_dir_entry *sysv_dotdot(struct inode *dir, struct page **p)
{
struct page *page = dir_get_page(dir, 0);
struct sysv_dir_entry *de = NULL;
struct sysv_dir_entry *de = dir_get_page(dir, 0, p);

if (!IS_ERR(page)) {
de = (struct sysv_dir_entry*) page_address(page) + 1;
*p = page;
}
return de;
if (IS_ERR(de))
return NULL;
/* ".." is the second directory entry */
return de + 1;
}

ino_t sysv_inode_by_name(struct dentry *dentry)
Expand All @@ -362,7 +382,7 @@ ino_t sysv_inode_by_name(struct dentry *dentry)

if (de) {
res = fs16_to_cpu(SYSV_SB(dentry->d_sb), de->inode);
dir_put_page(page);
dir_put_page(page, de);
}
return res;
}
42 changes: 22 additions & 20 deletions fs/sysv/namei.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -153,19 +153,18 @@ static int sysv_unlink(struct inode * dir, struct dentry * dentry)
struct inode * inode = d_inode(dentry);
struct page * page;
struct sysv_dir_entry * de;
int err = -ENOENT;
int err;

de = sysv_find_entry(dentry, &page);
if (!de)
goto out;
return -ENOENT;

err = sysv_delete_entry (de, page);
if (err)
goto out;

inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
out:
err = sysv_delete_entry(de, page);
if (!err) {
inode->i_ctime = dir->i_ctime;
inode_dec_link_count(inode);
}
dir_put_page(page, de);
return err;
}

Expand Down Expand Up @@ -227,7 +226,10 @@ static int sysv_rename(struct mnt_idmap *idmap, struct inode *old_dir,
new_de = sysv_find_entry(new_dentry, &new_page);
if (!new_de)
goto out_dir;
sysv_set_link(new_de, new_page, old_inode);
err = sysv_set_link(new_de, new_page, old_inode);
dir_put_page(new_page, new_de);
if (err)
goto out_dir;
new_inode->i_ctime = current_time(new_inode);
if (dir_de)
drop_nlink(new_inode);
Expand All @@ -240,23 +242,23 @@ static int sysv_rename(struct mnt_idmap *idmap, struct inode *old_dir,
inode_inc_link_count(new_dir);
}

sysv_delete_entry(old_de, old_page);
err = sysv_delete_entry(old_de, old_page);
if (err)
goto out_dir;

mark_inode_dirty(old_inode);

if (dir_de) {
sysv_set_link(dir_de, dir_page, new_dir);
inode_dec_link_count(old_dir);
err = sysv_set_link(dir_de, dir_page, new_dir);
if (!err)
inode_dec_link_count(old_dir);
}
return 0;

out_dir:
if (dir_de) {
kunmap(dir_page);
put_page(dir_page);
}
if (dir_de)
dir_put_page(dir_page, dir_de);
out_old:
kunmap(old_page);
put_page(old_page);
dir_put_page(old_page, old_de);
out:
return err;
}
Expand Down
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