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fs/ntfs3: atomic_open implementation

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Added ntfs_atomic_open function.
Relaxed locking in ntfs_create_inode.

Signed-off-by: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
This commit is contained in:
Konstantin Komarov 2022-10-07 19:53:30 +03:00
parent 07f4aa9dd2
commit 2b108260ea
No known key found for this signature in database
GPG key ID: A9B0331F832407B6
2 changed files with 120 additions and 4 deletions
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24
fs/ntfs3/inode.c
View file

@ -1184,6 +1184,18 @@ ntfs_create_reparse_buffer(struct ntfs_sb_info *sbi, const char *symname,
return ERR_PTR(err);
}
/*
* ntfs_create_inode
*
* Helper function for:
* - ntfs_create
* - ntfs_mknod
* - ntfs_symlink
* - ntfs_mkdir
* - ntfs_atomic_open
*
* NOTE: if fnd != NULL (ntfs_atomic_open) then @dir is locked
*/
struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
struct inode *dir, struct dentry *dentry,
const struct cpu_str *uni, umode_t mode,
@ -1213,7 +1225,8 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
struct REPARSE_DATA_BUFFER *rp = NULL;
bool rp_inserted = false;
ni_lock_dir(dir_ni);
if (!fnd)
ni_lock_dir(dir_ni);
dir_root = indx_get_root(&dir_ni->dir, dir_ni, NULL, NULL);
if (!dir_root) {
@ -1583,7 +1596,8 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
goto out6;
/* Unlock parent directory before ntfs_init_acl. */
ni_unlock(dir_ni);
if (!fnd)
ni_unlock(dir_ni);
inode->i_generation = le16_to_cpu(rec->seq);
@ -1643,7 +1657,8 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
out7:
/* Undo 'indx_insert_entry'. */
ni_lock_dir(dir_ni);
if (!fnd)
ni_lock_dir(dir_ni);
indx_delete_entry(&dir_ni->dir, dir_ni, new_de + 1,
le16_to_cpu(new_de->key_size), sbi);
/* ni_unlock(dir_ni); will be called later. */
@ -1671,7 +1686,8 @@ struct inode *ntfs_create_inode(struct user_namespace *mnt_userns,
out1:
if (err) {
ni_unlock(dir_ni);
if (!fnd)
ni_unlock(dir_ni);
return ERR_PTR(err);
}

100
fs/ntfs3/namei.c
View file

@ -8,6 +8,7 @@
#include <linux/fs.h>
#include <linux/nls.h>
#include <linux/ctype.h>
#include <linux/posix_acl.h>
#include "debug.h"
#include "ntfs.h"
@ -334,6 +335,104 @@ static int ntfs_rename(struct user_namespace *mnt_userns, struct inode *dir,
return err;
}
/*
* ntfs_atomic_open
*
* inode_operations::atomic_open
*/
static int ntfs_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, u32 flags, umode_t mode)
{
int err;
struct inode *inode;
struct ntfs_fnd *fnd = NULL;
struct ntfs_inode *ni = ntfs_i(dir);
struct dentry *d = NULL;
struct cpu_str *uni = __getname();
bool locked = false;
if (!uni)
return -ENOMEM;
err = ntfs_nls_to_utf16(ni->mi.sbi, dentry->d_name.name,
dentry->d_name.len, uni, NTFS_NAME_LEN,
UTF16_HOST_ENDIAN);
if (err < 0)
goto out;
#ifdef CONFIG_NTFS3_FS_POSIX_ACL
if (IS_POSIXACL(dir)) {
/*
* Load in cache current acl to avoid ni_lock(dir):
* ntfs_create_inode -> ntfs_init_acl -> posix_acl_create ->
* ntfs_get_acl -> ntfs_get_acl_ex -> ni_lock
*/
struct posix_acl *p = get_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(p)) {
err = PTR_ERR(p);
goto out;
}
posix_acl_release(p);
}
#endif
if (d_in_lookup(dentry)) {
ni_lock_dir(ni);
locked = true;
fnd = fnd_get();
if (!fnd) {
err = -ENOMEM;
goto out1;
}
d = d_splice_alias(dir_search_u(dir, uni, fnd), dentry);
if (IS_ERR(d)) {
err = PTR_ERR(d);
d = NULL;
goto out2;
}
if (d)
dentry = d;
}
if (!(flags & O_CREAT) || d_really_is_positive(dentry)) {
err = finish_no_open(file, d);
goto out2;
}
file->f_mode |= FMODE_CREATED;
/*
* fnd contains tree's path to insert to.
* If fnd is not NULL then dir is locked.
*/
/*
* Unfortunately I don't know how to get here correct 'struct nameidata *nd'
* or 'struct user_namespace *mnt_userns'.
* See atomic_open in fs/namei.c.
* This is why xfstest/633 failed.
* Looks like ntfs_atomic_open must accept 'struct user_namespace *mnt_userns' as argument.
*/
inode = ntfs_create_inode(&init_user_ns, dir, dentry, uni, mode, 0,
NULL, 0, fnd);
err = IS_ERR(inode) ? PTR_ERR(inode)
: finish_open(file, dentry, ntfs_file_open);
dput(d);
out2:
fnd_put(fnd);
out1:
if (locked)
ni_unlock(ni);
out:
__putname(uni);
return err;
}
struct dentry *ntfs3_get_parent(struct dentry *child)
{
struct inode *inode = d_inode(child);
@ -500,6 +599,7 @@ const struct inode_operations ntfs_dir_inode_operations = {
.setattr = ntfs3_setattr,
.getattr = ntfs_getattr,
.listxattr = ntfs_listxattr,
.atomic_open = ntfs_atomic_open,
.fiemap = ntfs_fiemap,
};