From: Gabriel Krisman Bertazi <krisman@collabora.com>
To: "André Almeida" <andrealmeid@collabora.com>
Cc: Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
smcv@collabora.com, kernel@collabora.com, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Daniel Rosenberg <drosen@google.com>
Subject: Re: [RFC PATCH 2/4] mm: shmem: Support case-insensitive file name lookups
Date: Tue, 23 Mar 2021 16:18:43 -0400 [thread overview]
Message-ID: <877dlxd3oc.fsf@collabora.com> (raw)
In-Reply-To: <20210323195941.69720-3-andrealmeid@collabora.com> (=?utf-8?Q?=22Andr=C3=A9?= Almeida"'s message of "Tue, 23 Mar 2021 16:59:39 -0300")
André Almeida <andrealmeid@collabora.com> writes:
> This patch implements the support for case-insensitive file name lookups
> in tmpfs, based on the encoding passed in the mount options.
Thanks for doing this.
>
> +#ifdef CONFIG_UNICODE
> +static const struct dentry_operations casefold_dentry_ops = {
> + .d_hash = generic_ci_d_hash,
> + .d_compare = generic_ci_d_compare,
> +};
> +#endif
Why not reuse struct generic_ci_dentry_ops ?
> +
> /*
> * shmem_file_setup pre-accounts the whole fixed size of a VM object,
> * for shared memory and for shared anonymous (/dev/zero) mappings
> @@ -2859,8 +2869,18 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
> struct inode *inode;
> int error = -ENOSPC;
>
> +#ifdef CONFIG_UNICODE
> + struct super_block *sb = dir->i_sb;
> +
> + if (sb_has_strict_encoding(sb) && IS_CASEFOLDED(dir) &&
> + sb->s_encoding && utf8_validate(sb->s_encoding, &dentry->d_name))
> + return -EINVAL;
> +#endif
> +
> inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE);
> if (inode) {
> + inode->i_flags |= dir->i_flags;
> +
> error = simple_acl_create(dir, inode);
> if (error)
> goto out_iput;
> @@ -2870,6 +2890,9 @@ shmem_mknod(struct user_namespace *mnt_userns, struct inode *dir,
> if (error && error != -EOPNOTSUPP)
> goto out_iput;
>
> + if (IS_CASEFOLDED(dir))
> + d_add(dentry, NULL);
> +
> error = 0;
> dir->i_size += BOGO_DIRENT_SIZE;
> dir->i_ctime = dir->i_mtime = current_time(dir);
> @@ -2925,6 +2948,19 @@ static int shmem_create(struct user_namespace *mnt_userns, struct inode *dir,
> return shmem_mknod(&init_user_ns, dir, dentry, mode | S_IFREG, 0);
> }
>
> +static struct dentry *shmem_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
> +{
> + if (dentry->d_name.len > NAME_MAX)
> + return ERR_PTR(-ENAMETOOLONG);
> +
> + if (IS_CASEFOLDED(dir))
> + return NULL;
I think this deserves a comment explaining why it is necessary.
> +
> + d_add(dentry, NULL);
> +
> + return NULL;
> +}
> +
> /*
> * Link a file..
> */
> @@ -2946,6 +2982,9 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentr
> goto out;
> }
>
> + if (IS_CASEFOLDED(dir))
> + d_add(dentry, NULL);
> +
> dir->i_size += BOGO_DIRENT_SIZE;
> inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
> inc_nlink(inode);
> @@ -2967,6 +3006,10 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry)
> inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode);
> drop_nlink(inode);
> dput(dentry); /* Undo the count from "create" - this does all the work */
> +
> + if (IS_CASEFOLDED(dir))
> + d_invalidate(dentry);
> +
> return 0;
> }
>
> @@ -3128,6 +3171,8 @@ static int shmem_symlink(struct user_namespace *mnt_userns, struct inode *dir,
> }
> dir->i_size += BOGO_DIRENT_SIZE;
> dir->i_ctime = dir->i_mtime = current_time(dir);
> + if (IS_CASEFOLDED(dir))
> + d_add(dentry, NULL);
> d_instantiate(dentry, inode);
> dget(dentry);
> return 0;
> @@ -3364,6 +3409,8 @@ enum shmem_param {
> Opt_uid,
> Opt_inode32,
> Opt_inode64,
> + Opt_casefold,
> + Opt_cf_strict,
> };
>
> static const struct constant_table shmem_param_enums_huge[] = {
> @@ -3385,6 +3432,8 @@ const struct fs_parameter_spec shmem_fs_parameters[] = {
> fsparam_u32 ("uid", Opt_uid),
> fsparam_flag ("inode32", Opt_inode32),
> fsparam_flag ("inode64", Opt_inode64),
> + fsparam_string("casefold", Opt_casefold),
> + fsparam_flag ("cf_strict", Opt_cf_strict),
> {}
> };
>
> @@ -3392,9 +3441,11 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> {
> struct shmem_options *ctx = fc->fs_private;
> struct fs_parse_result result;
> + struct unicode_map *encoding;
> unsigned long long size;
> + char version[10];
> char *rest;
> - int opt;
> + int opt, ret;
>
> opt = fs_parse(fc, shmem_fs_parameters, param, &result);
> if (opt < 0)
> @@ -3468,6 +3519,23 @@ static int shmem_parse_one(struct fs_context *fc, struct fs_parameter *param)
> ctx->full_inums = true;
> ctx->seen |= SHMEM_SEEN_INUMS;
> break;
> + case Opt_casefold:
> + if (strncmp(param->string, "utf8-", 5))
> + return invalfc(fc, "Only utf8 encondings are supported");
> + ret = strscpy(version, param->string + 5, sizeof(version));
Ugh. Now we are doing two strscpy for the parse api (in unicode_load).
Can change the unicode_load api to reuse it?
thanks,
--
Gabriel Krisman Bertazi
next prev parent reply other threads:[~2021-03-23 20:18 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 19:59 [RFC PATCH 0/4] mm: shmem: Add case-insensitive support for tmpfs André Almeida
2021-03-23 19:59 ` [RFC PATCH 1/4] Revert "libfs: unexport generic_ci_d_compare() and generic_ci_d_hash()" André Almeida
2021-03-23 20:15 ` Matthew Wilcox
2021-03-24 20:09 ` André Almeida
2021-03-23 19:59 ` [RFC PATCH 2/4] mm: shmem: Support case-insensitive file name lookups André Almeida
2021-03-23 20:18 ` Gabriel Krisman Bertazi [this message]
2021-03-24 20:17 ` André Almeida
2021-03-23 23:19 ` Al Viro
2021-03-24 20:44 ` André Almeida
2021-03-23 19:59 ` [RFC PATCH 3/4] mm: shmem: Add IOCTL support for tmpfs André Almeida
2021-03-23 22:15 ` Gabriel Krisman Bertazi
2021-03-23 19:59 ` [RFC PATCH 4/4] docs: tmpfs: Add casefold options André Almeida
2021-03-23 21:58 ` Randy Dunlap
2021-03-25 14:27 ` André Almeida
2021-03-23 22:19 ` Gabriel Krisman Bertazi
2021-03-24 20:47 ` André Almeida
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