diff options
Diffstat (limited to 'fs/libfs.c')
| -rw-r--r-- | fs/libfs.c | 200 |
1 files changed, 106 insertions, 94 deletions
diff --git a/fs/libfs.c b/fs/libfs.c index eec6031b0155..78c71a9e2e18 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -240,17 +240,22 @@ const struct inode_operations simple_dir_inode_operations = { }; EXPORT_SYMBOL(simple_dir_inode_operations); -static void offset_set(struct dentry *dentry, u32 offset) +/* 0 is '.', 1 is '..', so always start with offset 2 or more */ +enum { + DIR_OFFSET_MIN = 2, +}; + +static void offset_set(struct dentry *dentry, long offset) { - dentry->d_fsdata = (void *)((uintptr_t)(offset)); + dentry->d_fsdata = (void *)offset; } -static u32 dentry2offset(struct dentry *dentry) +static long dentry2offset(struct dentry *dentry) { - return (u32)((uintptr_t)(dentry->d_fsdata)); + return (long)dentry->d_fsdata; } -static struct lock_class_key simple_offset_xa_lock; +static struct lock_class_key simple_offset_lock_class; /** * simple_offset_init - initialize an offset_ctx @@ -259,11 +264,9 @@ static struct lock_class_key simple_offset_xa_lock; */ void simple_offset_init(struct offset_ctx *octx) { - xa_init_flags(&octx->xa, XA_FLAGS_ALLOC1); - lockdep_set_class(&octx->xa.xa_lock, &simple_offset_xa_lock); - - /* 0 is '.', 1 is '..', so always start with offset 2 */ - octx->next_offset = 2; + mt_init_flags(&octx->mt, MT_FLAGS_ALLOC_RANGE); + lockdep_set_class(&octx->mt.ma_lock, &simple_offset_lock_class); + octx->next_offset = DIR_OFFSET_MIN; } /** @@ -271,20 +274,19 @@ void simple_offset_init(struct offset_ctx *octx) * @octx: directory offset ctx to be updated * @dentry: new dentry being added * - * Returns zero on success. @so_ctx and the dentry offset are updated. + * Returns zero on success. @octx and the dentry's offset are updated. * Otherwise, a negative errno value is returned. */ int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) { - static const struct xa_limit limit = XA_LIMIT(2, U32_MAX); - u32 offset; + unsigned long offset; int ret; if (dentry2offset(dentry) != 0) return -EBUSY; - ret = xa_alloc_cyclic(&octx->xa, &offset, dentry, limit, - &octx->next_offset, GFP_KERNEL); + ret = mtree_alloc_cyclic(&octx->mt, &offset, dentry, DIR_OFFSET_MIN, + LONG_MAX, &octx->next_offset, GFP_KERNEL); if (ret < 0) return ret; @@ -300,17 +302,49 @@ int simple_offset_add(struct offset_ctx *octx, struct dentry *dentry) */ void simple_offset_remove(struct offset_ctx *octx, struct dentry *dentry) { - u32 offset; + long offset; offset = dentry2offset(dentry); if (offset == 0) return; - xa_erase(&octx->xa, offset); + mtree_erase(&octx->mt, offset); offset_set(dentry, 0); } /** + * simple_offset_empty - Check if a dentry can be unlinked + * @dentry: dentry to be tested + * + * Returns 0 if @dentry is a non-empty directory; otherwise returns 1. + */ +int simple_offset_empty(struct dentry *dentry) +{ + struct inode *inode = d_inode(dentry); + struct offset_ctx *octx; + struct dentry *child; + unsigned long index; + int ret = 1; + + if (!inode || !S_ISDIR(inode->i_mode)) + return ret; + + index = DIR_OFFSET_MIN; + octx = inode->i_op->get_offset_ctx(inode); + mt_for_each(&octx->mt, child, index, LONG_MAX) { + spin_lock(&child->d_lock); + if (simple_positive(child)) { + spin_unlock(&child->d_lock); + ret = 0; + break; + } + spin_unlock(&child->d_lock); + } + + return ret; +} + +/** * simple_offset_rename_exchange - exchange rename with directory offsets * @old_dir: parent of dentry being moved * @old_dentry: dentry being moved @@ -327,8 +361,8 @@ int simple_offset_rename_exchange(struct inode *old_dir, { struct offset_ctx *old_ctx = old_dir->i_op->get_offset_ctx(old_dir); struct offset_ctx *new_ctx = new_dir->i_op->get_offset_ctx(new_dir); - u32 old_index = dentry2offset(old_dentry); - u32 new_index = dentry2offset(new_dentry); + long old_index = dentry2offset(old_dentry); + long new_index = dentry2offset(new_dentry); int ret; simple_offset_remove(old_ctx, old_dentry); @@ -354,9 +388,9 @@ int simple_offset_rename_exchange(struct inode *old_dir, out_restore: offset_set(old_dentry, old_index); - xa_store(&old_ctx->xa, old_index, old_dentry, GFP_KERNEL); + mtree_store(&old_ctx->mt, old_index, old_dentry, GFP_KERNEL); offset_set(new_dentry, new_index); - xa_store(&new_ctx->xa, new_index, new_dentry, GFP_KERNEL); + mtree_store(&new_ctx->mt, new_index, new_dentry, GFP_KERNEL); return ret; } @@ -369,7 +403,7 @@ out_restore: */ void simple_offset_destroy(struct offset_ctx *octx) { - xa_destroy(&octx->xa); + mtree_destroy(&octx->mt); } /** @@ -399,15 +433,16 @@ static loff_t offset_dir_llseek(struct file *file, loff_t offset, int whence) /* In this case, ->private_data is protected by f_pos_lock */ file->private_data = NULL; - return vfs_setpos(file, offset, U32_MAX); + return vfs_setpos(file, offset, LONG_MAX); } -static struct dentry *offset_find_next(struct xa_state *xas) +static struct dentry *offset_find_next(struct offset_ctx *octx, loff_t offset) { + MA_STATE(mas, &octx->mt, offset, offset); struct dentry *child, *found = NULL; rcu_read_lock(); - child = xas_next_entry(xas, U32_MAX); + child = mas_find(&mas, LONG_MAX); if (!child) goto out; spin_lock(&child->d_lock); @@ -421,8 +456,8 @@ out: static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) { - u32 offset = dentry2offset(dentry); struct inode *inode = d_inode(dentry); + long offset = dentry2offset(dentry); return ctx->actor(ctx, dentry->d_name.name, dentry->d_name.len, offset, inode->i_ino, fs_umode_to_dtype(inode->i_mode)); @@ -430,12 +465,11 @@ static bool offset_dir_emit(struct dir_context *ctx, struct dentry *dentry) static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) { - struct offset_ctx *so_ctx = inode->i_op->get_offset_ctx(inode); - XA_STATE(xas, &so_ctx->xa, ctx->pos); + struct offset_ctx *octx = inode->i_op->get_offset_ctx(inode); struct dentry *dentry; while (true) { - dentry = offset_find_next(&xas); + dentry = offset_find_next(octx, ctx->pos); if (!dentry) return ERR_PTR(-ENOENT); @@ -444,8 +478,8 @@ static void *offset_iterate_dir(struct inode *inode, struct dir_context *ctx) break; } + ctx->pos = dentry2offset(dentry) + 1; dput(dentry); - ctx->pos = xas.xa_index + 1; } return NULL; } @@ -481,7 +515,7 @@ static int offset_readdir(struct file *file, struct dir_context *ctx) return 0; /* In this case, ->private_data is protected by f_pos_lock */ - if (ctx->pos == 2) + if (ctx->pos == DIR_OFFSET_MIN) file->private_data = NULL; else if (file->private_data == ERR_PTR(-ENOENT)) return 0; @@ -1704,16 +1738,28 @@ bool is_empty_dir_inode(struct inode *inode) static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, const char *str, const struct qstr *name) { - const struct dentry *parent = READ_ONCE(dentry->d_parent); - const struct inode *dir = READ_ONCE(parent->d_inode); - const struct super_block *sb = dentry->d_sb; - const struct unicode_map *um = sb->s_encoding; - struct qstr qstr = QSTR_INIT(str, len); + const struct dentry *parent; + const struct inode *dir; char strbuf[DNAME_INLINE_LEN]; - int ret; + struct qstr qstr; + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + * + * This comparison is safe under RCU because the caller + * guarantees the consistency between str and len. See + * __d_lookup_rcu_op_compare() for details. + */ + if (len == name->len && !memcmp(str, name->name, len)) + return 0; + + parent = READ_ONCE(dentry->d_parent); + dir = READ_ONCE(parent->d_inode); if (!dir || !IS_CASEFOLDED(dir)) - goto fallback; + return 1; + /* * If the dentry name is stored in-line, then it may be concurrently * modified by a rename. If this happens, the VFS will eventually retry @@ -1724,20 +1770,14 @@ static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, if (len <= DNAME_INLINE_LEN - 1) { memcpy(strbuf, str, len); strbuf[len] = 0; - qstr.name = strbuf; + str = strbuf; /* prevent compiler from optimizing out the temporary buffer */ barrier(); } - ret = utf8_strncasecmp(um, name, &qstr); - if (ret >= 0) - return ret; + qstr.len = len; + qstr.name = str; - if (sb_has_strict_encoding(sb)) - return -EINVAL; -fallback: - if (len != name->len) - return 1; - return !!memcmp(str, name->name, len); + return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr); } /** @@ -1752,7 +1792,7 @@ static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) const struct inode *dir = READ_ONCE(dentry->d_inode); struct super_block *sb = dentry->d_sb; const struct unicode_map *um = sb->s_encoding; - int ret = 0; + int ret; if (!dir || !IS_CASEFOLDED(dir)) return 0; @@ -1766,73 +1806,45 @@ static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) static const struct dentry_operations generic_ci_dentry_ops = { .d_hash = generic_ci_d_hash, .d_compare = generic_ci_d_compare, -}; -#endif - #ifdef CONFIG_FS_ENCRYPTION -static const struct dentry_operations generic_encrypted_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, +#endif }; #endif -#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) -static const struct dentry_operations generic_encrypted_ci_dentry_ops = { - .d_hash = generic_ci_d_hash, - .d_compare = generic_ci_d_compare, +#ifdef CONFIG_FS_ENCRYPTION +static const struct dentry_operations generic_encrypted_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, }; #endif /** - * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry - * @dentry: dentry to set ops on + * generic_set_sb_d_ops - helper for choosing the set of + * filesystem-wide dentry operations for the enabled features + * @sb: superblock to be configured * - * Casefolded directories need d_hash and d_compare set, so that the dentries - * contained in them are handled case-insensitively. Note that these operations - * are needed on the parent directory rather than on the dentries in it, and - * while the casefolding flag can be toggled on and off on an empty directory, - * dentry_operations can't be changed later. As a result, if the filesystem has - * casefolding support enabled at all, we have to give all dentries the - * casefolding operations even if their inode doesn't have the casefolding flag - * currently (and thus the casefolding ops would be no-ops for now). - * - * Encryption works differently in that the only dentry operation it needs is - * d_revalidate, which it only needs on dentries that have the no-key name flag. - * The no-key flag can't be set "later", so we don't have to worry about that. - * - * Finally, to maximize compatibility with overlayfs (which isn't compatible - * with certain dentry operations) and to avoid taking an unnecessary - * performance hit, we use custom dentry_operations for each possible - * combination rather than always installing all operations. + * Filesystems supporting casefolding and/or fscrypt can call this + * helper at mount-time to configure sb->s_d_op to best set of dentry + * operations required for the enabled features. The helper must be + * called after these have been configured, but before the root dentry + * is created. */ -void generic_set_encrypted_ci_d_ops(struct dentry *dentry) +void generic_set_sb_d_ops(struct super_block *sb) { -#ifdef CONFIG_FS_ENCRYPTION - bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME; -#endif #if IS_ENABLED(CONFIG_UNICODE) - bool needs_ci_ops = dentry->d_sb->s_encoding; -#endif -#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) - if (needs_encrypt_ops && needs_ci_ops) { - d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops); + if (sb->s_encoding) { + sb->s_d_op = &generic_ci_dentry_ops; return; } #endif #ifdef CONFIG_FS_ENCRYPTION - if (needs_encrypt_ops) { - d_set_d_op(dentry, &generic_encrypted_dentry_ops); - return; - } -#endif -#if IS_ENABLED(CONFIG_UNICODE) - if (needs_ci_ops) { - d_set_d_op(dentry, &generic_ci_dentry_ops); + if (sb->s_cop) { + sb->s_d_op = &generic_encrypted_dentry_ops; return; } #endif } -EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops); +EXPORT_SYMBOL(generic_set_sb_d_ops); /** * inode_maybe_inc_iversion - increments i_version |