--- /dev/null
+/*
+ * linux/fs/ext4/xattr.c
+ *
+ * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de>
+ *
+ * Fix by Harrison Xing <harrison@mountainviewdata.com>.
+ * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>.
+ * Extended attributes for symlinks and special files added per
+ * suggestion of Luka Renko <luka.renko@hermes.si>.
+ * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>,
+ * Red Hat Inc.
+ * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz
+ * and Andreas Gruenbacher <agruen@suse.de>.
+ */
+
+/*
+ * Extended attributes are stored directly in inodes (on file systems with
+ * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl
+ * field contains the block number if an inode uses an additional block. All
+ * attributes must fit in the inode and one additional block. Blocks that
+ * contain the identical set of attributes may be shared among several inodes.
+ * Identical blocks are detected by keeping a cache of blocks that have
+ * recently been accessed.
+ *
+ * The attributes in inodes and on blocks have a different header; the entries
+ * are stored in the same format:
+ *
+ * +------------------+
+ * | header |
+ * | entry 1 | |
+ * | entry 2 | | growing downwards
+ * | entry 3 | v
+ * | four null bytes |
+ * | . . . |
+ * | value 1 | ^
+ * | value 3 | | growing upwards
+ * | value 2 | |
+ * +------------------+
+ *
+ * The header is followed by multiple entry descriptors. In disk blocks, the
+ * entry descriptors are kept sorted. In inodes, they are unsorted. The
+ * attribute values are aligned to the end of the block in no specific order.
+ *
+ * Locking strategy
+ * ----------------
+ * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem.
+ * EA blocks are only changed if they are exclusive to an inode, so
+ * holding xattr_sem also means that nothing but the EA block's reference
+ * count can change. Multiple writers to the same block are synchronized
+ * by the buffer lock.
+ */
+
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/ext4_jbd2.h>
+#include <linux/ext4_fs.h>
+#include <linux/mbcache.h>
+#include <linux/quotaops.h>
+#include <linux/rwsem.h>
+#include <linux/vs_dlimit.h>
+#include "xattr.h"
+#include "acl.h"
+
+#define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data))
+#define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr))
+#define BFIRST(bh) ENTRY(BHDR(bh)+1)
+#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)
+
+#define IHDR(inode, raw_inode) \
+ ((struct ext4_xattr_ibody_header *) \
+ ((void *)raw_inode + \
+ EXT4_GOOD_OLD_INODE_SIZE + \
+ EXT4_I(inode)->i_extra_isize))
+#define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
+
+#ifdef EXT4_XATTR_DEBUG
+# define ea_idebug(inode, f...) do { \
+ printk(KERN_DEBUG "inode %s:%lu: ", \
+ inode->i_sb->s_id, inode->i_ino); \
+ printk(f); \
+ printk("\n"); \
+ } while (0)
+# define ea_bdebug(bh, f...) do { \
+ char b[BDEVNAME_SIZE]; \
+ printk(KERN_DEBUG "block %s:%lu: ", \
+ bdevname(bh->b_bdev, b), \
+ (unsigned long) bh->b_blocknr); \
+ printk(f); \
+ printk("\n"); \
+ } while (0)
+#else
+# define ea_idebug(f...)
+# define ea_bdebug(f...)
+#endif
+
+static void ext4_xattr_cache_insert(struct buffer_head *);
+static struct buffer_head *ext4_xattr_cache_find(struct inode *,
+ struct ext4_xattr_header *,
+ struct mb_cache_entry **);
+static void ext4_xattr_rehash(struct ext4_xattr_header *,
+ struct ext4_xattr_entry *);
+
+static struct mb_cache *ext4_xattr_cache;
+
+static struct xattr_handler *ext4_xattr_handler_map[] = {
+ [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler,
+#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
+ [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler,
+ [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler,
+#endif
+ [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler,
+#ifdef CONFIG_EXT4DEV_FS_SECURITY
+ [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler,
+#endif
+};
+
+struct xattr_handler *ext4_xattr_handlers[] = {
+ &ext4_xattr_user_handler,
+ &ext4_xattr_trusted_handler,
+#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
+ &ext4_xattr_acl_access_handler,
+ &ext4_xattr_acl_default_handler,
+#endif
+#ifdef CONFIG_EXT4DEV_FS_SECURITY
+ &ext4_xattr_security_handler,
+#endif
+ NULL
+};
+
+static inline struct xattr_handler *
+ext4_xattr_handler(int name_index)
+{
+ struct xattr_handler *handler = NULL;
+
+ if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map))
+ handler = ext4_xattr_handler_map[name_index];
+ return handler;
+}
+
+/*
+ * Inode operation listxattr()
+ *
+ * dentry->d_inode->i_mutex: don't care
+ */
+ssize_t
+ext4_listxattr(struct dentry *dentry, char *buffer, size_t size)
+{
+ return ext4_xattr_list(dentry->d_inode, buffer, size);
+}
+
+static int
+ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end)
+{
+ while (!IS_LAST_ENTRY(entry)) {
+ struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry);
+ if ((void *)next >= end)
+ return -EIO;
+ entry = next;
+ }
+ return 0;
+}
+
+static inline int
+ext4_xattr_check_block(struct buffer_head *bh)
+{
+ int error;
+
+ if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
+ BHDR(bh)->h_blocks != cpu_to_le32(1))
+ return -EIO;
+ error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size);
+ return error;
+}
+
+static inline int
+ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size)
+{
+ size_t value_size = le32_to_cpu(entry->e_value_size);
+
+ if (entry->e_value_block != 0 || value_size > size ||
+ le16_to_cpu(entry->e_value_offs) + value_size > size)
+ return -EIO;
+ return 0;
+}
+
+static int
+ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index,
+ const char *name, size_t size, int sorted)
+{
+ struct ext4_xattr_entry *entry;
+ size_t name_len;
+ int cmp = 1;
+
+ if (name == NULL)
+ return -EINVAL;
+ name_len = strlen(name);
+ entry = *pentry;
+ for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
+ cmp = name_index - entry->e_name_index;
+ if (!cmp)
+ cmp = name_len - entry->e_name_len;
+ if (!cmp)
+ cmp = memcmp(name, entry->e_name, name_len);
+ if (cmp <= 0 && (sorted || cmp == 0))
+ break;
+ }
+ *pentry = entry;
+ if (!cmp && ext4_xattr_check_entry(entry, size))
+ return -EIO;
+ return cmp ? -ENODATA : 0;
+}
+
+static int
+ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
+ void *buffer, size_t buffer_size)
+{
+ struct buffer_head *bh = NULL;
+ struct ext4_xattr_entry *entry;
+ size_t size;
+ int error;
+
+ ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
+ name_index, name, buffer, (long)buffer_size);
+
+ error = -ENODATA;
+ if (!EXT4_I(inode)->i_file_acl)
+ goto cleanup;
+ ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
+ bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+ if (!bh)
+ goto cleanup;
+ ea_bdebug(bh, "b_count=%d, refcount=%d",
+ atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+ if (ext4_xattr_check_block(bh)) {
+bad_block: ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: bad block %llu", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ error = -EIO;
+ goto cleanup;
+ }
+ ext4_xattr_cache_insert(bh);
+ entry = BFIRST(bh);
+ error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
+ if (error == -EIO)
+ goto bad_block;
+ if (error)
+ goto cleanup;
+ size = le32_to_cpu(entry->e_value_size);
+ if (buffer) {
+ error = -ERANGE;
+ if (size > buffer_size)
+ goto cleanup;
+ memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs),
+ size);
+ }
+ error = size;
+
+cleanup:
+ brelse(bh);
+ return error;
+}
+
+static int
+ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name,
+ void *buffer, size_t buffer_size)
+{
+ struct ext4_xattr_ibody_header *header;
+ struct ext4_xattr_entry *entry;
+ struct ext4_inode *raw_inode;
+ struct ext4_iloc iloc;
+ size_t size;
+ void *end;
+ int error;
+
+ if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+ return -ENODATA;
+ error = ext4_get_inode_loc(inode, &iloc);
+ if (error)
+ return error;
+ raw_inode = ext4_raw_inode(&iloc);
+ header = IHDR(inode, raw_inode);
+ entry = IFIRST(header);
+ end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+ error = ext4_xattr_check_names(entry, end);
+ if (error)
+ goto cleanup;
+ error = ext4_xattr_find_entry(&entry, name_index, name,
+ end - (void *)entry, 0);
+ if (error)
+ goto cleanup;
+ size = le32_to_cpu(entry->e_value_size);
+ if (buffer) {
+ error = -ERANGE;
+ if (size > buffer_size)
+ goto cleanup;
+ memcpy(buffer, (void *)IFIRST(header) +
+ le16_to_cpu(entry->e_value_offs), size);
+ }
+ error = size;
+
+cleanup:
+ brelse(iloc.bh);
+ return error;
+}
+
+/*
+ * ext4_xattr_get()
+ *
+ * Copy an extended attribute into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext4_xattr_get(struct inode *inode, int name_index, const char *name,
+ void *buffer, size_t buffer_size)
+{
+ int error;
+
+ down_read(&EXT4_I(inode)->xattr_sem);
+ error = ext4_xattr_ibody_get(inode, name_index, name, buffer,
+ buffer_size);
+ if (error == -ENODATA)
+ error = ext4_xattr_block_get(inode, name_index, name, buffer,
+ buffer_size);
+ up_read(&EXT4_I(inode)->xattr_sem);
+ return error;
+}
+
+static int
+ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry,
+ char *buffer, size_t buffer_size)
+{
+ size_t rest = buffer_size;
+
+ for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) {
+ struct xattr_handler *handler =
+ ext4_xattr_handler(entry->e_name_index);
+
+ if (handler) {
+ size_t size = handler->list(inode, buffer, rest,
+ entry->e_name,
+ entry->e_name_len);
+ if (buffer) {
+ if (size > rest)
+ return -ERANGE;
+ buffer += size;
+ }
+ rest -= size;
+ }
+ }
+ return buffer_size - rest;
+}
+
+static int
+ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+ struct buffer_head *bh = NULL;
+ int error;
+
+ ea_idebug(inode, "buffer=%p, buffer_size=%ld",
+ buffer, (long)buffer_size);
+
+ error = 0;
+ if (!EXT4_I(inode)->i_file_acl)
+ goto cleanup;
+ ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl);
+ bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+ error = -EIO;
+ if (!bh)
+ goto cleanup;
+ ea_bdebug(bh, "b_count=%d, refcount=%d",
+ atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount));
+ if (ext4_xattr_check_block(bh)) {
+ ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: bad block %llu", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ error = -EIO;
+ goto cleanup;
+ }
+ ext4_xattr_cache_insert(bh);
+ error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size);
+
+cleanup:
+ brelse(bh);
+
+ return error;
+}
+
+static int
+ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+ struct ext4_xattr_ibody_header *header;
+ struct ext4_inode *raw_inode;
+ struct ext4_iloc iloc;
+ void *end;
+ int error;
+
+ if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR))
+ return 0;
+ error = ext4_get_inode_loc(inode, &iloc);
+ if (error)
+ return error;
+ raw_inode = ext4_raw_inode(&iloc);
+ header = IHDR(inode, raw_inode);
+ end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+ error = ext4_xattr_check_names(IFIRST(header), end);
+ if (error)
+ goto cleanup;
+ error = ext4_xattr_list_entries(inode, IFIRST(header),
+ buffer, buffer_size);
+
+cleanup:
+ brelse(iloc.bh);
+ return error;
+}
+
+/*
+ * ext4_xattr_list()
+ *
+ * Copy a list of attribute names into the buffer
+ * provided, or compute the buffer size required.
+ * Buffer is NULL to compute the size of the buffer required.
+ *
+ * Returns a negative error number on failure, or the number of bytes
+ * used / required on success.
+ */
+int
+ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size)
+{
+ int i_error, b_error;
+
+ down_read(&EXT4_I(inode)->xattr_sem);
+ i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size);
+ if (i_error < 0) {
+ b_error = 0;
+ } else {
+ if (buffer) {
+ buffer += i_error;
+ buffer_size -= i_error;
+ }
+ b_error = ext4_xattr_block_list(inode, buffer, buffer_size);
+ if (b_error < 0)
+ i_error = 0;
+ }
+ up_read(&EXT4_I(inode)->xattr_sem);
+ return i_error + b_error;
+}
+
+/*
+ * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is
+ * not set, set it.
+ */
+static void ext4_xattr_update_super_block(handle_t *handle,
+ struct super_block *sb)
+{
+ if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR))
+ return;
+
+ if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) {
+ EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR);
+ sb->s_dirt = 1;
+ ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh);
+ }
+}
+
+/*
+ * Release the xattr block BH: If the reference count is > 1, decrement
+ * it; otherwise free the block.
+ */
+static void
+ext4_xattr_release_block(handle_t *handle, struct inode *inode,
+ struct buffer_head *bh)
+{
+ struct mb_cache_entry *ce = NULL;
+
+ ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
+ if (BHDR(bh)->h_refcount == cpu_to_le32(1)) {
+ ea_bdebug(bh, "refcount now=0; freeing");
+ if (ce)
+ mb_cache_entry_free(ce);
+ ext4_free_blocks(handle, inode, bh->b_blocknr, 1);
+ get_bh(bh);
+ ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
+ } else {
+ if (ext4_journal_get_write_access(handle, bh) == 0) {
+ lock_buffer(bh);
+ BHDR(bh)->h_refcount = cpu_to_le32(
+ le32_to_cpu(BHDR(bh)->h_refcount) - 1);
+ ext4_journal_dirty_metadata(handle, bh);
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+ DLIMIT_FREE_BLOCK(inode, 1);
+ DQUOT_FREE_BLOCK(inode, 1);
+ unlock_buffer(bh);
+ ea_bdebug(bh, "refcount now=%d; releasing",
+ le32_to_cpu(BHDR(bh)->h_refcount));
+ }
+ if (ce)
+ mb_cache_entry_release(ce);
+ }
+}
+
+struct ext4_xattr_info {
+ int name_index;
+ const char *name;
+ const void *value;
+ size_t value_len;
+};
+
+struct ext4_xattr_search {
+ struct ext4_xattr_entry *first;
+ void *base;
+ void *end;
+ struct ext4_xattr_entry *here;
+ int not_found;
+};
+
+static int
+ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s)
+{
+ struct ext4_xattr_entry *last;
+ size_t free, min_offs = s->end - s->base, name_len = strlen(i->name);
+
+ /* Compute min_offs and last. */
+ last = s->first;
+ for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+ if (!last->e_value_block && last->e_value_size) {
+ size_t offs = le16_to_cpu(last->e_value_offs);
+ if (offs < min_offs)
+ min_offs = offs;
+ }
+ }
+ free = min_offs - ((void *)last - s->base) - sizeof(__u32);
+ if (!s->not_found) {
+ if (!s->here->e_value_block && s->here->e_value_size) {
+ size_t size = le32_to_cpu(s->here->e_value_size);
+ free += EXT4_XATTR_SIZE(size);
+ }
+ free += EXT4_XATTR_LEN(name_len);
+ }
+ if (i->value) {
+ if (free < EXT4_XATTR_SIZE(i->value_len) ||
+ free < EXT4_XATTR_LEN(name_len) +
+ EXT4_XATTR_SIZE(i->value_len))
+ return -ENOSPC;
+ }
+
+ if (i->value && s->not_found) {
+ /* Insert the new name. */
+ size_t size = EXT4_XATTR_LEN(name_len);
+ size_t rest = (void *)last - (void *)s->here + sizeof(__u32);
+ memmove((void *)s->here + size, s->here, rest);
+ memset(s->here, 0, size);
+ s->here->e_name_index = i->name_index;
+ s->here->e_name_len = name_len;
+ memcpy(s->here->e_name, i->name, name_len);
+ } else {
+ if (!s->here->e_value_block && s->here->e_value_size) {
+ void *first_val = s->base + min_offs;
+ size_t offs = le16_to_cpu(s->here->e_value_offs);
+ void *val = s->base + offs;
+ size_t size = EXT4_XATTR_SIZE(
+ le32_to_cpu(s->here->e_value_size));
+
+ if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) {
+ /* The old and the new value have the same
+ size. Just replace. */
+ s->here->e_value_size =
+ cpu_to_le32(i->value_len);
+ memset(val + size - EXT4_XATTR_PAD, 0,
+ EXT4_XATTR_PAD); /* Clear pad bytes. */
+ memcpy(val, i->value, i->value_len);
+ return 0;
+ }
+
+ /* Remove the old value. */
+ memmove(first_val + size, first_val, val - first_val);
+ memset(first_val, 0, size);
+ s->here->e_value_size = 0;
+ s->here->e_value_offs = 0;
+ min_offs += size;
+
+ /* Adjust all value offsets. */
+ last = s->first;
+ while (!IS_LAST_ENTRY(last)) {
+ size_t o = le16_to_cpu(last->e_value_offs);
+ if (!last->e_value_block &&
+ last->e_value_size && o < offs)
+ last->e_value_offs =
+ cpu_to_le16(o + size);
+ last = EXT4_XATTR_NEXT(last);
+ }
+ }
+ if (!i->value) {
+ /* Remove the old name. */
+ size_t size = EXT4_XATTR_LEN(name_len);
+ last = ENTRY((void *)last - size);
+ memmove(s->here, (void *)s->here + size,
+ (void *)last - (void *)s->here + sizeof(__u32));
+ memset(last, 0, size);
+ }
+ }
+
+ if (i->value) {
+ /* Insert the new value. */
+ s->here->e_value_size = cpu_to_le32(i->value_len);
+ if (i->value_len) {
+ size_t size = EXT4_XATTR_SIZE(i->value_len);
+ void *val = s->base + min_offs - size;
+ s->here->e_value_offs = cpu_to_le16(min_offs - size);
+ memset(val + size - EXT4_XATTR_PAD, 0,
+ EXT4_XATTR_PAD); /* Clear the pad bytes. */
+ memcpy(val, i->value, i->value_len);
+ }
+ }
+ return 0;
+}
+
+struct ext4_xattr_block_find {
+ struct ext4_xattr_search s;
+ struct buffer_head *bh;
+};
+
+static int
+ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i,
+ struct ext4_xattr_block_find *bs)
+{
+ struct super_block *sb = inode->i_sb;
+ int error;
+
+ ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld",
+ i->name_index, i->name, i->value, (long)i->value_len);
+
+ if (EXT4_I(inode)->i_file_acl) {
+ /* The inode already has an extended attribute block. */
+ bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl);
+ error = -EIO;
+ if (!bs->bh)
+ goto cleanup;
+ ea_bdebug(bs->bh, "b_count=%d, refcount=%d",
+ atomic_read(&(bs->bh->b_count)),
+ le32_to_cpu(BHDR(bs->bh)->h_refcount));
+ if (ext4_xattr_check_block(bs->bh)) {
+ ext4_error(sb, __FUNCTION__,
+ "inode %lu: bad block %llu", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ error = -EIO;
+ goto cleanup;
+ }
+ /* Find the named attribute. */
+ bs->s.base = BHDR(bs->bh);
+ bs->s.first = BFIRST(bs->bh);
+ bs->s.end = bs->bh->b_data + bs->bh->b_size;
+ bs->s.here = bs->s.first;
+ error = ext4_xattr_find_entry(&bs->s.here, i->name_index,
+ i->name, bs->bh->b_size, 1);
+ if (error && error != -ENODATA)
+ goto cleanup;
+ bs->s.not_found = error;
+ }
+ error = 0;
+
+cleanup:
+ return error;
+}
+
+static int
+ext4_xattr_block_set(handle_t *handle, struct inode *inode,
+ struct ext4_xattr_info *i,
+ struct ext4_xattr_block_find *bs)
+{
+ struct super_block *sb = inode->i_sb;
+ struct buffer_head *new_bh = NULL;
+ struct ext4_xattr_search *s = &bs->s;
+ struct mb_cache_entry *ce = NULL;
+ int error;
+
+#define header(x) ((struct ext4_xattr_header *)(x))
+
+ if (i->value && i->value_len > sb->s_blocksize)
+ return -ENOSPC;
+ if (s->base) {
+ ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
+ bs->bh->b_blocknr);
+ if (header(s->base)->h_refcount == cpu_to_le32(1)) {
+ if (ce) {
+ mb_cache_entry_free(ce);
+ ce = NULL;
+ }
+ ea_bdebug(bs->bh, "modifying in-place");
+ error = ext4_journal_get_write_access(handle, bs->bh);
+ if (error)
+ goto cleanup;
+ lock_buffer(bs->bh);
+ error = ext4_xattr_set_entry(i, s);
+ if (!error) {
+ if (!IS_LAST_ENTRY(s->first))
+ ext4_xattr_rehash(header(s->base),
+ s->here);
+ ext4_xattr_cache_insert(bs->bh);
+ }
+ unlock_buffer(bs->bh);
+ if (error == -EIO)
+ goto bad_block;
+ if (!error)
+ error = ext4_journal_dirty_metadata(handle,
+ bs->bh);
+ if (error)
+ goto cleanup;
+ goto inserted;
+ } else {
+ int offset = (char *)s->here - bs->bh->b_data;
+
+ if (ce) {
+ mb_cache_entry_release(ce);
+ ce = NULL;
+ }
+ ea_bdebug(bs->bh, "cloning");
+ s->base = kmalloc(bs->bh->b_size, GFP_KERNEL);
+ error = -ENOMEM;
+ if (s->base == NULL)
+ goto cleanup;
+ memcpy(s->base, BHDR(bs->bh), bs->bh->b_size);
+ s->first = ENTRY(header(s->base)+1);
+ header(s->base)->h_refcount = cpu_to_le32(1);
+ s->here = ENTRY(s->base + offset);
+ s->end = s->base + bs->bh->b_size;
+ }
+ } else {
+ /* Allocate a buffer where we construct the new block. */
+ s->base = kmalloc(sb->s_blocksize, GFP_KERNEL);
+ /* assert(header == s->base) */
+ error = -ENOMEM;
+ if (s->base == NULL)
+ goto cleanup;
+ memset(s->base, 0, sb->s_blocksize);
+ header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
+ header(s->base)->h_blocks = cpu_to_le32(1);
+ header(s->base)->h_refcount = cpu_to_le32(1);
+ s->first = ENTRY(header(s->base)+1);
+ s->here = ENTRY(header(s->base)+1);
+ s->end = s->base + sb->s_blocksize;
+ }
+
+ error = ext4_xattr_set_entry(i, s);
+ if (error == -EIO)
+ goto bad_block;
+ if (error)
+ goto cleanup;
+ if (!IS_LAST_ENTRY(s->first))
+ ext4_xattr_rehash(header(s->base), s->here);
+
+inserted:
+ if (!IS_LAST_ENTRY(s->first)) {
+ new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce);
+ if (new_bh) {
+ /* We found an identical block in the cache. */
+ if (new_bh == bs->bh)
+ ea_bdebug(new_bh, "keeping");
+ else {
+ error = -ENOSPC;
+ if (DLIMIT_ALLOC_BLOCK(inode, 1))
+ goto cleanup;
+ /* The old block is released after updating
+ the inode. */
+ error = -EDQUOT;
+ if (DQUOT_ALLOC_BLOCK(inode, 1))
+ goto cleanup_dlimit;
+ error = ext4_journal_get_write_access(handle,
+ new_bh);
+ if (error)
+ goto cleanup_dquot;
+ lock_buffer(new_bh);
+ BHDR(new_bh)->h_refcount = cpu_to_le32(1 +
+ le32_to_cpu(BHDR(new_bh)->h_refcount));
+ ea_bdebug(new_bh, "reusing; refcount now=%d",
+ le32_to_cpu(BHDR(new_bh)->h_refcount));
+ unlock_buffer(new_bh);
+ error = ext4_journal_dirty_metadata(handle,
+ new_bh);
+ if (error)
+ goto cleanup_dquot;
+ }
+ mb_cache_entry_release(ce);
+ ce = NULL;
+ } else if (bs->bh && s->base == bs->bh->b_data) {
+ /* We were modifying this block in-place. */
+ ea_bdebug(bs->bh, "keeping this block");
+ new_bh = bs->bh;
+ get_bh(new_bh);
+ } else {
+ /* We need to allocate a new block */
+ ext4_fsblk_t goal = le32_to_cpu(
+ EXT4_SB(sb)->s_es->s_first_data_block) +
+ (ext4_fsblk_t)EXT4_I(inode)->i_block_group *
+ EXT4_BLOCKS_PER_GROUP(sb);
+ ext4_fsblk_t block = ext4_new_block(handle, inode,
+ goal, &error);
+ if (error)
+ goto cleanup;
+ ea_idebug(inode, "creating block %d", block);
+
+ new_bh = sb_getblk(sb, block);
+ if (!new_bh) {
+getblk_failed:
+ ext4_free_blocks(handle, inode, block, 1);
+ error = -EIO;
+ goto cleanup;
+ }
+ lock_buffer(new_bh);
+ error = ext4_journal_get_create_access(handle, new_bh);
+ if (error) {
+ unlock_buffer(new_bh);
+ goto getblk_failed;
+ }
+ memcpy(new_bh->b_data, s->base, new_bh->b_size);
+ set_buffer_uptodate(new_bh);
+ unlock_buffer(new_bh);
+ ext4_xattr_cache_insert(new_bh);
+ error = ext4_journal_dirty_metadata(handle, new_bh);
+ if (error)
+ goto cleanup;
+ }
+ }
+
+ /* Update the inode. */
+ EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0;
+
+ /* Drop the previous xattr block. */
+ if (bs->bh && bs->bh != new_bh)
+ ext4_xattr_release_block(handle, inode, bs->bh);
+ error = 0;
+
+cleanup:
+ if (ce)
+ mb_cache_entry_release(ce);
+ brelse(new_bh);
+ if (!(bs->bh && s->base == bs->bh->b_data))
+ kfree(s->base);
+
+ return error;
+
+cleanup_dquot:
+ DQUOT_FREE_BLOCK(inode, 1);
+cleanup_dlimit:
+ DLIMIT_FREE_BLOCK(inode, 1);
+ goto cleanup;
+
+bad_block:
+ ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: bad block %llu", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ goto cleanup;
+
+#undef header
+}
+
+struct ext4_xattr_ibody_find {
+ struct ext4_xattr_search s;
+ struct ext4_iloc iloc;
+};
+
+static int
+ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i,
+ struct ext4_xattr_ibody_find *is)
+{
+ struct ext4_xattr_ibody_header *header;
+ struct ext4_inode *raw_inode;
+ int error;
+
+ if (EXT4_I(inode)->i_extra_isize == 0)
+ return 0;
+ raw_inode = ext4_raw_inode(&is->iloc);
+ header = IHDR(inode, raw_inode);
+ is->s.base = is->s.first = IFIRST(header);
+ is->s.here = is->s.first;
+ is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size;
+ if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) {
+ error = ext4_xattr_check_names(IFIRST(header), is->s.end);
+ if (error)
+ return error;
+ /* Find the named attribute. */
+ error = ext4_xattr_find_entry(&is->s.here, i->name_index,
+ i->name, is->s.end -
+ (void *)is->s.base, 0);
+ if (error && error != -ENODATA)
+ return error;
+ is->s.not_found = error;
+ }
+ return 0;
+}
+
+static int
+ext4_xattr_ibody_set(handle_t *handle, struct inode *inode,
+ struct ext4_xattr_info *i,
+ struct ext4_xattr_ibody_find *is)
+{
+ struct ext4_xattr_ibody_header *header;
+ struct ext4_xattr_search *s = &is->s;
+ int error;
+
+ if (EXT4_I(inode)->i_extra_isize == 0)
+ return -ENOSPC;
+ error = ext4_xattr_set_entry(i, s);
+ if (error)
+ return error;
+ header = IHDR(inode, ext4_raw_inode(&is->iloc));
+ if (!IS_LAST_ENTRY(s->first)) {
+ header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC);
+ EXT4_I(inode)->i_state |= EXT4_STATE_XATTR;
+ } else {
+ header->h_magic = cpu_to_le32(0);
+ EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR;
+ }
+ return 0;
+}
+
+/*
+ * ext4_xattr_set_handle()
+ *
+ * Create, replace or remove an extended attribute for this inode. Buffer
+ * is NULL to remove an existing extended attribute, and non-NULL to
+ * either replace an existing extended attribute, or create a new extended
+ * attribute. The flags XATTR_REPLACE and XATTR_CREATE
+ * specify that an extended attribute must exist and must not exist
+ * previous to the call, respectively.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
+ const char *name, const void *value, size_t value_len,
+ int flags)
+{
+ struct ext4_xattr_info i = {
+ .name_index = name_index,
+ .name = name,
+ .value = value,
+ .value_len = value_len,
+
+ };
+ struct ext4_xattr_ibody_find is = {
+ .s = { .not_found = -ENODATA, },
+ };
+ struct ext4_xattr_block_find bs = {
+ .s = { .not_found = -ENODATA, },
+ };
+ int error;
+
+ if (!name)
+ return -EINVAL;
+ if (strlen(name) > 255)
+ return -ERANGE;
+ down_write(&EXT4_I(inode)->xattr_sem);
+ error = ext4_get_inode_loc(inode, &is.iloc);
+ if (error)
+ goto cleanup;
+
+ if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) {
+ struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc);
+ memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
+ EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW;
+ }
+
+ error = ext4_xattr_ibody_find(inode, &i, &is);
+ if (error)
+ goto cleanup;
+ if (is.s.not_found)
+ error = ext4_xattr_block_find(inode, &i, &bs);
+ if (error)
+ goto cleanup;
+ if (is.s.not_found && bs.s.not_found) {
+ error = -ENODATA;
+ if (flags & XATTR_REPLACE)
+ goto cleanup;
+ error = 0;
+ if (!value)
+ goto cleanup;
+ } else {
+ error = -EEXIST;
+ if (flags & XATTR_CREATE)
+ goto cleanup;
+ }
+ error = ext4_journal_get_write_access(handle, is.iloc.bh);
+ if (error)
+ goto cleanup;
+ if (!value) {
+ if (!is.s.not_found)
+ error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+ else if (!bs.s.not_found)
+ error = ext4_xattr_block_set(handle, inode, &i, &bs);
+ } else {
+ error = ext4_xattr_ibody_set(handle, inode, &i, &is);
+ if (!error && !bs.s.not_found) {
+ i.value = NULL;
+ error = ext4_xattr_block_set(handle, inode, &i, &bs);
+ } else if (error == -ENOSPC) {
+ error = ext4_xattr_block_set(handle, inode, &i, &bs);
+ if (error)
+ goto cleanup;
+ if (!is.s.not_found) {
+ i.value = NULL;
+ error = ext4_xattr_ibody_set(handle, inode, &i,
+ &is);
+ }
+ }
+ }
+ if (!error) {
+ ext4_xattr_update_super_block(handle, inode->i_sb);
+ inode->i_ctime = CURRENT_TIME_SEC;
+ error = ext4_mark_iloc_dirty(handle, inode, &is.iloc);
+ /*
+ * The bh is consumed by ext4_mark_iloc_dirty, even with
+ * error != 0.
+ */
+ is.iloc.bh = NULL;
+ if (IS_SYNC(inode))
+ handle->h_sync = 1;
+ }
+
+cleanup:
+ brelse(is.iloc.bh);
+ brelse(bs.bh);
+ up_write(&EXT4_I(inode)->xattr_sem);
+ return error;
+}
+
+/*
+ * ext4_xattr_set()
+ *
+ * Like ext4_xattr_set_handle, but start from an inode. This extended
+ * attribute modification is a filesystem transaction by itself.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+int
+ext4_xattr_set(struct inode *inode, int name_index, const char *name,
+ const void *value, size_t value_len, int flags)
+{
+ handle_t *handle;
+ int error, retries = 0;
+
+retry:
+ handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
+ if (IS_ERR(handle)) {
+ error = PTR_ERR(handle);
+ } else {
+ int error2;
+
+ error = ext4_xattr_set_handle(handle, inode, name_index, name,
+ value, value_len, flags);
+ error2 = ext4_journal_stop(handle);
+ if (error == -ENOSPC &&
+ ext4_should_retry_alloc(inode->i_sb, &retries))
+ goto retry;
+ if (error == 0)
+ error = error2;
+ }
+
+ return error;
+}
+
+/*
+ * ext4_xattr_delete_inode()
+ *
+ * Free extended attribute resources associated with this inode. This
+ * is called immediately before an inode is freed. We have exclusive
+ * access to the inode.
+ */
+void
+ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
+{
+ struct buffer_head *bh = NULL;
+
+ if (!EXT4_I(inode)->i_file_acl)
+ goto cleanup;
+ bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl);
+ if (!bh) {
+ ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: block %llu read error", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ goto cleanup;
+ }
+ if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) ||
+ BHDR(bh)->h_blocks != cpu_to_le32(1)) {
+ ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: bad block %llu", inode->i_ino,
+ EXT4_I(inode)->i_file_acl);
+ goto cleanup;
+ }
+ ext4_xattr_release_block(handle, inode, bh);
+ EXT4_I(inode)->i_file_acl = 0;
+
+cleanup:
+ brelse(bh);
+}
+
+/*
+ * ext4_xattr_put_super()
+ *
+ * This is called when a file system is unmounted.
+ */
+void
+ext4_xattr_put_super(struct super_block *sb)
+{
+ mb_cache_shrink(sb->s_bdev);
+}
+
+/*
+ * ext4_xattr_cache_insert()
+ *
+ * Create a new entry in the extended attribute cache, and insert
+ * it unless such an entry is already in the cache.
+ *
+ * Returns 0, or a negative error number on failure.
+ */
+static void
+ext4_xattr_cache_insert(struct buffer_head *bh)
+{
+ __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
+ struct mb_cache_entry *ce;
+ int error;
+
+ ce = mb_cache_entry_alloc(ext4_xattr_cache);
+ if (!ce) {
+ ea_bdebug(bh, "out of memory");
+ return;
+ }
+ error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash);
+ if (error) {
+ mb_cache_entry_free(ce);
+ if (error == -EBUSY) {
+ ea_bdebug(bh, "already in cache");
+ error = 0;
+ }
+ } else {
+ ea_bdebug(bh, "inserting [%x]", (int)hash);
+ mb_cache_entry_release(ce);
+ }
+}
+
+/*
+ * ext4_xattr_cmp()
+ *
+ * Compare two extended attribute blocks for equality.
+ *
+ * Returns 0 if the blocks are equal, 1 if they differ, and
+ * a negative error number on errors.
+ */
+static int
+ext4_xattr_cmp(struct ext4_xattr_header *header1,
+ struct ext4_xattr_header *header2)
+{
+ struct ext4_xattr_entry *entry1, *entry2;
+
+ entry1 = ENTRY(header1+1);
+ entry2 = ENTRY(header2+1);
+ while (!IS_LAST_ENTRY(entry1)) {
+ if (IS_LAST_ENTRY(entry2))
+ return 1;
+ if (entry1->e_hash != entry2->e_hash ||
+ entry1->e_name_index != entry2->e_name_index ||
+ entry1->e_name_len != entry2->e_name_len ||
+ entry1->e_value_size != entry2->e_value_size ||
+ memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len))
+ return 1;
+ if (entry1->e_value_block != 0 || entry2->e_value_block != 0)
+ return -EIO;
+ if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs),
+ (char *)header2 + le16_to_cpu(entry2->e_value_offs),
+ le32_to_cpu(entry1->e_value_size)))
+ return 1;
+
+ entry1 = EXT4_XATTR_NEXT(entry1);
+ entry2 = EXT4_XATTR_NEXT(entry2);
+ }
+ if (!IS_LAST_ENTRY(entry2))
+ return 1;
+ return 0;
+}
+
+/*
+ * ext4_xattr_cache_find()
+ *
+ * Find an identical extended attribute block.
+ *
+ * Returns a pointer to the block found, or NULL if such a block was
+ * not found or an error occurred.
+ */
+static struct buffer_head *
+ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
+ struct mb_cache_entry **pce)
+{
+ __u32 hash = le32_to_cpu(header->h_hash);
+ struct mb_cache_entry *ce;
+
+ if (!header->h_hash)
+ return NULL; /* never share */
+ ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
+again:
+ ce = mb_cache_entry_find_first(ext4_xattr_cache, 0,
+ inode->i_sb->s_bdev, hash);
+ while (ce) {
+ struct buffer_head *bh;
+
+ if (IS_ERR(ce)) {
+ if (PTR_ERR(ce) == -EAGAIN)
+ goto again;
+ break;
+ }
+ bh = sb_bread(inode->i_sb, ce->e_block);
+ if (!bh) {
+ ext4_error(inode->i_sb, __FUNCTION__,
+ "inode %lu: block %lu read error",
+ inode->i_ino, (unsigned long) ce->e_block);
+ } else if (le32_to_cpu(BHDR(bh)->h_refcount) >=
+ EXT4_XATTR_REFCOUNT_MAX) {
+ ea_idebug(inode, "block %lu refcount %d>=%d",
+ (unsigned long) ce->e_block,
+ le32_to_cpu(BHDR(bh)->h_refcount),
+ EXT4_XATTR_REFCOUNT_MAX);
+ } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) {
+ *pce = ce;
+ return bh;
+ }
+ brelse(bh);
+ ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash);
+ }
+ return NULL;
+}
+
+#define NAME_HASH_SHIFT 5
+#define VALUE_HASH_SHIFT 16
+
+/*
+ * ext4_xattr_hash_entry()
+ *
+ * Compute the hash of an extended attribute.
+ */
+static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
+ struct ext4_xattr_entry *entry)
+{
+ __u32 hash = 0;
+ char *name = entry->e_name;
+ int n;
+
+ for (n=0; n < entry->e_name_len; n++) {
+ hash = (hash << NAME_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
+ *name++;
+ }
+
+ if (entry->e_value_block == 0 && entry->e_value_size != 0) {
+ __le32 *value = (__le32 *)((char *)header +
+ le16_to_cpu(entry->e_value_offs));
+ for (n = (le32_to_cpu(entry->e_value_size) +
+ EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) {
+ hash = (hash << VALUE_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
+ le32_to_cpu(*value++);
+ }
+ }
+ entry->e_hash = cpu_to_le32(hash);
+}
+
+#undef NAME_HASH_SHIFT
+#undef VALUE_HASH_SHIFT
+
+#define BLOCK_HASH_SHIFT 16
+
+/*
+ * ext4_xattr_rehash()
+ *
+ * Re-compute the extended attribute hash value after an entry has changed.
+ */
+static void ext4_xattr_rehash(struct ext4_xattr_header *header,
+ struct ext4_xattr_entry *entry)
+{
+ struct ext4_xattr_entry *here;
+ __u32 hash = 0;
+
+ ext4_xattr_hash_entry(header, entry);
+ here = ENTRY(header+1);
+ while (!IS_LAST_ENTRY(here)) {
+ if (!here->e_hash) {
+ /* Block is not shared if an entry's hash value == 0 */
+ hash = 0;
+ break;
+ }
+ hash = (hash << BLOCK_HASH_SHIFT) ^
+ (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^
+ le32_to_cpu(here->e_hash);
+ here = EXT4_XATTR_NEXT(here);
+ }
+ header->h_hash = cpu_to_le32(hash);
+}
+
+#undef BLOCK_HASH_SHIFT
+
+int __init
+init_ext4_xattr(void)
+{
+ ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL,
+ sizeof(struct mb_cache_entry) +
+ sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6);
+ if (!ext4_xattr_cache)
+ return -ENOMEM;
+ return 0;
+}
+
+void
+exit_ext4_xattr(void)
+{
+ if (ext4_xattr_cache)
+ mb_cache_destroy(ext4_xattr_cache);
+ ext4_xattr_cache = NULL;
+}
git://git.onelab.eu / linux-2.6.git / blobdiff