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Message-ID: <20131127015617.GC3068@birch.djwong.org>
Date: Tue, 26 Nov 2013 17:56:17 -0800
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: tytso@....edu, linux-ext4@...r.kernel.org
Subject: Re: [PATCH 23/25] libext2fs: support modifying arbitrary extended
attributes
On Tue, Nov 26, 2013 at 03:21:16PM +0800, Zheng Liu wrote:
> On Thu, Oct 17, 2013 at 09:51:34PM -0700, Darrick J. Wong wrote:
> > Add functions to allow clients to get, set, and remove extended
> > attributes from any file. It also supports modifying EAs living in
> > i_file_acl.
> >
> > v2: Put the header declarations in the correct part of ext2fs.h,
> > provide a function to release an EA block from an inode, and check
> > i_extra_isize to make sure we actually have space for in-inode EAs.
>
> Is this the latest version? I am working on inline data patch set for
> e2fsprogs, and I want to use these API to manipulate the EA. So that
> would be great if you could point out which one is the latest version.
> Thanks in advance. Otherwise some nits below.
>
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
> > ---
> > lib/ext2fs/ext2_err.et.in | 18 +
> > lib/ext2fs/ext2fs.h | 28 ++
> > lib/ext2fs/ext_attr.c | 761 +++++++++++++++++++++++++++++++++++++++++++++
> > 3 files changed, 807 insertions(+)
> >
> >
> > diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
> > index 9cc1bd1..b819a90 100644
> > --- a/lib/ext2fs/ext2_err.et.in
> > +++ b/lib/ext2fs/ext2_err.et.in
> > @@ -482,4 +482,22 @@ ec EXT2_ET_BLOCK_BITMAP_CSUM_INVALID,
> > ec EXT2_ET_INLINE_DATA_CANT_ITERATE,
> > "Cannot block iterate on an inode containing inline data"
> >
> > +ec EXT2_ET_EA_BAD_NAME_LEN,
> > + "Extended attribute has an invalid name length"
> > +
> > +ec EXT2_ET_EA_BAD_VALUE_SIZE,
> > + "Extended attribute has an invalid value length"
> > +
> > +ec EXT2_ET_BAD_EA_HASH,
> > + "Extended attribute has an incorrect hash"
> > +
> > +ec EXT2_ET_BAD_EA_HEADER,
> > + "Extended attribute block has a bad header"
> > +
> > +ec EXT2_ET_EA_KEY_NOT_FOUND,
> > + "Extended attribute key not found"
> > +
> > +ec EXT2_ET_EA_NO_SPACE,
> > + "Insufficient space to store extended attribute data"
> > +
> > end
> > diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
> > index 5247922..93adae8 100644
> > --- a/lib/ext2fs/ext2fs.h
> > +++ b/lib/ext2fs/ext2fs.h
> > @@ -637,6 +637,13 @@ typedef struct stat ext2fs_struct_stat;
> > #define EXT2_FLAG_FLUSH_NO_SYNC 1
> >
> > /*
> > + * Modify and iterate extended attributes
> > + */
> > +struct ext2_xattr_handle;
> > +#define XATTR_ABORT 1
> > +#define XATTR_CHANGED 2
> > +
> > +/*
> > * function prototypes
> > */
> > static inline int ext2fs_has_group_desc_csum(ext2_filsys fs)
> > @@ -1151,6 +1158,27 @@ extern errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
> > char *block_buf,
> > int adjust, __u32 *newcount,
> > ext2_ino_t inum);
> > +errcode_t ext2fs_xattrs_expand(struct ext2_xattr_handle *h,
> > + unsigned int expandby);
> > +errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle);
> > +errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle);
> > +errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
> > + int (*func)(char *name, char *value,
> > + void *data),
> > + void *data);
> > +errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
> > + void **value, unsigned int *value_len);
> > +errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
> > + const char *key,
> > + const void *value,
> > + unsigned int value_len);
> > +errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
> > + const char *key);
> > +errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
> > + struct ext2_xattr_handle **handle);
> > +errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle);
> > +errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
> > + struct ext2_inode_large *inode);
> >
> > /* extent.c */
> > extern errcode_t ext2fs_extent_header_verify(void *ptr, int size);
> > diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
> > index 9649a14..2a1e5e7 100644
> > --- a/lib/ext2fs/ext_attr.c
> > +++ b/lib/ext2fs/ext_attr.c
> > @@ -186,3 +186,764 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
> > return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
> > newcount);
> > }
> > +
> > +/* Manipulate the contents of extended attribute regions */
> > +struct ext2_xattr {
> > + char *name;
> > + void *value;
> > + unsigned int value_len;
> > +};
> > +
> > +struct ext2_xattr_handle {
> > + ext2_filsys fs;
> > + struct ext2_xattr *attrs;
> > + unsigned int length;
> > + ext2_ino_t ino;
> > + int dirty;
> > +};
> > +
> > +errcode_t ext2fs_xattrs_expand(struct ext2_xattr_handle *h,
> > + unsigned int expandby)
> > +{
> > + struct ext2_xattr *new_attrs;
> > + errcode_t err;
> > +
> > + err = ext2fs_get_arrayzero(h->length + expandby,
> > + sizeof(struct ext2_xattr), &new_attrs);
> > + if (err)
> > + return err;
> > +
> > + memcpy(new_attrs, h->attrs, h->length * sizeof(struct ext2_xattr));
> > + ext2fs_free_mem(&h->attrs);
> > + h->length += expandby;
> > + h->attrs = new_attrs;
> > +
> > + return 0;
> > +}
> > +
> > +struct ea_name_index {
> > + int index;
> > + const char *name;
> > +};
> > +
> > +static struct ea_name_index ea_names[] = {
> > + {1, "user."},
> > + {2, "system.posix_acl_access"},
> > + {3, "system.posix_acl_default"},
> > + {4, "trusted."},
> > + {6, "security."},
> > + {7, "system."},
>
> It seems that we also have a _RICHACL name here.
Yes. Do you know what it's used for? EXT4_XATTR_INDEX_RICHACL isn't used as
of 3.13-rc1.
--D
>
> > + {0, NULL},
> > +};
> > +
> > +static const char *find_ea_prefix(int index)
> > +{
> > + struct ea_name_index *e;
> > +
> > + for (e = ea_names; e->name; e++)
> > + if (e->index == index)
> > + return e->name;
> > +
> > + return NULL;
> > +}
> > +
> > +static int find_ea_index(const char *fullname, char **name, int *index)
> > +{
> > + struct ea_name_index *e;
> > +
> > + for (e = ea_names; e->name; e++)
>
> Coding style problem:
> for (e = ea_names; e->name; e++) {
> ...
> }
>
> Thanks,
> - Zheng
>
> > + if (memcmp(fullname, e->name, strlen(e->name)) == 0) {
> > + *name = (char *)fullname + strlen(e->name);
> > + *index = e->index;
> > + return 1;
> > + }
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
> > + struct ext2_inode_large *inode)
> > +{
> > + struct ext2_ext_attr_header *header;
> > + void *block_buf = NULL;
> > + dgrp_t grp;
> > + blk64_t blk, goal;
> > + errcode_t err;
> > + struct ext2_inode_large i;
> > +
> > + /* Read inode? */
> > + if (inode == NULL) {
> > + err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)&i,
> > + sizeof(struct ext2_inode_large));
> > + if (err)
> > + return err;
> > + inode = &i;
> > + }
> > +
> > + /* Do we already have an EA block? */
> > + blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
> > + if (blk == 0)
> > + return 0;
> > +
> > + /* Find block, zero it, write back */
> > + if ((blk < fs->super->s_first_data_block) ||
> > + (blk >= ext2fs_blocks_count(fs->super))) {
> > + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> > + goto out;
> > + }
> > +
> > + err = ext2fs_get_mem(fs->blocksize, &block_buf);
> > + if (err)
> > + goto out;
> > +
> > + err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
> > + if (err)
> > + goto out2;
> > +
> > + header = (struct ext2_ext_attr_header *) block_buf;
> > + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> > + err = EXT2_ET_BAD_EA_HEADER;
> > + goto out2;
> > + }
> > +
> > + header->h_refcount--;
> > + err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
> > + if (err)
> > + goto out2;
> > +
> > + /* Erase link to block */
> > + ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, 0);
> > + if (header->h_refcount == 0)
> > + ext2fs_block_alloc_stats2(fs, blk, -1);
> > +
> > + /* Write inode? */
> > + if (inode == &i) {
> > + err = ext2fs_write_inode_full(fs, ino, (struct ext2_inode *)&i,
> > + sizeof(struct ext2_inode_large));
> > + if (err)
> > + goto out2;
> > + }
> > +
> > +out2:
> > + ext2fs_free_mem(&block_buf);
> > +out:
> > + return err;
> > +}
> > +
> > +static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
> > + struct ext2_inode_large *inode)
> > +{
> > + struct ext2_ext_attr_header *header;
> > + void *block_buf = NULL;
> > + dgrp_t grp;
> > + blk64_t blk, goal;
> > + errcode_t err;
> > +
> > + /* Do we already have an EA block? */
> > + blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
> > + if (blk != 0) {
> > + if ((blk < fs->super->s_first_data_block) ||
> > + (blk >= ext2fs_blocks_count(fs->super))) {
> > + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> > + goto out;
> > + }
> > +
> > + err = ext2fs_get_mem(fs->blocksize, &block_buf);
> > + if (err)
> > + goto out;
> > +
> > + err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
> > + if (err)
> > + goto out2;
> > +
> > + header = (struct ext2_ext_attr_header *) block_buf;
> > + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> > + err = EXT2_ET_BAD_EA_HEADER;
> > + goto out2;
> > + }
> > +
> > + /* Single-user block. We're done here. */
> > + if (header->h_refcount == 1)
> > + return 0;
> > +
> > + /* We need to CoW the block. */
> > + header->h_refcount--;
> > + err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
> > + if (err)
> > + goto out2;
> > + } else {
> > + /* No block, we must increment i_blocks */
> > + err = ext2fs_iblk_add_blocks(fs, (struct ext2_inode *)inode,
> > + 1);
> > + if (err)
> > + goto out;
> > + }
> > +
> > + /* Allocate a block */
> > + grp = ext2fs_group_of_ino(fs, ino);
> > + goal = ext2fs_inode_table_loc(fs, grp);
> > + err = ext2fs_alloc_block2(fs, goal, NULL, &blk);
> > + if (err)
> > + return err;
> > + ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, blk);
> > +out2:
> > + ext2fs_free_mem(&block_buf);
> > +out:
> > + return err;
> > +}
> > +
> > +
> > +static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
> > + struct ext2_xattr **pos,
> > + void *entries_start,
> > + unsigned int storage_size,
> > + unsigned int value_offset_correction)
> > +{
> > + struct ext2_xattr *x = *pos;
> > + struct ext2_ext_attr_entry *e = entries_start;
> > + void *end = entries_start + storage_size;
> > + char *shortname;
> > + unsigned int entry_size, value_size;
> > + int idx, ret;
> > +
> > + /* For all remaining x... */
> > + for (; x < handle->attrs + handle->length; x++) {
> > + if (!x->name)
> > + continue;
> > +
> > + /* Calculate index and shortname position */
> > + shortname = x->name;
> > + ret = find_ea_index(x->name, &shortname, &idx);
> > +
> > + /* Calculate entry and value size */
> > + entry_size = (sizeof(*e) + strlen(shortname) +
> > + EXT2_EXT_ATTR_PAD - 1) &
> > + ~(EXT2_EXT_ATTR_PAD - 1);
> > + value_size = ((x->value_len + EXT2_EXT_ATTR_PAD - 1) /
> > + EXT2_EXT_ATTR_PAD) * EXT2_EXT_ATTR_PAD;
> > +
> > + /*
> > + * Would entry collide with value?
> > + * Note that we must leave sufficient room for a (u32)0 to
> > + * mark the end of the entries.
> > + */
> > + if ((void *)e + entry_size + sizeof(__u32) > end - value_size)
> > + break;
> > +
> > + /* Fill out e appropriately */
> > + e->e_name_len = strlen(shortname);
> > + e->e_name_index = (ret ? idx : 0);
> > + e->e_value_offs = end - value_size - (void *)entries_start +
> > + value_offset_correction;
> > + e->e_value_block = 0;
> > + e->e_value_size = x->value_len;
> > +
> > + /* Store name and value */
> > + end -= value_size;
> > + memcpy((void *)e + sizeof(*e), shortname, e->e_name_len);
> > + memcpy(end, x->value, e->e_value_size);
> > +
> > + e->e_hash = ext2fs_ext_attr_hash_entry(e, end);
> > +
> > + e = EXT2_EXT_ATTR_NEXT(e);
> > + *(__u32 *)e = 0;
> > + }
> > + *pos = x;
> > +
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
> > +{
> > + struct ext2_xattr *x;
> > + struct ext2_inode_large *inode;
> > + void *start, *block_buf = NULL;
> > + struct ext2_ext_attr_header *header;
> > + __u32 ea_inode_magic;
> > + blk64_t blk;
> > + unsigned int storage_size;
> > + unsigned int i, written;
> > + errcode_t err;
> > +
> > + if (!EXT2_HAS_COMPAT_FEATURE(handle->fs->super,
> > + EXT2_FEATURE_COMPAT_EXT_ATTR))
> > + return 0;
> > +
> > + i = EXT2_INODE_SIZE(handle->fs->super);
> > + if (i < sizeof(*inode))
> > + i = sizeof(*inode);
> > + err = ext2fs_get_memzero(i, &inode);
> > + if (err)
> > + return err;
> > +
> > + err = ext2fs_read_inode_full(handle->fs, handle->ino,
> > + (struct ext2_inode *)inode,
> > + EXT2_INODE_SIZE(handle->fs->super));
> > + if (err)
> > + goto out;
> > +
> > + x = handle->attrs;
> > + /* Does the inode have size for EA? */
> > + if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize +
> > + sizeof(__u32))
> > + goto write_ea_block;
> > +
> > + /* Write the inode EA */
> > + ea_inode_magic = EXT2_EXT_ATTR_MAGIC;
> > + memcpy(((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize, &ea_inode_magic, sizeof(__u32));
> > + storage_size = EXT2_INODE_SIZE(handle->fs->super) -
> > + EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
> > + sizeof(__u32);
> > + start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize + sizeof(__u32);
> > +
> > + err = write_xattrs_to_buffer(handle, &x, start, storage_size, 0);
> > + if (err)
> > + goto out;
> > +
> > + /* Are we done? */
> > + if (x == handle->attrs + handle->length)
> > + goto skip_ea_block;
> > +
> > +write_ea_block:
> > + /* Write the EA block */
> > + err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
> > + if (err)
> > + goto out;
> > +
> > + storage_size = handle->fs->blocksize -
> > + sizeof(struct ext2_ext_attr_header);
> > + start = block_buf + sizeof(struct ext2_ext_attr_header);
> > +
> > + err = write_xattrs_to_buffer(handle, &x, start, storage_size,
> > + (void *)start - block_buf);
> > + if (err)
> > + goto out2;
> > +
> > + if (x < handle->attrs + handle->length) {
> > + err = EXT2_ET_EA_NO_SPACE;
> > + goto out2;
> > + }
> > +
> > + if (block_buf) {
> > + /* Write a header on the EA block */
> > + header = block_buf;
> > + header->h_magic = EXT2_EXT_ATTR_MAGIC;
> > + header->h_refcount = 1;
> > + header->h_blocks = 1;
> > +
> > + /* Get a new block for writing */
> > + err = prep_ea_block_for_write(handle->fs, handle->ino, inode);
> > + if (err)
> > + goto out2;
> > +
> > + /* Finally, write the new EA block */
> > + blk = ext2fs_file_acl_block(handle->fs,
> > + (struct ext2_inode *)inode);
> > + err = ext2fs_write_ext_attr3(handle->fs, blk, block_buf,
> > + handle->ino);
> > + if (err)
> > + goto out2;
> > + }
> > +
> > +skip_ea_block:
> > + blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
> > + if (!block_buf && blk) {
> > + /* xattrs shrunk, free the block */
> > + ext2fs_file_acl_block_set(handle->fs,
> > + (struct ext2_inode *)inode, 0);
> > + err = ext2fs_iblk_sub_blocks(handle->fs,
> > + (struct ext2_inode *)inode, 1);
> > + if (err)
> > + goto out;
> > + ext2fs_block_alloc_stats2(handle->fs, blk, -1);
> > + }
> > +
> > + /* Write the inode */
> > + err = ext2fs_write_inode_full(handle->fs, handle->ino,
> > + (struct ext2_inode *)inode,
> > + EXT2_INODE_SIZE(handle->fs->super));
> > + if (err)
> > + goto out2;
> > +
> > +out2:
> > + ext2fs_free_mem(&block_buf);
> > +out:
> > + ext2fs_free_mem(&inode);
> > + handle->dirty = 0;
> > + return err;
> > +}
> > +
> > +static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
> > + struct ext2_ext_attr_entry *entries,
> > + unsigned int storage_size,
> > + void *value_start)
> > +{
> > + struct ext2_xattr *x;
> > + struct ext2_ext_attr_entry *entry;
> > + const char *prefix;
> > + void *ptr;
> > + unsigned int remain, prefix_len;
> > + errcode_t err;
> > +
> > + x = handle->attrs;
> > + while (x->name)
> > + x++;
> > +
> > + entry = entries;
> > + while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
> > + __u32 hash;
> > +
> > + /* header eats this space */
> > + remain -= sizeof(struct ext2_ext_attr_entry);
> > +
> > + /* is attribute name valid? */
> > + if (EXT2_EXT_ATTR_SIZE(entry->e_name_len) > remain)
> > + return EXT2_ET_EA_BAD_NAME_LEN;
> > +
> > + /* attribute len eats this space */
> > + remain -= EXT2_EXT_ATTR_SIZE(entry->e_name_len);
> > +
> > + /* check value size */
> > + if (entry->e_value_size > remain)
> > + return EXT2_ET_EA_BAD_VALUE_SIZE;
> > +
> > + /* e_value_block must be 0 in inode's ea */
> > + if (entry->e_value_block != 0)
> > + return EXT2_ET_BAD_EA_BLOCK_NUM;
> > +
> > + hash = ext2fs_ext_attr_hash_entry(entry, value_start +
> > + entry->e_value_offs);
> > +
> > + /* e_hash may be 0 in older inode's ea */
> > + if (entry->e_hash != 0 && entry->e_hash != hash)
> > + return EXT2_ET_BAD_EA_HASH;
> > +
> > + remain -= entry->e_value_size;
> > +
> > + /* Allocate space for more attrs? */
> > + if (x == handle->attrs + handle->length) {
> > + err = ext2fs_xattrs_expand(handle, 4);
> > + if (err)
> > + return err;
> > + x = handle->attrs + handle->length - 4;
> > + }
> > +
> > + /* Extract name/value */
> > + prefix = find_ea_prefix(entry->e_name_index);
> > + prefix_len = (prefix ? strlen(prefix) : 0);
> > + err = ext2fs_get_memzero(entry->e_name_len + prefix_len + 1,
> > + &x->name);
> > + if (err)
> > + return err;
> > + if (prefix)
> > + memcpy(x->name, prefix, prefix_len);
> > + if (entry->e_name_len)
> > + memcpy(x->name + prefix_len,
> > + (void *)entry + sizeof(*entry),
> > + entry->e_name_len);
> > +
> > + err = ext2fs_get_mem(entry->e_value_size, &x->value);
> > + if (err)
> > + return err;
> > + x->value_len = entry->e_value_size;
> > + memcpy(x->value, value_start + entry->e_value_offs,
> > + entry->e_value_size);
> > + x++;
> > + entry = EXT2_EXT_ATTR_NEXT(entry);
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
> > +{
> > + struct ext2_xattr *attrs = NULL, *x;
> > + unsigned int attrs_len;
> > + struct ext2_inode_large *inode;
> > + struct ext2_ext_attr_header *header;
> > + __u32 ea_inode_magic;
> > + unsigned int storage_size;
> > + void *start, *block_buf = NULL;
> > + blk64_t blk;
> > + int i;
> > + errcode_t err;
> > +
> > + if (!EXT2_HAS_COMPAT_FEATURE(handle->fs->super,
> > + EXT2_FEATURE_COMPAT_EXT_ATTR))
> > + return 0;
> > +
> > + i = EXT2_INODE_SIZE(handle->fs->super);
> > + if (i < sizeof(*inode))
> > + i = sizeof(*inode);
> > + err = ext2fs_get_memzero(i, &inode);
> > + if (err)
> > + return err;
> > +
> > + err = ext2fs_read_inode_full(handle->fs, handle->ino,
> > + (struct ext2_inode *)inode,
> > + EXT2_INODE_SIZE(handle->fs->super));
> > + if (err)
> > + goto out;
> > +
> > + /* Does the inode have size for EA? */
> > + if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize +
> > + sizeof(__u32))
> > + goto read_ea_block;
> > +
> > + /* Look for EA in the inode */
> > + memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize, sizeof(__u32));
> > + if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
> > + storage_size = EXT2_INODE_SIZE(handle->fs->super) -
> > + EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
> > + sizeof(__u32);
> > + start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
> > + inode->i_extra_isize + sizeof(__u32);
> > +
> > + err = read_xattrs_from_buffer(handle, start, storage_size,
> > + start);
> > + if (err)
> > + goto out;
> > + }
> > +
> > +read_ea_block:
> > + /* Look for EA in a separate EA block */
> > + blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
> > + if (blk != 0) {
> > + if ((blk < handle->fs->super->s_first_data_block) ||
> > + (blk >= ext2fs_blocks_count(handle->fs->super))) {
> > + err = EXT2_ET_BAD_EA_BLOCK_NUM;
> > + goto out;
> > + }
> > +
> > + err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
> > + if (err)
> > + goto out;
> > +
> > + err = ext2fs_read_ext_attr3(handle->fs, blk, block_buf,
> > + handle->ino);
> > + if (err)
> > + goto out3;
> > +
> > + header = (struct ext2_ext_attr_header *) block_buf;
> > + if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
> > + err = EXT2_ET_BAD_EA_HEADER;
> > + goto out3;
> > + }
> > +
> > + if (header->h_blocks != 1) {
> > + err = EXT2_ET_BAD_EA_HEADER;
> > + goto out3;
> > + }
> > +
> > + /* Read EAs */
> > + storage_size = handle->fs->blocksize -
> > + sizeof(struct ext2_ext_attr_header);
> > + start = block_buf + sizeof(struct ext2_ext_attr_header);
> > + err = read_xattrs_from_buffer(handle, start, storage_size,
> > + block_buf);
> > + if (err)
> > + goto out3;
> > +
> > + ext2fs_free_mem(&block_buf);
> > + }
> > +
> > + ext2fs_free_mem(&block_buf);
> > + ext2fs_free_mem(&inode);
> > + return 0;
> > +
> > +out3:
> > + ext2fs_free_mem(&block_buf);
> > +out:
> > + ext2fs_free_mem(&inode);
> > + return err;
> > +}
> > +
> > +#define XATTR_ABORT 1
> > +#define XATTR_CHANGED 2
> > +errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
> > + int (*func)(char *name, char *value,
> > + void *data),
> > + void *data)
> > +{
> > + struct ext2_xattr *x;
> > + errcode_t err;
> > + int ret;
> > +
> > + for (x = h->attrs; x < h->attrs + h->length; x++) {
> > + if (!x->name)
> > + continue;
> > +
> > + ret = func(x->name, x->value, data);
> > + if (ret & XATTR_CHANGED)
> > + h->dirty = 1;
> > + if (ret & XATTR_ABORT)
> > + return 0;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
> > + void **value, unsigned int *value_len)
> > +{
> > + struct ext2_xattr *x;
> > + void *val;
> > + errcode_t err;
> > +
> > + for (x = h->attrs; x < h->attrs + h->length; x++) {
> > + if (!x->name)
> > + continue;
> > +
> > + if (strcmp(x->name, key) == 0) {
> > + err = ext2fs_get_mem(x->value_len, &val);
> > + if (err)
> > + return err;
> > + memcpy(val, x->value, x->value_len);
> > + *value = val;
> > + *value_len = x->value_len;
> > + return 0;
> > + }
> > + }
> > +
> > + return EXT2_ET_EA_KEY_NOT_FOUND;
> > +}
> > +
> > +errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
> > + const char *key,
> > + const void *value,
> > + unsigned int value_len)
> > +{
> > + struct ext2_xattr *x, *last_empty;
> > + char *new_value;
> > + errcode_t err;
> > +
> > + last_empty = NULL;
> > + for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
> > + if (!x->name) {
> > + last_empty = x;
> > + continue;
> > + }
> > +
> > + /* Replace xattr */
> > + if (strcmp(x->name, key) == 0) {
> > + err = ext2fs_get_mem(value_len, &new_value);
> > + if (err)
> > + return err;
> > + memcpy(new_value, value, value_len);
> > + ext2fs_free_mem(&x->value);
> > + x->value = new_value;
> > + x->value_len = value_len;
> > + handle->dirty = 1;
> > + return 0;
> > + }
> > + }
> > +
> > + /* Add attr to empty slot */
> > + if (last_empty) {
> > + err = ext2fs_get_mem(strlen(key) + 1, &last_empty->name);
> > + if (err)
> > + return err;
> > + strcpy(last_empty->name, key);
> > +
> > + err = ext2fs_get_mem(value_len, &last_empty->value);
> > + if (err)
> > + return err;
> > + memcpy(last_empty->value, value, value_len);
> > + last_empty->value_len = value_len;
> > + handle->dirty = 1;
> > + return 0;
> > + }
> > +
> > + /* Expand array, append slot */
> > + err = ext2fs_xattrs_expand(handle, 4);
> > + if (err)
> > + return err;
> > +
> > + x = handle->attrs + handle->length - 4;
> > + err = ext2fs_get_mem(strlen(key) + 1, &x->name);
> > + if (err)
> > + return err;
> > + strcpy(x->name, key);
> > +
> > + err = ext2fs_get_mem(value_len, &x->value);
> > + if (err)
> > + return err;
> > + memcpy(x->value, value, value_len);
> > + x->value_len = value_len;
> > + handle->dirty = 1;
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
> > + const char *key)
> > +{
> > + struct ext2_xattr *x;
> > + errcode_t err;
> > +
> > + for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
> > + if (!x->name)
> > + continue;
> > +
> > + if (strcmp(x->name, key) == 0) {
> > + ext2fs_free_mem(&x->name);
> > + ext2fs_free_mem(&x->value);
> > + x->value_len = 0;
> > + handle->dirty = 1;
> > + return 0;
> > + }
> > + }
> > +
> > + return EXT2_ET_EA_KEY_NOT_FOUND;
> > +}
> > +
> > +errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
> > + struct ext2_xattr_handle **handle)
> > +{
> > + struct ext2_xattr_handle *h;
> > + errcode_t err;
> > +
> > + err = ext2fs_get_memzero(sizeof(*h), &h);
> > + if (err)
> > + return err;
> > +
> > + h->length = 4;
> > + err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
> > + &h->attrs);
> > + if (err) {
> > + ext2fs_free_mem(&h);
> > + return err;
> > + }
> > + h->ino = ino;
> > + h->fs = fs;
> > + *handle = h;
> > + return 0;
> > +}
> > +
> > +errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
> > +{
> > + unsigned int i;
> > + struct ext2_xattr_handle *h = *handle;
> > + struct ext2_xattr *a = h->attrs;
> > + errcode_t err;
> > +
> > + if (h->dirty) {
> > + err = ext2fs_xattrs_write(h);
> > + if (err)
> > + return err;
> > + }
> > +
> > + for (i = 0; i < h->length; i++) {
> > + if (a[i].name)
> > + ext2fs_free_mem(&a[i].name);
> > + if (a[i].value)
> > + ext2fs_free_mem(&a[i].value);
> > + }
> > +
> > + ext2fs_free_mem(&h->attrs);
> > + ext2fs_free_mem(handle);
> > + return 0;
> > +}
> >
> > --
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> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
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