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Message-Id: <1375436989-18948-4-git-send-email-wenqing.lz@taobao.com> Date: Fri, 2 Aug 2013 17:49:30 +0800 From: Zheng Liu <gnehzuil.liu@...il.com> To: linux-ext4@...r.kernel.org Cc: Zheng Liu <wenqing.lz@...bao.com>, Theodore Ts'o <tytso@....edu> Subject: [PATCH v1 03/22] libext2fs: add functions to operate on extended attribute From: Zheng Liu <wenqing.lz@...bao.com> We need to define some functions to operate extended attribute in order to support inline data. Signed-off-by: Zheng Liu <wenqing.lz@...bao.com> Signed-off-by: Theodore Ts'o <tytso@....edu> --- lib/ext2fs/ext2_err.et.in | 3 + lib/ext2fs/ext2_ext_attr.h | 31 ++++++++ lib/ext2fs/ext2fs.h | 9 +++ lib/ext2fs/ext_attr.c | 186 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 229 insertions(+) diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in index d20c6b7..7e6d6e5 100644 --- a/lib/ext2fs/ext2_err.et.in +++ b/lib/ext2fs/ext2_err.et.in @@ -476,4 +476,7 @@ ec EXT2_ET_MMP_CSUM_INVALID, ec EXT2_ET_FILE_EXISTS, "Ext2 file already exists" +ec EXT2_ET_EXT_ATTR_CURRUPTED, + "Extended attribute currupted" + end diff --git a/lib/ext2fs/ext2_ext_attr.h b/lib/ext2fs/ext2_ext_attr.h index bbb0aaa..99ad849 100644 --- a/lib/ext2fs/ext2_ext_attr.h +++ b/lib/ext2fs/ext2_ext_attr.h @@ -15,6 +15,10 @@ /* Maximum number of references to one attribute block */ #define EXT2_EXT_ATTR_REFCOUNT_MAX 1024 +/* Name indexes */ +#define EXT4_EXT_ATTR_INDEX_SYSTEM 7 +#define EXT4_EXT_ATTR_SYSTEM_DATA "data" + struct ext2_ext_attr_header { __u32 h_magic; /* magic number for identification */ __u32 h_refcount; /* reference count */ @@ -25,6 +29,10 @@ struct ext2_ext_attr_header { __u32 h_reserved[3]; /* zero right now */ }; +struct ext2_ext_attr_ibody_header { + __u32 h_magic; +}; + struct ext2_ext_attr_entry { __u8 e_name_len; /* length of name */ __u8 e_name_index; /* attribute name index */ @@ -57,6 +65,29 @@ struct ext2_ext_attr_entry { #define EXT2_XATTR_SIZE(size) \ (((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND) +#define IHDR(inode) \ + ((struct ext2_ext_attr_ibody_header *) \ + ((char *)inode + \ + EXT2_GOOD_OLD_INODE_SIZE + \ + inode->i_extra_isize)) +#define IFIRST(hdr) ((struct ext2_ext_attr_entry *)((hdr)+1)) +#define EXT2_ZERO_EXT_ATTR_VALUE ((void *)-1) + +struct ext2_ext_attr_info { + int name_index; + const char *name; + const void *value; + size_t value_len; +}; + +struct ext2_ext_attr_search { + struct ext2_ext_attr_entry *first; + void *base; + void *end; + struct ext2_ext_attr_entry *here; + int not_found; +}; + #ifdef __KERNEL__ # ifdef CONFIG_EXT2_FS_EXT_ATTR extern int ext2_get_ext_attr(struct inode *, const char *, char *, size_t, int); diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h index 3346c00..8c30197 100644 --- a/lib/ext2fs/ext2fs.h +++ b/lib/ext2fs/ext2fs.h @@ -1136,6 +1136,15 @@ extern errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk, char *block_buf, int adjust, __u32 *newcount, ext2_ino_t inum); +extern errcode_t ext2fs_ext_attr_ibody_find(ext2_filsys fs, + struct ext2_inode_large *inode, + struct ext2_ext_attr_info *i, + struct ext2_ext_attr_search *s); +extern errcode_t ext2fs_ext_attr_find_entry(struct ext2_ext_attr_entry **pentry, + int name_index, const char *name, + size_t size, int sorted); +extern errcode_t ext2fs_ext_attr_set_entry(struct ext2_ext_attr_info *i, + struct ext2_ext_attr_search *s); /* 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..6d55340 100644 --- a/lib/ext2fs/ext_attr.c +++ b/lib/ext2fs/ext_attr.c @@ -186,3 +186,189 @@ errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk, return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust, newcount); } + +static errcode_t +ext2fs_ext_attr_check_names(struct ext2_ext_attr_entry *entry, void *end) +{ + while (!EXT2_EXT_IS_LAST_ENTRY(entry)) { + struct ext2_ext_attr_entry *next = EXT2_EXT_ATTR_NEXT(entry); + if ((void *)next >= end) + return EXT2_ET_EXT_ATTR_CURRUPTED; + entry = next; + } + return 0; +} + +static inline errcode_t +ext2fs_ext_attr_check_entry(struct ext2_ext_attr_entry *entry, size_t size) +{ + size_t value_size = entry->e_value_size; + + if (entry->e_value_block != 0 || value_size > size || + entry->e_value_offs + value_size > size) + return EXT2_ET_EXT_ATTR_CURRUPTED; + return 0; +} + +errcode_t ext2fs_ext_attr_find_entry(struct ext2_ext_attr_entry **pentry, + int name_index, const char *name, + size_t size, int sorted) +{ + struct ext2_ext_attr_entry *entry; + size_t name_len; + int cmp = 1; + + if (name == NULL) + return EXT2_ET_INVALID_ARGUMENT; + name_len = strlen(name); + for (entry = *pentry; !EXT2_EXT_IS_LAST_ENTRY(entry); + entry = EXT2_EXT_ATTR_NEXT(entry)) { + cmp = name_index - entry->e_name_index; + if (!cmp) + cmp = name_len - entry->e_name_len; + if (!cmp) + cmp = memcmp(name, EXT2_EXT_ATTR_NAME(entry), + name_len); + if (cmp <= 0 && (sorted || cmp == 0)) + break; + } + *pentry = entry; + if (!cmp && ext2fs_ext_attr_check_entry(entry, size)) + return EXT2_ET_EXT_ATTR_CURRUPTED; + return cmp ? ENODATA : 0; +} + +errcode_t ext2fs_ext_attr_ibody_find(ext2_filsys fs, + struct ext2_inode_large *inode, + struct ext2_ext_attr_info *i, + struct ext2_ext_attr_search *s) +{ + struct ext2_ext_attr_ibody_header *header; + errcode_t error; + + if (inode->i_extra_isize == 0) + return 0; + header = IHDR(inode); + s->base = s->first = IFIRST(header); + s->here = s->first; + s->end = (char *)inode + EXT2_INODE_SIZE(fs->super); + + error = ext2fs_ext_attr_check_names(IFIRST(header), s->end); + if (error) + return error; + /* Find the named attribute. */ + error = ext2fs_ext_attr_find_entry(&s->here, i->name_index, + i->name, (char *)s->end - + (char *)s->base, 0); + if (error && error != ENODATA) + return error; + s->not_found = error; + return 0; +} + +errcode_t ext2fs_ext_attr_set_entry(struct ext2_ext_attr_info *i, + struct ext2_ext_attr_search *s) +{ + struct ext2_ext_attr_entry *last; + size_t freesize, min_offs = (char *)s->end - (char *)s->base; + size_t name_len = strlen(i->name); + + /* Compute min_offs and last. */ + last = s->first; + for (; !EXT2_EXT_IS_LAST_ENTRY(last); last = EXT2_EXT_ATTR_NEXT(last)) { + if (!last->e_value_block && last->e_value_size) { + size_t offs = last->e_value_offs; + if (offs < min_offs) + min_offs = offs; + } + } + freesize = min_offs - ((char *)last - (char *)s->base) - sizeof(__u32); + if (!s->not_found) { + if (!s->here->e_value_block && s->here->e_value_size) { + size_t size = s->here->e_value_size; + freesize += EXT2_EXT_ATTR_SIZE(size); + } + freesize += EXT2_EXT_ATTR_LEN(name_len); + } + if (i->value) { + if (freesize < EXT2_EXT_ATTR_SIZE(i->value_len) || + freesize < EXT2_EXT_ATTR_LEN(name_len) + + EXT2_EXT_ATTR_SIZE(i->value_len)) + return ENOSPC; + } + + if (i->value && s->not_found) { + /* Insert the new name. */ + size_t size = EXT2_EXT_ATTR_LEN(name_len); + size_t rest = (char *)last - (char *)s->here + sizeof(__u32); + memmove((char *)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(EXT2_EXT_ATTR_NAME(s->here), i->name, name_len); + } else { + if (!s->here->e_value_block && s->here->e_value_size) { + char *first_val = (char *) s->base + min_offs; + size_t offs = s->here->e_value_offs; + char *val = (char *)s->base + offs; + size_t size = EXT2_EXT_ATTR_SIZE(s->here->e_value_size); + + if (i->value && size == EXT2_EXT_ATTR_SIZE(i->value_len)) { + /* The old and the new value have the same + * size. Just replace. */ + s->here->e_value_size = i->value_len; + if (i->value == EXT2_ZERO_EXT_ATTR_VALUE) { + memset(val, 0, size); + } else { + memset(val + size - EXT2_EXT_ATTR_PAD, 0, + EXT2_EXT_ATTR_PAD); + 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 (!EXT2_EXT_IS_LAST_ENTRY(last)) { + size_t o = last->e_value_offs; + if (!last->e_value_block && + last->e_value_size && o < offs) + last->e_value_offs = o + size; + last = EXT2_EXT_ATTR_NEXT(last); + } + } + if (!i->value) { + /* Remove the old name. */ + size_t size = EXT2_EXT_ATTR_LEN(name_len); + last = (struct ext2_ext_attr_entry *)last - size; + memmove(s->here, (char *)s->here + size, + (char *)last - (char *)s->here + sizeof(__u32)); + memset(last, 0, size); + } + } + + if (i->value) { + /* Insert the new value. */ + s->here->e_value_size = i->value_len; + if (i->value_len) { + size_t size = EXT2_EXT_ATTR_SIZE(i->value_len); + char *val = (char *)s->base + min_offs - size; + s->here->e_value_offs = min_offs - size; + if (i->value == EXT2_ZERO_EXT_ATTR_VALUE) { + memset(val, 0, size); + } else { + memset(val + size - EXT2_EXT_ATTR_PAD, 0, + EXT2_EXT_ATTR_PAD); + memcpy(val, i->value, i->value_len); + } + } + } + return 0; +} -- 1.7.9.7 -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in 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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