diff options
Diffstat (limited to 'src/os/filestore/chain_xattr.cc')
| -rw-r--r-- | src/os/filestore/chain_xattr.cc | 413 |
1 files changed, 413 insertions, 0 deletions
diff --git a/src/os/filestore/chain_xattr.cc b/src/os/filestore/chain_xattr.cc new file mode 100644 index 00000000..e4dedd29 --- /dev/null +++ b/src/os/filestore/chain_xattr.cc @@ -0,0 +1,413 @@ +// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- +// vim: ts=8 sw=2 smarttab + +#include "chain_xattr.h" +#include <errno.h> // for ERANGE, ENODATA, ENOMEM +#include <stdio.h> // for size_t, snprintf +#include <stdlib.h> // for free, malloc +#include <string.h> // for strcpy, strlen +#include "include/ceph_assert.h" // for assert +#include "include/buffer.h" + +#if defined(__linux__) +#include <linux/fs.h> +#endif + +#include "include/ceph_assert.h" + +/* + * chaining xattrs + * + * In order to support xattrs that are larger than the xattr size limit that some file systems + * impose, we use multiple xattrs to store the value of a single xattr. The xattrs keys + * are set as follows: + * The first xattr in the chain, has a key that holds the original xattr name, with any '@' char + * being esacped ("@@"). + * The chained keys will have the first xattr's key (with the escaping), and a suffix: "@<id>" + * where <id> marks the num of xattr in the chain. + */ + +void get_raw_xattr_name(const char *name, int i, char *raw_name, int raw_len) +{ + int pos = 0; + + while (*name) { + switch (*name) { + case '@': /* escape it */ + pos += 2; + ceph_assert (pos < raw_len - 1); + *raw_name = '@'; + raw_name++; + *raw_name = '@'; + break; + default: + pos++; + ceph_assert(pos < raw_len - 1); + *raw_name = *name; + break; + } + name++; + raw_name++; + } + + if (!i) { + *raw_name = '\0'; + } else { + int r = snprintf(raw_name, raw_len - pos, "@%d", i); + ceph_assert(r < raw_len - pos); + } +} + +static int translate_raw_name(const char *raw_name, char *name, int name_len, bool *is_first) +{ + int pos = 0; + + *is_first = true; + while (*raw_name) { + switch (*raw_name) { + case '@': /* escape it */ + raw_name++; + if (!*raw_name) + break; + if (*raw_name != '@') { + *is_first = false; + goto done; + } + + /* fall through */ + default: + *name = *raw_name; + break; + } + pos++; + ceph_assert(pos < name_len); + name++; + raw_name++; + } +done: + *name = '\0'; + return pos; +} + + +// setxattr + +static int getxattr_len(const char *fn, const char *name) +{ + int i = 0, total = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int r; + + do { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_getxattr(fn, raw_name, 0, 0); + if (!i && r < 0) + return r; + if (r < 0) + break; + total += r; + i++; + } while (r == CHAIN_XATTR_MAX_BLOCK_LEN || + r == CHAIN_XATTR_SHORT_BLOCK_LEN); + + return total; +} + +int chain_getxattr(const char *fn, const char *name, void *val, size_t size) +{ + int i = 0, pos = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int ret = 0; + int r; + size_t chunk_size; + + if (!size) + return getxattr_len(fn, name); + + do { + chunk_size = size; + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + + r = sys_getxattr(fn, raw_name, (char *)val + pos, chunk_size); + if (i && r == -ENODATA) { + ret = pos; + break; + } + if (r < 0) { + ret = r; + break; + } + + if (r > 0) { + pos += r; + size -= r; + } + + i++; + } while (size && (r == CHAIN_XATTR_MAX_BLOCK_LEN || + r == CHAIN_XATTR_SHORT_BLOCK_LEN)); + + if (r >= 0) { + ret = pos; + /* is there another chunk? that can happen if the last read size span over + exactly one block */ + if (chunk_size == CHAIN_XATTR_MAX_BLOCK_LEN || + chunk_size == CHAIN_XATTR_SHORT_BLOCK_LEN) { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_getxattr(fn, raw_name, 0, 0); + if (r > 0) { // there's another chunk.. the original buffer was too small + ret = -ERANGE; + } + } + } + return ret; +} + +int chain_getxattr_buf(const char *fn, const char *name, bufferptr *bp) +{ + size_t size = 1024; // Initial + while (1) { + bufferptr buf(size); + int r = chain_getxattr( + fn, + name, + buf.c_str(), + size); + if (r > 0) { + buf.set_length(r); + if (bp) + bp->swap(buf); + return r; + } else if (r == 0) { + return 0; + } else { + if (r == -ERANGE) { + size *= 2; + } else { + return r; + } + } + } + ceph_abort_msg("unreachable"); + return 0; +} + +static int chain_fgetxattr_len(int fd, const char *name) +{ + int i = 0, total = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int r; + + do { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_fgetxattr(fd, raw_name, 0, 0); + if (!i && r < 0) + return r; + if (r < 0) + break; + total += r; + i++; + } while (r == CHAIN_XATTR_MAX_BLOCK_LEN || + r == CHAIN_XATTR_SHORT_BLOCK_LEN); + + return total; +} + +int chain_fgetxattr(int fd, const char *name, void *val, size_t size) +{ + int i = 0, pos = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int ret = 0; + int r; + size_t chunk_size; + + if (!size) + return chain_fgetxattr_len(fd, name); + + do { + chunk_size = size; + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + + r = sys_fgetxattr(fd, raw_name, (char *)val + pos, chunk_size); + if (i && r == -ENODATA) { + ret = pos; + break; + } + if (r < 0) { + ret = r; + break; + } + + if (r > 0) { + pos += r; + size -= r; + } + + i++; + } while (size && (r == CHAIN_XATTR_MAX_BLOCK_LEN || + r == CHAIN_XATTR_SHORT_BLOCK_LEN)); + + if (r >= 0) { + ret = pos; + /* is there another chunk? that can happen if the last read size span over + exactly one block */ + if (chunk_size == CHAIN_XATTR_MAX_BLOCK_LEN || + chunk_size == CHAIN_XATTR_SHORT_BLOCK_LEN) { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_fgetxattr(fd, raw_name, 0, 0); + if (r > 0) { // there's another chunk.. the original buffer was too small + ret = -ERANGE; + } + } + } + return ret; +} + + +// setxattr + +int get_xattr_block_size(size_t size) +{ + if (size <= CHAIN_XATTR_SHORT_LEN_THRESHOLD) + // this may fit in the inode; stripe over short attrs so that XFS + // won't kick it out. + return CHAIN_XATTR_SHORT_BLOCK_LEN; + return CHAIN_XATTR_MAX_BLOCK_LEN; +} + +// removexattr + +int chain_removexattr(const char *fn, const char *name) +{ + int i = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int r; + + do { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_removexattr(fn, raw_name); + if (!i && r < 0) { + return r; + } + i++; + } while (r >= 0); + return 0; +} + +int chain_fremovexattr(int fd, const char *name) +{ + int i = 0; + char raw_name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int r; + + do { + get_raw_xattr_name(name, i, raw_name, sizeof(raw_name)); + r = sys_fremovexattr(fd, raw_name); + if (!i && r < 0) { + return r; + } + i++; + } while (r >= 0); + return 0; +} + + +// listxattr + +int chain_listxattr(const char *fn, char *names, size_t len) { + int r; + + if (!len) + return sys_listxattr(fn, names, len) * 2; + + r = sys_listxattr(fn, 0, 0); + if (r < 0) + return r; + + size_t total_len = r * 2; // should be enough + char *full_buf = (char *)malloc(total_len); + if (!full_buf) + return -ENOMEM; + + r = sys_listxattr(fn, full_buf, total_len); + if (r < 0) { + free(full_buf); + return r; + } + + char *p = full_buf; + const char *end = full_buf + r; + char *dest = names; + char *dest_end = names + len; + + while (p < end) { + char name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int attr_len = strlen(p); + bool is_first; + int name_len = translate_raw_name(p, name, sizeof(name), &is_first); + if (is_first) { + if (dest + name_len > dest_end) { + r = -ERANGE; + goto done; + } + strcpy(dest, name); + dest += name_len + 1; + } + p += attr_len + 1; + } + r = dest - names; + +done: + free(full_buf); + return r; +} + +int chain_flistxattr(int fd, char *names, size_t len) { + int r; + char *p; + const char * end; + char *dest; + char *dest_end; + + if (!len) + return sys_flistxattr(fd, names, len) * 2; + + r = sys_flistxattr(fd, 0, 0); + if (r < 0) + return r; + + size_t total_len = r * 2; // should be enough + char *full_buf = (char *)malloc(total_len); + if (!full_buf) + return -ENOMEM; + + r = sys_flistxattr(fd, full_buf, total_len); + if (r < 0) + goto done; + + p = full_buf; + end = full_buf + r; + dest = names; + dest_end = names + len; + + while (p < end) { + char name[CHAIN_XATTR_MAX_NAME_LEN * 2 + 16]; + int attr_len = strlen(p); + bool is_first; + int name_len = translate_raw_name(p, name, sizeof(name), &is_first); + if (is_first) { + if (dest + name_len > dest_end) { + r = -ERANGE; + goto done; + } + strcpy(dest, name); + dest += name_len + 1; + } + p += attr_len + 1; + } + r = dest - names; + +done: + free(full_buf); + return r; +} |