From 3523dd761db148a1214269f6d3dd357231dcbcff Mon Sep 17 00:00:00 2001 From: Boris Burkov Date: Fri, 21 Aug 2020 00:40:05 -0700 Subject: [PATCH] btrfs-progs: receive: process encoded_write commands Add a new btrfs_send_op and support for both dumping and proper receive processing which does actual encoded writes. Encoded writes are only allowed on a file descriptor opened with an extra flag that allows encoded writes, so we also add support for this flag when opening or reusing a file for writing. Signed-off-by: Boris Burkov --- cmds/receive-dump.c | 16 +++++- cmds/receive.c | 48 ++++++++++++++++ common/send-stream.c | 29 ++++++++++ common/send-stream.h | 4 ++ ioctl.h | 132 +++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 228 insertions(+), 1 deletion(-) diff --git a/cmds/receive-dump.c b/cmds/receive-dump.c index 00ad4fd1..83701b62 100644 --- a/cmds/receive-dump.c +++ b/cmds/receive-dump.c @@ -318,6 +318,19 @@ static int print_update_extent(const char *path, u64 offset, u64 len, offset, len); } +static int print_encoded_write(const char *path, const void *data, u64 offset, + u64 len, u64 unencoded_file_len, + u64 unencoded_len, u64 unencoded_offset, + u32 compression, u32 encryption, void *user) +{ + return PRINT_DUMP(user, path, "encoded_write", + "offset=%llu len=%llu, unencoded_file_len=%llu, " + "unencoded_len=%llu, unencoded_offset=%llu, " + "compression=%u, encryption=%u", + offset, len, unencoded_file_len, unencoded_len, + unencoded_offset, compression, encryption); +} + struct btrfs_send_ops btrfs_print_send_ops = { .subvol = print_subvol, .snapshot = print_snapshot, @@ -339,5 +352,6 @@ struct btrfs_send_ops btrfs_print_send_ops = { .chmod = print_chmod, .chown = print_chown, .utimes = print_utimes, - .update_extent = print_update_extent + .update_extent = print_update_extent, + .encoded_write = print_encoded_write, }; diff --git a/cmds/receive.c b/cmds/receive.c index d106e554..8226ca32 100644 --- a/cmds/receive.c +++ b/cmds/receive.c @@ -29,12 +29,14 @@ #include #include #include +#include #include #include #include #include #include +#include #include #include @@ -49,6 +51,7 @@ #include "cmds/receive-dump.h" #include "common/help.h" #include "common/path-utils.h" +#include "stubs.h" struct btrfs_receive { @@ -982,6 +985,50 @@ static int process_update_extent(const char *path, u64 offset, u64 len, return 0; } +static int process_encoded_write(const char *path, const void *data, u64 offset, + u64 len, u64 unencoded_file_len, + u64 unencoded_len, u64 unencoded_offset, + u32 compression, u32 encryption, void *user) +{ + int ret; + struct btrfs_receive *rctx = user; + char full_path[PATH_MAX]; + struct iovec iov = { (char *)data, len }; + struct btrfs_ioctl_encoded_io_args encoded = { + .iov = &iov, + .iovcnt = 1, + .offset = offset, + .len = unencoded_file_len, + .unencoded_len = unencoded_len, + .unencoded_offset = unencoded_offset, + .compression = compression, + .encryption = encryption, + }; + + if (encryption) { + error("encoded_write: encryption not supported"); + return -EOPNOTSUPP; + } + + ret = path_cat_out(full_path, rctx->full_subvol_path, path); + if (ret < 0) { + error("encoded_write: path invalid: %s", path); + return ret; + } + + ret = open_inode_for_write(rctx, full_path); + if (ret < 0) + return ret; + + ret = ioctl(rctx->write_fd, BTRFS_IOC_ENCODED_WRITE, &encoded); + if (ret < 0) { + ret = -errno; + error("encoded_write: writing to %s failed: %m", path); + return ret; + } + return 0; +} + static struct btrfs_send_ops send_ops = { .subvol = process_subvol, .snapshot = process_snapshot, @@ -1004,6 +1051,7 @@ static struct btrfs_send_ops send_ops = { .chown = process_chown, .utimes = process_utimes, .update_extent = process_update_extent, + .encoded_write = process_encoded_write, }; static int do_receive(struct btrfs_receive *rctx, const char *tomnt, diff --git a/common/send-stream.c b/common/send-stream.c index 81a830d9..ce7c40f5 100644 --- a/common/send-stream.c +++ b/common/send-stream.c @@ -357,6 +357,8 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx) struct timespec mt; u8 uuid[BTRFS_UUID_SIZE]; u8 clone_uuid[BTRFS_UUID_SIZE]; + u32 compression; + u32 encryption; u64 tmp; u64 tmp2; u64 ctransid; @@ -366,6 +368,9 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx) u64 clone_offset; u64 offset; u64 ino; + u64 unencoded_file_len; + u64 unencoded_len; + u64 unencoded_offset; int len; int xattr_len; @@ -452,6 +457,30 @@ static int read_and_process_cmd(struct btrfs_send_stream *sctx) TLV_GET(sctx, BTRFS_SEND_A_DATA, &data, &len); ret = sctx->ops->write(path, data, offset, len, sctx->user); break; + case BTRFS_SEND_C_ENCODED_WRITE: + TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path); + TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset); + TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_FILE_LEN, + &unencoded_file_len); + TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_LEN, &unencoded_len); + TLV_GET_U64(sctx, BTRFS_SEND_A_UNENCODED_OFFSET, + &unencoded_offset); + /* Compression and encryption default to none if omitted. */ + if (sctx->cmd_attrs[BTRFS_SEND_A_COMPRESSION].data) + TLV_GET_U32(sctx, BTRFS_SEND_A_COMPRESSION, &compression); + else + compression = BTRFS_ENCODED_IO_COMPRESSION_NONE; + if (sctx->cmd_attrs[BTRFS_SEND_A_ENCRYPTION].data) + TLV_GET_U32(sctx, BTRFS_SEND_A_ENCRYPTION, &encryption); + else + encryption = BTRFS_ENCODED_IO_ENCRYPTION_NONE; + TLV_GET(sctx, BTRFS_SEND_A_DATA, &data, &len); + ret = sctx->ops->encoded_write(path, data, offset, len, + unencoded_file_len, + unencoded_len, unencoded_offset, + compression, encryption, + sctx->user); + break; case BTRFS_SEND_C_CLONE: TLV_GET_STRING(sctx, BTRFS_SEND_A_PATH, &path); TLV_GET_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, &offset); diff --git a/common/send-stream.h b/common/send-stream.h index 2de51eac..44abbc9d 100644 --- a/common/send-stream.h +++ b/common/send-stream.h @@ -53,6 +53,10 @@ struct btrfs_send_ops { struct timespec *mt, struct timespec *ct, void *user); int (*update_extent)(const char *path, u64 offset, u64 len, void *user); + int (*encoded_write)(const char *path, const void *data, u64 offset, + u64 len, u64 unencoded_file_len, u64 unencoded_len, + u64 unencoded_offset, u32 compression, + u32 encryption, void *user); }; int btrfs_read_and_process_send_stream(int fd, diff --git a/ioctl.h b/ioctl.h index 368a87b2..8adf63c2 100644 --- a/ioctl.h +++ b/ioctl.h @@ -777,6 +777,134 @@ struct btrfs_ioctl_get_subvol_rootref_args { }; BUILD_ASSERT(sizeof(struct btrfs_ioctl_get_subvol_rootref_args) == 4096); +/* + * Data and metadata for an encoded read or write. + * + * Encoded I/O bypasses any encoding automatically done by the filesystem (e.g., + * compression). This can be used to read the compressed contents of a file or + * write pre-compressed data directly to a file. + * + * BTRFS_IOC_ENCODED_READ and BTRFS_IOC_ENCODED_WRITE are essentially + * preadv/pwritev with additional metadata about how the data is encoded and the + * size of the unencoded data. + * + * BTRFS_IOC_ENCODED_READ fills the given iovecs with the encoded data, fills + * the metadata fields, and returns the size of the encoded data. It reads one + * extent per call. It can also read data which is not encoded. + * + * BTRFS_IOC_ENCODED_WRITE uses the metadata fields, writes the encoded data + * from the iovecs, and returns the size of the encoded data. Note that the + * encoded data is not validated when it is written; if it is not valid (e.g., + * it cannot be decompressed), then a subsequent read may return an error. + * + * Since the filesystem page cache contains decoded data, encoded I/O bypasses + * the page cache. Encoded I/O requires CAP_SYS_ADMIN. + */ +struct btrfs_ioctl_encoded_io_args { + /* Input parameters for both reads and writes. */ + + /* + * iovecs containing encoded data. + * + * For reads, if the size of the encoded data is larger than the sum of + * iov[n].iov_len for 0 <= n < iovcnt, then the ioctl fails with + * ENOBUFS. + * + * For writes, the size of the encoded data is the sum of iov[n].iov_len + * for 0 <= n < iovcnt. This must be less than 128 KiB (this limit may + * increase in the future). This must also be less than or equal to + * unencoded_len. + */ + const struct iovec __user *iov; + /* Number of iovecs. */ + unsigned long iovcnt; + /* + * Offset in file. + * + * For writes, must be aligned to the sector size of the filesystem. + */ + __s64 offset; + /* Currently must be zero. */ + __u64 flags; + + /* + * For reads, the following members are output parameters that will + * contain the returned metadata for the encoded data. + * For writes, the following members must be set to the metadata for the + * encoded data. + */ + + /* + * Length of the data in the file. + * + * Must be less than or equal to unencoded_len - unencoded_offset. For + * writes, must be aligned to the sector size of the filesystem unless + * the data ends at or beyond the current end of the file. + */ + __u64 len; + /* + * Length of the unencoded (i.e., decrypted and decompressed) data. + * + * For writes, must be no more than 128 KiB (this limit may increase in + * the future). If the unencoded data is actually longer than + * unencoded_len, then it is truncated; if it is shorter, then it is + * extended with zeroes. + */ + __u64 unencoded_len; + /* + * Offset from the first byte of the unencoded data to the first byte of + * logical data in the file. + * + * Must be less than unencoded_len. + */ + __u64 unencoded_offset; + /* + * BTRFS_ENCODED_IO_COMPRESSION_* type. + * + * For writes, must not be BTRFS_ENCODED_IO_COMPRESSION_NONE. + */ + __u32 compression; + /* Currently always BTRFS_ENCODED_IO_ENCRYPTION_NONE. */ + __u32 encryption; + /* + * Reserved for future expansion. + * + * For reads, always returned as zero. Users should check for non-zero + * bytes. If there are any, then the kernel has a newer version of this + * structure with additional information that the user definition is + * missing. + * + * For writes, must be zeroed. + */ + __u8 reserved[64]; +}; + +/* Data is not compressed. */ +#define BTRFS_ENCODED_IO_COMPRESSION_NONE 0 +/* Data is compressed as a single zlib stream. */ +#define BTRFS_ENCODED_IO_COMPRESSION_ZLIB 1 +/* + * Data is compressed as a single zstd frame with the windowLog compression + * parameter set to no more than 17. + */ +#define BTRFS_ENCODED_IO_COMPRESSION_ZSTD 2 +/* + * Data is compressed sector by sector (using the sector size indicated by the + * name of the constant) with LZO1X and wrapped in the format documented in + * fs/btrfs/lzo.c. For writes, the compression sector size must match the + * filesystem sector size. + */ +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_4K 3 +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_8K 4 +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_16K 5 +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_32K 6 +#define BTRFS_ENCODED_IO_COMPRESSION_LZO_64K 7 +#define BTRFS_ENCODED_IO_COMPRESSION_TYPES 8 + +/* Data is not encrypted. */ +#define BTRFS_ENCODED_IO_ENCRYPTION_NONE 0 +#define BTRFS_ENCODED_IO_ENCRYPTION_TYPES 1 + /* Error codes as returned by the kernel */ enum btrfs_err_code { notused, @@ -951,6 +1079,10 @@ static inline char *btrfs_err_str(enum btrfs_err_code err_code) struct btrfs_ioctl_ino_lookup_user_args) #define BTRFS_IOC_SNAP_DESTROY_V2 _IOW(BTRFS_IOCTL_MAGIC, 63, \ struct btrfs_ioctl_vol_args_v2) +#define BTRFS_IOC_ENCODED_READ _IOR(BTRFS_IOCTL_MAGIC, 64, \ + struct btrfs_ioctl_encoded_io_args) +#define BTRFS_IOC_ENCODED_WRITE _IOW(BTRFS_IOCTL_MAGIC, 64, \ + struct btrfs_ioctl_encoded_io_args) #ifdef __cplusplus } -- 2.35.1