diff options
| -rw-r--r-- | source3/smbd/vfs-wrap.c | 78 |
1 files changed, 70 insertions, 8 deletions
diff --git a/source3/smbd/vfs-wrap.c b/source3/smbd/vfs-wrap.c index b2d73561af..48d16bdaaf 100644 --- a/source3/smbd/vfs-wrap.c +++ b/source3/smbd/vfs-wrap.c @@ -476,6 +476,62 @@ int vfswrap_utime(connection_struct *conn, const char *path, struct utimbuf *tim return result; } +/********************************************************************* + A version of ftruncate that will write the space on disk if strict + allocate is set. +**********************************************************************/ + +static int strict_allocate_ftruncate(files_struct *fsp, int fd, SMB_OFF_T len) +{ + struct vfs_ops *vfs_ops = &fsp->conn->vfs_ops; + SMB_STRUCT_STAT st; + SMB_OFF_T currpos = vfs_ops->lseek(fsp, fd, 0, SEEK_CUR); + unsigned char zero_space[4096]; + SMB_OFF_T space_to_write = len - st.st_size; + + if (currpos == -1) + return -1; + + if (vfs_ops->fstat(fsp, fd, &st) == -1) + return -1; + +#ifdef S_ISFIFO + if (S_ISFIFO(st.st_mode)) + return 0; +#endif + + if (st.st_size == len) + return 0; + + /* Shrink - just ftruncate. */ + if (st.st_size > len) + return sys_ftruncate(fd, len); + + /* Write out the real space on disk. */ + if (vfs_ops->lseek(fsp, fd, st.st_size, SEEK_SET) != st.st_size) + return -1; + + space_to_write = len - st.st_size; + + memset(zero_space, '\0', sizeof(zero_space)); + while ( space_to_write > 0) { + SMB_OFF_T retlen; + SMB_OFF_T current_len_to_write = MIN(sizeof(zero_space),space_to_write); + + retlen = vfs_ops->write(fsp,fsp->fd,(char *)zero_space,current_len_to_write); + if (retlen <= 0) + return -1; + + space_to_write -= retlen; + } + + /* Seek to where we were */ + if (vfs_ops->lseek(fsp, fd, currpos, SEEK_SET) != currpos) + return -1; + + return 0; +} + int vfswrap_ftruncate(files_struct *fsp, int fd, SMB_OFF_T len) { int result = -1; @@ -486,13 +542,21 @@ int vfswrap_ftruncate(files_struct *fsp, int fd, SMB_OFF_T len) START_PROFILE(syscall_ftruncate); + if (lp_strict_allocate(SNUM(fsp->conn))) { + result = strict_allocate_ftruncate(fsp, fd, len); + END_PROFILE(syscall_ftruncate); + return result; + } + /* we used to just check HAVE_FTRUNCATE_EXTEND and only use sys_ftruncate if the system supports it. Then I discovered that you can have some filesystems that support ftruncate expansion and some that don't! On Linux fat can't do ftruncate extend but ext2 can. */ + result = sys_ftruncate(fd, len); - if (result == 0) goto done; + if (result == 0) + goto done; /* According to W. R. Stevens advanced UNIX prog. Pure 4.3 BSD cannot extend a file with ftruncate. Provide alternate implementation @@ -506,7 +570,7 @@ int vfswrap_ftruncate(files_struct *fsp, int fd, SMB_OFF_T len) size in which case the ftruncate above should have succeeded or shorter, in which case seek to len - 1 and write 1 byte of zero */ - if (vfs_ops->fstat(fsp, fd, &st) < 0) { + if (vfs_ops->fstat(fsp, fd, &st) == -1) { goto done; } @@ -527,19 +591,17 @@ int vfswrap_ftruncate(files_struct *fsp, int fd, SMB_OFF_T len) goto done; } - if (vfs_ops->lseek(fsp, fd, len-1, SEEK_SET) != len -1) { + if (vfs_ops->lseek(fsp, fd, len-1, SEEK_SET) != len -1) goto done; - } - if (vfs_ops->write(fsp, fd, &c, 1)!=1) { + if (vfs_ops->write(fsp, fd, &c, 1)!=1) goto done; - } /* Seek to where we were */ - if (vfs_ops->lseek(fsp, fd, currpos, SEEK_SET) != currpos) { + if (vfs_ops->lseek(fsp, fd, currpos, SEEK_SET) != currpos) goto done; - } result = 0; + done: END_PROFILE(syscall_ftruncate); |